醚链改性聚环氧乙烷的合成及性能研究

Synthesis and Properties of Ether Chain Modified Poly(ethylene oxide)

考察烷基磷酸铝催化剂i-Bu_(3)Al/H_(3)PO_(4)/DBU催化环氧乙烷(EO)、甘醇甲基缩水甘油醚(nGE)与烯丙基缩水甘油醚(AGE)二元及三元共聚合的催化性能,通过核磁共振波谱(NMR)、凝胶渗透色谱(GPC)和示差扫描量热仪(DSC)对共聚物微观结构和热性能进行表征分析。结果表明25℃甲苯溶剂中,i-Bu_(3)Al/H_(3)PO_(4)/DBU催化剂可以高效催化不同比例的EO、nGE和AGE共聚合,以100%收率获得组成精确可控的高分子量EO-nGE二元及EO-AGE-nGE三元无规共聚物;nGE的醚链长度对聚合性能无影响,二甘醇甲基缩水甘油醚(2GE)和四甘醇甲基缩水甘油醚(4GE)均可实现可控引入聚环氧乙烷制备醚链改性聚环氧乙烷。EO-AGEnGE三元共聚物以1,2-乙二硫醇为交联剂制备了交联聚合物。测试醚链改性聚环氧乙烷的性能,发现醚链长度、含量及交联对聚合物电导率和力学性能有很大影响。4GE为共聚单体的聚环氧乙烷电导率高于2GE。随着醚链含量增大,聚合物电导率上升,力学性能下降。合适的交联程度不仅能提高聚环氧乙烷的力学性能,还可以进一步提升其电导率。4GE含量为39 mol%,AGE含量为2 mol%时,EO-4GE-AGE交联聚合物电解质的拉伸强度可达1.41 MPa,30℃电导率可达9×10^(-5)S·cm^(-1)。

The copolymerization of ethylene oxide(EO),glycol methyl glycidyl ether(nGE)and allyl glycidyl ether(AGE)catalyzed by i-Bu_(3)Al/H_(3)PO_(4)/DBU has been examined.The microstructures,thermal properties and molecular weights of the obtained polymers were characterized by nuclear magnetic resonance spectroscopy(NMR),gel permeation chromatography(GPC)and differential scanning calorimeter(DSC).The results showed that the i-Bu_(3)Al/H_(3)PO_(4)/DBU catalyst serves as an excellent catalyst for the copolymerization of EO,nGE,and AGE to afford a family of ether chain modified poly(ethylene oxide).The obtained EO-nGE copolymers and EO-nGE-AGE terpolymers with controllable contents were conveniently obtained in 100%yield within 30 min by changing the feed ratio.The ether chain length of nGE has no effect on the copolymerization.The cross-linked copolymers were prepared using the EO-nGE-AGE terpolymer as precursors and 1,2-ethanedithiol as a crosslinking agent.The properties of copolymers revealed that the ether chain length and content,crosslinking had a significant impact on the conductivity and mechanical properties of copolymers.The copolymers with tetraethylene glycol methyl glycidyl ether(4GE)as a comonomer exhibited higher conductivity than that of diethylene glycol methyl glycidyl ether(2GE).With the increase of the content of 4GE in the EO-4GE copolymers,the conductivity increased,but the mechanical properties decreased.The appropriate crosslinking degree improved not only the mechanical properties but also conductivity.The cross-linked EO-4GE-AGE polymer electrolytes containing 39 mol%4GE and 2 mol%AGE showed the tensile strength and conductivity of 1.41 MPa and 9×10^(-5)S·cm^(-1)at 30℃,respectively.