摘要
聚甲基丙烯酰亚胺(PMI)泡沫经两步制得:(1)通过本体聚合得到可发性甲基丙烯酸/丙烯腈共聚物板;(2)190℃发泡1 h制得PMI泡沫。采用傅里叶变换红外光谱仪(FTIR)、核磁共振氢谱(1H-NMR)、动态机械热分析(DMTA)、差示扫描量热法(DSC)分析了热处理对共聚物结构的影响,并研究了发泡过程中的分子结构转变。结果表明共聚物在发泡过程中分子内生成六元酰亚胺环以及酸酐环;发泡剂分解产生的氨气亦参与反应,并使得酸酐环进一步转变为酰亚胺环;同时分子间生成交联结构;酰亚胺环中N-H键氢的化学位移δ为10.50。SEM照片表明所得泡沫为高闭孔率结构,泡孔结构完整,泡孔尺寸较均一。
Polymethacrylimide（PMI） foam was obtained by two steps：（1）a expandable tablet was prepared via bulk copolymerization of monomers mixture;（2）polymethacrylimide（PMI） foam was produced by heating the expandable tablet at 190℃ for 1 hour.Fourier transform infrared（FTIR）,1H-NMR,dynamic mechanical thermal analyses（DMTA） and differential scanning calorimetry（DSC） was used to investigate the effects of thermal treatment in copolymer structures,meanwhile,the molecule structure transformation during foaming process was studied.The results indicate that some adjacent AN and MAA monomeric units transformed into six-membered imide ring structures and some of the adjacent MAA monomeric units changed into six-membered anhydride ring structures,furthermore,some imide ring structure is formed due to the reaction between NH3（the decomposition products of blowing agents） and anhydride ring structures;insolubility of after-heated copolymer suggested crosslinking structure is generated;the peak at δ 10.50 in 1H-NMR spectrum is related to imide ring（—CO—NH—CO—） proton.Scanning electron microscope（SEM） image shows a closed-cell foam with fine cell structures is obtained.
出处
《宇航材料工艺》
CAS
CSCD
北大核心
2011年第5期32-36,共5页
Aerospace Materials & Technology
关键词
聚甲基丙烯酰亚胺
酰亚胺环
闭孔
动态机械热分析
Polymethacrylimide
Imide ring
Closed-cell
Dynamic mechanical thermal analyses
