Статті в журналах: "UV-LED curing"

1

Ho, Shin-Chan, Jong-Gu Kim, Jin-Who Hong, Tae-Jung Ahn, and Hyun-Kyoung Kim. "Curing Properties of UV-LED Curable Color Coating." Adhesion and Interface 13, no. 1 (March 31, 2012): 31–37. http://dx.doi.org/10.17702/jai.2012.13.1.031.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Ayub, Nur Farizah, Shahrir Hashim, Jamarosliza Jamaluddin, Roshafima Rasit Ali, and Nadia Adrus. "UV LED Curing Formulation for Polyacrylamide Hydrogels." Advanced Materials Research 1125 (October 2015): 84–88. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.84.

Повний текст джерела

Анотація:

Current studies showed that UV LED system is a green technology and highly efficient as compared to UV Mercury (UV Hg) system. In this study, the UV LED curing formulations of polyacrylamide (PAAm) hydrogels were developed. The formulations consisted of acrylamide (AAm) as a main monomer,N,N’-methylenebisacrylamide as a crosslinker and photoinitiator. UV LED emits monochromatic light sources only (365 nm or 385 nm). Thus, in order to developed formulation of UV LED curable hydrogels, a suitable water soluble photoinitiator (i.e. λ ~ 365 nm) has to be employed. A commercially available photoinitiator Oligo [2-hydroxy-2-methyl-1-[4-(1-methylvinyl) phenyl] propanone] under the trade name Chivacure 300 (λ ~ 330 nm) was chosen in the first formulations. However, due to limited solubility in water, addition of tetrahydrofuran (THF) at 9.5:0.5 ratio of water/THF was required for Chivacure 300. We also synthesized a photoinitiator based on 2,2-dimethoxy-2-phenyl acetophenone (DMPA) and methylated-β-cyclodextrin (MβCD) to be used in the second formulation. The complexation of DMPA and MβCD resulted in transparent and water-soluble supramolecular-structured photoinitiator (SSPI) (λ ~ 330 nm). Both formulations were irradiated using UV LED system (Hoenle AG, Germany, 365 nm) for 15 min. Synthesis of PAAm hydrogels with both photoinitiators has yielded almost complete conversion of hydrogels (> 80 %). Clearly, this study has revealed that enhanced formulation of UV LED curable hydrogels are due to appropriate choice of excellent water-solubility photoinitiators (Chivacure 300 and modified DMPA). We concluded that UV LED is an important tool for curing hydrogel formulations of various acrylate water-based monomers.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Landry, Véronic, Pierre Blanchet, Gabrielle Boivin, Jean-François Bouffard, and Mirela Vlad. "UV-LED Curing Efficiency of Wood Coatings." Coatings 5, no. 4 (December 18, 2015): 1019–33. http://dx.doi.org/10.3390/coatings5041019.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Zhou, Rui Hua, and Xiu Yun Tian. "Irradiation System Design of Rotating Painting Ink Curing Based on UV LED." Applied Mechanics and Materials 568-570 (June 2014): 1737–42. http://dx.doi.org/10.4028/www.scientific.net/amm.568-570.1737.

Повний текст джерела

Анотація:

The effects of painting ink’s color on UV absorptivity and UV-light wavelength on curing depth in the process of rotating curing are analysed. Aiming at radial uneven curing, the scheme is proposed that using the UV LED with wavelengths of 365nm and 395nm to form a fan-shaped array on cylindrical surface. The curing system can achieve UV irradiance be enhanced gradually along the radial, and the technique problem of uneven curing is solved. The simulation result shows that the curing system meets design requirements on Tracepro.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Bao, Chuan Mei, Chang Liang Liu, Chun Jun Li, Gu Chang Wang, Fei Gao, and Zhe Jing Yi. "A Security UV Curing Device Based on LED Array." Advanced Materials Research 1037 (October 2014): 152–55. http://dx.doi.org/10.4028/www.scientific.net/amr.1037.152.

Повний текст джерела

Анотація:

The study mentioned a curing equipment with UV LED array based on pyroelectric sensor and AP3706, which is based on the primary side control circuit so that it can complete the LED array constant voltage constant current output.the light source drive can output the constant voltage and constant current. The sensing signal processing signal integrated circuit BISS0001 as the pyroelectric sensor amplifier circuit as core, with relay making up the protection module of curing device. The experimental results show that, the curing equipment can realize the stable and homogeneous UV output, and when a human body in front of LED, the array will disabled to keep the human body away from damage UV induced.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Yi, Qing, Xian Fu Wei, Bei Qing Huang, and Qi Wang. "Effect of Monomer on Performance of UV-LED Inkjet Ink." Applied Mechanics and Materials 469 (November 2013): 68–73. http://dx.doi.org/10.4028/www.scientific.net/amm.469.68.

Повний текст джерела

Анотація:

UV-LED inkjet ink is a promising environmental ink which has advantages as higher reaction speed, higher efficiency and energy saving, better environmental protection, its research and development can contribute to realizing green printing and its important for food packing security. Monomer is the important component of the UV-LED ink, in order to investigate the impact of monomer on dispersivity of UV-LED inkjet ink, seven kinds of monomers were chosen to prepare cyan color paste respectively and test their particle size and distribution. Then the ratio of co-monomers was achieved by formulation experiment to obtain the best dispersivity. In order to improve the performance of the UV-LED inkjet ink, different monomers were used to make ink samples separately, viscosity, surface tension, curing rate of the ink and flexibility and adhesion were tested. In the end, the ratio of co-monomers was achieved by formulation experiment to obtain the best overall performance. The results show that the monomer has a significant influence on the dispersion and curing rate of the UV-LED inkjet ink, but also has a great impact on film-forming properties of the ink after UV-LED curing.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Letson, Benjamin C., Simon Barke, Samantha Parry Kenyon, Taiwo Olatunde, Guido Mueller, Peter Wass, Fan Ren, Stephen J. Pearton, and John W. Conklin. "High volume UV LED performance testing." Review of Scientific Instruments 93, no. 11 (November 1, 2022): 114503. http://dx.doi.org/10.1063/5.0107372.

Повний текст джерела

Анотація:

There is increasing interest in deep UV Light-Emitting Diodes (LEDs) for applications in water purification, virus inactivation, sterilization, bioagent detection, and UV curing, as well as charge management control in the Laser Interferometer Space Antenna (LISA), which will be the first gravitational wave detector in space. To fully understand the current state of commercial UV LEDs and assess their performance for use on LISA, large numbers of UV LEDs need to be tested across a range of temperatures while operating in air or in a vacuum. We describe a new hardware system designed to accommodate a high volume of UV LED performance tests and present the performance testing results from over 200 UV LEDs with wavelengths in the 250 nm range.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Lee, Sangmin, Jaebum Son, Dong Geon Kim, Joonbum Choi, and Yong Kyun Kim. "Characterization of plastic scintillator fabricated by UV LED curing machine." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 929 (June 2019): 23–28. http://dx.doi.org/10.1016/j.nima.2019.03.048.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Wu, Kuo-Tsai, Sheng-Jye Hwang, and Huei-Huang Lee. "Study of Exposure Uniformity of UV LED Exposure System for Wafer-Level Camera Lenses." Applied Sciences 9, no. 19 (October 1, 2019): 4110. http://dx.doi.org/10.3390/app9194110.

