Studies On Synthesis, Characterization And Properties Of Novel Poly(Benzobisoxazole)s

A series of novel Poly(benzobisoxazole)s(DHPZ-PBO) with 4-(4-hydroxyphenyl)-1(2H)-phthalazinone(DHPZ) were designed and synthesized in order to improve their solubility,fusing performance as well as optical performance.4,6-diaminoresorcinol dihydrochloride(DAR·2HCl) and 4,6-diaminoresorcinol diphosphate(DAR·2H₃PO₄) were synthesized from resorcinol by acetylation reaction, oximation reaction and Beckmann rearrangement.The structures of these the two final products and the intermediates were characterized and confirmed by FT-IR,elemental analysis,¹H NMR and ¹³C NMR etc.The results show that all the products are very pure.In short it is a useful method with simple process and low cost of synthesis of DAR which also can avoid involving any nitro or aniline compounds as carcinogenic chemical compounds and releasing the hydrogen chloride gas(HCl).Polybenzoxazole(PBO) was synthesized by three different methods,its structure is conformed by FT-IR,thermal properties and optical properties of PBO were studied in this thesis.By compare these three polymerization methods,we can derive:the method of polycondensation from TPA salt in this thesis is the optimum polymerization to synthesize PBO.It has two main advantages after optimizing;firstly,it can avoid the degassing process which has a serious influence to the polymerization.Secondly,it combines the step of synthesis of TPA salt with polymerization in the same reactor,which can avoid oxidation of the TPA salt so as to increase M_w.Meanwhile,the method using DAR·2H₃PO₄ as the monomer features simple operation,no degassing process and no influence to the polymerization process of monomer's salt,it is worth further studying.According to the hard-soluble property of PBO and the advantage of the DHPZ which is the twisted,noncoplanar phthalazinone moieties,A series of novel Poly(benzobisoxazole)s DHPZ-PBO with 4-(4-hydroxyphenyl)-1(2H)-phthalazinone(DHPZ) were synthesized by polycondensation form DAR·2HCl and 4-[4-(4-carboxyphenoxyl) phenyl]-2-(4-carboxyphenyl) phthalazin-1-one(H-DA).Structures were conformed by FT-IR, thermal properties,solubility properties and optical properties of DHPZ-PBO were studied in this thesis.The results show that:compare to PBO,DHPZ-PBO has a better solubility to some extent which can be dissolved in m-cresol in the condition of 100℃.Though its thermal performance degrades,DHPZ-PBO still has a high degradation temperature and good optical performance.