【作者】 张贺；

【导师】 黄志明；

【作者基本信息】 浙江大学 ， 化学工程， 2004， 硕士

【摘要】 针对聚丙烯（PP）粘合性差、纤维较难染色、低温呈脆性、收缩率大等缺陷，本文采用工艺简单、污染较少的水相悬浮法对等规聚丙烯（IPP）进行氯化改性，探讨氯化机理并建立动力学模型，研究氯化工艺规律，为工业制备氯化等规聚丙烯（CIPP）树脂打下基础。 聚丙烯在水中的良好分散是水相悬浮氯化法的必要条件。500mL玻璃釜中的分散研究表明，降低氯化温度、提高搅拌转速，减小固液比、增加PP粒径和分散剂用量都有助于聚丙烯在水相中的悬浮分散。在一定温度和固液比下，存在着上、下两临界搅拌转速。低于下临界转速时，即使加分散剂也不能使PP在水中分散；高于上临界转速时，无需加分散剂，单靠搅拌所提供的剪切力就足以使PP在水中分散；在氯化时，应使搅拌转速高于下临界转速。离子型表面活性剂十二烷基苯磺酸钠优于十二烷基硫酸钠和非离子型表面活性剂聚乙烯吡咯烷酮。 聚丙烯的热氯化属自由基链式反应，在消除外扩散影响以后，水相悬浮氯化过程可分为表面反应控制和内扩散控制两阶段，并建立了相应的动力学模型：和。由于等规聚丙烯的高规整性和高结晶度，整个氯化过程受内扩散过程控制，氯化程度从粒子表层到中心递减。 PP等规度越低、熔融指数越高、粒径越小、PP接枝马来酸酐（MAH），氯化速率越快、氯含量越高、氯化越均匀。体系添加惰性溶胀剂、粉碎和氯化交替进行增强粒子的表面更新能促进氯化，提高了产物CIPP的氯含量及均匀性、溶解性能。金属离子的存在则抑制氯化。添加分散剂、提高通氯速率和搅拌转速，可以强化氯气在气液相的传质扩散，消除外扩散的影响。温度的提高有助于氯自由基的产生和反应活性的提高，而且能加快气体扩散传质的速度。但温度也不能过高，否则容易发生副反应，聚丙烯容易降解，氯气在水中的溶解度会减少，不利于反应和产品性能。采用热引发的方式，氯化前期表面反应的活化能E=30.69kJ／mol，频率因子A=3.015s^-1。紫外光照和热同时引发IPP时，能促浙江大学硕士学位论文进氯化，提高了产物氯含量，连续光照优于间歇光照。表面反应控制阶段，其活化能E=28.10IcJ/mol，指前因子A=51.025一’。 从结构、熔点、结晶度、溶解性能和降解等方面对氯化聚丙烯的性能进行了表征，发现随着氯化程度的深入，等规聚丙烯三种氢的取代顺序为仲氢、叔氢和伯氢，a晶型没有变化，但是结晶度逐渐减小，熔点缓慢降低。在氯含量约为63%时，结晶破坏完全，能全溶于甲苯溶剂（20w七%）。与IPP相比，CIPP的热稳定性降低，在空气环境中容易降解变色。更多还原

【Abstract】 Chlorinated isotatic polypropylene (CIPP) is a modified product of. polypropylene (IPP) and has better adhesion and fire resistance. This paper was devoted to the chlorination of IPP by aqueous suspension process, which was simple and produced little pollution. The chlorination laws were investigated and the chlorination mechanism and kinetics model were proposed. The results will provide the basement for industrial preparation of CIPP.Chlorination of IPP in aqueous suspension required well dispersion of IPP in water. Study of aqueous dispersion in 500mL flask showed that reducing temperature and solid/liquid ratio, rising agitation speed and particle size benefited aqueous dispersion of IPP. When temperature and solid/liquid ratio were fixed, the system had upper and lower critical agitation speeds. Dispersants had no function on aqueous dispersion of IPP when the agitation speed was less than lower critical agitation speed. IPP could be well dispersed in water with no surfactants by agitation when the agitation speed was greater than upper critical agitation speed. So, agitation speed should be greater than lower critical agitation speed in chlorination process. The dispersion effect of sodium dodecyl benzyl sulfate (SDBS) was better than that of sodium dodecyl sulfate (SDS) and polyvinyl pyrrolidone (PVPP).The thermal-initiated chlorination process of IPP could be divided into two steps: surface reaction-control stage (about within 1hr) and ash layer diffusion-control stage (about after 1hr). A surface reaction-control model and a ash layer diffusion-control model were proposed and conversion equations were obtained:chlorination process was controlled by ash layer diffusion. The chlorine content decreased from particle surface to center.The chlorination rate and uniformity could be improved by decreasing the actic index, molecular weight and particle size of IPP, and surface grafting of MAH onto IPP. Adding of inertia swelling agent, and alternate crushing and chlorination, could accelerate particle surface renewal and increase the chlorine content, uniformity and solubility of products. Metal ion inhibited the chlorination. Adding of dispersant, raising the feeding rate of chlorine and agitation speed could promote diffusion ofchlorine in gas and liquid phase and remove the effect of outer diffusion. Higher temperature benefited producing of chloride radicals, rising of reaction activity and chlorine diffusion. Too high temperature could facilitate the degradation of IPP and reduce product property. The activation energy E was 30.69 kJ/mol and thefrequency factor A was 3.015 s-1 in the surface reaction stage under thermalinitiation. Both UV-photo and thermal initiation could promote chlorination. Continuous lighting was better than intermittent lighting. E=28. 10kJ/mol and A =51.02 s-1 in the surface reaction stage under both UV-photo and thermal initiation.The structure, melting point, crystallization degree, solubility and degradation of CIPP were studied. The results showed that p-, s- and t- hydrogen were substituted in turn as the chlorination proceeded, a crystal wasn’t destroyed, but the crystallization degree decreased and melting point reduced gradually. Crystal was destroyed completely and CIPP could be dissolved in methylbenzene (20wt%) when the content of chlorine of CIPP achieved 63%. The thermal stability of CIPP decreased, and it was easy to degradate, as chlorine content increased.更多还原