Повний текст джерела

Анотація:

Wafer-level camera lenses are a very promising process for camera lens fabrication. However, there exist some problems with this technology, such as uneven exposure due to curing non-uniformities. In this study, an optical simulation was implemented to simulate the UV light-emitting diodes (LEDs) curing process. We design the LED arrangement, and then find the corresponding LED and adjust the LED power to improve exposure uniformity. The simulation results are very close to the experimental data, and the uniformity is also within the standard range.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Xie, Ruidong, and Dichen Li. "Research on the curing performance of UV-LED light based stereolithography." Optics & Laser Technology 44, no. 4 (June 2012): 1163–71. http://dx.doi.org/10.1016/j.optlastec.2011.09.019.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Jia, Jingru, and Jinhai Zhang. "Study on environment-frientdly UV-led ceramic ink transfer film." E3S Web of Conferences 38 (2018): 02025. http://dx.doi.org/10.1051/e3sconf/20183802025.

Повний текст джерела

Анотація:

UV polyurethane acrylate (PUA-1) oligomer was synthesized and used to prepare the UV-LED ceramic ink transfer film. The effects of active thinner (or active monomer), photosensitizer type, photo-sen-sitizer percentage, photosensitizer consumption, etc. on the ceramic ink transfer film performance was studied. The results showed that the prepared PUA prepolymer, single functional group thinner, and the UV-LED curing system consisting of 2,4,6-Trimethyl Benzoyl Diphenyl Phosphine Oxide (TPO), 2,4-Diethyl-9H-Thioxanthen-9-one(DETX) and Reactive Amine (P115) could meet the technical requirements of transfer film.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Manjunath, M. A., K. Naveen, Prakash Vinod, N. Balashanmugam, and M. R. Shankar. "Mechanical Characterization of UV Photopolymerized PMMA with Different Photo-Initiator Concentration." Applied Mechanics and Materials 903 (April 2021): 11–16. http://dx.doi.org/10.4028/www.scientific.net/amm.903.11.

Повний текст джерела

Анотація:

Polymethyl methacrylate (PMMA) is one among few known photo-polymeric resin useful in lithography for fabricating structures having better mechanical properties to meet the requirement in electronics and biomedical applications. This study explores the effect of Photo Initiator (PI) concentration and also curing time on strength and hardness of Polymethyl methacrylate (PMMA) obtained by UV photopolymerization of Methyl methacrylate (MMA) monomer. The UV LED light source operating at the wavelength of 364 nm is used with Benzoin Ethyl Ether (BEE) as photo initiator. The curing of PMMA resin is supported with peltier cooling device placed at the bottom of the UV light source. The characterisation study of UV photo cured PMMA is analysed through nano indenter (Agilent Technologies-G200). The current work investigates the influence of PI concentration and curing time in achieving maximum mechanical properties for UV photopolymerized PMMA.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Xiao, Yan, Sihuan Lang, Miaomiao Zhou, Jing Qin, Rui Yin, Jingming Gao, Andreas Heise та Meidong Lang. "A highly stretchable bioelastomer prepared by UV curing of liquid-like poly(4-methyl-ε-caprolactone) precursors". Journal of Materials Chemistry B 5, № 3 (2017): 595–603. http://dx.doi.org/10.1039/c6tb02507b.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Zhou Ruihua, 周瑞华, and 田秀云 Tian Xiuyun. "Research on UV LED Source System for CD Painting Ink Coating Curing." Laser & Optoelectronics Progress 51, no. 9 (2014): 092203. http://dx.doi.org/10.3788/lop51.092203.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Ayub, Nur Farizah, Shahrir Hashim, Jamarosliza Jamaluddin, and Nadia Adrus. "New UV LED curing approach for polyacrylamide and poly(N-isopropylacrylamide) hydrogels." New Journal of Chemistry 41, no. 13 (2017): 5613–19. http://dx.doi.org/10.1039/c7nj00176b.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Naemuddin, Nurul Hazlina, Farahin M. Mizi, Siti Samahani Suradi, Jamarosliza Jamaluddin, Mohd Hafiz Dzarfan Othman, and Nadia Adrus. "UV LED Curing of Hydrogel-Modified Textiles with High Anti-Fouling Resistance." Journal of Photopolymer Science and Technology 32, no. 5 (June 24, 2019): 699–704. http://dx.doi.org/10.2494/photopolymer.32.699.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Seipel, Sina, Junchun Yu, Aravin P. Periyasamy, Martina Viková, Michal Vik, and Vincent A. Nierstrasz. "Inkjet printing and UV-LED curing of photochromic dyes for functional and smart textile applications." RSC Advances 8, no. 50 (2018): 28395–404. http://dx.doi.org/10.1039/c8ra05856c.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Taki, Kentaro, and Keigo Sawa. "Hybrid UV LED Device for Simulating Spectrum of High-Pressure Mercury Lamp: Evaluation in UV Curing Process." Journal of Photopolymer Science and Technology 31, no. 6 (December 15, 2018): 753–57. http://dx.doi.org/10.2494/photopolymer.31.753.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Tae, Joon-Sung, Kyung-Gyu Yim, Byung-Ohk Rhee, and Jae B. Kwak. "Characterization of curing behavior of UV-curable LSR for LED embedded injection mold." Korea-Australia Rheology Journal 28, no. 4 (November 2016): 247–53. http://dx.doi.org/10.1007/s13367-016-0026-3.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Haichao, Li, Li Jinyao, Xu Jingxiang, Zhang Mingming, Cai Jifei, and Zhang Guishan. "Research on Heat Sissipation System Based on High Power LED-UV Curing Equipment." IOP Conference Series: Materials Science and Engineering 565 (June 26, 2019): 012016. http://dx.doi.org/10.1088/1757-899x/565/1/012016.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Lavrič, Gregor, Igor Karlovits, Deja Muck, Eva Petra Forte Tavčer, and Urška Kavčič. "Influence of Ink Curing in UV LED Inkjet Printing on Colour Differences, Ink Bleeding and Abrasion Resistance of Prints on Textile." TEKSTILEC 64, no. 3 (October 26, 2021): 221–29. http://dx.doi.org/10.14502/tekstilec2021.64.221-229.

