一类含芴结构改性聚芳酰胺的合成与性能研究

SYNTHESIS AND PROPERTIES OF POLYARAMIDES MODIFIED WITH FLUORINE STRUCTURE

采用三步反应制备出含芴结构的二胺单体9,9-双[3,5-二甲氧基-4-(4-氨基-2-甲基苯氧基)苯基]芴,再通过低温溶液缩聚与4种商业化的芳香二酸[对苯二酸、2,2-双(4-羧基苯基)六氟丙烷、4,4-二苯醚二甲酸、4-叔丁基间苯二酸]反应得到系列含芴结构改性聚芳酰胺(PA 3a~3d)。利用核磁共振氢谱、傅里叶变换红外光谱、凝胶渗透色谱等方法对该聚芳酰胺的结构、溶解性、耐热性和力学性能进行表征。结果表明:含芴结构聚芳酰胺在高沸点极性溶剂(N,N-二甲基乙酰胺、N,N-甲基吡咯烷酮、二甲基甲酰胺、吡啶)和低沸点溶剂四氢呋喃中均能较好地溶解;玻璃化转变温度(T_(g))在217~234℃之间,空气和N 2中的10%热失重温度均高于450℃,耐热性优异;其薄膜的拉伸强度在76.6 MPa以上,断裂伸长率在8.7%以上,表现出较好的力学性能;含芴结构聚芳酰胺表现出优异的综合性能。

Firstly,a novel diamine monomer 9,9-bis(3,5-dimethoxy-4-(4-amino-2-methylphenoxy)phenyl)containing fluorene was prepared by three-step organic reaction.This monomer was then used to synthesize a series of polyarylamides(PA 3a-3d)with fluorine by low-temperature solution condensation with four commercial aromatic diacids(terephthalic acid,2,2-bis(4-carboxyphenyl)hexafluoropropane,4,4-diphenyl ether dicarboxylic acid,and 4-tert-butylisophthalic acid).The structure and properties of these polymers were characterized by 1H NMR,FT-IR and GPC.The solubility,thermal properties,optical properties and mechanical properties of the polymers were investigated.The results showed that the polyarylamides could be dissolved in high-boiling polar solvents such as DMAc,NMP,DMF,and pyridine and low-boiling point solvent THF.The glass-transition temperature T_(g) of these polymers ranged from 217℃to 234℃.The 10%mass loss temperature in air and nitrogen were both above 450℃,indicating excellent thermal stability.The prepared films exhibited excellent mechanical properties,with tensile strength more than 76.6 MPa and elongation at break above 8.7%.These polymers with fluorene structures showed excellent comprehensive properties.