摘要
A novel aromatic diamine monomer bearing tertbutyl and 4-tertbutylphenyl groups,3,3'-ditertbutyl-4,4'-diaminodiphenyl-4''-tertbutylphenylmethane(TADBP),was prepared and characterized.A series of non-coplanar polyimides(PIs)were synthesized via a conventional one-step polycondensation from TADBP and various aromatic dianhydrides including pyromellitic dianhydride(PMDA),3,3',4,4'-biphenyltetracarboxylic dianhydride(BPDA),4,4'-oxydiphthalic anhydride(OPDA),3,3',4,4'-benzophenone tetracarboxylic dianhydride(BTDA)and 4,4'-(hexafluoroisopropylidene)dipthalic anhydride(6FDA).All PIs exhibit excellent solubility in common organic solvents such as N,N-dimethylformamide(DMF),N,N-dimethylacetamide(DMAc),N-methyl-2-pyrrolidone(NMP),dimethyl sulfoxide(DMSO),chloroform(CHCl3),tetrahydrofuran(THF),and so on.Furthermore,the obtained transparent,strong and flexible polyimide films present good thermal stability and outstanding optical properties.Their glass transition temperatures(Tgs)are in the range of 298 to 347℃,and 10%weight loss temperatures are in excess of 490℃with more than 53%char yield at 800℃in nitrogen.All the polyimides can be cast into transparent and flexible films with tensile strength of 80.5-101 MPa,elongation at break of 8.4%-10.5%,and Young's modulus of 2.3-2.8 GPa.Meanwhile,the PIs show the cutoff wavelengths of 302-356 nm,as well as low moisture absorption(0.30%-0.55%)and low dielectric constant(2.78-3.12 at 1 MHz).
基金
supported by the National Natural Science Foundation of China(Nos.51163003,21264005 and 51263005)
the fund of Guangxi Natural Science Foundation(Nos.2014GXNSFAA118040,2013GXNSFDA019008)
Guangxi Small Highland Innovation Team of Talents in Colleges and Universities,and Fund。