Повний текст джерела

Анотація:

Digital printing techniques are increasingly present in the field of textile printing. Particularly prominent is the inkjet printing technique using water-based inks, while UV LED inkjet printing also increasingly being in use. UV LED inkjet is primarily not intended for direct clothing printing; however, it can be used especially as a hybrid solution in the soft signage market. It is a great option for the printers that are not engaged only in textile print¬ing, and want a more versatile print portfolio, extending it to non-clothing textile products, e.g. soft signage and non-wearable products. As these types of products often require colour reproduction of logos, accurate colour reproduction, good ink adhesion and sharpness are important just like in other printing technologies. In order to evaluate the impact of UV LED radiation amount on colour differences, ink bleeding and abrasion resistance, six different fabric samples (five woven and one nonwoven) were printed using a UV LED inkjet printer. Based on the results of colour difference, it was established that a reduction of UV radiation (by half the manufacturer’s recommended amount) had no effect on this parameter. However, perceptible colour differences were observed with the use of different M measurement conditions defined by the international standard ISO 13655-2017. Reducing the amount of UV radiation had no effect on the adhesion and durability of the printed ink. Small differences detected in these two parameters were mainly a consequence of the properties of textile materials and not of decreased UV radiation.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Liang, Banglong, Zili Wang, Cheng Qian, Yi Ren, Bo Sun, Dezhen Yang, Zhou Jing, and Jiajie Fan. "Investigation of Step-Stress Accelerated Degradation Test Strategy for Ultraviolet Light Emitting Diodes." Materials 12, no. 19 (September 25, 2019): 3119. http://dx.doi.org/10.3390/ma12193119.

Повний текст джерела

Анотація:

III-nitride-based ultraviolet light emitting diode (UV LED) has numerous attractive applications in air and water purification, UV photolithography, and in situ activation of drugs through optical stimulus, solid state lighting, polymer curing, and laser surgery. However, the unclear failure mechanisms and uncertainty reliability have limited its application. Therefore, a design of an appropriate reliability test plan for UV LEDs has become extremely urgent. Compared to traditional reliability tests recommended in LED lighting industry, the step-stress accelerated degradation test (SSADT) is more cost-effective and time-effective. This paper compares three SSADT testing plans with temperature and driving currents as stepwise increasing loads to determine an appropriate test strategy for UV LEDs. The study shows that: (1) the failure mechanisms among different SSADT tests seem to be very different, since the driving current determines the failure mechanisms of UV LEDs more sensitively, and (2) the stepped temperature accelerated degradation test with an appropriate current is recommended for UV LEDs.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Xu, Qianwen, Jeffery Lo, and Shi-Wei Lee. "Directly Printed Hollow Connectors for Microfluidic Interconnection with UV-Assisted Coaxial 3D Printing." Applied Sciences 10, no. 10 (May 14, 2020): 3384. http://dx.doi.org/10.3390/app10103384.

Повний текст джерела

Анотація:

Effective and reliable interconnections are crucial for microfluidics to connect with the macro world. Current microfluidic interfaces are still bulky, expensive, or with issues of clogging and material limitation. In this study, a novel ultraviolet (UV)-assisted coaxial three-dimensional (3D) printing approach was proposed to fabricate hollow microfluidic connectors with advantages of rapid prototyping, fixture-free, and materials compatible. An assembled coaxial nozzle was designed to enable co-flow extrusion, where the inner flow (water) served as the sacrificial layer and the outer flow (adhesive) was cured for shell formation. Furthermore, a converged UV-LED light source was attached to the coaxial nozzle for UV curing of adhesives. UV rheological characterizations were performed to study the UV curing kinematics, and the gelation time was employed to describe the state transition behaviors of UV curable adhesives used in the study. To explore requirements for successful hollow connectors direct printing, processing criteria such as co-flow regime and pre-cure time were investigated. The hollow connectors with an inner channel diameter of ~150 μ m and a height of 5 mm were successfully printed on polymethyl methacrylate (PMMA) and glass substrate. The integration feasibility of the proposed method was also demonstrated by the presented microfluidic device with printed hollow connectors.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Qazzazie-Hauser, Afnan, Kirsten Honnef, and Thomas Hanemann. "Crosslinking Behavior of UV-Cured Polyorganosilazane as Polymer-Derived Ceramic Precursor in Ambient and Nitrogen Atmosphere." Polymers 13, no. 15 (July 23, 2021): 2424. http://dx.doi.org/10.3390/polym13152424.

Повний текст джерела

Анотація:

Polymer-derived ceramics (PDCs) based on silicon precursor represent an outstanding material for ceramic coatings thanks to their extraordinary versatile processibility. A promising example of a silicone precursor, polyorganosilazane (Durazane 1800), was studied concerning its crosslinking behavior by mixing it with three different photoinitiators, and curing it by two different UV-LED sources under both nitrogen and ambient atmosphere. The chemical conversion during polymerization and pyrolysis was monitored by FTIR spectroscopy. Pyrolysis was performed in a nitrogen atmosphere at 950 °C. The results demonstrate that polyorganosilazane can be cured by the energy-efficient UV-LED source at room temperature in nitrogen and ambient atmosphere. In nitrogen atmosphere, already common reactions for polysilazanes, including polyaddition of the vinyl group, dehydrogenation reactions, hydrosilylation, and transamination reaction, are responsible for crosslinking. Meanwhile, in ambient atmosphere, hydrolysis and polycondensation reactions occur next to the aforementioned reactions. In addition, the type of photoinitiator has an influence on the conversion of the reactive bonds and the chemical composition of the resulting ceramic. Furthermore, thermogravimetric analysis (TGA) was conducted in order to measure the ceramic yield of the cured samples as well as to study their decomposition. The ceramic yield was observed in the range of 72 to 78% depending on the composition and the curing atmosphere. The curing atmosphere significantly impacts the chemical composition of the resulting ceramics. Depending on the chosen atmosphere, either silicon carbonitride (SiCN) or a partially oxidized SiCN(O) can be produced.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Fan, Shuheng, Xun Sun, Xianglong He, Yulian Pang, Yangyang Xin, Yanhua Ding, and Yingquan Zou. "Coumarin Ketoxime Ester with Electron-Donating Substituents as Photoinitiators and Photosensitizers for Photopolymerization upon UV-Vis LED Irradiation." Polymers 14, no. 21 (October 28, 2022): 4588. http://dx.doi.org/10.3390/polym14214588.

