聚氨酯预聚体增韧改性酚醛泡沫塑料

摘要

The toughening phenolic foam with low pulverization was prepared by adding polyurethane prepolymer which is terminated with isocyanate and without free isocyanate monomer,and by reducing the consumption of acidic curing agent in the foaming process. The effect of isocyanate content on the apparent density,compressive strength,water intake,flame retardant and heat conductivity of phenolic foam were also discussed. The results showed that the apparent density and compressive strength of the modified phenolic foam tended to increase with the content of polyurethane prepolymer and corresponding isocyanate group. Meanwhile,the resistance to pulverization is the best when the isocyanate content is 8.6%. However,the water absorption and heat conductivity of the modified polyurethane foam changed little with the increase of polyurethane prepolymer. The critical oxygen index was still more than 40 when the content of polyurethane was less than 6%.%采用异氰酸酯封端且不含游离异氰酸酯单体的聚氨酯预聚体作为酚醛泡沫的增韧改性剂，并在后期混合发泡工艺中减少酸性固化剂的用量，制备了不粉化、韧性高的改性酚醛泡沫体，并考察了异氰酸酯基含量对酚醛泡沫体的表观密度、压缩强度、吸水率、阻燃性和导热性能等的影响。结果表明：随着聚氨酯预聚体用量以及异氰酸酯基含量的增加，改性酚醛泡沫体的表观密度、压缩强度增大；当异氰酸酯基含量为8.6%时，抗粉化程度最好；随着聚氨酯预聚体用量的增加，吸水率和热导率变化不大，当聚氨酯用量不超过6%时，临界氧指数仍大于40。