Preparation And Performance Of Crosslinkable Poly(arylene Ether)s Containing Azobenzene

Because of the unique optics response of the azobenzene chromophores,azobenzene containing polymer(azo polymers) have attracted in the optical datastorage considerable attention, optical switching and optical materials. For improvingthe stability of photoactive,the researchers did a lot of research these years.Peopleusually improve the glass transition temperature of polymers to improve the stabilityof photoactive. Poly(aryl ether)s (PAEs) is a class of high performance engineeringthermoplastics with excellent thermal, mechanical and electrical properties.Functionalized poly(aryl ether)s have been extensively studied as a proton exchangemembrane (PEM), the light emitting material and optical material. PAEs can improvethe stability of photoactive. Crosslinking is a effective method to make the chain ofpolymer limited.Thereby enhancing the stability of photoactive.In this work, we designed and synthesized two kinds of photoresponsiveazo-poly(arylene ether)s with azobenzene group and crosslinkable group by directcopolymerization or post-functionalization. Their structures were characterized, andtheir thermodynamic behavior and photoactive behavior were investigated. Detailedresearchs were summarized as the following:（1） In order to introduce cross-linkable group alkynyl and azo group intoPoly(aryl ether)s, a kind of monomer with alkynyl group and azo group weresynthesized, a kind of azobenzene functionalized poly(arylene ether)s with high glass transition temperature via post-functonalizaton reaction weresynthesized. Then we synthesized poly(arylene ether)s with azo group andalkynyl group by grafting the monomer to the polymer. This polymer exhibithigh glass transition temperature(196℃). Significant crosslinking exothermicwere observed in the range of325-390℃by DSC scan, the exothermic peakwas370℃. It proved polymers can be crosslinked. Upon irradiation with a532nm Nd:YAG laser beam, copolymers presented large photoinducedbirefringence with a remnant value greater than84%of the saturation value.But it is shown that the crosslinking temperature(350℃) is too high for azogroup by TGA scan. For reducing the crosslinking temperature, moreresearches were needed.（2） In order to reducing the crosslinking temperature, a new kind of Poly(arylether)s with allyl group and azo group were synthesized. Allyl group haslower crosslinkng temperature(250℃) which is lower than the decompositiontemperature of azo group. The polymer was heat-treated at250℃for20-60mins, It can be seen that Tg of the polymer increases with the degree ofcross-linking increases. After heat-treated for60mins, Tg of the polymerincrease37℃.（3） Upon irradiation with a532nm Neodymium-doped yttrium aluminum garnet(Nd: YAG laser) laser, PAEs with allyl group and azo group showed goodPhotoluminescence stable orientation and value of photoinduced birefringence.The remnant value of the polymer before crossling is84%, which is89%aftercrosslinking. It means that polymer after crosslinking shows betterPhotoinduced birefringence stable orientation than before crosslinking.