三聚氰胺甲醛树脂改性羟基封端聚二甲基硅氧烷的性能

Study on properties of hydroxy-terminated polydimethylsilane modified with melamine-formaldehyde

为了提高羟基封端的聚二甲硅基烷的热稳定性,采用三聚氰胺甲醛乙阶预聚体对羟基封端的聚二甲硅基烷进行改性,以热重和红外分析改性前后的聚二甲硅基烷,同时考察三聚氰胺与甲醛物质的量比、pH值、温度以及催化剂种类等因素对改性产物储存稳定性以及游离甲醛含量的影响。结果表明:当三聚氰胺/甲醛物质的量比为1∶3、pH值为8.5、温度为80.0℃及催化剂为乙醇胺时,聚二甲基硅氧烷的失重率由改性前的350.0℃完全失重,降低至改性后的370.0℃失重50.00%,且改性物的溶液稳定,游离甲醛的含量仅为0.68%。

To improve the thermal stability of hydroxy-terminated polydimethylsilane,hydroxy-terminated polydimethylsilyl was modified with melamine formaldehyde B-stage prepolymer.Thermochromic and infrared analysis were conducted on polydimethylsiloxane before and after modification.The effect of molar ratio of melamine and formaldehyde,pH value,temperature and catalyst type on the storage stability and free formaldehyde content of modified products was studied.The results show that under the conditions of amount ratio of melamine/formaldehyde of 1∶3,pH of8.5,temperature of 80.0℃,and ethanolamine as catalyst,the weight loss rate situation of polydimethylsiloxane changes from 100%weight loss at the temperature 350.0℃before modification into 50%weight lossat the temperature 370.0℃.Besides,the modified solutionis stable and the content of free formaldehyde is only 0.68%.