【作者】 吕世军；

【导师】 郭睿威；

【作者基本信息】 天津大学 ， 材料学， 2004， 硕士

【摘要】 聚合物聚醚多元醇（POP）是在聚醚多元醇中原位形成微米级聚合物粒子的稳定粒子分散体。本文以苯乙烯和丙烯腈在聚醚中分散聚合制备高固含量（45%）POP，对比研究了间歇、单釜与双釜连续和种子聚合工艺对合成POP性能的影响，探讨了POP稳定、粘度及粒径分布的各影响因素。为考察稳定剂大分子单体结构对POP性能的影响，合成了不同结构的马来酸聚醚酯大分子单体，以GPC、NMR和双键滴定等方法，表征了大分子单体。结果表明大分子单体官能度、分子量是影响其稳定效能的主要因素。并在此基础上合成了四官能度的高效稳定剂，显著降低了其用量和POP的粘度。对比研究了半连续、单釜与双釜连续和种子聚合中各参数对POP稳定性、粘度和分散相粒子粒度分布的影响规律，用SEM和激光粒度仪测定了各条件下分散粒子的形态及分布。研究表明双釜连续与种子法可以有效地加宽POP中粒径分布，降低POP的粘度。在体系稳定条件下，分散粒子的分布宽度和POP中小粒子的多少是控制体系粘度的关键因素，粒径分布越宽POP粘度越低，但小粒子有极强增粘作用。制备大粒径和宽分布的分散相粒子是合成低粘度POP的关键。通过优化聚合条件，采用双釜连续与种子聚合工艺合成了固含量为45%、粘度4700~5200mPa.s(25℃)的POP产品。对双釜连续聚合产物POP中粒度分布的研究表明，在双釜连续聚合时，第二釜存在明显的再成核现象，这种再成核降低了POP中分散粒子的尺寸，产生了大量的细小粒子，不利于降低POP的粘度。减少第二釜的再成核是进一步降低双釜连续POP粘度的关键。更多还原

【Abstract】 Polymer polyol (POP) are stable dispersions of glassy polymers in polyether polyols. In this work, the POP with high solid content of 45% were prepared by dispersion copolymerization of styrene (St) and acrylonitrile (AN) in polyether polyols with polyether meilate-type macromonomer as stabilizer precursor in semi-batch, single- reactor and two-reactor continuous and seeded-batch processes. The stability and viscosity and the distribution of particle size of POP were studied. For the purpose of improving the stabilizing ability of the macromonomer for the POP, various macromonomers were synthesized by reacting various polyethers with maleic anhydride at different temperature, and evaluated for their stabilizing abilities. The results showed that the functionality and molecular mass of macromonomer were the crucial factors for their stabilizing ability.. Therefore, a novel macromonomer with four functionality was synthesized. The effects of polymerization parameters on stability and viscosity of POP were investigated in semi-batch, seeded-batch and continuous processes, respectively, while the corresponding particle shape and size distribution were determined by SEM and laser grading analysis. The results indicated that the polymerization in both particle phase and disperse phase played important roles on the stability and particle number of POP. And that the particle size and distribution were the key factor for controlling the viscosity of POP, wide particle distribution can low the viscosity of POP, while small particles increasing the viscosity of POP. So POP with low viscosity can be obtained in both two-reactor continuous and seeded-batch process, which can produce POP with large particle size with wide distribution. By optimizing, the POP with solid content of 45% and viscosity of 4700mPa.s was obtained. The polymerization mechanism of continuous process was studied. The result indicated that there was the phenomenon of neculation in the second reactor in two-reactor continuous process. The phenomenon can increase the viscosity of POP. So the key factor in two-reactor continuous process was the reducing of neuclation in the second reactor.更多还原