原位制备PEI/SiO2复合材料及其改性环氧树脂的研究

在N,N-二甲基乙酰胺/四氢呋喃(DMAc/THF)混合溶剂中,在正硅酸乙酯(TEOS)存在条件下,通过溶胶-凝胶法原位制备了聚醚酰亚胺(PEI)/SiO2复合材料.在该复合材料中,当SiO2含量低于20 wt％时,透射电镜(TEM)和扫描电镜(SEM)的观察表明,SiO2纳米粒子可以均匀分散,粒径可在80～300 n...

in situ PREPARATION OF PEI/SiO2 COMPOSITES AND THEIR MODIFICATION FOR EPOXY RESIN

Polyetherimide(PEI)/SiO2 composites were in situ prepared via sol-gel process in the presence of tetraethyl orthosilicate(TEOS) in a mixed solvent of N,N-Dimethylacetamide/tetrahydrofuran(DMAc/THF).Electronic microscopy was used to check dispersion quality in transmission mode and scanning mode,and the results showed that SiO2 particles could be uniformly dispersed in the composite under a certain amount(20 wt%) and the average size of the particles could be controlled within a compass of 80~300 nm.However,glomeration may occur if the concentration of SiO2 particles was beyond this range.Results of Differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) showed that the glass transition temperature(Tg) and decomposition temperature(Td) of PEI were improved by introducing SiO2 particles.The phase separation morphology of blends of 4,4′-diaminodiphenyl sulphone cured epoxy with PEI or PEI/SiO2composite was investigated by SEM and it showed that the introduction of SiO2 particles could reduce the size of the dispersion phase(PEI rich phase).Dynamic rheological measurement of epoxyresin(ER)/PEI/silica blends with different silica particle content was conducted at same isothermal temperature.The onset time of phase separation decreased as silica particles in the blend system increased because the silica particles could act as catalyst in the polymerization reaction and make the phase separation easier to occur.After that,the viscosity of system with higher particle concentration grew faster and made the phase separation process ends in an earlier stage.Dynamic mechanical thermal analysis(DMTA) and impact tests showed that using PEI/SiO2 as the modifier could enhance the modulus and toughness property of the epoxy resin system simultaneously.