The effects of ultrasonic irradiation on extrusion processing and crystallization behavior of polypropylene (PP) are examined. The results show that appropriate irradiation intensity can prominently decrease die pressure and apparent viscosity, increase output, reduce extrudate swell, and improve apparent quality of PP. DSC and WAXD analysis demonstrate that the crystalline structure of PP is changed and the content of the pcrystalline increases through ultrasonic vibration. Special effects can be induced by ultrasound, such as strong stress, shatter and vibration, which alter the growth of PP crystals and may favor a special crystal transformation -j PI.

采用动态激光光散射及环境扫描电镜研究了羧甲基纤维素系列高分子表面活性剂与大庆原油形成超低界面张力的机理。 结果表明, CMC系列高分子表面活性剂具有与低分子量表面活性剂相比拟的表/界面活性, 其水溶液的表面张力可达2835mN/m, 界面张力达到10-110mN/m。 碱的加入可显著降低高分子表面活性剂与原油的界面张力, 在适当条件下界面张力达到超低值(10-3mN/m), 可望作为三次采油的驱油剂。等效烷烃模型研究表明, 用碱与原油酸性组分的作用来解释碱能使界面张力下降至超低值的传统观点是不完善的, 加入碱能使高分子表面活性剂胶束解缔, 胶束数量增多, 胶束粒径减小, 单分子自由链增加, 有利于高分子表面活性剂向界面迁移和排布, 这是高分子表面活性剂和碱复配体系与原油界面张力下降至超低值的主要原因。

采用紫外光谱、相图、动态激光光散射、同位素示踪、光学显微镜、电导率等研究了羧甲基纤维素系列高分子表面活性剂与甲苯-水-异丙醇体系微乳液的形成过程, 发现微乳液粒子大小均一, 形态一致, 其尺寸比低分子表面活性剂所形成的微乳液粒子大得多。 醇分子插入到油水界面, 改变了两相界面结构, 促使微乳液的生成。电导率测定表明所形成的微乳液区均为水包油结构, 即使在富含甲苯区域, 亦不会有油包水的反相胶束形成。

The thermooxidative degradation of poly-(oxymethylene) copolymer (CPOM-Y) powder was studied in air in 150

The processing of ultrahigh molecular weight polyethylene (UHMWPE) by the addition of polypropylene (PP) and high-density polyethylene (HDPE) was investigated. The results show that the addition of PP improves the processability of UHMWPE more effectively than does the addition of HDPE. UHMWPE/PP blends can be effectively processed with a twin-roller and general singlescrew extruder. In the extrusion of UHMWPE/PP blends, PP is enriched at the surface of the blend adjacent to the barrel wall, thus increasing the frictional force on the wall; the conveyance of the solid down to the channel can then be carried out. The melt pool against the active flight flank exerts a considerable pressure on the UHMWPE powder in the passive flight flank, which overcomes the hard compaction of UHMWPE. The PP penetrates into the gaps between the particles, acting as a heat-transfer agent and adhesive, thus enhancing the heat-transfer ability in the material.