Academic literature on the topic 'Photopolymeric nanocomposite'

Purpose – The purpose of this paper is to evaluate the mechanical properties of photopolymer/CB (carbon black) nanocomposite when applied in a visible-light rapid prototyping (RP) machine. Design/methodology/approach – The mechanical properties of the samples such as hardness and tensile strength along with thermal stability were analyzed. The curing time behavior of the photopolymer/CB nanocomposites was tested by using a rigid-body pendulum rheometer. The shrinkage property and dimensional stability were also analyzed using the technique according to ASTM D2566 and ASTM D1204, respectively. Findings – The results showed that the prototype fabricated from pristine photopolymer tended to exhibit poor mechanical properties and low thermal stability. However, after adding the photopolymer with various concentrations of nano-CB and dispersant in appropriate composition, the photopolymer/CB nanocomposite prototype not only reduced its curing time but also enhanced its mechanical properties, thermal stability and dimensional stability. Practical implications – The presented results can be used in a visible-light RP machine. Originality/value – The mechanical and thermal properties of photopolymer are improved with nano-CB additives for a RP system.

Functionalised holograms are important for applications utilising smart diffractive optical elements for light redirection, shaping and in the development of sensors/indicators. This paper reports on holographic recording in novel magnetic nanocomposites and the observed temperature change in dry layers and liquid samples exposed to alternating magnetic field (AMF). The nanocomposite consists of N-isopropylacrylamide (NIPA)-based polymer doped with magnetic nanoparticles (MNPs), and local heating is achieved through magnetic induction. Here, volume transmission holographic gratings (VTHGs) are recorded with up to 24% diffraction efficiency (DE) in the dry layers of magnetic nanocomposites. The dry layers and liquid samples are then exposed to AMF. Efficient heating was observed in the liquid samples doped with Fe3O4 MNPs of 20 nm average size where the temperature increased from 27 °C to 64 °C after 300 s exposure to 111 mT AMF. The temperature increase in the dry layers doped with the same nanoparticles after exposure to 4.4 mT AMF was observed to be 6 °C. No temperature change was observed in the undoped layers. Additionally, we have successfully recorded Denisyuk holograms in the magnetic nanocomposite materials. The results reveal that the magnetic nanocomposite layers are suitable for recording holograms and need further optimisation in developing holographic indicators for mapping AMFs.

AbstractThis study represents an in situ polymerization by preparation of tetrafunction polyester acrylate mixed with 1,6-hexanediol diacrylate/clay nanocomposite by digital light processor rapid prototyping. The morphology of nano-clay fillers and the dispersing agent in the photopolymer matrix are investigated by scanning electron microscopy (SEM). Degradation temperature, tensile strength, impact strength, and hardness are characterized by using thermogravimetric analysis, universal tensile machine, Izod impact tester, and hardness shore A tester, respectively. Results show that the effect of clay loading with an appropriate amount of dispersant tends to significantly increase not only the tensile strength and hardness but also the degradation temperature of photopolymer/clay nanocomposite; however, the impact strength is not affected. In the same conditions, as visualized on SEM images, the nanocomposite tends to form the exfoliated structure with agglomeration of clay, which is caused by uneven distribution of nano-clay in the photopolymer matrix.

Glass is increasingly desired as a material for manufacturing complex microscopic geometries, from the micro-optics in compact consumer products to microfluidic systems for chemical synthesis and biological analyses. As the size, geometric, surface roughness, and mechanical strength requirements of glass evolve, conventional processing methods are challenged. We introduce microscale computed axial lithography (micro-CAL) of fused silica components, by tomographically illuminating a photopolymer-silica nanocomposite that is then sintered. We fabricated three-dimensional microfluidics with internal diameters of 150 micrometers, free-form micro-optical elements with a surface roughness of 6 nanometers, and complex high-strength trusses and lattice structures with minimum feature sizes of 50 micrometers. As a high-speed, layer-free digital light manufacturing process, micro-CAL can process nanocomposites with high solids content and high geometric freedom, enabling new device structures and applications.

