【作者】 李敏；

【导师】 李方； 鲁燕萍；

【作者基本信息】 天津大学 ， 材料工程（专业学位）， 2016， 硕士

【摘要】 本文主要是通过种子溶胀和分散聚合两种方法制备交联PS-DVB微球,利用扫描电子显微镜、红外光谱分析、索氏抽提等方法研究了溶胀聚合法中St浓度、PVP用量以及溶剂中乙醇/水对PS微球的粒径和粒径分布的影响,超声时间和St/DVB对交联度的影响以及分散聚合中各反应条件对交联PS-DVB微球形貌、粒径和交联度的影响,并得出以下结论:(1)用分散聚合法制备的PS微球,粒径和粒径分布都随着单体浓度的增加逐渐增加;PVP不是影响微球粒径的主要因素;微球粒径随着溶剂中水的比例的增加而变小,粒径分布小幅度变宽,当水的比例达到30%时,粒径分布明显变宽,甚至发生畸变,制备单分散PS微球要求St浓度在10%~30%以内,PVP的用量在7%~10%以内,溶剂中水的比例不能超过20%。(2)以制备的粒径为2.0μm的PS微球作为种子,通过在二步种子溶胀法中引入超声技术,将溶胀时间从传统的48h缩短到了30h左右,大大缩短了反应时间;超声时间过短或过长都会增大交联PS-DVB微球的粒径分布,在30min左右时单分散性最好。超声小于30min时,微球的交联度随着超声时间的增加有显著提高,超声大于30min后,随着超声时间的增加,交联度基本不变;当St/DVB从5:1增加到11:1时,PS-DVB的交联度从79.48%下降到了64.60%,微球交联度的下降幅度远小于单体中DVB的减少幅度。(3)在乙醇中加入5%的二氯乙烷作溶剂,20%的苯乙烯为单体,利用分散聚合法,在反应开始2.5h后开始滴加DVB,成功的制得了DVB的加入量为6%,平均粒径在7.69μm左右的,粒径分布较窄、表面光滑的单分散交联PS-DVB微球;该聚合过程中齐聚物沉淀机理和接枝共聚物聚合机理同时存在。随着DVB用量或溶剂中二氯乙烷比例的增加,微球的粒径和粒径分布均增加。制备单分散交联PS-DVB微球的最佳St浓度为20%~25%,二氯乙烷比例为5%~10%;单体浓度分别为10%、20%、25%和30%时,对应的开始滴加DVB的最佳时间大约分别为1.5h、2.5h、3h和4.5h。更多还原

【Abstract】 In this paper,the crosslinking PS-DVB micro-spheres were synthesized with the seed swelling method and dispersion polymerization method.The ultrasonic technology was introduced in the seed swelling method to shorten the reaction time.The mixed solution of ethanol/ethylene dichloride was the solvent of the dispersion polymerization.The effects of the the various reaction conditions on the crosslinked PS-DVB microspheres morphology,particle size and the crosslinking degree were studied with scanning electron microscope,infrared spectrum analysis and soxhlet method.The following conclusions were got:(1)The particle size and the size distribution of the PS microspheres synthesized with the dispersion polymerization method were increased with the the increase of St concentration.The influence of PVP on the particle size was very small.When the water was more than 30%,particle size distribution was significantly widen.Monodisperse PS microspheres require the St within 10% ~ 30%,PVP within the scope of 7% ~ 10%,the proportion of water within 20%.(2)The introduction of the ultrasonic technology into the seed swelling method greatly shortened the reaction time.The crosslinking degree of the PS-DVB was higher with the ultrasonic time increasing when the ultrasonic time was less than 30 minutes.But,when it was more than 30 minutes,with the ultrasonic time increasing,the crosslinking degree was remain unchanged.When the St/DVB increased from5:1to 11:1,the crosslinking degree fell from 79.48% to 64.60%.(3)In dispersion polymerization method,when the solvent was ethanol/ethylene dichloride(ethanol:ethylene dichloride=100:5)and St was 20%,monodisperse particles could be obtained containing up to 6 wt % DVB based on styrene and the particle was about 7.69μm by adding DVB into the reaction after 2.5h.The particle size and the size distribution of the crosslinked PS-DVB micro-spheres were both increasing with the increasing of the DVB and ethylene dichloride.The optimum reaction conditions of synthesizing crosslinked PS-DVB micro-spheres was that St was 20%~25%,ethanol/ethylene dichloride was 100/5~100/10.When the monomer concentration was 10%,20%,25% and 20% respectively,the corresponding best time of beginning to add DVB was 1.5h,2.5h,3h and 4.5h.更多还原