聚苯醚(PPE)是一种高性能热塑性工程塑料,具有优异的电性能和耐热性能,广泛应用于新能源汽车、光伏、电子电器等领域。然而,PPE极易发生黄变,尤其对于浅色PPE产品的生产和使用产生了严重的负面影响。为寻找有效方法抑制PPE的黄变现象,研...聚苯醚(PPE)是一种高性能热塑性工程塑料,具有优异的电性能和耐热性能,广泛应用于新能源汽车、光伏、电子电器等领域。然而,PPE极易发生黄变,尤其对于浅色PPE产品的生产和使用产生了严重的负面影响。为寻找有效方法抑制PPE的黄变现象,研究PPE的黄变机理具有重要意义。本文主要利用X射线光电子能谱(XPS)、傅里叶红外光谱仪(FTIR)、分光测色仪、核磁共振氢谱(1 H NMR)等表征技术,对不同温度下PPE的黄变现象进行测试与表征,提出黄变动力学,并结合PPE热氧老化过程中化学结构变化,分析致色物质并提出黄变机理。展开更多
A new biphenol-like monomer,4,4′-methylenebis[4-(1,4-phenylene)-phthalazin-1(2H)-one] was synthesized from phthalic anhydride and diphenylmethane in two steps.In the first step,Friedel-Crafts reaction was carried out...A new biphenol-like monomer,4,4′-methylenebis[4-(1,4-phenylene)-phthalazin-1(2H)-one] was synthesized from phthalic anhydride and diphenylmethane in two steps.In the first step,Friedel-Crafts reaction was carried out in 1,2-dichloroethane between diphenylmethane and phthalic anhydride.The obtained product was used in the second step with hydrazine monohydrate added into its solution,followed by recrystallization in acetic acid.The melting point showed by differential scanning calorimetry of the bis(phthalazinone) monomer was 338.1℃.The overall yield of the biphenol-like monomer was 60%.A new polyphthalazinone was prepared from 4,4′-difluorodiphenylketone(DFK) and 4,4′-methylenebis[4-(1,4-phenylene)-phthalazin-1(2H)-one] by solution polycondensation in N-methyl-2-pyrrolidone(NMP) with anhydrous K 2CO 3 as a catalyst.High molecular weight polymer was formed in 8 h at 190℃.The polymer was refined by precipitation from its 15% NMP solution with methanol as the precipitating agent.The powder of the polymer was dried in a vacuum oven under 120℃ for 48*!h and then under 200℃ for 4*!h.The intrinsic viscosity of the polymer was 0.58*!dL/g in NMP at 25℃.The polymer showed high glass transition temperature (T g) at 258℃ by DSC.The decomposition temperature for 5% weight loss (T d5) in nitrogen measured by thermogravimetric analysis occurred at 431℃.The solubility of the polymer was investigated at room temperature.The polymer was soluble in NMP,m-cresol and partially soluble in chloroform,and insoluble in N,N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSO).The methylene group and bis-(phthalazinone) structure in the backbone of the polymer contribute much to the good solubility,and the rigid structure of bis(phthalazinone) retains its good thermal properties.展开更多
文摘聚苯醚(PPE)是一种高性能热塑性工程塑料,具有优异的电性能和耐热性能,广泛应用于新能源汽车、光伏、电子电器等领域。然而,PPE极易发生黄变,尤其对于浅色PPE产品的生产和使用产生了严重的负面影响。为寻找有效方法抑制PPE的黄变现象,研究PPE的黄变机理具有重要意义。本文主要利用X射线光电子能谱(XPS)、傅里叶红外光谱仪(FTIR)、分光测色仪、核磁共振氢谱(1 H NMR)等表征技术,对不同温度下PPE的黄变现象进行测试与表征,提出黄变动力学,并结合PPE热氧老化过程中化学结构变化,分析致色物质并提出黄变机理。
文摘A new biphenol-like monomer,4,4′-methylenebis[4-(1,4-phenylene)-phthalazin-1(2H)-one] was synthesized from phthalic anhydride and diphenylmethane in two steps.In the first step,Friedel-Crafts reaction was carried out in 1,2-dichloroethane between diphenylmethane and phthalic anhydride.The obtained product was used in the second step with hydrazine monohydrate added into its solution,followed by recrystallization in acetic acid.The melting point showed by differential scanning calorimetry of the bis(phthalazinone) monomer was 338.1℃.The overall yield of the biphenol-like monomer was 60%.A new polyphthalazinone was prepared from 4,4′-difluorodiphenylketone(DFK) and 4,4′-methylenebis[4-(1,4-phenylene)-phthalazin-1(2H)-one] by solution polycondensation in N-methyl-2-pyrrolidone(NMP) with anhydrous K 2CO 3 as a catalyst.High molecular weight polymer was formed in 8 h at 190℃.The polymer was refined by precipitation from its 15% NMP solution with methanol as the precipitating agent.The powder of the polymer was dried in a vacuum oven under 120℃ for 48*!h and then under 200℃ for 4*!h.The intrinsic viscosity of the polymer was 0.58*!dL/g in NMP at 25℃.The polymer showed high glass transition temperature (T g) at 258℃ by DSC.The decomposition temperature for 5% weight loss (T d5) in nitrogen measured by thermogravimetric analysis occurred at 431℃.The solubility of the polymer was investigated at room temperature.The polymer was soluble in NMP,m-cresol and partially soluble in chloroform,and insoluble in N,N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSO).The methylene group and bis-(phthalazinone) structure in the backbone of the polymer contribute much to the good solubility,and the rigid structure of bis(phthalazinone) retains its good thermal properties.