可聚合纳米SiO_2杂化材料的制备及其性能研究

PREPARATION OF POLYMERIC NANOSILICA HYBRID MATERIALS AND THEIR PROPERTIES

利用异佛尔酮二异氰酸酯(IPDI)和纳米SiO2表面—OH基团反应的特点,制备了表面含—NCO基团的纳米SiO2,用端羟基聚丙二醇醚(PPG)对其扩链并进一步和丙烯酸羟乙酯(HEA)反应,制备了丙烯酸酯封端、IPDI和PPG连接纳米SiO2粒子的纳米SiO2杂化材料.用红外光谱(FTIR)、热失重(TGA)和扫描电镜(SEM)对接枝前后纳米SiO2进行表征分析,结果表明,IPDI、PPG和HEA以化学键的形式接枝于纳米SiO2表面,接枝率为92.2%.改性后的纳米SiO2团聚现象明显得到改善.虽然整个杂化材料的粒径超过了纳米材料的定义范围,但纳米SiO2粒子仍然保持纳米尺寸,粒度分布为30～50 nm.和未改性的纳米SiO2相比,将3%的改性纳米SiO2加入紫外光固化涂料中,涂料黏度从55 mPa.s降低到48 mPa.s(25℃);在相同的UV固化时间内,C C双键转化率提高;固化膜的铅笔硬度从3 H提高到4 H;经300 r/min的耐磨性能测试,磨耗量从6.2 mg降低到4.6 mg.

This work relates to the development of polymeric nanosilica hybrid materials with nanosilica as node,IPDI and PPG as link and acrylate as terminal group for photopolymerization.The preparation process was as follow：nanosilica was first reacted with isophorone diisocyanate（IPDI）,then extended the chain with polypropylene glycol（PPG） in proportion to the mole of NCO on the surface of silica,further terminated the left NCO groups with hydoxyethyl acrylate（HEA）.Characterization of preparation by Fourier transform infrared spectroscopy（FTIR） and thermogravimetric analysis（TGA） showed that IPDI,PPG and HEA were grafted onto nanosilica with chemical bonds and the percentage of grafting based on silica could be up to 92.2%.The morphology analysis of nanosilica and modified nanosilica by scanning electron microscopy（SEM） disclosed that modified nanosilica had lower aggregation and the diameters of silica particles were 30 ～ 50 nm although the sizes of nanosilica hybrid materials were beyond nanomaterial definition.Added 3% modified nanosilica into coating and compared with the coating with the same amount unmodified nanosilica,it was found that the viscosity of the coating decreased from 55 mPa.s to 48 mPa.s at 25℃ due to improvement of the compatibility of modified nanosilica with acrylic matrix,the conversion of C C double bonds in coating increased at the same UV curing time because of modified nanosilica’s better distributive performance in coating and lower scattering property for UV rays.After being cured,the pencil hardness of films increased from 3 H to 4 H and the weight loss decreased from 6.2 mg to 4.6 mg after 300 r/min abrasion due to a strong Si— O—Si bonding formed with network of film after polymeric nanosilica hybrid materials were used.