Повний текст джерела

Анотація:

High-performance photoinitiators (PIs) are essential for ultraviolet–visible (UV-Vis) light emitting diode (LED) photopolymerization. In this study, a series of coumarin ketoxime esters (COXEs) with electron-donating substituents (tert-butyl, methoxy, dimethylamino and methylthio) were synthesized to study the structure/reactivity/efficiency relationships for substituents for the photoinitiation performance of PIs. The introduction of heteroatom electron-donating substituents leads to a redshift in the COXE absorption of more than 60 nm, which matches the UV-Vis LED emission spectra. The PIs also show acceptable thermal stability via differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The results from real-time Fourier transform infrared (RT-FTIR) measurements indicate that COXEs show an excellent photoinitiation efficiency for free radical polymerization under UV-Vis LED irradiation (365–450 nm); in particular, the conversion efficiency for tri-(propylene glycol) diacrylate (TPGDA) polymerization initiated by COXE-O and COXE-S (4.8 × 10−5 mol·g–1) in 3 s can reach more than 85% under UV-LED irradiation (365, 385 nm). Moreover, the photosensitization of COXEs in the iodonium hexafluorophosphate (Iod-PF6) and hexaarylbiimidazole/N-phenylglycine (BCIM/NPG) systems was investigated via RT-FTIR. As a coinitiator, COXEs show excellent performance in dry film photoresist (DFR) photolithography. This excellent performance of COXEs demonstrates great potential for UV-curing and photoresist applications, providing a new idea for the design of PIs.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Strongone, Valentina, Mattia Bartoli, Pravin Jagdale, Rossella Arrigo, Alberto Tagliaferro, and Giulio Malucelli. "Preparation and Characterization of UV-LED Curable Acrylic Films Containing Biochar and/or Multiwalled Carbon Nanotubes: Effect of the Filler Loading on the Rheological, Thermal and Optical Properties." Polymers 12, no. 4 (April 2, 2020): 796. http://dx.doi.org/10.3390/polym12040796.

Повний текст джерела

Анотація:

UV-LED curable coatings represent an up-to-date attractive field due to the high curing efficiency even in the presence of high filler loadings, as well as to the absence of infrared wavelengths that may negatively impact on heat-sensitive substrates. The addition of carbonaceous materials, such as biochar (BC) and/or multiwalled carbon nanotubes (MWCNTs) could positively improve both the rheological and thermal properties. In this study we report on the synthesis and characterization of carbon-reinforced films containing nanometric (MWCNTs) and micrometric (BC) carbon-based materials. We analyze the rheological properties of the UV-LED curable dispersions, as well as the thermal and optical properties of the resulting films, establishing some correlations between filler dispersion/loading with the main observed properties.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Lu, Weixing, Linling Wu, Chunyu Ma, and Qian-Feng Zhang. "UV-LED Curing Cationic Passivation Film for the Surface of Hot-Dip Aluminum-Zinc Coated Steel Plate." Journal of Materials Science and Chemical Engineering 10, no. 09 (2022): 27–48. http://dx.doi.org/10.4236/msce.2022.109003.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Santini, Ario, Iranzihuatl Torres Gallegos, and Christopher M. Felix. "Photoinitiators in Dentistry: A Review." Primary Dental Journal 2, no. 4 (December 2013): 30–33. http://dx.doi.org/10.1308/205016814809859563.

Повний текст джерела

Анотація:

Polymerization of Resin Based Composites (RBCs) initiated by a light curing unit activating photoinitiators. Different RBCs require different light energy levels for proper curing. Manufacturers are now producing RBCs with more than one initiator and not all of these will be properly polymerised with blue LED lights. An added problem is that manufacturers do not always indicate the type of photoinitiators in their materials. This review discusses the importance of matching the spectral output of LCUs to the absorption spectra of RBCs and the consequences of spectral mismatch. Resin based composites (RBCs) were first introduced in the 1960s1 and with development of effective and reliable dentine bonding systems2, have been used routinely as a filling material for both anterior and posterior teeth. The early RBCs were either chemically cured two component materials or photo-initiated materials that used UV initiators in the beginning and then transitioned to visible light initiators such as camphorquinine which was introduced in 1978.3 The first report of a light curing material was of an ultraviolet (UV) cured fissure sealant.4 However, due to the limited penetration depth of the UV light and the potential health hazards, this system was quickly abandoned. The advancement of science yielded light curing materials which contributed to a significant clinical progress over the UV and chemically cured RBCs.4 Additional advancements to direct RBC restoration materials included luting agents for ceramic restorations, pit and fissure sealants and resin modified glass ionomers. Polymerization in an RBC is initiated by a light curing unit (LCU); this technology is based on the use of photoreactive systems that absorb light irradiation from the LCUs at appropriate wavelength. Then the photoinitiators contained in the RBCs, absorb the incoming photons from the LCU and the monomers in the molecular structure become excited and in that active state, there is a change from monomers into a polymer network6. The success of this technology hinges on matching the spectral emission of the LCU with the requirements of the photoinitiator system to convert the monomers into a polymer network. The amount of activated photo initiator depends on the concentration of photoinitiator in the material, the number of photons to which the material is exposed and the energy of the photons (wavelength), the latter depending on the curing light.6 The most common photoinitiator in dental materials today is camphorquinone, which has a peak activity around 470 nanometres.6 The factors affecting polymerization include filler type, size and loading, the thickness and shade of the restorative material, the effectiveness of light transmission (eg. light guide tips being free from debris and scratches), exposure time, distance of the light source from the restorative material and light intensity.7 It is important to note that the photoinitiator activation occurs at specific wavelengths, in other words, the optimum efficiency is obtained when the peak absorptivity of the photoinitiator corresponds with the spectral emission from the LCU. Commercially available curing units have different light intensities and light sources, with energy levels in QTH, LED and other LCUs ranging from 300 to more than 2000 mW/cm.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Pugliese, Diego, and Giulio Malucelli. "UV-LED Curable Acrylic Films Containing Phosphate Glass Powder: Effect of the Filler Loading on the Thermal, Optical, Mechanical and Flame Retardant Properties." Polymers 14, no. 9 (May 6, 2022): 1899. http://dx.doi.org/10.3390/polym14091899.

Повний текст джерела

Анотація:

In this work, we thoroughly investigate the effects of the incorporation of a phosphate glass micrometric powder on the morphology, as well as on the thermal, optical, mechanical and flame retardant properties of UV-LED curable acrylic films. To this aim, the filler loading was changed within 10 and 50 wt.%. UV-LED initiated curing was selected as a fast and reliable system, as the standard UV-curing process was not suitable because of the presence of the glass powder that decreased the quantum efficiency during the UV exposure, hence preventing the transformation of the liquid system into a solid network. The glass powder slightly increased the glass transition temperature of the acrylic network, hence showing a limited effect on the chain segments mobility; besides, increasing filler loadings were responsible for a progressive decrease of the transparency of films, irrespective of a marginal effect on their refractive index. Conversely, the presence of increasing amounts of phosphate glass improved the thermal and thermo-oxidative stability of the cured products. Besides, phosphate glass was capable of remarkably enhancing the flame retardance of the acrylic network at 50 wt.% loading, which achieved self-extinction in vertical flame spread tests (and was V-0 rated). This formulation, as assessed by forced-combustion tests, also displayed a remarkable decrease of peak of Heat Release Rate and Total Heat Release (by 44 and 33%, respectively) and of Total Smoke Release and Specific Extinction Area (by 53 and 56%, respectively). Further, the filler promoted an increase of the stiffness and surface hardness of the films, at the expense of a decrease in ductility. All these findings may justify the potential use of these composite films as flame retardant coatings for different flammable substrates.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Burkhardt, T., M. Hornaff, A. Acker, T. Peschel, E. Beckert, K. H. Suphan, K. Mensel, S. Jirak, R. Eberhardt, and A. Tünnermann. "Die-Attach Technologies for Ultraviolet LED Multichip Module Based on Ceramic Substrate." Journal of Microelectronics and Electronic Packaging 9, no. 3 (July 1, 2012): 113–19. http://dx.doi.org/10.4071/imaps.334.

