脲醛树脂/淀粉复合体系的常温固化及其力学性能

在脲醛树脂(UF)/淀粉(St)复合体系中引入聚醋酸乙烯酯(PVAc)、聚丙烯酰胺(PAM),氨基硅烷偶联剂(A212),通过力学性能测试和扫描电镜分析研究了复合体系的常温固化过程、材料微观结构及其性能变化的关系。结果表明,当m(UF)/m(St)/m(PVAc)/m(固化剂CA)/m(PAM)/m(A212)=200/50/2/3/5/0.06时,体系冲击强度为190kJ/m2,弯曲强度为24MPa。PVAc的引入延长了体系的固化时间,PAM较好地改善了体系的分散状态。A212明显改善了体系分散的均匀性和相界面结合状态,材料微观结构更为致密,力学性能提高,尤其是韧性明显改善。

Room temperature curing process of urea-formaldehyde/starch composite and its mechanical properties

Polyvinylacetate( PVAc) ,polyacrylamide( PAM) and aminosilane coupling agent( A212) were added into urea-formaldehyde resin( UF) /starch( St) blending system. The relationship among room temperature curing process ,interface microstructure and mechanical properties of the modified thermosetting composites were investigated by mechanical property test and SEM analysis. The result showed that the impact strength and bending strength of UF/St system with mass ratio UF∶ St∶ PVAc∶ curing agent CA∶ PAM∶ A212 = 200∶ 50∶ 2∶ 3∶ 5∶ 0. 06 were 190 kJ/m2 and 24 MPa respectively. The curing time of UF/St system was extended by PVAc and the dispersion state of UF/St was improved by PAM The dispersion uniformity and the interface integration of the system were en-henced by A212 and the microstrture was more compact,therefore the mechanical properties of UF/St were increased. In particular,the toughness was significantly improved.