Preparation And Photochromism Properties Of Polystyrene With Azobenzene Group

It is promising to obtain optical storage materials by bonding azobenzene groups onto polystyrene molecular chain.In this work,a novel main chain azo-polystyrene is prepared through the condensation polymerization of azobenzene dicarbonylic chloride and polystyrene with dihydroxyl end groups.Meanwhile a well-defined side chain azo-polystyrene is obtained by imidal reaction.My work can be described as follows:DEPS was synthesized under relatively elevated temperature using BPO as initiator.Subsequently, DHPS was obtained by the alkaline hydrolysis of DEPS.Two main chain azo polystyrenes,PS-azo-DPA and PS-azo-HDO were synthesized by the condensation polymerization of azobenzene dicarbonylic chloride,DHPS,Bisphenol A and hexanediol. The synthesized two main chain azo polystyrenes are freely soluble in common solvents s and have good thermal stability.The photochromic property of the copolymers was characterized by UV-Vis.Trans-cis photo isomerisation of copolymers was found irradiation with UV light at 365nm.The equilibrium state was reached with 30 min.PS-azo-IMIDE was obtained by the reaction of 4-(phenylazo)aniline and SMA.The structure change of modified polymer was analyzed by FT-IR.There is no obvious isomerization for 4-(4'-phenylazo)aniline,4-(4'-nitrophenylazoaniline and their modified intermediates.Yet after the cyclization to imide,trans-cis isomerization was obviously observed.The equilibrium was reached after 20-30min irradiated by UV light at 365nm and took 48h under dark condition to reconvert.Photo isomerisation of the modified intermediate of SMA with 4-(4'-aminephenyl)azo phenyl sulpholic acid was observed at pH 10.The equilibrium was reached after 10min irradiated by UV light at 365nm.5B-2 is freely soluble in a wide pH range and trans-cis photo isomerisation was also observed by 365nm irradiation.In alkaline environment the isomerization rate was considerably high and up to equilibrium for 10 min.under neutral condition,the isomerization was relatively slow and up to equilibrium for about 40 min.