Повний текст джерела

Анотація:

A high power UV light emitting diode (LED) multichip module package based on aluminum nitride (AlN) and alumina (Al2O3) is presented. The AlN substrate with a high thermal conductivity of up to 180 W/(m·K) and LED chips based on a copper alloy provide superb thermal management and heat extraction. Efficient cooling is an important prerequisite for the increase of extractable optical power and for the reduction of thermally induced wavelength shift. A design of a stackable module featuring arrays of 7×2 indium-gallium-aluminum-nitride UV LED chips at 395 nm is developed. This configuration of submodules allows for the scalable assembly of line sources with different lengths. Applications using UV LEDs cover market segments such as curing of adhesives, inks, and coatings, sterilization of medical equipment, and treatment of potable water, as well as various uses in chemical detection, biochemical analytics, and spectroscopy. Thermal and thermomechanical modeling of the submount is conducted using finite element analysis. Die attach using eutectic gold-tin solder, lower melting tin-lead solder, and silver-filled adhesive are compared with respect to optical output power and wavelength drift. Mechanical strength and structure of the resulting joints are investigated using shear force measurements, cross-sectioning, and microtomography. An optical output power of 7.7 W is achieved using a cluster of 14 LED chips at 1050 mA, resulting in a peak irradiance of 33.9 W/cm2 at the LED surface with respect to the footprint and pitch of the attached chips.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Burkhardt, T., M. Hornaff, A. Acker, T. Peschel, E. Beckert, K. H. Suphan, K. Mensel, S. Jirak, R. Eberhardt, and A. Tünnermann. "Ultraviolet LED Multi-Chip Module Based on Ceramic Substrate." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000238–45. http://dx.doi.org/10.4071/cicmt-2012-tp61.

Повний текст джерела

Анотація:

A high power ultraviolet (UV) light emitting diode (LED) multi-chip module package based on aluminum nitride (AlN) and alumina (Al2O3) is presented. The AlN substrate with a high thermal conductivity of up to 180 W/(m· K) and LED chips based on a copper alloy provide superb thermal management and heat extraction. Efficient cooling is an important prerequisite for the increase of extractable optical power and decrease of thermally induced wavelength shift. A design of a stackable module featuring arrays of 7×2 indium-gallium-aluminum- nitride UV LED chips at 395 nm is developed. This configuration of sub-modules allows for the scalable assembly of line sources with different lengths. Applications using UV LEDs cover market segments such as curing of adhesives, inks and coatings, sterilization of medical equipment and treatment of potable water, as well as various uses in chemical detection, biochemical analytics and spectroscopy. Thermal and thermo-mechanical modelling of the sub-mount is conducted using finite elements analysis. Die attach using eutectic gold-tin solder, lower melting tin-lead solder and silver-filled adhesive are compared with respect to optical output power and wavelength drift. Mechanical strength and structure of the resulting joints are investigated using shear force measurements, cross-sectioning and micro-tomography. An optical output power of 7.7 W is achieved using a cluster of 14 LED chips at 1050 mA resulting in a peak irradiance of 30.8 W/cm2 at the LED surface with respect to the footprint and pitch of the attached chips.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Giorgi, Maria Cecília Caldas, Flávio Henrique Baggio Aguiar, Luís Luís Soares, Airton Abrahão Martin, Priscila Christiane Suzy Liporoni, and Luís Alexandre Maffei Sartini Paulillo. "Does an additional UV LED improve the degree of conversion and Knoop Hardness of light-shade composite resins?" European Journal of Dentistry 06, no. 04 (October 2012): 396–401. http://dx.doi.org/10.1055/s-0039-1698978.

Повний текст джерела

Анотація:

ABSTRACTObjective: The purpose of this study was to evaluate the degree of conversion (DC) using FTRaman spectroscopy and the Knoop hardness (KHN) of composites cured by second and third-generation LED light curing-units (LCU), Radii Cal and Ultralume 5.Methods: Three composites (Filtek Supreme XT, Filtek Z350, and Esthet X) were selected for this study. KHN testing (n=10) was performed with 10 indentations for the top (T) and bottom (B) surfaces. For DC (n=10), both the T and B surfaces were analyzed.Results: For KHN, the three composites differed in hardens. There was a “LCU-surface” interaction, in which Radii Cal showed significantly greater hardens in the B surface. For DC, there was a “composite-surface-LCU” interaction. For the “composite” factor, there was no significant difference between the groups, except for Supreme XT-Radii Cal (T or B surfaces). For the “LCU” factor there was a significant difference for Supreme XT T surface, Ultralume 5 obtained a higher DC. For the Z350 T surface, a significant difference in the DC in which Radii Cal obtained better results. For the “surface” factor, all groups presented T surfaces with a higher DC than the B surfaces, the sole exceptions involved Esthet X-Radii Cal and Z350-Ultralume 5.Conclusion: Knowledge regarding composite composition and the characteristics of LCUs are important for effective polymerization. (Eur J Dent 2012;6:396-401)

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Pires-de-Souza, Fernanda de Carvalho Panzeri, Lucas da Fonseca Roberti Garcia, Hisham Mohamad Hamida, and Luciana Assirati Casemiro. "Color stability of composites subjected to accelerated aging after curing using either a halogen or a light emitting diode source." Brazilian Dental Journal 18, no. 2 (2007): 119–23. http://dx.doi.org/10.1590/s0103-64402007000200006.

