Toughened electrospun nanofibers from crosslinked elastomer‐thermoplastic blends

A crosslink‐able elastomeric polyester urethane (PEU) was blended with a thermoplastic, polyacrylonitrile (PAN), and electrospun into nanofibers. The effects of the PEU/PAN ratio and the crosslinking reaction on the morphology and the tensile properties of the as‐spun fiber mats were investigated. With the same overall polymer concentration (9 wt %), the nanofiber containing higher composition of PEU shows a slight decrease in the average fiber diameter, but the tensile strength, the elongation at break and tensile modulus of the nanofiber mats are all improved. These tensile properties are further enhanced by slight crosslinking of the PEU component within the nanofibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

木粉增强聚丙烯力学性能的改善方法

以废弃木粉为增强材料,制备了木粉增强聚丙烯复合材料,研究了改善废弃木粉增强聚丙烯复合材料力学性能的途径。结果表明,通过适当的处理方法对木粉进行表面处理、对基体树脂进行改性,可以有效地提高复合体系的界面粘接强度,能大幅度改善复合体系的力学性能;采用短切玻璃纤维及玻璃纤维毡与废弃木粉组合,可以获得力学性能很高、能作为结构材料使用的复合材料。     

超临界烯烃聚合

论述了超临界流体对烯烃聚合的影响，总结了超临界聚合技术的研究与应用。认为：在单体临界点以上进行的超临界聚合技术的研究开发已比较成熟；而新近开发的超临界流体介质中的烯烃取合技术更为重要，可以充分发挥超临界技术的优点，提高聚合产率，并能制备性能特殊的取合物。特别是采用超临界CO2为介质的聚合过程，为实现烯烃聚合的绿色生产奠定了基础。     

国内外氟碳粉末涂料的开发现状与发展趋势

论述了国内外氟碳粉末树脂及涂料的开发现状,重点介绍热固性氟碳粉末树脂和涂料,比较了热塑性氟碳粉末涂料和热固性氟碳粉末涂料的性能及应用领域,指出今后氟碳粉末涂料的发展方向。     

Thermoplastic extrusion—the mechanism of the formation of extrudate structure and properties

Systems processed by thermoplastic extrusion can be regarded as heterophase polymer melts of incompatible water-plasticized biopolymers. In the process of thermoplastic extrusion, proteins and polysaccharides are melted at high pressure and temperature below the temperature region of their thermal decomposition. Dispersed particles of these systems can be deformed in flow. The mixed-melt anisotropic structure, formed in flow, is fixed by rapid conversion of the melt jet that lets the extruder die from a viscous state to a rubber-like state and then to a glassy state caused by cooling and drying. Incompatibility of proteins and polysaccharides in their water-plasticized melt mixtures impacts on structure formation and texturization during thermoplastic extrusion. Presented at the 20th ISF World Congress and 83rd AOCS Annual Meeting and Expo, May 10–14, 1992, Toronto, Ontario, Canada.     

Morphology of epoxy resin modified with silyl‐crosslinked urethane elastomer

Silyl‐crosslinked urethane elastomer modifying epoxy resin has drawn much interest. Here the triethoxysilyl‐terminated polycaprolactone elastomer (PCL‐TESi) modifying diglycidylether of bisphenol A epoxy resins (DGEBA) system was chosen, and then the effect of the type of curing agent on the phase structure of the studied epoxy resin system was investigated. The modified systems were obtained with different phase structures by varying the formulations of the curing agent. It was experimentally shown that with the addition of aminosilane (KBE‐9103), the crosslinked density was greatly increased. The cured system also showed from SEM and TEM analysis that addition of KBE‐9103 increased the compatibility between the PCL‐TESi and DGEBA, which made the ductility of the system decrease, but also indicated from TEM that addition of much KBE‐9103 made the reacted silicone particles coagulate each other. The state of phase separation from TEM in the cured system was theoretically explained. These would serve the deeper studies of the mechanism of silyl‐crosslinked urethane elastomer modifying epoxy resin in the future. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 611–619, 2005     

环氧胶粘剂增韧改性研究进展

概述了关于近些年环氧树脂以及环氧树脂胶粘剂增韧改性的研究进展情况,简单地介绍了以无机刚性填料(颗粒)增韧改性环氧胶粘剂的情况,比较详细地叙述了以橡胶弹性体和热塑性树脂增韧改性环氧胶粘剂的一些重要研究情况及相关的增韧机理,指出了国内外之间环氧胶粘剂发展的差距,同时提出了环氧胶粘剂将来的重点和发展趋势。     

弹性条缝筛网用聚氨酯弹性体的研制

采用预聚法常压浇注制备煤矿用聚氨酯筛网，考察了聚醚多元醇、甲苯二异氰酸酯异构体种类、预聚体的NCO质量分数、扩链反应温度、后熟化温度及时间等条件对制筛网用的浇注型聚氨酯弹性体体系操作性能及物理性能的影响。实验表明，采用聚四氢呋喃二醇与聚氧化丙烯二醇的混合二醇(质量比为80：20)，制得的预聚体NCO质量分数控制在4．5％左右；再以MOCA和一种三官能度扩链剂的混合扩链剂进行扩链，制得的浇注型聚氨酯弹性体满足洗煤用筛网的性能要求。     

Synthesis and Characterization of Segmented Block Copolymers Based on Hydroxyl‐Terminated Liquid Natural Rubber and α,ω‐Diisocyanato Telechelics

Summary: Segmented block copolymers, consisting of non‐polar soft segments from hydroxyl‐terminated liquid natural rubber (HTNR) and polar hard segments from α,ω‐diisocyanato telechelics obtained by “criss‐cross”‐cycloaddition, have been synthesized. The block copolymer formation took place under relatively mild reaction conditions at 80 °C in dichloroethane in the presence of dibutyltin dilaurate as a catalyst. The resulting block copolymers were characterized by spectroscopic techniques (¹H NMR, FTIR, UV‐vis spectroscopy) as well as GPC for molar mass determination. The block copolymers were compression molded in a hot stage press, and the resulting samples were characterized by DSC and stress‐strain measurement. The solubility and phase morphology of the materials have also been studied.

Segmented block copolymer from HTNR and α,ω‐diisocyanato telechelics     

废弃木粉与短切玻璃纤维组合增强聚丙烯的力学性能

用废弃木粉与短切玻璃纤维作为增强材料，制得了组合增强的聚丙烯复合材料，研究了制备工艺及设备、材料配方及界面改性方法等对材料力学性能的影响。结果表明，用单螺杆挤出机制备组合增强材料，可减少对玻璃纤维的损伤，保持较长的玻璃纤维，有利于其增强作用的发挥；随着玻璃纤维含量的增加，体系的力学性能提高，而木粉含量对材料力学性能的影响与玻璃纤维的含量相关；采用硅烷偶联剂对木粉进行表面处理，在基体中添加接枝极性基团的改性聚丙烯，可改善体系的界面结合，提高力学性能。