硅烷化聚氨酯预聚体的合成及其固化物的性能

Preparation and Properties of Siloxane End-Capped Polyurethane

在无溶剂条件下采用聚氨酯(PU)预聚体法合成端—NCO基PU,再与活性硅烷进行封端反应,制备了硅烷化聚氨酯(SPU)预聚体。考察了聚醚二元醇(PPG)的数均相对分子质量(Mn)、异氰酸酯种类、n(NCO)∶n(OH)和硅烷封端剂种类对SPU预聚体固化物(简称固化物)性能的影响。实验结果表明,通过改变PPG的Mn、异氰酸酯种类、n(NCO)∶n(OH)和硅烷封端剂种类可制备符合设计性能要求的SPU预聚体。室温下SPU预聚体固化得到无气泡、无针孔的均质胶膜,且其指干时间比PU短,固化物疏水性能提高;红外光谱表征结果表明,采用仲氨基硅烷(S IL-3)封端后,产物的—NCO基吸收峰消失。当采用Mn为4000的PPG与1,6-六亚甲基二异氰酸酯在n(NCO)∶n(OH)=1.80的条件下反应,再经SIL-3封端后得到的固化物拉伸强度为0.30M Pa,断裂伸长率为120%。

Isocyanate end -capped polyurethane （PU） was synthesized in absence of solvent and further reacted with active siloxane to prepare siloxane end -capped polyurethane （SPU） prepolymer. Effects of number average relative molecular mass （ Mn ） of polypropylene glycol （ PPG）, isocyanate types, n （NCO） ： n （OH） and siloxane types on properties of cured SPU prepolymer resin （cured resin） were investigated. The cured resin films with hydrophobicity, free of bubbles, pinpricks and spots, can be obtained at room temperature. Tack - free time of the cured resin is shorter than that of PU resin. The IR absorption peak of isocyanate radical disappeared after end - capping reaction between PU and secondary amino siloxane （ SIL - 3 ）. PPG （ Mn 4 000 ） reacted with hexamethylene diisocyanate（HDI） at n（NCO） ： n（OH） 1.80, and was end- capped with SIL- 3 to produce SPU. Tensile strength and elongation at break of the cured resin are 0.30 MPa and 120%, respectively.