A copolymer contains repeating units represented by the following chemical formulae 1 and 2:
In the chemical formulae 1 and 2, R represents a hydrogen atom or a cation; X represents an alkylene group having 2 to 18 carbon atoms; Y represents a single bond, an oxycarbonyl group [(X)—O—CO—(Z)], a carbonyloxy group [(X)—CO—O—(Z)], an ether group (—O—), or an imido group [(X)—N—CO—(—CO—)(Z)]; and Z represents a biphenyl group or a naphthyl group).
一个共聚物包含由以下
化学式1和2表示的重复单元:在
化学式1和2中,R代表氢原子或阳离子; X代表具有2至18个碳原子的烷基基团; Y代表单键,氧羰基团[(X)-O-CO-(Z)],羰氧基[(X)-CO-O-(Z)],醚基(-O-)或
亚胺基[(X)-N-CO-(-CO-)(Z)]; Z代表
联苯基团或
萘基团。