共查询到20条相似文献,搜索用时 125 毫秒
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采用偏光显微镜对聚丁二酸丁二醇酯(PBS)的结晶影响因素进行了研究。结果表明:在等温结晶时,PBS的最佳结晶温度随着分子量的增大而提高,当分子量增到一定值后,最佳结晶温度受分子量的影响很小。结晶温度一定时,PBS的晶体尺寸随着结晶时间的延长而增大。结晶时间一定时,PBS的晶体尺寸随着结晶温度的提高而先增大后减小。数均分子量为1×103、8×103、6×104、1×105的PBS最佳结晶温度分别为40℃~50℃、80℃、80℃、90℃。低分子量的PBS在较短的结晶时间内晶体尺寸就已较大,而高分子量的PBS在较长的时间内才能形成较大尺寸的晶体,数均分子量为8×103、6×104、1×105的PBS在最佳结晶温度形成较好结晶的时间分别为10min、20min、25min。 相似文献
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王锦燕;孙玉周;李冬霞 《中国塑料》2011,25(8):14-18
介绍了有关聚合物流动诱导结晶的研究工作,以及剪切诱导条件下结晶动力学、结晶形态学和结晶对材料流变参数的影响这三方面的主要研究模型,并进行了比较和讨论。 相似文献
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工业结晶的现在与未来 总被引:18,自引:0,他引:18
本文综述了工业结晶技术与设备的新进展,特别介绍了自溶液结晶与自熔融物系结晶装置的研制与工业应用的现状,并对国内外发展状况进行了简单的比较。同时展望了工业结晶未来的发展动向。 相似文献
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磁场影响溶液结晶过程研究进展 总被引:1,自引:0,他引:1
论述了磁场对溶液结晶过程影响的研究进展情况,指出磁场不仅可以化溶液结晶过程,刺激结晶成核,提高结晶生长速率,控制晶体粒径的分布,也可抑制溶液的结晶,降低结晶生长速率。针对不同的工程目的,选择合理的磁处理参数显得尤为重要。并提出磁场技术目前存在的问题和展望。 相似文献
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The effect of the cooling rate of melts of pyroxene waste from the Koitashskoe ore field on the type of crystallization is demonstrated. It is established that pyroxene skarn melts have sufficiently high crystallization capacity and with additional introduction of crystallization stimulators can be used in production of glass ceramics with a finely disperse structure. 相似文献
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分类讨论了目前萃取结晶技术在无机盐及有机物分离领域中的应用现状、发展趋势和相应的分离原理,概括得到萃取结晶的一般原理。与传统的蒸发、结晶过程相比,萃取结晶技术具有很多优势,必将得到更大的发展。 相似文献
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Magnetic influence on the crystallization and orientation of poly(trimethylene terephthalate) (PTT) were studied by Fourier
transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD) during isothermal
crystallization at 195 °C under pulsed magnet. The results showed that the crystallization properties of PTT are changed under
the influence of pulsed magnetic field. It should be emphasized that the pulsed magnetic field can be applied as a new method
to control the crystallization and orientation of polymers. 相似文献
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介绍了聚合物在力场作用下结晶行为的研究进展;概述了不同力场(剪切、拉伸、振动)对聚合物结晶形态和结晶动力学的影响;重点论述了剪切力场下,剪切速率、剪切方式、分子量和分子量分布等对聚合物成核和生长的影响,简述了拉伸、振动对结晶的影响。认为力场的加入对聚合物的成核和晶体生长都有促进作用。 相似文献
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H. Habazaki T. Ogasawara K. Fushimi K. Shimizu S. Nagata T. Izumi P. Skeldon G.E. Thompson 《Electrochimica acta》2008,53(28):8203-8210
The present work demonstrates effective inhibition of field crystallization of amorphous anodic niobium oxide by incorporation of silicon species from substrate. The field crystallization, detrimental for capacitor application of niobium, occurs during anodizing of magnetron sputtered niobium at 100 V in 0.1 mol dm−3 ammonium pentaborate electrolyte at 333 K, while amorphous structure of the anodic oxide is totally retained during anodizing of magnetron sputtered Nb–12 at%Si. Even after prior thermal treatment in air, which accelerates field crystallization of anodic oxide on niobium, no crystallization occurs on the Nb–12 at%Si. Through examination of the crystallization behaviours of anodic films formed on a thin Nb–12 at%Si layer superimposed on a niobium layer as well as on a thin niobium layer superimposed on an Nb–12 at%Si layer, it has been confirmed that air-formed oxide or thermal oxide becomes a nucleation site for crystallization. Modification of the air-formed or thermal oxide by incorporation of silicon species inhibits the nucleation of crystalline oxide. The modification, however, does not influence the growth of crystalline oxide. The growth is suppressed by continuous incorporation of silicon species into anodic film from the substrate during anodizing. 相似文献
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The crystallization in flow of various 1,4-cis-polybutadienes, including an extremely high cis-polybutadiene content obtained with uranium catalyst, has been studied in a capillary rheometer. The influence on the crystallization in flow of temperature, pressure, shear rate has been investigated and compared with the conditions in the flow field of a roll-mill. It is shown that when these conditions are suitable for inducing, the crystallization of the rubber, the processability at the roll-mill is substantially improved. The molecular weight distribution plays only a minor role for the highest cistactic polybutadienes. The reason of the correlation between crystallization and roll-mill processability is briefly discussed. 相似文献