Variously substituted phenyl hepta cyclopentyl-polyhedral oligomeric silsesquioxane (ph,hcp-POSS)/polystyrene (PS) nanocomposites
作者:Ignazio Blanco、Lorenzo Abate、Francesco Agatino Bottino
DOI:10.1007/s10973-013-2997-3
日期:2013.4
A comparative study concerning the thermal stability of polystyrene (PS) and six POSS/PS nanocomposites of general formula R7R′(SiO1.5)8/PS (where R = cyclopentyl and R′ = phenyl, 4-methoxyphenyl, 4-tolyl, 3,5-xilyl, 4-fluorophenyl, and 2,4-difluorophenyl) was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Nanocomposites were prepared by in situ polymerization of styrene in the presence of 5 % w/w of POSS, but the actual filler concentration in the obtained nanocomposites, determined by 1H NMR spectroscopy, was in all cases slightly higher than that in the reactant mixtures. FTIR spectra of nanocomposites evidenced the presence of filler-polymer interactions. Inherent viscosity (η inh) determinations indicated that the average molar mass of polymer in methylated and fluorinated derivatives was lower than neat PS, and were in agreement with calorimetric glass transition temperature (T g) measurements. Degradations were performed into a thermobalance, in the scanning mode, at 10 °C min−1, and the temperatures at 5 % mass loss (T 5 %), of various nanocomposites were determined. The effects of various substituents of the POSS phenyl group on the thermal stability of nanocomposites were evaluated. The results were discussed and interpreted.
关于聚苯乙烯(PS)和通式为 R7R′(SiO1.5)8/PS(其中 R = 环戊基,R′ = 苯基、4-甲氧基苯基、4-甲苯基、3,5-硅基、4-氟苯基和 2,4-二氟苯基)纳米复合材料的热稳定性的比较研究在惰性(流动氮气)和氧化性(静态空气)气氛中进行。纳米复合材料是在 5% w/w POSS 的存在下通过苯乙烯原位聚合制备的,但通过 1H NMR 光谱测定,所获得纳米复合材料中的实际填料浓度在所有情况下都略高于反应物混合物中的浓度。纳米复合材料的傅立叶变换红外光谱证明了填料与聚合物之间存在相互作用。固有粘度(η inh)测定结果表明,甲基化和氟化衍生物中聚合物的平均摩尔质量低于纯 PS,这与量热玻璃化转变温度(T g)测量结果一致。以 10 ℃ min-1 的扫描模式在热平衡仪中进行降解,并测定了各种纳米复合材料质量损失 5 % 时的温度(T 5 %)。评估了 POSS 苯基的各种取代基对纳米复合材料热稳定性的影响。对结果进行了讨论和解释。