共单体促进聚乙烯熔融接枝硅氧烷的研究

以低密度聚乙烯和线性低密度聚乙烯为基体,研究了两种共轭效应大于3-(甲基丙烯酰氧基)丙基三甲氧基硅氧烷(KH570)、极性效应与KH570差值较大的共单体N-苯基马来酰亚胺(N-PMI)和甲基丙烯酸-2-羟基丙酯(2-HPMA)的加入对聚乙烯(PE)接枝硅氧烷KH570的影响。利用红外光谱分析证实了PE已经成功接枝了硅氧烷KH570和共单体,熔体流动速率、接枝率、凝胶率测试结果表明,两种共单体的加入,均能提高PE接枝硅氧烷的效果,而且N-PMI促进接枝的效果明显优于2-HPMA。当KH570用量为0.84g,共单体N-PMI和2-HPMA用量分别为0.84g和1.26g时,产物接枝率达到最大,分别为1.23%和0.85%。

西南桦木材表面的硅烷化及憎水和憎油特性

目的解决制备憎油性材料时对含氟化合物的依赖,减小木材对水和油的吸收性,赋予木材表面双憎功能。方法采用甲基三甲氧基硅烷(MTMS)与0.1 mol/L的盐酸以4∶1的体积比混合,并置于冰浴中超声水解不同的时间,将木材放入水解溶液中浸渍处理5 min,利用X-射线光电子能谱仪(XPS)、傅里叶红外光谱仪(FT-IR)分析改性前后木材表面的元素组成及化学结构,借助接触角测量仪考察改性木材对水和油的润湿特性,计算其吸水率和吸油率。结果改性木材表面引入了大量的Si元素,并键合了低表面能的—CH3基团;水解时间由30 min延长至240 min,水接触角由79.8°增加至90.7°,但油接触角却稳定在50°左右;改性前后的吸水率均大于吸油率。结论所制备的木材都具有双憎功能,憎水稳定性随水解时间的延长而提高,但憎油稳定性受水解时间的影响较小。

Nano-indentation profiles of intrinsic hardness and modulus of films based on silsesquioxane modified with titanium tetrabutoxide

This study is to analyze the influence of the modifier, 5～25 wt % titanium tetrabutoxide (TBO), on the hardness and elastic modulus of the films based on SSO deriving from hydrolytic condensation of (3-glycidoxypropyl)trimethoxysilane (GPMS) and vinyltrimethoxysilane (VMS), by the continuous stiffness measurement (CSM) technique of an instrumented-indentation testing (IIT) device. Films were synthesized by adding the stoichiometric amount of ethylenediamine (EDA) and benzoyl proxide (BPO) to SSO solutions in ethanol, dip-coating over glass substrates, and curing using an appropriate thermal cycle. Intrinsic values of hardness and elastic modulus were determined with the average values in “plateau region” from “four-layer” explanation. And the brittle index of the modified coating systems was analyzed.