Synthesis And Properties Of Polyarylates And Poly(Arylate Imide)s Containing Heterocyclic Moieties

Aromatic polyester (polyarylate) has been known as one of high performance polymers, and widely applied in the aviation, automobile, electronic and mechanical industries because of its good thermal stabilities, fire resistanceand, mechanical properties, ultraviolet resistance and resistance to creep. However, most polyarylates obtained commercially encounter processing difficulty due to their high glass transition or melting temperature coupled with insolubility in common organic solvents, which restricts their application in the insulating coating and separative membrane, etc. In this work, our efforts have been focused on synthesis of polyarylates and poly(arylate imide)s with good solubility and high thermal properties by introduction of twisted and non-coplanar phthalazinone moieties into polyarylates and poly(arylate imide)s backbones.A series of novel phthalazinone-based polyarylates (PPARs) were prepared from 4-[4-(4-carboxyphenoxyl)phenyl]-2-(4-carboxyphenyl)phthalazin-l-one (DHPZ-DA) and 4,4'-dicarboxydiphenyl ether (DAPE) with 2,2-bis(4-hydroxyphenyl)propane (BPA) by solution polycondensation. The structures of these polyarylates were confirmed by FT-IR, GPC and'H NMR. The thermal properties, mechanical property, crystalline property and solubility of polyarylates were investigated by DSC, TGA, Material Testing Machine and WAXD, etc. The resultant polymers have good solubility in polar aprotic solvents, such as N, N-dimethylacetamide (DMAc), tetrahydrofuran (THF), chloroform, etc. PPARs exhibite amorphous nature as evident by WAXD. And they show high thermal properties with the glass transition temperatures from 156℃to 229℃, and the temperatures for 5% and 10% weight loss in the range of 441-461℃and 462-490℃in nitrogen, respectively. The polyarylates can be formed into transparent, strong and flexible films.Imide-containing polyarylates were designed and synthesized by introduction of imide group into the polyarylates backbone to impart them with high thermal stability and good mechanical property. The resultant poly(arylate imide)s (PPAIRs) were prepared from DHPZ-DA and bis[4-(4-trimellitimido phenoxyl)phenyl]ether (Diimide-DA) with 4,4'-Dihydroxydiphenylmethane (6FBPA) by solution polycondensation. The structures of these PPAIRs were confirmed by FT-IR, GPC and 1H NMR. The thermal properties, mechanical property, crystalline property and solubility of PPAIRs were studied by DSC, TGA, WAXD and Material Testing Machine, etc. The PPAIRs exhibite amorphous nature as evident by WAXD, and have good solubility in polar aprotic solvents, such as DMAc, chloroform, etc. The resultant PPAIRs show high thermal stability with the glass transition temperatures from 238℃to 246℃, and the temperatures for 5% and 10% weight loss of the PPAIRs were in the range of 471-479℃and 496～501℃in nitrogen, respectively. The PPAIRs can be formed into transparent, strong and flexible films.Allyl group was introduced into the main chain of poly(arylate imide)s containing phthalazinone moiety in order to impart them with good chemical resistance and high thermal properties. Poly(arylate imide)s containing allyl group (PPAIARs) were prepared from DHPZ-DA and Diimide-DA with 6FBPA and 3,3'-diallyldiallyl-4,4'-dihydroxybiphenyl (DABP) by solution polycondensation. The PPAIARs have good solubility in polar aprotic solvents, such as DMAc and chloroform, etc. PPAIARs were cured to afford structure of crosslinked macromolecules polymers under high temperature. The thermal properties and solubility of PPAIARs were characterized studied through DSC and TGA. The crosslinked PPAIARs have can not be undissolved in polar aprotic solvents, such as DMAc and chloroform, etc, showing good chemical resistance. The crosslinked PPAIARs show high thermal stability properties with the glass transition temperatures from 238℃to 248℃, Tg values were increased at 15～18℃upon crosslinking, higher than the corresponding linear ones, and the temperatures for 5% and 10% weight loss of the crosslinked PPAIARs were in the range of 463～488℃and 488～522℃in nitrogen, respectively.