Повний текст джерела

Анотація:

The purpose of this study was to evaluate, in vitro, the color stability of three composite resins of two different shades (A3 and C3) cured with either a quartz tungsten halogen (QTH) or a light emitting diode (LED) source. Forty specimens (20 x 2 mm) were prepared for each composite (Tetric Ceram®, Heliomolar® and Esthet-X®), being 20 for each shade. In each group, 10 specimens were light-cured using the QTH unit and 10 with the LED source. The shade of the materials was evaluated before and after submitting the specimens to artificial accelerated aging (4 h UV-B/4 h condensing vapor), using a reflection spectrophotometer. deltaE means were calculated and analyzed statistically by 2-way ANOVA and Tukey's test at 5% significance level. Both A3 and C3 shades of Esthet-X composite resin showed the lowest color change when cured with the QTH light, while Tetric C3 cured with the QTH light showed the highest color change.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Van den Mooter, Peter-Renaat, Nick Daems, and Ivo F. J. Vankelecom. "Preparation of solvent resistant supports through formation of a semi-interpenetrating polysulfone/polyacrylate network using UV cross-linking - Part 2: Optimization of synthesis parameters for UV-LED curing." Reactive and Functional Polymers 146 (January 2020): 104403. http://dx.doi.org/10.1016/j.reactfunctpolym.2019.104403.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Wei, Shih-Min, Ming-Ying Pei, Whei-Lin Pan, Helmut Thissen, and Shiao-Wen Tsai. "Gelatin Hydrogels Reinforced by Absorbable Nanoparticles and Fibrils Cured In Situ by Visible Light for Tissue Adhesive Applications." Polymers 12, no. 5 (May 13, 2020): 1113. http://dx.doi.org/10.3390/polym12051113.

Повний текст джерела

Анотація:

Most gelatin hydrogels used in regenerative medicine applications today are fabricated by photocrosslinking due to the convenience and speed of this method. However, in most cases photoinitiators are used, which require UV light, which, in turn, can cause cell and tissue damage, or using functionalized gelatin. Recently, ruthenium (II) tris-bipyridyl chloride has been studied as an initiator that can induce dityrosine bond formation using visible light. In addition, continuous fibrils and small particles are often used to reinforce composite materials. Therefore, this study investigated the visible-light-induced photocrosslinking of native gelatin molecules via dityrosine bonds formation as well as gel reinforcement by collagen fibrils and mesoporous bioactive glass (MBG) particles. The results show that collagen and MBG exerted a synergistic effect on maintaining gel integrity with a dental LED curing light when the irradiation time was shortened to 30 s. Without the two reinforcing components, the gel could not form a geometric shape stable gel even when the exposure time was 120 s. The shear strength increased by 62% with the collagen and MBG compared with the blank control. Furthermore, our results demonstrate that the addition of collagen and MBG enhanced gel stability in an artificial saliva solution. These results demonstrate the considerable advantages of using tyrosine-containing biomolecules, and using a dental LED curing light for the crosslinking of hydrogels in terms of their suitability and feasibility for use as bioadhesives in confined clinical working space, such as the oral cavity, and in application as in situ-crosslinked injectable hydrogels.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Lu, Chunmeng, Huiju Liu, Linjie Zhu, Subhash H. Patel, Ming-Wan Young, Costas G. Gogos, and Peter Bonnett. "In-situ, simultaneous milling, coating and curing of brittle particulates pre-coated with a LED UV-curable formulation in a fluid energy mill." Powder Technology 218 (March 2012): 169–75. http://dx.doi.org/10.1016/j.powtec.2011.12.014.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Dias, Myrna Carvalho, Evandro Piva, Rafael Ratto de Moraes, Gláucia Maria Bovi Ambrosano, Mário Alexandre Coelho Sinhoreti, and Lourenço Correr-Sobrinho. "UV-Vis spectrophotometric analysis and light irradiance through hot-pressed and hot-pressed-veneered glass ceramics." Brazilian Dental Journal 19, no. 3 (2008): 197–203. http://dx.doi.org/10.1590/s0103-64402008000300004.

Повний текст джерела

Анотація:

This study evaluated the irradiance of curing units through core and veneered hot-pressed ceramics as well as the transmittance of these materials. Discs of 0.7, 1.4 and 2 mm in thickness of Empress (EMP) and Empress Esthetic (EST), and 0.8 (n=5) and 1.1 mm (n=5) thickness of Empress 2 (E2) were obtained. For E2, two of the 0.8-mm-thick discs were covered with dentin (1.2- and 1.4-mm-thick) and two with dentin + enamel (1.5-mm-thick). The 1.1-mm-thick specimens were submitted to the same veneering procedures. Specimens were evaluated by UV-Vis transmittance analysis and the percentage of transmittance was recorded. Irradiance through each specimen was evaluated with a quartz-tungsten-halogen (QTH), used in continuous or intermittent exposure modes, or a blue light-emitting diode (LED). Data were analyzed by Dunnett's test, ANOVA and Tukey's test at 5% significance level. Exposure through ceramic decreased the irradiance for all ceramics. Irradiance through EST was significantly higher than through EMP. For E2, reduction in irradiance depended on the core and/or veneer thickness. The QTH intermittent mode showed higher irradiance than the continuous mode, and both showed higher irradiance than LED. The ceramic significantly influenced irradiance and transmittance, which were found to decrease with the increase in thickness.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Chae, Wookil, Bumsang Kim, Won Sun Ryoo, and Taeshik Earmme. "A Brief Review of Gel Polymer Electrolytes Using In Situ Polymerization for Lithium-ion Polymer Batteries." Polymers 15, no. 4 (February 5, 2023): 803. http://dx.doi.org/10.3390/polym15040803.

Повний текст джерела

Анотація:

Polymer electrolytes (PEs) have been thoroughly investigated due to their advantages that can prevent severe problems of Li-ion batteries, such as electrolyte leakage, flammability, and lithium dendrite growth to enhance thermal and electrochemical stabilities. Gel polymer electrolytes (GPEs) using in situ polymerization are typically prepared by thermal or UV curing methods by initially impregnating liquid precursors inside the electrode. The in situ method can resolve insufficient interfacial problems between electrode and electrolyte compared with the ex situ method, which could led to a poor cycle performance due to high interfacial resistance. In addition to the abovementioned advantage, it can enhance the form factor of bare cells since the precursor can be injected before polymerization prior to the solidification of the desired shapes. These suggest that gel polymer electrolytes prepared by in situ polymerization are a promising material for lithium-ion batteries.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Zarinwall, Ajmal, Rytis Mitkus, Axel Marth, Viktor Maurer, Michael Sinapius, and Georg Garnweitner. "Processing of 3-(Trimethoxysilyl)propyl Methacrylate (TMSPM) Functionalized Barium Titanate/Photopolymer Composites: Functionalization and Process Parameter Investigation." Journal of Composites Science 7, no. 2 (January 24, 2023): 47. http://dx.doi.org/10.3390/jcs7020047.

