直接由SiO_2低温合成含硅聚氨酯及其结构表征

有机硅材料是一类应用非常广泛的材料,但这些产品所用基本原料几乎都来源于石英沙(SiO2)的高温碳热还原[1],这个方法已大规模的工业化,但它的高能耗、高腐蚀成为人们越来越关注的问题.1991年美国Laine[2]直接以SiO2为原料成功地制备了五配位、六配位有机硅化合物,并进一步合成了导电材料和高性能陶瓷[3～7].我们实验室自1995年以来,在Laine的基础上,发现如果以沙子为原料,则产率非常低,即使在超声波作用下,反应一周合成的五配位硅化合物其产率不足10%,这可能是由于沙子的晶型非常完美,在200℃下很难打破Si-O键生成配位硅,如果以无定型SiO2为原料(如白碳黑,稻壳灰等),合成的五配位硅其产率几乎为100%,而且反应时间缩短为4h.然后以高活性的五配位硅为原料制备了一系列的含硅有机物,如与环氯丙烷反应[8],不仅消除了五配位硅化合物的水解可逆性反应,中和了它的强碱性,而且把环氧基团接到了配位硅化合物上,生成了一种非常类似于液态环氧树脂的淡黄色的粘稠状液体.我们按Laine的路线,向含硅聚合物方向发展[9].本文合成的双羟基四配位硅单体是五配位硅钾化合物向含硅聚合物转化的关键,由于其结构带有两个活泼羟基,可以和二元酰氯、二元羧酸、二异氰酸酯、导氰酸酯基封端的聚醚或异氰酸酯基封端的聚酯进行缩聚反应,合成主连含硅的聚合物.

SYNTHESIS OF SILICON-CONTAINING POLYURETHANE BY A NON-CARBOTHERMAL METAL DIRECTLY FROM SiO2 AND CHARACTERIZATION OF ITS STRUCTURE

A new technical approach to the synthesis of novel silicon containing polyurethane by the non carbothermal method directly from SiO 2 was studied.Firstly a high reactive pentacoordinate organic silicon complex[(KSi(OCH 2CH 2O) 2(OCH 2CH 2OH)]was prepared,by means of the reaction of a high surface area silica with ethylene glycol and potassium hydroxide.Then a novel tetracoordinate silicon (OCH 2CH 2O)Si(OCH 2CH 2OH)(OCH 2CH 2OCH 2CH 2OH)was synthesized by the reaction of ClCH 2CH 2OH with reactive pentacoordinate silicon complex.Lastly a novel silicon containing polyurethane was synthesized by low temperature solution condensation between tetracoordinate silicon and 2,4 toluene diisocyanate in dimethyl sulfoxide.The product was characterized and analyzed by FTIR,TG,DSC,GPC etc. The IR spectra exhibited a characteristic strong absorption band for ester carbonyl at 1724 05cm -1 .TG analysis showed a better thermal stability.DSC curves declared that its T g was 115 09℃,GPC analysis showed that the molecular weight of silicon containing polyurethane is between several ten thousand and a hundred thousand.