聚甲基丙烯酰亚胺(PMI)泡沫塑料的制备与表征

Preparation and Characterization of Polymethacrylimide Foams

以甲基丙烯酸(MAA)和甲基丙烯腈(MAN)为单体,采用浇注法制得了聚甲基丙烯酰亚胺(PMI)泡沫塑料,利用红外光谱(FTIR)、光学显微镜、差示扫描量热法(DSC)和热失重分析(TG)等手段对其结构和性能进行分析和测试。研究结果表明:将50份MAA、50份MAN、1～5份氧化镁、2～8份正丁醇、叔丁醇的混合物、0.2～0.3份过氧化二苯甲酰和过氧化苯甲酸叔丁酯和0.1～0.2份的甲酰胺,混合均匀后在40～60℃聚合为可发泡的MAA/MAN共聚物,该共聚物在200～220℃下发泡2～3h,在160℃下热处理5～6h,制得PMI泡沫塑料,其力学性能和耐热性能优异。在发泡和热处理过程中分子链发生分子重排反应,生成六元酰亚胺环结构;PMI泡沫为闭孔泡沫塑料,泡孔平均孔径在0.5～0.7mm之间;制得的泡沫塑料热稳定性好,热分解温度在221.5℃左右。

Polymethacrylimide（PMI）foams were prepared by the casting process using methacrylie acid （MAA）and methaerylonitrile（MAN）as monomers. The structure and properties of the PMI foams were analyzed by infrared adsorption spectrum（FTIR）, optical microscope, differential scanning calorimeter （DSC） and thermogravimeter （TG）. The results show that the foamable MAA/MAN copolymers were prepared at 40-60℃ by polymerizing the mixture of 50phr MAA, 50phr MAN, 1-5phr magnesium oxide, 2-8phr butanol and tert-butanol, 0.2-0.3phr dibenzoyl peroxide and tert-butyl perbenzoate and 0.1-0. 2phr DMF. Then the resulting copolymers were expanded at 200-220℃ for 2-3h, subsequently treated at 160℃ for 5-6h, generating PMI foams with excellent mechanical properties and heat-resistance. Molecular rearrangement reaction occurs during the foaming and post-treatment forming hexahydric imide ring. The prepared PMI foams have closed cell structure with the cell size ranging from 0.5mm to 0. 7mm and have a good thermostability with the characteristic degradation temperature at about 221.5℃.