聚氨酯改性酚醛泡沫塑料

以聚氨酯预聚物作为改性剂加入到酚醛树脂中,再与其他助剂复合发泡制成酚醛泡沫塑料.讨论了预聚物加入量对酚醛泡沫掉渣程度、压缩强度、弯曲强度、热稳定性及临界氧指数等性能的影响,并对改性泡沫的形态结构进行了研究.结果表明,预聚物加入3%(相对酚醛树脂质量)时,改性泡沫的掉渣程度与纯酚醛泡沫相比减少22.5%,加入13%时可减少65.3%,且泡沫断面致密均匀、光滑无沫、有回弹性;预聚物加入量小于8%时,压缩强度与相应容重的纯酚醛泡沫类似,但大于8%时明显提高;弯曲强度与同容重酚醛泡沫相比略有下降;热稳定性、氧指数等性能基本不变;相差显微镜图片证明了改性泡沫体内形成了交联网络.

Polyurethane modified phenolic foam

Polyurethane prepolymer was used as modifier and mixed with phenolic resin and other additives to prepare the foam. The effects of the amount of prepolymer on compressive strength, bending strength, surface brittleness, heat stability and limited oxygen index were discussed and the structure of the modified foam was researched. The results indicated that, when the amount of prepolymer was 3%(compared with the amount of phenolic resin), the loss weight of powder of the foam was decreased by 22 5%, and when the amount of prepolymer was 13%, the loss weight of powder of the foam could be decreased by 65 3%,which demonstrated that the surface brittleness and the back elastic character of the foam were promoted obviously. When the amount of prepolymer was less than 8%(compared with the amount of phenolic resin), the compressive strength of the foam was similar to that of pure phenolic foam, while when the added amount of prepolymer was more than 8%,the compressive strength was higher than that of pure phenolic foam. The bending strength of the former was a little lower than that of the latter. At the same time, basically the heat stability and the limited oxygen index and other properties were unchanged. The crosslinking structure was detected in the foam by phase differential microscopy.