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用两步法合成出一端接异氰酸酯基(—NCO)的聚丙烯酸酯低聚物。首先以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为单体,巯基乙醇(2-ME)为链转移剂,低浓度的偶氮二异丁腈(AIBN)为引发剂,在110℃将按n(MMA):n(BA):n(2-ME):n(AIBN)=500:500:25:1配制的溶液,在2.5h内滴加到甲苯中,反应4h,得到多分散系数Mw/Mn=1.8、一端带羟基的聚丙烯酸酯低聚物〔(MMA—BAOH〕;再加入甲苯-2,4-二异氰酸酯(TDI)与其端羟基反应,合成出一端接异氰酸酯基的聚丙烯酸酯低聚物〔(MMA—BANCO〕。该低聚物结构与热性能用FTIR、1HNMR、13CNMR、GPC、DSC、TGA进行了表征。结果表明,产物的分子结构符合分子设计,即一端接有异氰酸酯基(—NCO),数均相对分子质量Mn在4500左右,DSC显示合成的低聚物的Tg在40℃左右,TGA测出其主要热失重在300～450℃。该低聚物可作为大分子表面改性剂,用于氮化硅、氮化铝等纳米粉体的表面修饰改性。
A polyacrylate oligomer terminated with isocyanate group (-NCO) was synthesized in two steps. Firstly, methyl methacrylate (MMA) and butyl acrylate (BA) as monomers, mercaptoethanol (2-ME) as chain transfer agent and low concentration of azobisisobutyronitrile (AIBN) The solution was prepared by dropwise addition of n (BA): n (2-ME): n (AIBN) = 500: 500: 25: 1 at 110 ℃ for 2.5 h. (MMA-BAOH) having a polydispersity coefficient Mw / Mn of 1.8 and one terminal hydroxyl group was added, and then the toluene terminal 2,4-diisocyanate (TDI) was reacted with its terminal hydroxyl group to synthesize one terminal isocyanate (MMA-BANCO) .The structure and thermal properties of the oligomer were characterized by FTIR, 1HNMR, 13CNMR, GPC, DSC and TGA.The results showed that the molecular structure of the product was in accordance with the molecular design, (-NCO) at one end, the number average molecular weight (Mn) is about 4500, DSC shows that the Tg of the synthesized oligomer is about 40 ℃, and the TGA has the main thermal weight loss at 300-450 ℃ .This low Polymers can be used as macromolecule surface modifier for surface modification modification of nano-powders such as silicon nitride and aluminum nitride.