NR/HDPE 共混热塑性弹性体的结构与性能研究

用抽提法、流变仪、示差扫描量热仪、热重法、动态粘弹谱仪、扫描电镜等仪器研究了ＮＲ／ＨＤＰＥ共混热塑性弹性体（ＴＰＥ）的结构与性能。实验结果表明，动态和静态硫化共混物的交联程度相近。控制ＮＲ的交联程度可改善共混物的流动性。ＮＲ／ＨＤＰＥ共混热塑性弹性体中、ＨＤＰＥ结晶度则随ＮＲ的增加而略微降低。只要ＨＤＰＥ足以包裹胶胶粒子就可以形成连续相。动态硫化增加了共混物中ＮＲ与ＨＤＰＥ相界面间的结合力。     

端羟基聚乳酸改性HTPB/液化MDI型聚氨酯的研究

用液化改性MDI、丁羟胶(HTPB)和端羟基聚乳酸(PLA-OH)为原料，合成一系列不同结构的聚氨酯弹性体，并对这些聚合物进行了红外结构、力学性能、热稳定性的研究，初步探讨了其在37℃KH2PO4-Na2HPO4缓冲溶液(pH=7．0)中的降解性能。     

TiO2增强聚氨酯弹性体的制备和表征

采用三步法合成了金红石型TiO2-R和锐钛矿型TiO2-A增强聚氨酯弹性体。用GPC、DSC、SEM等技术对增强聚氨酯弹性体进行了表征,并测试了其力学性能。结果表明,TiO2-R仅作为聚氨酯弹性体的硬链段成核剂;TiO2-A不仅作为硬链段成核剂,而且还参与聚氨酯的链增长反应,聚氨酯在TiO2-A表面缠绕使其在聚氨酯弹性体中分散不均匀,TiO2-A增强聚氨酯弹性体的性能低于TiO2-R。当TiO2-R在聚氨酯弹性体质量分数为4％～5％时,TiO2-R增强聚氨酯弹性体性能达到最优。     

动态硫化法制备三元乙丙橡胶/聚酰胺热塑性弹性体

采用动态硫化技术制备了三元乙丙橡胶(EPDM)／聚酰胺(PA)热塑性弹性体,研究了增容剂种类及用量、硫化体系及其用量、加料顺序、PA用量对其性能的影响,用扫描电镜分析了其相态结构。结果表明,用13份(质量份,下同)的氯化聚乙烯作为增容剂时,对该共混体系的增容效果最好;硫黄硫化体系是EPDM／PA热塑性弹性体的最佳硫化剂,当硫黄用量为2份时,既保证了该热塑性弹性体中的橡胶相能充分交联,又可避免过硫化对产品性能造成的负面影响;PA用量为35份的EPDM／PA热塑性弹性体具有良好的力学性能、耐溶剂性能和耐热老化性能;EPDM以平均粒径为2～5μm的粒子形态均匀分布于PA连续相中。     

对位芳香族聚酰胺纤维及其增强复合材料的发展

介绍了对位芳香族聚酰胺纤维(对位芳纶)特别是聚对苯二甲酰对苯二胺纤维的国内外发展情况,包括纤维品种、产量、性能和该类纤维作为先进复合材料骨架的发展情况。指出我国发展包括芳纶Ⅲ在内的对位芳纶产业的必要性和紧迫性,以及芳纶表面改性、树脂基体及增强复合材料的研究重点和方向。     

用双螺杆挤出机进行熔体扩链的PUR-T结构与性能研究

以预聚物为扩链剂,用双螺杆挤出机在熔融状态下对热塑性聚氨酯弹性体(PUR—T)进行熔体扩链．用热重分析仪、动态热机械仪、差示扫描量热仪和扫描电镜研究了扩链后PUR—T的形态结构、拉伸性能、回弹性、热降解稳定性、热转变和动态力学性能。结果表明,用双螺杆挤出机进行熔体扩链是可行的,而且扩链后的PUR—T性能较扩链前优异。     

Structural characterization of reactor blends of polypropylene and ethylene‐propylene rubber

Blends of isotactic polypropylene (PP), ethylene‐propylene rubber copolymer (EPR), and ethylene‐propylene crystalline copolymer (EPC) can be produced through in situ polymerization processes directly in the reactor and blends with different structure and composition can be obtained. In this work we studied the structure of five reactor‐made blends of PP, EPR, and EPC produced by a Ziegler‐Natta catalyst system. The composition of EPR was related to the ratio between ethylene and propylene used in the copolymerization step. The ethylene content in the EPR was in the range of 50–70 mol %. The crystallization behavior of PP and EPC in the blends was influenced by the presence of the rubber, and some specific interactions between the components could be established. By preparative temperature rising elution fractionation (P‐TREF) analysis, the isolation and characterization of crystalline EPC fractions were made. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2155–2162, 2004     

Surface characterization of cross-linked elastomers by shear modulation force microscopy

Brominated poly(isobutylene-co-4-methylstyrene) (BIMS) is a synthetic terpolymer which can be stoichiometrically cross-linked by N,N′-dicinnamylidene-1,6-hexanediamine (DIAK). The degree of cross-links on bulk samples was determined by measuring the low frequency shear modulus with parallel plate method. The surface modulus of the same samples was measured using a new method, shear modulation force microscopy (SMFM). The moduli of the bulk sample and the surface were found to have the same scaling with the cross-link density, and good agreement with rubber elasticity theory was obtained in both cases. The SMFM was then used to monitor the cross-linking process, as a function of DIAK concentration and curing time, in thin films where standard rheological methods cannot be applied. The results show that in all cases the cross-linking reaction at the surface reaches saturation in less than 10 min as compared to at least 1 h in the bulk samples.     

动态硫化聚氨酯/硅橡胶热塑性弹性体研究进展

从原料选择、加工工艺和增容剂方面总结了动态硫化聚氨酯/硅橡胶热塑性弹性体的研究进展。     

铁路废弃聚酰胺部件回收再生利用

通过采用长度为4.5 mm、直径为10 μm的玻璃纤维和马来酸酐接枝聚烯烃弹性体（POE⁃g⁃MAH）增韧剂且添加量为10 %时所制得的再生聚酰胺部件产品尺寸和性能指标满足要求,且部件具有良好的尺寸稳定性等,部件经组装疲劳性能测试后未发生损坏,各项组装性能均满足要求。结果表明,废弃聚酰胺部件经过收集、破碎、清洗、改性等工序后可成为良好的可再生资源,可继续应用于铁路市场。