DBP/DVB对聚甲基丙烯酸甲酯耐热性的影响

Effect of DBP/DVB on Heat Resistance of Polymethyl Methacrylate

将邻苯二甲酸二丁酯(DBP)、二乙烯苯(DVB)作为改性剂,采用本体聚合的方法合成聚甲基丙烯酸甲酯(PMMA),研究改性剂对PMMA耐热性的影响。利用红外光谱(FTIR)、热重分析(TG)、示差扫描量热法(DSC)、维卡软化点测试等方法测试PMMA及改性PMMA的分子结构、热稳定性、玻璃化转变温度以及耐热温度的变化。结果表明,DBP改性PMMA的分子链运动能力增强,玻璃化转变温度和维卡软化点分别下降了7.5%、9.4%;DVB能显著提高PMMA的热稳定性,当DVB含量为5份时,PMMA的分解温度提高了20.0%,软化点温度提高了56.1%;同时,DBP和DVB明显降低了PMMA的吸水率和密度。因此,DVB能有效提高PMMA的热稳定性,降低成型加工时热分解风险,耐热性的改善可以进一步扩大其应用范围。

Poly(methyl methacrylate)(PMMA)was synthesized by bulk polymerization using dibutyl phthalate(DBP)and divinylbenzene(DVB)as modifiers.The changes of molecular structure,thermal stability,glass transition temperature and heat resistance temperature of PMMA before and after modification were tested by FTIR,TG,DSC and Vicat softening point test.The results showed that after the modification of DBP,the molecular chain movement ability of PMMA was enhanced,the glass transition temperature and Vicat softening point were decreased by 7.5%and 9.4%,respectively;while DVB could significantly improve the thermal stability of PMMA,when DVB was added to 5 phr,the decomposition temperature of PMMA was increased by 20.0%,and the softening point temperature was increased by 56.1%;the water absorption and density of PMMA significantly reduced after the modification of DBP and DVB.With the addition of DVB,the thermal stability of PMMA was effectively improved,the risk of thermal decomposition was reduced.The improvement of heat resistance could further expand its application range.