PMMA增韧PVC/ABS共混物共混工艺的探讨

初步探讨了不同的共混工艺过程对增韧效果的影响，结果表明，先ABS和PMMA共混，再加入PVC共混，增韧效果最佳，加工性能和热稳定性均有不同程度的提高。     

无机纳米粒子SiO2增韧增强PVC的性能

通过偶联剂处理及用球磨机混合方法使纳米SiO2在基体均匀分散，制备出纳米SiO2／PVC复合材料。利用冲击、拉伸测试测定纳米SiO2对复合材料力学性能的影响。实验结果表明，纳米SiO2起到了增韧、增强PVC的作用。     

纳米复相陶瓷刀具性能研究

纳米复相陶瓷刀具材料的研究成功有望从根本上解决陶瓷材料的脆性问题,比起传统陶瓷刀具材料,它具有更高的抗弯强度、断裂韧性等力学性能。本文介绍纳米复相陶瓷的增韧补强机理;对研制高性能纳米陶瓷刀具材料需考虑的主要因素进行了探讨。     

增韧陶瓷的设计

陶瓷作为一种新材料已广泛应用于各个领域。为了进一步改善陶瓷材料的性能使其增韧化、高强化，文章介绍了增韧陶瓷材料的设计开发现状及发展前景。     

聚苯乙烯增韧的新机理

采用种子乳液聚合法合成了丁苯橡胶接枝聚苯乙烯（SBR－g-PS）共聚物，将其与高抗冲聚苯乙烯（HIPS）共混，研究了共混物的力学性能和微观形态结构。结果发现，SBR－g-PS共聚物能均匀地分散于HIPS基体中，其粒径尺寸约为0．05－0．015μm，HIPS中原有的尺寸为1－4μm的大橡胶子未受破坏，形成了大小两种橡胶粒子共存的结构。共混物的冲击强度和断裂伸长率均较HIPS进一步提高，而屈服强度未表现出明显下降，获得了良好的综合力学性能，这表明大小两种橡胶粒子具有显著的协同增韧作用。提出了HIPS的脆－韧转变模型和聚苯乙烯（PS）增韧的新机理，即HIPS中的大橡胶颗粒引发了大量的银纹，使相邻银纹间的“基体层”变得很薄，分散于HIPS基体中的SSBR－g-PS橡胶小粒子促进了这些很薄的基体层发生屈服形变，从而吸收了大量的断裂应变能，有效地实现了对HIPS的进一步增韧。     

核壳胶粒增韧改性聚丙烯研究3. 冲击断裂行为和增韧机理

用扫描电子显微方法研究了核壳胶粒与聚丙烯 ( PP)反应共混物试样的冲击断裂行为 .通过对冲击断裂表面分区显微分析 ,揭示了冲击断裂的断面形态和形变特征 .结合冲击测试实验数据和断面显微分析结果 ,对核壳胶粒增韧改性 PP的增韧机理作了探讨 .结果表明 ,PP断面上可以区别出以银纹化机理为主的脆性断裂特征和以剪切屈服为主的韧性断裂特征 ,提高试样冲击断裂韧性主要是基体聚合物的剪切屈服 ,同一断面上可以同时出现脆性断裂与韧性断裂的断裂特征 ;核壳胶粒改性 PP共混物的增韧机理是核壳橡胶粒子的空穴化和 PP基体的剪切屈服     

Effect of Unplasticized Poly Vinyl Chloride (UPVC) Molecular Weight and Graft-Acrylonitrile-Butadiene-Styrene (g-ABS) Content on Compatibility and Izod Impact Strength of UPVC/g-ABS Blends

In this study three grades of rigid poly vinyl chloride (PVC) having different molar masses were melt blended with graft-acrylonitrile-butadiene-styrene (g-ABS) in different compositions. The effect of PVC molecular weight and g-ABS composition on the compatibility and Izod impact strength of the blends were investigated. Differential scanning calorimetry (DSC) results showed a single glass transition temperature (T_g) for all the blends, representative of miscibility between the PVC phase and the styrene-acrylonitrile copolymer (SAN) phase of g-ABS which, in turn, led to compatibility of the PVC/g-ABS blends. It was observed that in all the PVC grades the blends Izod impact strength increased with increasing g-ABS content. Also, at a given composition of g-ABS, by increasing the molecular weight of the PVC phase the impact strength of the blends increased. The morphology of the fracture surfaces from the impact tests were analyzed using scanning electron microscopy (SEM) micrographs and the results showed that with increasing g-ABS content in the blend, cloudy regions increased and eventually begin to overlap each other, and the deformed material on the fracture surfaces increased. This was attributed to the blend compatibility causing greater energy dissipation in the fracture process.     

线性聚酯酰胺对聚碳酸亚丙酯的改性

通过己内酯和氨基己酸开环、缩合反应制备了酯段含量为81%的线性聚酯酰胺（PEA）,并用熔融共混的方法制备了PEA/聚碳酸亚丙酯（PPC）共混物,考察了PEA的引入对共混体系相容性、热力学稳定性和机械性能的影响。 结果表明,PEA与PPC之间有较好的相容性,共混物的热力学稳定性比PPC有显著提高,当PEA质量分数为3%时,共混体系的起始分解温度（T-5%）和最大分解速率时的温度（Tmax）比PPC分别提高了52.7%和46.4%。 通过调节PEA的含量可以使共混体系同时达到增强和增韧的效果。     

Ce—TZP陶瓷材料马氏体相变内耗的研究

本文观察了Ce—TZP陶瓷材料马氏体相变内耗的现象,发现加入13mol％的CeO_2能使ZrO_2的正逆马氏体相变点分别降至203k和243k,而且使ZrO_2马氏体相变的滞后现象减小。观察到在对应的内耗峰附近有软模现象发生,从而推断Ce—TZP相变增韧陶瓷材料的马氏体相变可能是外力感生界面上位错的运动而引起的。     

A novel staining technique for studying toughening mechanisms in saturated acrylic rubber-modified polymers

A novel technique which utilizes a two-stage staining approach, (i.e., styrene absorption followed by osmium tetraoxide staining) is introduced for staining saturated polyacrylate rubbers. This novel staining approach, which stains and hardens polyacrylate rubber, is found to be useful for room temperature microtomy of polyacrylate rubber-modified polymers. Therefore, both the morphology and the crack tip toughening mechanisms of polyacrylate rubber-modified systems can be studied. Details concerning staining time, staining media, and use of solvents are discussed.