硅烷改性聚氨酯的合成及力学性能的研究

采用异氰酸酯与聚醚二元醇反应合成端异氰酸酯基聚氨酯预聚体(PU),PU再与偶联剂硅烷进行加成反应合成硅烷改性聚氨酯(SPU),用傅里叶变换红外光谱表征了PU和SPU的结构,表征结果显示,硅烷接枝于PU的端基上。通过改变聚醚二元醇的数均相对分子质量、异氰酸酯结构、硅烷结构和官能度对SPU结构进行了设计,并对各种结构的SPU进行了力学性能研究。实验结果表明,当SPU的数均相对分子质量一定、PU中聚醚二元醇的数均相对分子质量增大时,SPU黏度降低,硫化后SPU的拉伸强度降低、断裂伸长率增加和邵氏硬度减小;当SPU的数均相对分子质量增大时,SPU黏度增大,硫化后SPU的拉伸强度降低、断裂伸长率增加和邵氏硬度减小。对比几种不同异氰酸酯制成的SPU,由二苯甲烷二异氰酸酯制成的硫化后SPU的拉伸强度大、断裂伸长率大;对比几种不同硅烷制成的SPU,由官能度高的硅烷制得的硫化后SPU的拉伸强度大、邵氏硬度大。

Synthesis and Mechanical Properties of Silylated Polyurethane

Polyurethane(PU) with NCO group as end groups was synthesized from isocyanate and dual-polyether glycol.The silylated polyurethane(SPU) was further synthesized by addition reaction of PU and silane.PU and SPU were characterized by means of FTIR.Structure design of SPU was accomplished by changing relative molecular mass(Mn) of polyether,type of isocyanate and functionality of silane.When Mn of SPU is kept constant,with increase of Mn of polyether in SPU,its viscosity reduces,tensile strength and hardness of vulcanized SPU drop,and elongation increases.If Mn of SPU increases,its viscosity rises,tensile strength and hardness of vulcanized SPU drop,and elongation goes up.Tensile strength and elongation of vulcanized SPU prepared from methylene diphenyl isocyanate are higher than those prepared from other isocyanates.Silane with high functionality significantly enhances both tensile strength and hardness of vulcanized SPU and reduces its elongation.