PMMA-b-PS结构及有机累托石对其凝胶聚合物电解质性能的影响

Effects of structure of PMMA-b-PS and nano-organic rectorite on the gel polymer electrolytes

通过原子转移自由基聚合反应(ATRP)合成3种嵌段比不同的聚甲基丙烯酸甲酯-b-聚苯乙烯(PMMA-b-PS),研究其嵌段比例对凝胶聚合物电解质(GPE)电性能的影响。结果发现,以3种嵌段共聚物为基体的GPE导电性均优于纯PMMA基GPE,这可能是因为刚性链段的存在改变了凝胶体系的自由体积;当聚合物含量为40%(质量分数)时,PMMA-b-1PS基GPE的电导率最高。选择电性能较优的PM-MA-b-1PS为基体,研究有机累托石(OREC)对该凝胶电解质(NGPE)性能的影响。在保持凝胶体系固含量为40%(质量分数),OREC添加量为聚合物的3%(质量分数)时,室温下NGPE的电导率达到了3.11×10-4S/cm,约为PMMA基GPE的18倍;热失重分析表明,质量损失5%时,PMMA-b-1PS基GPE热分解温度比PMMA基GPE热分解温度高66.1℃,NGPE的热分解温度相比PMMA基GPE提高了78.0℃。

Polymethylmethacrylate（PMMA）-based gel polymer electrolytes（GPE） have excellent compatibility with electrodes and ion transport property,but the low thermal stability and mechanical strength are still open to improvement.Novel polymer matrixes was compounded and organic rectorite was added to enhance the properties of PMMA-based GPE,with block polymer PMMA-b-PS as the matrixes,propylene carbonate（PC） as the plasticizer and lithium perchlorate（LiClO4） as the electrolyte salt.Three kinds of block polymer,PMMA-b-1PS,PMMA-b-2PS and PMMA-b-3PS were synthesized by atom transfer radical polymerization（ATRP） with different mole ratio of MMA and St varying from 1∶1 to 1∶3.The ion conductivity of GPE membranes was characterized by AC impedance.It was found that all the three types of PMMA-b-PS based GPE have higher conductivity than PMMA-based GPE,in which PMMA-b-1PS based GPE was the best one with the ion conductivity of 5.99×10-5S/cm.A series of PMMA-b-1PS based NGPE membranes were prepared.The microstructure of NGPE was characterized by X-ray diffraction（XRD）.The results of AC impedance indicate that the conductivity of all NGPE are superior to the conductivity of PMMA-b-1PS based GPE without nano-organic rectorite.Typically,the conductivity of NGPE with 3wt% nano-organic rectorite was 3.11×10-4S/cm at room temperature.TGA curves display that the thermal decomposition temperature of PMMA-b-1PS based GPE was 66.1℃ higher than PMMA based GPE when it lost 5% in weight,and the addition of nano-organic rectorite improve the thermal stability of PMMA-based GPE further.