Повний текст джерела

Анотація:

To improve the performance of lead-free piezoelectric composites, the functionalization of the filler particles has been suggested as a successful strategy in several recent reports. The details of the functionalization process, however, are not clear, nor is its influence on the dielectric properties of the composites. This study reports a systematic investigation of the functionalization process parameters of barium titanate nanoparticles (BTONP) with 3-(trimethoxysilyl)propyl methacrylate (TMSPM) used as a linker to an acrylate-based matrix polymer. Functionalization process temperature, time, functionalization agent ratio, solvent, and catalyst influence on the functionalization degree were measured by thermogravimetric analysis (TGA), elemental analysis, and Fourier-transform infrared (FTIR) spectroscopy. Elevated temperature and average functionalization time led to the highest functionalization degree in the form of a TMSPM monolayer on the particle surface. Three solvents, with and without catalysts, were investigated and two types of functionalized BTONP were selected for composite manufacturing. To this end, the functionalized particles were used to manufacture 10 vol.% BTONP/photopolymer UV light-curable composite suspensions. After solidification of the suspensions by exposure to UV light, the microstructure and dielectric properties of the resulting composites were investigated. It was seen that functionalization improves the dispersion of particles, increases suspension viscosity, and decreases the curing depth and dielectric properties.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Xiong, Nana, Zhili Li, Hui Xie, Yuzhen Zhao, Mei Li, Yuehui Wang, and Jingze Li. "Synthesis and electrical properties of silver nanoplates for electronic applications." Materials Science-Poland 33, no. 2 (June 1, 2015): 242–50. http://dx.doi.org/10.1515/msp-2015-0032.

Повний текст джерела

Анотація:

AbstractIn this paper, silver nanoplates of 100 to 500 nm size were synthesized by reduction of silver nitrate with N,Ndimethylformamide, using poly(vinylpyrolidone) as a surfactant and ferric chloride as a controlling agent, at 120 to 160 °C for 5 to 24 hours. The influence of the concentration of ferric chloride, the reaction temperature and reaction time on the morphology of the product has been investigated by transmission electron microscopy, scanning electron microscopy and UV-Vis spectroscopy. The results indicated that the products obtained at the low reaction temperature and short reaction time in the presence of FeCl3 in the reaction solution were in the form of silver nanoplates, whose morphology was mainly triangular and hexagonal. In addition, the size and thickness of the nanoplates increased with increasing of the FeCl3 concentration. At a high reaction temperature and long reaction time, the truncated triangle and hexagonal nanoplates were mainly produced. Furthermore, the sintering behavior of nanoplates was studied and the results showed that sintering of the silver nanoplates started at 180 °C, and a typical sintering behavior was observed at higher temperatures. The incorporation of the silver nanoplates into the polymer matrix with micro-sized silver flakes led to an increase in the matrix resistivity in almost all cases, especially at high fractions and low curing temperatures. The curing temperature had an influence on the resistivity of the conductive adhesives filled with micro-sized silver flakes and silver nanoplates due to sintering of the silver nanoplates.

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Hlaváček, Petr, Vit Šmilauer, and František Škvára. "Alkali-Activated Fly Ash Foams – Synthesis, Chemo-Physical Properties and Microstructure Modeling." Advances in Science and Technology 92 (October 2014): 14–19. http://dx.doi.org/10.4028/www.scientific.net/ast.92.14.

Повний текст джерела

Анотація:

Inorganic foams offer several unique properties such as low thermal conductivity, fire resistance, or UV stability. Inorganic foam specimens were synthesized from fly ash and aluminium powder through an alkali-activation process. Depending on mix proportions, bulk densities ranged between 400 and 800 kg/m3. Thermal treatment at 80°C for 12 hours accelerated curing process. Compressive strength was found in the range 4.5-9.0 MPa, flexural strength 0.6-1.7 MPa, Young's modulus 0.6-1.1 GPa, thermal conductivity 0.14-0.16 W/m/K and thermal capacity around 1100 J/kg/K. Exposing the foams to temperature 800°C led to a small decrease of compressive strength while exposure to 1100°C sintered the foam to higher strength of 13 MPa. Volumetric shrinkage 20% occurred at 1100°C without further disintegration. Residual compressive strength was determined after exposure to NaCl, HCl, Na2SO4, MgSO4, H2SO4. The highest reduction to 20% occured in both acids with pH=2 after one year of exposition. Digitized microstructures entered finite element analysis to validate a stress-strain diagram.

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Nagasawa, Yosuke, and Akira Hirano. "A Review of AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes on Sapphire." Applied Sciences 8, no. 8 (July 31, 2018): 1264. http://dx.doi.org/10.3390/app8081264.

Повний текст джерела

Анотація:

This paper reviews the progress of AlGaN-based deep-ultraviolet (DUV) light emitting diodes (LEDs), mainly focusing in the work of the authors’ group. The background to the development of the current device structure on sapphire is described and the reason for using a (0001) sapphire with a miscut angle of 1.0° relative to the m-axis is clarified. Our LEDs incorporate uneven quantum wells (QWs) grown on an AlN template with dense macrosteps. Due to the low threading dislocation density of AlGaN and AlN templates of about 5 × 108/cm2, the number of nonradiative recombination centers is decreased. In addition, the uneven QW show high external quantum efficiency (EQE) and wall-plug efficiency, which are considered to be boosted by the increased internal quantum efficiency (IQE) by enhancing carrier localization adjacent to macrosteps. The achieved LED performance is considered to be sufficient for practical applications. The advantage of the uneven QW is discussed in terms of the EQE and IQE. A DUV-LED die with an output of over 100 mW at 280–300 nm is considered feasible by applying techniques including the encapsulation. In addition, the fundamental achievements of various groups are reviewed for the future improvements of AlGaN-based DUV-LEDs. Finally, the applications of DUV-LEDs are described from an industrial viewpoint. The demonstrations of W/cm2-class irradiation modules are shown for UV curing.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Ansari, Jawaad A., Refat Al-Shannaq, Jamal Kurdi, Shaheen A. Al-Muhtaseb, Charles A. Ikutegbe, and Mohammed M. Farid. "A Rapid Method for Low Temperature Microencapsulation of Phase Change Materials (PCMs) Using a Coiled Tube Ultraviolet Reactor." Energies 14, no. 23 (November 24, 2021): 7867. http://dx.doi.org/10.3390/en14237867.

