水体系中原子转移自由基聚合法制备纳米复合乳液的研究

发布时间：2018-04-18 13:51

  本文选题：ATRP + 纳米复合微粒　； 参考：《河北科技大学》2011年硕士论文

【摘要】：原子转移自由基聚合(ATRP)技术作为一种新颖的聚合方法,是实现“活性”/可控聚合的有效途径,将ATRP技术用于无机纳米粒子的表面接枝聚合改性,既能充分发挥“活性可控”的特点,又能使产物兼具有机/无机材料的特点。 本研究首先以水为反应介质,通过细乳液聚合工艺采用原子转移自由基聚合法制备了分子量分布窄的聚合物粒子。研究了水体系中的原子转移自由基聚合工艺,探讨了可控反应机理并考察了其反应特点；研究了不同类型乳化剂、不同分子结构的配体对水体系ATRP反应稳定性和可控性的影响；优化了水体系中ATRP反应的工艺条件和工艺参数。结果表明：采用细乳液工艺进行ATRP反应要比常规乳液体系中的可控性较好；催化剂在油水两相中的分配对反应的可控性有较大的影响；当采用非离子型乳化剂TW-80时,其乳化剂用量为15.4%(g/g-St)、助乳化剂用量为3%、催化体系(CuCl/dNbpy)的用量为0.15(mol/mol-St),反应温度为75℃时,反应体系的稳定性及可控性较好,并且聚合物的分子量随单体转化率的增大呈线性增长趋势,分子量的大小可通过单体与引发剂的比例来调控。通过GPC、FI-IR、TEM、SEM、激光粒度分布仪、TGA等对所制备的聚合物进行了表征,结果表明：聚合物的分子量分布较窄(Mw/Mn=1.32),乳胶粒粒径分布均匀约为200nm左右,为规则的球形。 在上述工艺研究基础上,采用原子转移自由基聚合法制备了纳米SiO2/PSt复合乳液粒子。首先对纳米粒子表面进行了改性,将ATRP引发剂接枝到纳米粒子表面,采用ATRP法制备了接枝型纳米SiO2/聚合物复合粒子,并对其进行了分析表征,结果表明：硅烷偶联剂分子可与纳米SiO2表面的羟基反应,其改性和接枝的温度分别为65℃和70℃,负载率和接枝率最高分别可达到21%和12%；当SiO2-Cl与单体的用量比例为0.06(g/g)、反应温度为75℃时,所合成的接枝型纳米SiO2/PSt复合乳液的转化率为85%,接枝效率最高可达81%,复合乳液稳定性较好,其聚合物的分子量分布较窄(Mw/Mn=1.34)。通过TGA分析,纳米SiO2/PSt的热分解温度要比纯聚苯乙烯的热分解温度高约40℃,可有效地提高材料的耐热性能。
[Abstract]:As a novel polymerization method, atom transfer radical polymerization (ATRP) is an effective way to realize "active" / controllable polymerization. ATRP technology is used to modify the surface of inorganic nanoparticles by grafting polymerization.It can not only give full play to the characteristics of "activity controllable", but also make the product have the characteristics of organic / inorganic materials.In this study, polymer particles with narrow molecular weight distribution were prepared by atom transfer radical polymerization with water as reaction medium.The atomic transfer radical polymerization process in water system was studied, the controllable reaction mechanism and reaction characteristics were investigated, the effects of different emulsifiers and ligands with different molecular structures on the stability and controllability of ATRP reaction in water system were studied.The process conditions and parameters of ATRP reaction in water system were optimized.The results show that the ATRP reaction with fine emulsion process is better than that in the conventional emulsion system, the distribution of catalyst in oil-water phase has a great influence on the controllability of the reaction, and when the non-ionic emulsifier TW-80 is used, the controllability of the reaction is greatly affected by the distribution of catalyst in the oil-water two-phase system.The amount of emulsifier is 15.4g / g-Sti, the dosage of co-emulsifier is 3um, the amount of catalytic system CuCl-dNbpyy is 0.15kmol / mol -Sti, the reaction temperature is 75 鈩，

本文编号：1768631