Rapid prototyping (RP) is a new technology to fabricate a prototype part layer-by-layer. This technique has been achieved in many industrial sectors, but parts fabricated using this technique exhibit low mechanical properties, this makes it difficult to apply to fast growing applications. This technology can not only effectively save production time and cost of the prototypes, but also produce complicated product. In this study, we investigate the effect of the addition of halloysite nanotubes on mechanical properties of nanocomposites made by the RP process. Test specimens were fabricated using tetrafunctional polyester acrylate (TPA) and 1, 6 hexanediol diacrylate (HDDA) photopolymer as a matrix material and halloysite nanotubes as a reinforcing material. The adhesion between TPA/HDDA and halloysite nanotubes has been improved by using surface modification of a silane coupling agent. When compared with neat photopolymer, the tensile strength of nanocomposites decreased by about 22%, because the halloysites had poor interfacial adhesion. Silane treatment of halloysites using 3-aminopropyl triethoxysilane was succeeded to improve tensile strength of nanocomposites (2 phr halloysite nanotubes) by 31%.

The photopolymerization of aromatic methacrylate in organic-inorganic nanocomposite films for holographic recording media was investigated. Thick photopolymer films (thickness>200 µm) were prepared using organic-inorganic hybrid solutions containing high refractive index monomers, through the sol-gel process. These photopolymer films were polymerized upon exposure to a visible light with high photo conversions. The photopolymerization was highly effective under visible light irradiation and could be applied to a holographic medium with high diffraction efficiency (>95 %) by using a 532nm laser. The diffraction efficiency of the film was much affected by morphology, which might affect monomer diffusion during the recording.

This paper describes our research results on nanometers sizes subwavelength nanostructure fabrication by UV curing of special nanocomposite material with self-organization and light self-focusing effects. For this purpose, special UV curable nanocomposite material with a set of effects was developing: light self-focusing in the photopolymer with positive refractive index change, self-organization based on photo-induced nanoparticles transportation, and oxygen-based polymerization threshold. Both holographic and projection lithography writing methods application for microstructure making shows geometrical optical laws perturbation as result of nanocomposite self-organization effects with formation of nanometers-sized high-aspect-ratio structures. Obtained results will be useful for diffraction limit overcoming in projection lithography as well as for deep lithography technique.

AbstractThe acrylate-based photopolymer consists of tetra-functional polyester acrylate (TPA), and hexanediol diacrylate (HDDA) has been successfully composited with nano barium titanate (BaTiO3) and completely cured via a digital light processor RP machine. The degradation temperature, tensile strength, hardness, resistivity, and dielectric constant of samples were characterized by Thermo Gravimetric Analyzer Hi-Res TGA2950, Universal Tensile Machine JIA701, Hardness Shore D tester, Fluke 117 multimeter, and Agilent B1500A Semiconductor Device Analyzer, respectively. The morphology changes of the samples were also investigated using the JEOL JSM-6390LV scanning electron microscopy (SEM). The results show that the improvement of degradation temperature is not obvious. Furthermore, the modulus elasticity, hardness, and dielectric constant increase as the filler loading increases up to 2 phr, but the resistivity is vice versa. Interestingly, there is an inverse correlation between dielectric constant and resistivity of photopolymer/BaTiO3 nanocomposite.

Projection Stereolithography (PSL) is an Additive Manufacturing process that digitally patterns light to selectively expose and layer photopolymer into three dimensional objects. Nanomaterials within the photopolymer are therefore embedded inside fabricated objects. Adding varying concentrations of multi-walled carbon nanotubes (MWCNT) to the photopolymer may allow for the engineering of an objects tensile strength and electric conductivity. This research has two goals (i) the fabrication of three-dimensional structures using PSL and (ii) the material characterization of nanocomposite photopolymers. A morphological matrix design tool was developed and used to categorically analyze published PSL systems. These results were used to justifying design tradeoffs during the design and fabricate of a new PSL system. The developed system has 300μm resolution, 45mm x 25mm fabrication area, 0.23mW/cm2 intensity, and 76.2mm per hour vertical build rate. Nanocomposite materials were created by mixing Objet VeroClear FullCure 810 photopolymer with 0.1, 0.2, and 0.5 weight percent MWCNT using non-localized bath sonication. The curing properties of these nanocomposite mixtures were characterized; adding 0.1 weight-percent MWCNT increases the critical exposure by 10.7% and decreases the depth of penetration by 40.1%. The material strength of these nanocomposites were quantified through tensile testing; adding 0.1 weight-percent MWCNT decreases the tensile stress by 45.89%, the tensile strain by 33.33%, and the elastic modulus by 28.01%. Higher concentrations always had exaggerated effects. Electrical conductivity is only measurable for the 0.5 weight-percent nanocomposite with a 8k/mm resistance. The 0.1 weight-percent nanocomposite was used in the PSL system to fabricate a three-dimensional nanocomposite structure.
Master of Science

Роботу виконано та захищено в Інституті фізики НАН України.
Кохтич Л. M. Закономірності формування об'ємних періодичних структур полімер-наночастинки голографічним методом. - На правах рукопису. Дисертація на здобуття наукового ступеня кандидата фізико-математичних наук за спеціальністю 01.04.05 - оптика, лазерна фізика. - Інститут фізики НАЛ України, Київ, 2014. У дисертації представлено результати дослідження об'ємних періодичних структур полімер - НЧ різної природи, отриманих голографічним методом. В роботі вперше показана можливість отримання стабільних об'ємних структур з НЧ металу шляхом синтезу НЧ з прекурсору металу, попередньо розподіленого в полімерній матриці. Розроблені та оптимізовані органо-неорганічні нанокомпозити, чутливі в діапазоні 400-520 нм, основані на комерційних доступних акрилових мономерах, які забезпечують ефективний дифузний перерозподіл НЧ різної природи та прекурсору НЧ в полімерній матриці. Досліджені голографічні властивості отриманих нанокомпозитів та механізми впорядкування НЧ. З використанням НЧ різної природи (TiO2, SiO2, ZrO2, LaPO4, CdSe/ZnS, прекурсору НЧ Ag) отримані стабільні об'ємні структури (ґратки пропускаючого типу) з періодом 0.3 - 3 мкм і амплітудою модуляції показника заломлення 0.005 - 0.026, що в деяких випадках на порядок перевищує раніше досягнуті величини. Досліджено дифракційні, люмінесцентні та лазерні властивості періодичних структур з НЧ різних типів.
Kokhtych L.M. Regularities in formation of volume periodic structures polymer – nanoparticles by the holographic method. – Used only as a manuscript. This thesis is for obtaining the scientific degree candidate of sciences (physics and mathematics) by the specialty 01.04.05 – optics, laser physics. – Institute for Physics, NAS of Ukraine, – Kyiv, 2014. The results of study of volume periodic structures polymer – nanoparticles (NP) of different kinds fabricated by holographic method are introduced in this thesis. For the first time it was shown the possibility to obtain the stable volume structures polymer – metal NP by using the synthesis of NP from the metal precursor preliminary distributed in a polymer matrix. Based on commercially available acryl monomers organic-inorganic nanocomposites light-sensitive within the range 400 – 520 nm have been developed and optimized. These materials provide efficient diffusion redistribution of NP and NP precursor in polymer matrix. Holographic properties of the obtained nanocomposites as well as the mechanism of NP ordering have been investigated. Using of NP of various nature (TiO2, SiO2, ZrO2, LaPO4, CdSe/ZnS, precursor of Ag NP), we have obtained stable volume transmission gratings with the period 0.3 - 3 µm and the amplitude of refractive index modulation from 0.005 up to 0.026, that sometimes exceeds by one order the values reached earlier. Diffraction, luminescent and laser properties of the obtained structures were also investigated.
Кохтич Л. М. Закономерности формирования объемных периодических структур полимер-наночастицы голографическим методом. - На правах рукописи. Диссертация на соискание ученой степени кандидата физико-математических наук по специальности 01.04.05 – оптика, лазерная физика. – Институт физики НАН Украины, Киев, 2014. В диссертации представлены результаты исследования особенностей формирования периодических структур полимер – НЧ различной природы: SiO2, LaPO4:Ce,Tb, CdSe/ZnS, TiO2, ZrO2 и Ag голографическим методом. Для достижения поставленных задач, в отличие от известных двухкомпонентных систем, включающих мономер и НЧ, была реализованная идея использования трьохкомпонентной системы, базирующейся на двух акриловых мономерах с разным количеством двойных связей (CH=CH2)m и разной реакционной способностью. Установлено, что оптимальной мономерной составляющей является смесь поли- и однофункционального мономеров. Первый должен иметь высокую скорость полимеризации и формировать трехмерную полимерную сетку, второй, с низкой скоростью полимеризации, – образовывать линейные полимерные цепи и иметь низкое термодинамическое сродство к полимерной сетке, что способствует вытеснению низкореакционного мономера и НЧ из максимумов светового поля в минимумы поля. Показано, что наиболее универсальным вариантом является мономерная смесь, которая состоит с SR444 (m=3) и IBA (m=1). Она обеспечивает эффективное пространственное перераспределение компонент для всех исследуемых НЧ. Использование других комбинаций может обеспечивать дополнительные свойства структур. Для получения высокого контраста структуры, нанокомпозит должен включать не менее 10об.% НЧ. Детально исследован механизм формирования периодических структур полимер - НЧ и усовершенствована его полимеризационно-дифузная модель. Определено влияние фазового разделения, вязкости среды, концентрации мономеров и НЧ на степень их пространственного перераспределения и, соответственно, эффективность структуры. Упорядочение НЧ в полимерной матрице происходит вследствие неоднородной полимеризации и диффузионного перераспределения компонент композита в пространственно периодическом поле. Относительная модуляция объемной концентрации НЧ достигается при концентрационном соотношении SR444:IBA 30:70вес.% составляет 85-99%. В результате, формируется объемная структура, эффективность которой определяется различием показателей преломления в облученных и необлученных областях решетки и степенью пространственного перераспределения компонент. Амплитуда модуляции показателя преломления n1 определяется также соотношением характерных времен полимеризации и диффузионного массопереноса на расстояние порядка периода поля. Максимальное n1 достигается в случае, когда диффузионный массоперенос происходит быстрее, чем формирование полимерной сетки, что определяется условиями голографической экспозиции: интенсивностью и периодом поля, которые составляют I=0.8÷9мВт/см2, Λ= 0.8÷1.2 мкм, соответственно. С использованием НЧ различной природы получены объемные периодические структуры с периодом 0.4 – 2 мкм и величиной n1 0.005 – 0.026, что существенно превышает величины, достигнутые для тех же НЧ в композитах, включающих один мономер. В работе впервые показана возможность получения стабильных объемных структур полимер - НЧ металла с высоким содержанием НЧ и низким уровнем дефектности. Формирование структур происходит в результате синтеза НЧ из металлического прекурсора, периодически распределенного в полимерной матрице. На первом этапе при фотополимеризации в интерференционном поле формируется стабильная периодическая структура (объемная решетка) полимер – металлический прекурсор. Образование НЧ металла происходит, главным образом, после голографической записи вследствие термической обработки. Фотостабильность решеток обеспечивается необратимым диффузионным разделением компонент в процессе записи. В зависимости от условий записи и используемого инициатора средний диаметр НЧ составляет 5 и 3 нм. Образование НЧ серебра подтверждено электронно-микроскопическими и спектральными исследованиями. Исследовано механизмы фото- и термостимулированного синтеза НЧ в полимерных слоях. Для структур с периодом 0.3 – 3 мкм показано, что термоиндуцированный синтез НЧ Ag обеспечивает максимальное значение n1 = 0.02, что в два раза превышает величину, полученную при фотоиндуцированном восстановлении. Предложена наиболее вероятная схема восстановления Ag+ и образования НЧ серебра в периодических структурах. Исследованы дифракционные, люминесцентные и лазерные свойства периодических структур с НЧ различных типов. На базе разработанных материалов изготовлены голографические оптические элементы 1D-2D размерности и РЗЗ-структуры. Стабильность параметров структур сохраняется не менее 8 лет. Дифракционная эффективность одномерных структур на длинах волн 440-650 нм составляет 80-99%, двумерных – 65-70%.

Au cours de ce travail, nous avons préparé des nanocomposites magnétiques constitués de nanoparticules de maghémite modifiées en surface, dispersées dans une matrice photopolymère renforcée ou non par des argiles. Les nanoparticules de maghémite ont été synthétisées selon le procédé décrit par Massart ou Bee. La compatibilité de ces particules avec la matrice polymère a été apportée par l'immobilisation de différents organosilanes à la surface des nanoparticules de maghémite selon deux voies thermiques différentes. L'état de dispersion de ces particules dans différents monomères photopolymérisables a été caractérisé et étudié afin d'obtenir, après photopolymérisation, le nanocomposite final. Une étude cinétique de la réaction de photopolymérisation a été menée avec ou sans les nanoparticules de maghémite fonctionnalisées. Les propriétés mécaniques et les propriétés de surface de ces nanocomposites obtenus ont été évaluées. L'incorporation de montmorillonite exfoliée par les nanoparticules de maghémite dans la matrice photopolymère a été également étudiée et la cinétique comparée avec le premier nanocomposite préparé. L'exfoliation partielle de la montmorillonite a été réalisé grâce à un procédé intitulé "in-situ": les cations compensateurs (Na+) de la montmorillonite ont été échangés contre des cations Fei+. La transformation des cations Fei+ en maghémite a ensuite été réalisée en deux étapes. Les résultats finaux montrent que l'ajout de nanocharges (nanoparticules de maghémite seule ou avec de la montmorillonite exfoliée) n'influe pas la cinétique de polymérisation et améliore les propriétés mécaniques des nanocomposites fmaux
In this work, nanocomposites of photopolymer-oxide and photopolymer-oxide-MMT (oxide: nanoparticles of yFe2O3, MMT: montmorillonite) were prepared by photochemical procedure. Conceming the first on (photopolymer-oxide), the maghemite nanoparticles were synthesized according to the process described by Massart. The compatibility of these particles with the polymeric matrix was obtained by immobilization of MPDMS at their surface using a thermic procedure. Conceming the second one, the mixture of different nanofillers (nanofillers mixture yFe2O3-MMT) were prepared by a new method based on the ion exchange reaction and different chemical and thermal treatments. The incorporation of both nanofillers in the diacrylate photopolymeric matrix was studied and optimized. A kinetic study of the photopolymerization reaction in presence of both nanofillers was also performed by FTIR spectroscopy. The addition of both nanofillers did not effect significantly the polymerization kinetics in thin films (10µm) at nanofillers concentration up to 2 wt%. It was found that nanocomposites had a came photopolymerization rates in comparison with pure diacrylate. The experimental results showed that photopolymer-oxide-MMT nanocomposite can improve by 66% the mechanical properties (E')

博士
國立臺灣科技大學
材料科學與工程系
102
There are some advantages of UV-cured technology process to synthesize the polymer materials such as low energy consuming, short time processes and solvent-free. These have been promoting UV-curable polymer materials become increasingly applied in various scientific and industrial fields. While a lot of studies have been done on thermal curable polymer systems, but only few have focused on preparation of UV-curable polymer nanocomposites. In this research, we propose a novel, cheap and easy handling method to synthesize acrylate-based photopolymer/inorganic (clay and BaTiO3) nanocomposite by using Digital (visible) Light Rapid Prototyping (DLRP) machine. This preparation method provides layer by layer curing process of photopolymer nanocomposite from liquid to solid resulting a layered structure of cured-prototype. The resulted sample then examined its mechanical, thermal, and its electrical properties. The mechanical properties including hardness, tensile strength, modulus elasticity and storage modulus will be examined by using hardness tester type shore D and universal tensile machine, and dynamic mechanical analyzer, respectively. The degradation temperature will be examined by using thermal gravimetric analyzer (TGA). The electric properties such as dielectric constant and resistivity will be examined by using Agilent B1500A Semiconductor Device Analyzer at 1 MHz and -5 to 5 volt and Fluke 117 multimeter respectively. The prototype of photopolymer/inorganic nanocomposite resulted by this method in accordance with several reliable properties is expected to be feasibly applied in several applications especially on Rapid Prototyping Technology and it will also feasible to be applied in related application such as a special part that subjected to heat, thermal barrier, electrical or electronic insulator or coating, film substrates, and embedded dielectric materials.

碩士
國立臺灣科技大學
材料科學與工程系
101
Rapid Prototyping system is a product manufacturing system using light as main energy source. It can reduce cost of developing new product from the initial idea to production. A major drawback of Rapid Prototyping technology is the photopolymer, material uses in this system, are brittle. In order to overcome this problem, a composite system of nano Barium Titanate (nano BaTiO3) and Tetra-function Polyacrylate (TPA) was investigated. TPA is UV-curing acrylate resin that suitable for rapid prototyping system. It also has environment-friendly aspect (no VOC emission and low energy consumption). As reactive diluents, 1,6 Hexanediol Acrylate (HDDA) was added. As result, Addition BaTiO3 can increase mechanical properties and thermal properties .

Abstract Bacterial infections have been recognized as a critical challenge to public health, resulting in substantial morbidity, mortality, and enormous costs. In this paper, a digital light processing (DLP) based 3D printing system is employed to rapidly manufacture photocurable thermoset polymers and nanocomposites for potential antibacterial applications. This work shows how nanoparticles that present antibacterial properties can be added to traditional DLP manufacturing and their effects on the physical properties. In this paper, titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles in the 10 to 30-nm range are mixed with photocurable resins for rapid 3D printing and prototyping. The two resins used are a standard photopolymer rapid resin and an ABS-like photopolymer rapid resin. A 1% composite percentage is utilized to avoid the requirement of modification to the printing system due to greatly increased viscosity. Tensile testing data, contact angle data, and abrasion data are performed on a total of four different composites and two controls. These composites have shown a tensile strength of 29.53 MPa. At the 1% nanoparticle weight concentration, the 3D printing nanocomposites are transparent and demonstrate a complete penetration of particles throughout the entire print. The detailed experimental characterization will be conducted to understand the 3D printed material’s mechanical properties and microstructures fully. This research can enhance public health by providing a novel approach to control the spread of bacteria and other microbial.