异氰酸酯刚性对硅烷改性聚脲性能的影响

Influence of Stiffness of Isocyanate on the Properties of Silane Modified Polyurea

以二官能度端氨基聚氧丙烯和4种不同的二元异氰酸酯(HDI、IPDI、TDI、MDI)为原料,合成了异氰酸酯封端的聚脲预聚体,再用硅烷偶联剂KH550对预聚体进行改性,制备了一系列链段刚性不同的硅烷改性聚脲(SPUA)(H1~2、I1~2、T1~2、M1~2)。用FTIR、TGA、动态机械热分析(DMA)、力学性能测试、XRD对材料的结构和性能进行了表征,并讨论了不同刚性链段对材料性能的影响。结果表明,当n(NCO)/n(NH2)为1.1时,随着SPUA链段刚性的增强,材料失重5%的温度(T5%)从H1的319.5℃上升到M1的334.1℃,失重50%的温度(T50%)从H1的390.1℃上升到M1的400.9℃,最大失重速率时的温度(Tmax)从H1的395.0℃上升到M1的405.5℃;材料的拉伸强度逐渐增大,从H1的2.78 MPa提高到M1的4.80 MPa,而韧性则逐渐下降,断裂伸长率从H1的337%减少到M1的224%;玻璃化转变温度(Tg)逐渐上升,从H1的-65.8℃上升到M1的-57.7℃。

A series of silane modified polyurea（ SPUA） were prepared by using polyether amine and four types of diisocyanates as raw materials,silane coupling agent KH550 as modifier. The structure and properties of the samples were characterized by means of FTIR,thermogravimetric analysis（ TGA）,dynamic mechanical thermal analysis（ DMA）,mechanics testing,and X-ray diffraction techniques.Furthermore,the influences of stiff chain segment on the properties of samples were discussed. The results showed that when the molar ratio of isocyanate and amino was 1. 1,with increasing of the stiffness of chain segment,the temperatures at 5% weight loss（ T5%） and 50% weight loss（ T50%） of samples increased from 319. 5 ℃ to 334. 1 ℃ and from 390. 1 ℃ to 400. 9 ℃,respectively. And the temperatures at the maximum weight loss rate（ Tmax） increased from 395. 0 ℃ to 405. 5 ℃. Moreover,the tensile strength of the samples increased from 2. 78 MPa to 4. 80 MPa,while the elongation at break decreased from 337% to 224%. Meanwhile,the glass transition temperatures of samples increased from-65. 8 ℃ to-57. 7 ℃.