聚丙二醇基可剥离双组分聚氨酯材料的制备及性能

Preparation and properties of polypropylene glycol-based peelable two-component polyurethane materials

摘要:

以线性结构的六亚甲基二异氰酸酯（HDI）和聚丙二醇（PPG）为原料，合成系列黏度的聚氨酯预聚体，采用1,4-丁二醇为扩链剂，合成了不同氰羟比〔n(—NCO)∶n(—OH)，下同〕的可剥离双组分聚氨酯材料。基于黏度测定，考察R值〔n(—NCO)/n(—OH)，下同〕、PPG数均分子量和温度对聚氨酯预聚体黏度的影响。采用FTIR、DSC、TGA、万能拉伸试验机对可剥离双组分聚氨酯材料的结构组成和热稳定性、力学性能进行表征和测试。结果表明，聚氨酯预聚体的黏度随R值、PPG数均分子量增大而增加的，随温度升高而降低。当R＝3时，由PPG400制备的聚氨酯预聚体黏度为800 mPa·s。随着氰羟比的增大，可剥离双组分聚氨酯材料软段和硬段的玻璃化转变温度逐渐增加，初始分解温度先增大后减小；PPG400可剥离双组分聚氨酯材料最大初始热分解温度为300 ℃；可剥离双组分聚氨酯材料的剥离强度随着氰羟比的增大而逐渐增大，但随时间延长而逐渐下降。PPG400可剥离双组分聚氨酯材料的2 h最大剥离强度为202.4 N/m，表干时间为5 min，固化时间为2 h；随着氰羟比的增大，可剥离双组分聚氨酯材料的断裂伸长率逐渐下降，抗拉强度先增大后减小。当氰羟比＝1.4∶1时，PPG400可剥离双组分聚氨酯材料抗拉强度最大为35.9 MPa，断裂伸长率为383.9%。

Abstract:

Series of viscosity polyurethane prepolymers were synthesized from linearly structured hexamethylene diisocyanate (HDI) and polypropylene glycol (PPG), and peelable two-component polyurethane materials with different cyano hydroxyl ratios [ n (-NCO): n (-OH), hereinafter] were synthesized by using 1,4-butanediol as the chain extender. Based on the viscosity determination, the effects of R-value [ n (-NCO) /n (-OH), hereinafter], PPG number average molecular weight and temperature on the viscosity of polyurethane prepolymer were investigated. FTIR, DSC, TGA, and universal tensile tester were used to characterize and test the structural composition and thermal stability and mechanical properties of the peelable two-component polyurethane materials. The results showed that the viscosity of the polyurethane prepolymer increased with increasing R value, PPG number average molecular weight, and decreased with increasing temperature. When R = 3, the viscosity of polyurethane prepolymer prepared by PPG400 is 800 mPa-s. With the increase of the cyanohydroxyl ratio, the glass transition temperatures of the soft and hard segments of the peelable two-component polyurethane materials increase gradually, and the initial decomposition temperature increases and then decreases; the maximum initial thermal decomposition temperature of the PPG400 peelable two-component polyurethane material is 300 ℃; the peel strength of the peelable two-component polyurethane material increases with the cyanohydroxyl ratio. The peel strength of the peelable two-component polyurethane material increases gradually with the increase of the cyanohydroxyl ratio, but decreases gradually with the extension of time; the maximum peel strength of the PPG400 peelable two-component polyurethane material is 202.4 N/m for 2 h, the surface drying time is 5 min, and the curing time is 2 h. With the increase of the cyanohydroxyl ratio, the elongation at break of the peelable two-component polyurethane material decreases gradually, and the tensile strength increases first and then decreases. When the ratio of cyanohydroxyl = 1.4:1, the tensile strength of PPG400 peelable two-component polyurethane material was 35.9 MPa, and the elongation at break was 383.9%.