纳米TiO_2-聚氨酯复合制备研究

Study on the preparation of nano TiO_2-PU composite emulsion

采用纳米TiO_2直接加入及预聚体分散法,制备了稳定的纳米TiO_2-聚氨酯复合乳液.考察了纳米TiO_2改性、加入方式、用量、不同R(n_(-NCO)/n_(-OH))值等影响因素,发现通过硅烷偶联剂(KH-570)、二甲苯改性的纳米TiO_2沉降性有较大改善,分散在介质中呈良好乳液状;反应初直接加入TiO_2合成的纳米TiO_2-聚氨酯在手感上优于其它加入方式,力学强度较高;当R值为3.5时、纳米TiO_2加入量控制在0.5%以内获得的纳米TiO_2-聚氨酯杂化材料性能优良,铅笔硬度大于2H,耐冲击强度大于80 cm,粒子平均粒径在100 nm以内。

By the method of the direct addition of nano TiO2 and pre-polymer dispersion, nano TiO2-polyurethane composite emulsion was successfully prepared. After studying some relavant factors, such as modifying measures of nano-TiO2, adding mesaures and amount of nana-TiO2 as well as the differenet ratio（n Nco/n-oH）, the results showed that the selttleability of nano-TiO2, modified by the nature of KH-570 and xylene, gains a large improvement, with fine emulsion shape in dispersible media, that the coat of nano-TiO2/aqueous polyurethane obtained by adding the modified nano-TiO2, after the mix of PPG, feels better and its Strength was also improved; What＇s more, the nano- TiO2/aqueous polyurethane produced when ratio（n-Nco/n-oH） was 3. 5 and the amount of nano-TiO2 was controled within 0.5 %, can make the pencil hardness beyond at least 2H, and it bears the impact strength to be stronger than 80 cm. Under this case, particle