Повний текст джерела

Анотація:

Microencapsulation of phase change materials (PCMs) remain a suitable option within building materials, as they contribute to the thermal mass and provide an energy buffer, an added benefit. This paper presents a novel method for the rapid fabrication of microencapsulated phase change materials (PCMs) at ambient conditions in a perfluoroalkoxy (PFA) coiled tube ultraviolet (UV) reactor. The objective of this study was to optimize key parameters such as the product yield and quality of the as-prepared microcapsules. Rubitherm® RT-21™ PCM was microencapsulated within shells of poly-methyl-methacrylate (PMMA) through a suspension emulsion polymerization approach, where the crosslinking of polymers was driven by UV radiations with an appropriate photoinitiator. The characteristics of the resulting PCM microcapsules were found to be affected by the volumetric flow rate of the emulsion inside the coiled tube reactor. Higher volumetric flow rates led to higher PCM contents and higher microencapsulation efficiency, resulting in an average particle size of 6.5 µm. Furthermore, the effect of curing time on the PCM microcapsule properties was investigated. The optimum encapsulation yield, conversion, efficiency and PCM content were observed after 10 min of polymerization time. The thermal analysis indicated that the developed process had an efficiency of 85.8%, and the capsules were characterized with excellent thermal properties. Compared to the conventional thermal microencapsulation processes, the use of a coiled tube UV reactor with an appropriate photoinitiator enables the encapsulation of heat-sensitive PCMs at ambient conditions, and reduces the microencapsulation time dramatically. As a result, this novel microencapsulation approach can lead to a wider scope of PCM encapsulation and enable rapid, continuous and potentially large-scale industrial production of PCM microcapsules with low energy consumption.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Guo, Yudi, Dongyan Tang, and Fan Yang. "Transparent fluorinate acrylic polyurethane with hydrophobicity obtained by crosslinking of hydroxyl-containing fluoroacrylate copolymer with HDI trimer." Materials Science-Poland 33, no. 3 (September 1, 2015): 451–59. http://dx.doi.org/10.1515/msp-2015-0076.

Повний текст джерела

Анотація:

Abstract Hydroxyl-containing fluoroacrylate copolymers with different fluorine and hydroxyl concentrations were synthesized via free-radical solution polymerization. Transparent fluorinated polyurethane (FPU) films were prepared by curing the copolymers with HDI (hexamethylene diisocyanate) trimer. The Fourier transform infrared spectroscopy (FT-IR) results revealed introduction of fluorine both into the copolymer and polyurethane. X-ray photoelectron spectroscopy (XPS) analyses indicated that a gradient concentration of fluorine existed in the depth profile of the fluorinated polyurethane films. The highest contact angle (CA) was obtained for the FPU film with fluoroacrylate monomer concentration of 22 wt.% because of fluorine present on the film surface. The surface topographies detected by SEM and AFM indicated that surface roughness contributed little to the film hydrophobicity. By increasing the fluoroacrylate monomer concentration, the decreasing of crosslinking degree of hard segment resulted in lowering the first degradation temperature, while more C-F groups in soft segment led to higher second degradation temperature. UV-Vis spectrophotometer measurements indicated that the FPU film with the fluoroacrylate monomer concentration of 16 wt.% still had a high transmittance of more than 90 % in the whole visible wavelength range.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Feng, Guangxia, Qinghua He, WenYue Xie, Yonghong He, Xuejing Chen, Bei Wang, Bangrong Lu, and Tian Guan. "Dual-spectra encoded suspension array using reversed-phase microemulsion UV curing and electrostatic self-assembling." RSC Advances 8, no. 38 (2018): 21272–79. http://dx.doi.org/10.1039/c8ra02410c.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Se-Jin Choi, Ju-Hyung Kim, and H. H. Lee. "Deep-UV Curing of Poly(4-Vinyl Phenol) Gate Dielectric for Hysteresis-Free Organic Thin-Film Transistors." IEEE Electron Device Letters 30, no. 5 (May 2009): 454–56. http://dx.doi.org/10.1109/led.2009.2015782.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

47

"UV-Cured Powder Coatings and LED-Curing Technology." Focus on Powder Coatings 2019, no. 4 (April 2019): 4. http://dx.doi.org/10.1016/j.fopow.2019.03.018.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Smith, Ryan S., Ting Tsui, and Paul S. Ho. "The Effect of Ultraviolet Light Curing on the Material and Fracture Properties of a k∼2.5 Low-k Dielectric." MRS Proceedings 990 (2007). http://dx.doi.org/10.1557/proc-0990-b02-03.

Повний текст джерела

Анотація:

ABSTRACTIn this paper, we investigated the role of ultra-violet light (UV) curing on the molecular structure and fracture properties of a porous organosilicate glass (OSG) dielectric with k∼2.5. A correlation between material properties, including fracture toughness, and molecular structure was found. Multiple analytical techniques including Fourier Transform IR (FTIR) Spectroscopy, x-ray photo-emission spectroscopy (XPS) and x-ray reflectivity were used to investigate changes in the molecular bonding and material properties with UV curing. Overall, UV seems to be highly penetrating leading to uniform composition and density changes in the low k film to improve its properties. The decrease of methyl and hydrogen content relative to the Si-O-Si bonding structures led to increasing density and dielectric constant with UV exposure. UV curing increases the critical fracture toughness, while the sub-critical fracture toughness is insensitive to UV cure. The correlation between critical fracture toughness and material properties is discussed.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Peng, Yang, Renli Liang, Yun Mou, Jiangnan Dai, Mingxiang Chen, and Xiaobing Luo. "Progress and Perspective of Near-Ultraviolet and Deep-Ultraviolet Light-Emitting Diode Packaging Technologies." Journal of Electronic Packaging 141, no. 4 (September 19, 2019). http://dx.doi.org/10.1115/1.4044624.

Повний текст джерела

Анотація:

Abstract Ultraviolet light-emitting diodes (UV-LEDs) have drawn considerable attention in environment, life science, and industry fields, such as the applications of near UV-LEDs in resin curing, illumination, and identification, and deep UV-LEDs in disinfection, medical treatment, and biochemical inspection. However, due to the limitation of packaging technology, UV-LED devices exhibit low light efficiency and poor reliability compared with visible LEDs. The organic encapsulation materials are prone to UV aging, thermal degradation, and nonairtightness, which significantly reduce the performances of UV-LEDs. In order to solve this issue, UV-LED packaging technology has been proposed for UV-LED devices instead of conventional LED packaging. In this review, we investigated in detail the overview and challenges of near-ultraviolet light-emitting diodes (NUV-LED)/deep-ultraviolet light-emitting diodes (DUV-LED) packaging. For the packaging of UV-LEDs, all inorganic encapsulation materials, hermetic packaging structures with low-temperature bonding, reduced reflection losses, UV stable and transparent materials, and effective thermal management are key progresses to enhance the light efficiency and reliability of UV-LEDs. In addition, the summary and perspectives of NUV-LED/DUV-LED packaging were introduced and discussed.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Dossin, Ricardo, Alessandra Lavoratti, Rodrigo Cercena, Alexandre Gonçalves Dal-bó, Matheus Vinicius Gregory Zimmermann, and Ademir José Zattera. "Influence of different photoinitiatiors in the UV-LED curing of polyester acrylated varnishes." Journal of Coatings Technology and Research, October 17, 2022. http://dx.doi.org/10.1007/s11998-022-00679-x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "UV-LED curing"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями