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Journal articles on the topic 'Crystallinity'

Author: Grafiati

Published: 4 June 2021

Last updated: 18 May 2024

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1

Zhang, Weiwei, Linjiang Chen, Sheng Dai, Chengxi Zhao, Cheng Ma, Lei Wei, Minghui Zhu, et al. "Reconstructed covalent organic frameworks." Nature 604, no. 7904 (April 6, 2022): 72–79. http://dx.doi.org/10.1038/s41586-022-04443-4.

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AbstractCovalent organic frameworks (COFs) are distinguished from other organic polymers by their crystallinity1–3, but it remains challenging to obtain robust, highly crystalline COFs because the framework-forming reactions are poorly reversible4,5. More reversible chemistry can improve crystallinity6–9, but this typically yields COFs with poor physicochemical stability and limited application scope5. Here we report a general and scalable protocol to prepare robust, highly crystalline imine COFs, based on an unexpected framework reconstruction. In contrast to standard approaches in which monomers are initially randomly aligned, our method involves the pre-organization of monomers using a reversible and removable covalent tether, followed by confined polymerization. This reconstruction route produces reconstructed COFs with greatly enhanced crystallinity and much higher porosity by means of a simple vacuum-free synthetic procedure. The increased crystallinity in the reconstructed COFs improves charge carrier transport, leading to sacrificial photocatalytic hydrogen evolution rates of up to 27.98 mmol h−1 g−1. This nanoconfinement-assisted reconstruction strategy is a step towards programming function in organic materials through atomistic structural control.

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2

Kübler, Bernard, and Michel Jaboyedoff. "Illite crystallinity." Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 331, no. 2 (July 2000): 75–89. http://dx.doi.org/10.1016/s1251-8050(00)01395-1.

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3

Duta, Anca, and I. Kadas-Iluna. "Polyvinyl Alcohol Crystallinity." Materials Science Forum 133-136 (January 1993): 951–0. http://dx.doi.org/10.4028/www.scientific.net/msf.133-136.951.

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4

Jaboyedoff, M. "Illite “Crystallinity” Revisited." Clays and Clay Minerals 49, no. 2 (2001): 156–67. http://dx.doi.org/10.1346/ccmn.2001.0490205.

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5

Zhang, Xiao Xun, Luo Wang, and Qiu Hui Liao. "Experimental Study on the Crystallinity and Mechanical Properties of the Injection Molded Polypropylene." Advanced Materials Research 239-242 (May 2011): 2809–12. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.2809.

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Polypropylene specimens were made by the injection molding experiments under different processing conditions. The crystallinity of each polypropylene specimen was obtained using the X-ray diffraction method. The effects of the injection molding processes on the crystallinity of polypropylene were revealed: (1) the crystallinity decreases as the melt temperature increases, and the higher the melt temperature, the slower the crystallinity decreases, (2) the crystallinity decreases as the mould temperature increases, and the higher the mould temperature, the faster the crystallinity decreases, (3) the crystallinity increases as the injection speed increases, and the larger the injection speed, the faster the crystallinity increases. By the tensile experiments of the injection molded specimens, it is also found that the crystallinity has a major impact on the mechanical properties of polypropylene. The yield strength and tensile strength of polypropylene specimens increase as the crystallinity increases.

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6

Kosa, Tamas, Ludmila Sukhomlinova, Linli Su, Bahman Taheri, Timothy J. White, and Timothy J. Bunning. "Light-induced liquid crystallinity." Nature 485, no. 7398 (May 2012): 347–49. http://dx.doi.org/10.1038/nature11122.

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7

van Soest, Jeroen J. G., S. H. D. Hulleman, D. de Wit, and J. F. G. Vliegenthart. "Crystallinity in starch bioplastics." Industrial Crops and Products 5, no. 1 (March 1996): 11–22. http://dx.doi.org/10.1016/0926-6690(95)00048-8.

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8

Duta, Anca, R. Tica, Dana Perniu, and B. Cismas. "Poly (Vinyl Butyral) Crystallinity." Materials Science Forum 228-231 (July 1996): 889–94. http://dx.doi.org/10.4028/www.scientific.net/msf.228-231.889.

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9

Yu, Sze-Man, and Stefan Mecking. "Variable Crystallinity Polyethylene Nanoparticles." Macromolecules 42, no. 11 (June 9, 2009): 3669–73. http://dx.doi.org/10.1021/ma9003665.

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10

Löwen, Hartmut, and Thomas Beier. "Crystallinity in liquid films." Physical Review B 41, no. 7 (March 1, 1990): 4435–40. http://dx.doi.org/10.1103/physrevb.41.4435.

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11

Ludvigsson, M., J. Lindgren, and J. Tegenfeldt. "Crystallinity in Cast Nafion." Journal of The Electrochemical Society 147, no. 4 (2000): 1303. http://dx.doi.org/10.1149/1.1393354.

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12

Ballard, D. G. H., A. N. Burgess, J. M. Dekoninck, and E. A. Roberts. "The ‘crystallinity’ of PVC." Polymer 28, no. 1 (January 1987): 3–9. http://dx.doi.org/10.1016/0032-3861(87)90312-0.

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13

Matta, V. K., R. B. Mathur, O. P. Bahl, and K. C. Nagpal. "Crystallinity of PAN precursors." Carbon 28, no. 1 (1990): 241–43. http://dx.doi.org/10.1016/0008-6223(90)90123-g.

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14

Dole, Malcolm. "Crystallinity from thermal measurements." Journal of Polymer Science Part C: Polymer Symposia 18, no. 1 (March 7, 2007): 57–68. http://dx.doi.org/10.1002/polc.5070180106.

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15

Alwaan, I. M. "Effect of Cyclo-Olefin Copolymer Loading on Kinetics, Thermodynamics and Model of Linear Low Density Polyethylene Crystallinity." Progress in Rubber, Plastics and Recycling Technology 34, no. 1 (February 2018): 55–74. http://dx.doi.org/10.1177/147776061803400104.

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The behavior of kinetic and thermodynamic characteristics of linear low-density polyethylene (LLDPE) crystallinity containing cyclo-olefin copolymer (COC) were investigated by means of differential scanning calorimeter (DSC). The crystallinity kinetic parameters including the crystallinity apparent activation energy (E), rate of crystallinity constant (K) and the order of crystallinity (n) were calculated with Borchardt and Daniels methods. The results have shown that the activation energy of blends increased with increase in the COC loading and the order of crystallinity was the first order for all blends. Gibbs free energy, enthalpy and entropy of the LLDPE crystallinity increased with the loading of COC. The different crystallinity kinetic models of LLDPE were observed with the loading of COC. It was concluded that the COC hindered the chains of polymer from aligning in a row.

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16

Gibril, Magdi E., Hai Feng Li, Xin Da Li, Huan Li, Xuan Zhong, Yue Zhang, Ke Qing Han, and Mu Huo Yu. "Application of Twin Screw Extruder in Cellulose Dissolution with Ionic Liquid." Applied Mechanics and Materials 268-270 (December 2012): 605–9. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.605.

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Twin-screw extruder was used as a dissolution unit for microcrystalline cellulose with ionic liquid. Ionic liquid (1-butyl-3-methylimidazolium chloride) was applied as solvent and plasticizer; it was mixed with cellulose to prepare the extrusion mixture. The extrusion mixture was feed into twin screw extruder which was run under conditions; speed 65 rpm and 1400C. In order to determine whether the cellulose I has been transformed into cellulose II, the solubility, structure, crystallinty and thermal stability of the extrude cellulose were investigated by polarizing Optical microscope, FTIR, XRD and TGA, respectively. The results which were obtained from polarizing optical microscope showed a clear cellulose solution without undissolved cellulose. FTIR confirmed the transfer cellulose I into cellulose II. XRD result showed a decrease in degree of crystallinity and confirmed the change of cellulose I into cellulose II. Finally, TGA analysis approved that the thermal stability was decreased according to the decrease in crystallinity.

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17

Fauziyah, N. A., D. S. Perwitasari, T. A. Fadly, S. Soontaranon, and S. Pratapa. "A Comparative Study of The Crystallinity Value of Polyethylene Glycol-Based Composites Using XRD and WAXS." Journal of Physics: Conference Series 2392, no. 1 (December 1, 2022): 012033. http://dx.doi.org/10.1088/1742-6596/2392/1/012033.

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Abstract Crystallinity is an important parameter of thermoplastic polymers. Furthermore, crystallinity is closely related to processing conditions such as temperature and applied shear stress. However, determining the degree of crystallinity is very complicated because of the different interpretations of crystallinity according to each technique. In this paper, we analyze the crystallinity of polyethylene glycol-based composites using two instruments, i.e., X-Ray Diffraction (XRD) and wide-angle X-Ray Scattering (WAXS). The results showed that with the addition of 60 wt.% silica, the degree of crystallinity revealed by XRD was 81.24%, while WAXS showed a degree of crystallinity of 80.93%. In general, the crystallinity results obtained with WAXS were almost identical, only 0.31% different from the XRD results. This difference in results was due to more presence as a consequence of the broad amorphous halo and background instrumentation exhibited by the higher background from XRD. Thus, the instrument effect must first be removed from the XRD data and it is possible that the amorphous region of the sample will also be reduced and result in a slightly higher crystallinity. At the same time WAXS with the transmission technique will minimize the possibility of background instrumentation. Therefore, WAXS was recommended to analyze the crystallinity of polymer-based and amorphous materials.

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18

Gout, Robert, and Giles Verdes. "Effect of crystallinity on diaspore and boehmite relative stability." European Journal of Mineralogy 5, no. 2 (April 27, 1993): 215–18. http://dx.doi.org/10.1127/ejm/5/2/0215.

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19

Okuno, T., T. Yasuda, and H. Yasuda. "Effect of Crystallinity of PET and Nylon 66 Fibers on Plasma Etching and Dyeability Characteristics." Textile Research Journal 62, no. 8 (August 1992): 474–80. http://dx.doi.org/10.1177/004051759206200807.

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We investigated the correlation between crystallinity and plasma susceptibility for PET and nylon 66 fibers. Plasma susceptibility is measured by the weight loss observed when fibers of varying crystallinity are exposed to air plasma. We varied the crystallinity of samples by annealing fibers at different temperatures. Plasma susceptibility and dyeability as a function of the crystallinity of fibers showed a striking resemblance: both decreased with increasing crystallinity up to a threshold crystallinity, above which there were appreciable increases. Plasma susceptibilities of these fibers, under the conditions used in this investigation, are believed to be proportional to the dyeable non-crystalline region, but not to the total noncrystalline phase of fibers.

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20

CYR, NATSUKO, R. M. ELOFSON, and G. W. MATHISON. "DETERMINATION OF CRYSTALLINITY OF CARBOHYDRATES BY 13C CROSS POLARIZATION/MAGIC ANGLE SPINNING NMR WITH APPLICATIONS TO THE NUTRITIVE VALUE OF FORAGES." Canadian Journal of Animal Science 70, no. 2 (June 1, 1990): 695–701. http://dx.doi.org/10.4141/cjas90-082.

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An NMR technique using solid samples is presented. The relative "crystallinity" of carbohydrates is estimated by the use of a 20 ms delayed contact pulse sequence. There was good agreement between the crystallinity of cellulose determined by the NMR procedure and that estimated by using an acid hydrolysis procedure. The "crystallinity index" (crystallinity relative to that of cellulose powder at 100) of timothy stems increased from seven for samples cut on 30 June to 16 for those cut on 15 July. Mature-weathered timothy stems which were collected in the spring had a "crystallinity index" of 20. The carbohydrate crystallinity index increased from 10 in alfalfa-grass hay to 49 in a sample of fecal fiber from a steer fed this hay indicating that noncrystalline carbohydrate is preferentially digested in the animal. Treatment of fecal fiber with ammonia decreased the crystallinity index. It was concluded that the NMR technique can provide useful information concerning the nature of the carbohydrates in forages. Key words: I3C CP/MAS NMR, delayed contact pulse sequence, crystallinity, carbohydrates

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21

Ni, Tie Quan, and Chang Jun Ke. "Study on Crystallinity Degree of Hydration Products in Autoclaved Samples with Solid Wastes." Advanced Materials Research 168-170 (December 2010): 1169–73. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1169.

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The ratio of the dissolved amount difference between in cool hydrochloride and hot hydrochloride to the bound water amount of the samples is regarded as crystallinity degree; approximate expressed the proportion relation of crystal and gel in the samples. And studied the relationship of compressive strength and dissolved amount difference, bound water amount and crystallinity degree of autoclaved silicate products using solid waste. The results shown, dissolved amount difference, bound water amount and crystallinity degree of autoclaved samples are related to kinds of hydration products. When well-crystallized hydrated amount is smaller, the crystallinity degree and its change are also smaller, and compressive strength of the sample increases with bound water amount increasing. When well-crystallized hydrated amount is larger, dissolved amount difference is larger, and crystallinity degree is larger, compressive strength of the sample increases with crystallinity degree decreased. There is an optimal value of crystallinity degree for compressive strength of the autoclaved samples.

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22

Yang, Liulin, Yanming Dong, Xiaolan Hu, and Anhua Liu. "Dendronized CarbohydratesⅡ—Liquid Crystallinity Study." Acta Chimica Sinica 70, no. 1 (2012): 27. http://dx.doi.org/10.6023/a1109097.

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23

Skoulios, A., and D. Guillon. "Amphiphilic Character and Liquid Crystallinity." Molecular Crystals and Liquid Crystals Incorporating Nonlinear Optics 165, no. 1 (December 1988): 317–32. http://dx.doi.org/10.1080/00268948808082205.

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24

Stuart, H. A. "PROBLEMS OF HIGH-POLYMER CRYSTALLINITY." Annals of the New York Academy of Sciences 83, no. 1 (December 15, 2006): 3–19. http://dx.doi.org/10.1111/j.1749-6632.1960.tb40879.x.

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25

Samulski, Edward T. "Macromolecular structure and liquid crystallinity." Faraday Discussions of the Chemical Society 79 (1985): 7. http://dx.doi.org/10.1039/dc9857900007.

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26

Wang, Xuewen, Hong Wang, Yang Gu, Wei Fu, Lu Zheng, Guowei Liu, Yongmin He, et al. "Programmable high crystallinity carbon patterns." 2D Materials 4, no. 2 (February 2, 2017): 025011. http://dx.doi.org/10.1088/2053-1583/aa59b4.

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27

Isogai, Akira, and Makoto Usuda. "Crystallinity indexes of cellulosic materials." Sen'i Gakkaishi 46, no. 8 (1990): 324–29. http://dx.doi.org/10.2115/fiber.46.8_324.

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28

Chang, Chunrui, Ying Zhao, Ying Liu, and Libao An. "Liquid crystallinity of carbon nanotubes." RSC Advances 8, no. 28 (2018): 15780–95. http://dx.doi.org/10.1039/c8ra00879e.

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29

Gilbert, Marianne. "Crystallinity in Poly(vinyl Chloride)." Journal of Macromolecular Science, Part C: Polymer Reviews 34, no. 1 (February 1994): 77–135. http://dx.doi.org/10.1080/15321799408009633.

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30

Palmer, D. Jason. "Route to engineering nanoparticle crystallinity." Materials Today 10, no. 10 (October 2007): 8. http://dx.doi.org/10.1016/s1369-7021(07)70222-5.

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31

Ogawa, Kozo, and Toshifumi Yui. "Crystallinity of PartiallyN-Acetylated Chitosans." Bioscience, Biotechnology, and Biochemistry 57, no. 9 (January 1993): 1466–69. http://dx.doi.org/10.1271/bbb.57.1466.

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32

Mehmet-Alkan, A. A., and J. N. Hay. "The crystallinity of PEEK composites." Polymer 34, no. 16 (January 1993): 3529–31. http://dx.doi.org/10.1016/0032-3861(93)90487-u.

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33

Mognonov, D. M., Zh P. Mazurevskaya, V. V. Khakhinov, and O. V. Il’ina. "Manifestations of crystallinity in polyamidobenzimidazoles." Russian Journal of Applied Chemistry 81, no. 8 (August 2008): 1476–78. http://dx.doi.org/10.1134/s1070427208080302.

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34

Obande, O. P., and M. Gilbert. "Crystallinity changes during PVC processing." Journal of Applied Polymer Science 37, no. 6 (February 20, 1989): 1713–26. http://dx.doi.org/10.1002/app.1989.070370622.

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35

Richards, R. B. "Polyethylene-structure, crystallinity and properties." Journal of Applied Chemistry 1, no. 8 (May 4, 2007): 370–76. http://dx.doi.org/10.1002/jctb.5010010812.

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36

Yu, Luping, and Zhenan Bao. "Conjugated polymers exhibiting liquid crystallinity." Advanced Materials 6, no. 2 (February 1994): 156–59. http://dx.doi.org/10.1002/adma.19940060214.

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37

Ioelovich, Michael. "Accessibility and crystallinity of cellulose." BioResources 4, no. 3 (July 26, 2009): 1168–77. http://dx.doi.org/10.15376/biores.4.3.1168-1177.

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The accessibility of cellulose samples having various degrees of crystallinity was studied with respect to molecules of water, lower primary alcohols, and lower organic acids. It was found that small water molecules have full access to non-crystalline domains of cellulose (accessibility coefficient α = 1). Molecules of the lowest polar organic liquids (methanol, ethanol, and formic acid) have partial access into the non-crystalline domains ( α <1), and with increasing diameter of the organic molecules their accessibility to cellulose structure decreases. Accessibility of cellulose samples to molecules of various substances is a linear function of the coefficient α and the content of non-crystalline domains. The relationship between crystallinity (X) and accessibility (A) of cellulose to molecules of some liquids has been established as A = α (1-X). The water molecules were found to have greater access to cellulose samples than the molecules of the investigated organic liquids. The obtained results permit use of accessibility data to estimate the crystallinity of cellulose, to examine the structural state of non-crystalline domains, and to predict the reactivity of cellulose samples toward some reagents.

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38

STRAUSS, R., G. W. BRÜMMER, and N. J. BARROW. "Effects of crystallinity of goethite: I. Preparation and properties of goethites of differing crystallinity." European Journal of Soil Science 48, no. 1 (March 1997): 87–99. http://dx.doi.org/10.1111/j.1365-2389.1997.tb00188.x.

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39

TAKEMASA, Takashi, and Satoshi SOMIYA. "Establishment of crystallinity adjusting method of CFRPI, and effect of crystallinity on bending characters." Proceedings of the JSME annual meeting 2002.6 (2002): 307–8. http://dx.doi.org/10.1299/jsmemecjo.2002.6.0_307.

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40

Li, Yao Xiang, and Li Chun Jiang. "Modeling Wood Crystallinity with Multiple Linear Regression." Key Engineering Materials 480-481 (June 2011): 550–55. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.550.

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The crystallinity of wood has an important effect on the physical, mechanical and chemical properties of cellulose fibers. Crystallinity of larch plantation wood was investigated with near infrared spectroscopy and multiple linear regression. Five typical wave lengths were selected to establish prediction model for wood crystallinity. Full-cross validation was applied to the model development. The model performance is satisfied with prediction correlation coefficient of 0.896 and bias of 0.0004. The results indicated that prediction of wood crystallinity with near infrared spectroscopy and multiple linear regression is feasible, which provides a fast and nondestructive method for wood crystallinity prediction.

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41

Li, Jianguo, Peimin Zhao, Liyan Zhao, Qiang Chen, Shikun Nong, Qiang Li, and Lingqiang Wang. "Integrated VIS/NIR Spectrum and Genome-Wide Association Study for Genetic Dissection of Cellulose Crystallinity in Wheat Stems." International Journal of Molecular Sciences 25, no. 5 (March 6, 2024): 3028. http://dx.doi.org/10.3390/ijms25053028.

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Cellulose crystallinity is a crucial factor influencing stem strength and, consequently, wheat lodging. However, the genetic dissection of cellulose crystallinity is less reported due to the difficulty of its measurement. In this study, VIS/NIR spectra and cellulose crystallinity were measured for a wheat accession panel with diverse genetic backgrounds. We developed a reliable VIS/NIR model for cellulose crystallinity with a high determination coefficient (R2) (0.95) and residual prediction deviation (RPD) (4.04), enabling the rapid screening of wheat samples. A GWAS of the cellulose crystallinity in 326 wheat accessions revealed 14 significant SNPs and 13 QTLs. Two candidate genes, TraesCS4B03G0029800 and TraesCS5B03G1085500, were identified. In summary, this study establishes an efficient method for the measurement of cellulose crystallinity in wheat stems and provides a genetic basis for enhancing lodging resistance in wheat.

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42

Kun, Eva, and Kálmán Marossy. "Effect of Crystallinity on PLA’s Microbiological Behaviour." Materials Science Forum 752 (March 2013): 241–47. http://dx.doi.org/10.4028/www.scientific.net/msf.752.241.

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Recent work describes changes in polylactic acid samples with different crystallinity during microbiological degradation. We treated PLA at 93°C for different periods of time, which yielded samples with particular crystallinity. The fraction of crystalline phase was determined by differential scanning calorimetry, and the visual effect of crystallinity was measured by colorimetric method with black and white backgrounds. The medium for biological degradation process was living sludge under room temperature and normal atmospheric pressure. Furthermore, the change in mass was also measured. The results show that increased crystallinity reduces the rate of mass lost. The volumetric proportion of crystallinity is in direct correlation with opacity, so checking transparency is also a suitable possibility for estimating crystallinity. DSC, colorimetric method and visual observation experiments confirm that crystallinity has increased proportionally by the time of heat treatment and caused opacity. The experiments show that water uptake happened faster and in much higher volume in polymers having dominantly amorphous structure than in the case of samples with higher crystallinity. In the case of materials with only 2.43% crystallinity, weight lost began later because they had a greater water uptake during the first 7-12 days, while this period took only 7 days with a very low water uptake for samples containing approximately 35% crystalline phase. After swelling, weight loss of the crystalline samples was much slower than that of samples containing more amorphous parts, because crystalline phases inhibit the diffusion of small water molecules and the microbes with it.

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43

Hosseini, S. M. Amin, Martin Schäkel, Ismet Baran, Henning Janssen, Martin van Drongelen, and Remko Akkerman. "Non-uniform crystallinity and temperature distribution during adjacent laser-assisted tape winding process of carbon/PA12 pipes." International Journal of Advanced Manufacturing Technology 111, no. 11-12 (November 7, 2020): 3063–82. http://dx.doi.org/10.1007/s00170-020-06215-8.

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AbstractThe non-uniform temperature and crystallinity distributions present in carbon fiber–reinforced PA12 composite pipes, produced via laser-assisted tape winding (LATW), are investigated in this paper. The width of the laser source is usually larger than the substrate width which causes multiple heating and cooling of some regions of the (neighboring) substrate and hence temperature and crystallinity gradients during the adjacent hoop winding. A kinematic-optical-thermal (KOT) model coupled with a non-isothermal crystallinity model is developed to capture the transient temperature and crystallinity distributions for growing substrate thickness and width. The predicted temperature trends are validated with thermocouple and thermal camera measurements. The substrate temperature varies in the width direction up to 52%. This will lead to extra polymer remelting and possible degradation. The maximum variation of the crystallinity degree across the width is found to be 270% which shows agreement with the trend of the measured crystallinity degree. It is found that a more realistic description of the melting behavior of the matrix is needed to obtain a more accurate prediction of the crystallinity distribution.

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44

Guggenheim, S., D. C. Bain, F. Bergaya, M. F. Brigatti, V. A. Drits, D. D. Eberl, M. L. L. Formoso, et al. "Report of the Association Internationale pour l'Etude des Argiles (AIPEA) Nomenclature Committee for 2001: Order, disorder and crystallinity in phyllosilicates and the use of the ‘Crystallinity Index’." Clay Minerals 37, no. 2 (June 2002): 389–93. http://dx.doi.org/10.1180/0009855023720043.

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AbstractThe purpose of this report is to describe the appropriate use of indices relating to crystallinity, such as the ‘crystallinity index’, the ‘Hinckley index’, the ‘Kü bler index’, and the ‘Árkai index’. A ‘crystalline’ solid is defined as a solid consisting of atoms, ions, or molecules packed together in a periodic arrangement. A ‘crystallinity index’ is purported to be a measure of crystallinity, although there is uncertainty about what this means (see below). This report discusses briefly the nature of order, disorder and crystallinity in phyllosilicates and discusses why the use of a ‘crystallinity index’ should be avoided. If possible, it is suggested that indices be referred to using the name of the author who originally described the parameter, as in ‘Hinckley index’ or ‘Kübler index’, or in honour of a researcher who investigated the importance of the parameter extensively, as in ‘Árkai index’.

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45

Shi, Changxia, Michael L. McGraw, Zi-Chen Li, Luigi Cavallo, Laura Falivene, and Eugene Y. X. Chen. "High-performance pan-tactic polythioesters with intrinsic crystallinity and chemical recyclability." Science Advances 6, no. 34 (August 2020): eabc0495. http://dx.doi.org/10.1126/sciadv.abc0495.

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Three types of seemingly unyielding trade-offs have continued to challenge the rational design for circular polymers with both high chemical recyclability and high-performance properties: depolymerizability/performance, crystallinity/ductility, and stereo-disorder/crystallinity. Here, we introduce a monomer design strategy based on a bridged bicyclic thiolactone that produces stereo-disordered to perfectly stereo-ordered polythiolactones, all exhibiting high crystallinity and full chemical recyclability. These polythioesters defy aforementioned trade-offs by having an unusual set of desired properties, including intrinsic tacticity-independent crystallinity and chemical recyclability, tunable tacticities from stereo-disorder to perfect stereoregularity, as well as combined high-performance properties such as high thermal stability and crystallinity, and high mechanical strength, ductility, and toughness.

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46

Mayo Greenberg, J., Aigen Li, Tetsuo Yamamoto, and Takashi Kozasa. "On the crystalline silicate component of comet dust." International Astronomical Union Colloquium 150 (1996): 497–506. http://dx.doi.org/10.1017/s0252921100502103.

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AbstractThe effects of preaggregation silicate crystallinity and postaggregation silicate crystallinity on the 11.3μm structure in comet dust emission have been calculated. Of the order of 10 - 20% crystallinity provides the best agreement to date with observation but the fits are not yet fully satisfactory.

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47

Revol, J. F., A. Dietrich, and D. A. I. Goring. "Effect of mercerization on the crystallite size and crystallinity index in cellulose from different sources." Canadian Journal of Chemistry 65, no. 8 (August 1, 1987): 1724–25. http://dx.doi.org/10.1139/v87-288.

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Native cellulose samples having a wide range of crystallinity and crystallite size were mercerized by treatment with sodium hydroxide. The resultant cellulose II samples showed only a narrow range of crystallinity and an essentially constant crystallite size. For the low-crystallinity samples, crystallinity and crystallite size actually increased on mercerization. These results are in line with the proposal that mercerization involves the mingling of chains from adjacent and antiparallel cellulose I microfibrils to form cellulose II crystals of antiparallel chains.

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48

Aizawa, Takafumi. "Application of CO2-Assisted Polymer Compression to Polylactic Acid and the Relationship between Crystallinity and Plasticization." Compounds 1, no. 2 (August 4, 2021): 75–82. http://dx.doi.org/10.3390/compounds1020007.

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CO2-assisted polymer compression (CAPC) is an environmentally friendly processing method that uses CO2 to plasticize and crimp polymer fibers at room temperature, enabling low-energy processing within a short time. In this study, CAPC was applied to polylactic acid (PLA), a carbon-neutral polymer. To evaluate the relationships between CO2 plasticization and the crystallinity degree and plasticization of PLA, samples with different degrees of crystallinity were layered and simultaneously compressed to observe the most collapsed layer. The sample with lower crystallinity exhibited better crushing and higher plasticization than the crystallized samples. The PLA with high crystallinity developed cracks on the fiber surfaces with consequent loss of strength. Based on the results, CAPC is a potentially effective method for PLA with low crystallinity.

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49

Katogi, Hideaki, and Kenichi Takemura. "Effect of Crystallinity on Mechanical Properties of Carbon Fiber Reinforced Polypropylene." Key Engineering Materials 577-578 (September 2013): 77–80. http://dx.doi.org/10.4028/www.scientific.net/kem.577-578.77.

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In this study, effect of crystallinity on mechanical properties of carbon fiber reinforced thermoplastics (CFRTP) was investigated. Polypropylene (PP) and maleic anhydride modified polypropylene (MAPP) were used as matrix. The crystallinity of PP was controlled by using heat treatment after hot press molding of CFRTP. The range of crystallinity of PP and MAPP were from 26% to 40%. Flexural tests and izod impact tests of CFRTP were conducted based on Japanese Industrial Standard (JIS) K 7074 and JIS K 7110, respectively. As a result, flexural property and izod impact value of CFRTP using PP increased with an increase of crystallinity. However, flexural property and izod impact value of CFRTP using MAPP almost did not change with an increase of crystallinity.

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50

Tang, Haomiao, Wenbin Wang, Jun Zhou, Tiantian Li, and Zhu Shu. "Optimizing the Crystallinity of Heptazine-Based Crystalline Carbon Nitride by Regulating Temperature for Enhanced Photocatalytic H2 Evolution." Journal of Nanomaterials 2022 (November 18, 2022): 1–12. http://dx.doi.org/10.1155/2022/4923588.

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Polymeric carbon nitride (PCN), as a metal-free photocatalyst, has drawn wide attention in the photocatalytic H2 evolution. However, the photocatalytic activity of directly synthesized PCN is limited by its low crystallinity. Currently, regulating the melon-based PCN into tri-s-triazine-based crystalline PCN to further optimize its structure has been proved to effectively improve its photocatalytic activity. The heptazine-based crystalline carbon nitride, potassium poly(heptazine imide) (abbreviated as K-PHI), has been used in photocatalytic H2 evolution benefiting from its high crystallinity, as the high crystallinity narrows the bandgap and increases the light capture efficiency and increases the charge mobility. Nevertheless, the effect of synthesis temperature on crystallinity has not yet been reported. In this work, the effect of temperature on the crystallinity of heptazine-based crystalline carbon nitride was studied by one-step synthesis at different temperatures. It shows that the heptazine-based crystalline structure appears when the temperature exceeds 540°C. Additionally, the crystallinity of all samples is gradually improved with increasing temperature until the sample begins to decompose beyond 630°C. The sample synthesized at 630°C demonstrates the highest photocatalytic H2 evolution rate of 1.798 mmol h−1 g−1 under visible light irradiation, which is 31.5 times that of bulk PCN. Based on systematic material characterizations, the mechanism of the effect of synthesis temperature on crystallinity and the contribution of crystallinity to photocatalytic efficiency were revealed.

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