氧化木薯淀粉改性MUF共缩聚树脂性能评价

摘要

A series of modified amino resins were synthesized with different ratios of oxidated cassava starch that was added during resin preparation.Effects of oxidated cassava starch content on basic resin performance were examined,such as wettability,curing and thermal resistance,and bond strength.The results showed that as the increase of oxidated cassava starch dosage,free formaldehyde content in the resin decreased,curing time shortened,while viscosity obviously increased,and the wettability presented a tendency to decrease.The dry strength,wet strength of three plywoods produced in laboratory,after treated by cold water and boiling water,showed the tendency of first increase then decrease with the increase of oxidated cassava starch content.DSC and TG results indicated that modified resins with fast curing ratio,had better heat resistance properties and durability within 350℃.%通过在树脂合成反应过程中加入不同比例的氧化木薯淀粉,合成了一系列改性氨基树脂,考察了不同用量氧化木薯淀粉与树脂基本性能、润湿性、固化及耐热性、胶接强度等之间的相互影响.结果表明,随着氧化木薯淀粉用量的增加,树脂中的游离甲醛含量逐渐下降,树脂固化时间不断缩短,黏度显著增加,树脂在杨木单板表面的接触角逐渐增加,即表明润湿性不断减弱.实验室压制3层胶合板的干状胶接强度、耐冷水强度和耐沸水强度均伴随着氧化木薯淀粉用量的增加而呈现出先增加后降低的趋势.差示扫描量热(DSC)和热重(TG)分析表明,改性后的树脂固化速度更快,且在350℃以内时具有更好的耐热和耐久性.