Synthesis Of Polyarylate Containing Phthalazinone Structure Through High-Temperature Solution Polycondensation

Polyarylate is a kind of polymer with excellent comprehensive performances, especially with excellent weather resistance and transparency, and it is widely used in aerospace, automotive and other fields. However, traditional polyarylate,such as the commercial U polymer and thermotropic liquid crystalline polymer Vectra-950, is insoluble in room temperature, which leads to problems in terms of its synthesis, high cost and limits its further popularization and application. This article embarked from the molecular structure design, introducing the distorted non-coplanar phthalazinone biphenyl structure into the main chain of the polyarylate. At the same time, the article prepared a novel soluble and thermostability polyarylate through controlling molecular chain flexibility or introducing fluorine structure, in order to improve the processing and application performance.In this article,4-(4-hydroxyphenyl)-phthlazin-l(2H)-one(DHPZ), bisphenol-like monomer were used to design and synthesize dichloride compound(DCA) containing phthalazinone biphenyl structure. The first step. the reaction between DHPZ and K2CO3generated phenate, and the nucleophilic substitution between phenate and dichlobenil generated dinitrile compound (DND).Then, the hydrolysis of DND generated dicarboxy compound (DAD).At last, the reaction between DAD and an excess of thionyl chloride created DCA, using with N.N-Dimethylformamide (DMF) as a catalyst. Each product was consistent with the design, proved by FT-IR,’H-NMR,13C-NMR, MS and LC.DCA, Terephthaloyldichloride(TPC) and4,4’-dihydroxy diphenyl sulfide were used to synthesize a serie of polyarylates PARls, and each product was consistent with the design proved by FT-IR,’H-NMR and GPC. With the ratio of phthalazinone biphenyl structure in molecular chain increasing, the solubility of polyarylate enhanced. When the feeding molar ratio of DCA was more than60%, the polyarylates were dissolved in NMP, DMAc, m-Cresol, Py, CHCb, THF, and other common organic solvents. The glass transition temperatures of PARls were controlled in180-220℃and5%weight loss temperatures ranged in456-472℃. The results of WAXD and DSC showed that degree of crystallinity in copolymer could be regulated and controlled by changing the ratio and method of feeding. When feeding with one-step method, the higher content of TPC, the more degree of crystallinity, and the melting point of PAR1-0505was236℃. When feeding with step-by-step method, the degree of crystallinity increased slightly. DCA, TPC and4,4’-(hexafluoro-isopropylidene) bisphenol were used to synthesize a serie of polyarylates PAR2s, and each product was consistent with the design proved by FT-IR,1H-NMR and GPC. The solubility of PAR2s was better than that of PAR1s, and the solubility variation of the former was the same as that of the latter. When the feeding molar ratio of DCA was more than40%, the polyarylates were dissolved in common organic solvents; The glass transition temperatures of PAR2s were controlled in199-246℃and5%weight loss temperatures ranged in453-489℃, which were all higher than that of PAR1s. The WAXD results showed that the degree of crystallinity in PAR2s were less than that in PAR1s, and that the tendency of them were the same.