酶解淀粉改性三聚氰胺甲醛树脂的研究

Study on melamine formaldehyde resin modified by enzymatic hydrolysis of starch

以淀粉(S)、甲醛(F)、三聚氰胺(M)为主要原料,合成酶解淀粉(ES)改性三聚氰胺甲醛树脂(ESMF),分析了ES添加量、淀粉种类对ESMF树脂性能的影响,并对ES成分和ESMF树脂的结构进行了探讨。研究结果表明:随着ES添加量的增加,ESMF树脂的黏度、固体含量逐渐下降;游离甲醛含量下降,最低为0.186%;贮存期延长,在添加量为40%时贮存期最长达35 d(25℃);胶合强度降低,最低胶合强度仍大于1.0 MPa。酶解马铃薯淀粉(EPS)相比酶解木薯淀粉(ECS)改性的MF树脂综合性能较好。红外光谱分析表明:ES中含有葡萄糖、麦芽糖及其他多糖,其含有大量的羟基,在碱性条件下与羟甲基三聚氰胺形成亚甲基桥键和醚键,多糖中C=O还可能与羟甲基三聚氰胺发生缩合反应,生成ESMF树脂。

Enzymatic starch modified melamine formaldehyde resin(ESMF)was synthesized with starch(S),formaldehyde(F)and melamine(M)as main raw materials. The effect of ES content and starch type on the properties of ESMF resin was analyzed,and ES composition and ESMF resin structure were also discussed. The research results showed that with the increase of ES content,the viscosity and solid content of ESMF resin decreased gradually;the content of free formaldehyde decreased,the minimum value was 0.186%;the storage period was extended,the storage period could be up to 35 days(25 ℃)when the addition was 40%;the bonding strength was reduced,the minimum bonding strength was still greater than 1.0 MPa. The comprehensive properties of MF resin modified by enzymatic potato starch(EPS)were better than that of enzymatic cassava starch(ECS). The infrared spectroscopy analysis showed that the ES contained glucose,maltose and other polysaccharides,which contained a lot of hydroxyl groups. Methylene bridge bond and ether bond were formed with hydroxymethyl melamine in alkaline condition,C=O in polysaccharides might also condensation react with hydroxymethyl melamine to form ESMF resin.