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首页> 外文期刊>Journal of Materials Science >Organic solvent treatment and physicochemical properties of nanoporous polymer-SBA-15 composite materials
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Organic solvent treatment and physicochemical properties of nanoporous polymer-SBA-15 composite materials

机译：纳米多孔聚合物-SBA-15复合材料的有机溶剂处理及其理化性质

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Mesoporous polymer-silica composites are attractive new materials because these systems can combine the advantages of highly porous silica and the vast functional diversity of organic polymers in a single robust structure. This contribution deals with the effects of organic solvent treatment on the physicochemical properties of mesostructured polymer-SBA-15 silica nanocomposites. For this study, two distinct reference mesoporous nanocomposites were prepared using a previously reported surface-confined polymerization technique, e.g., poly(styrene)(PS)-SBA-15 composite and poly(2-hydroxyethyl methacrylate)(PHEMA)-SBA-15 composite. The resulting materials are treated either with chloroform or toluene under heating for a prolonged period of time (24 h). Both materials are characterized prior and after solvent treatment by nitrogen physisorption at -196 A degrees C, thermogravimetry and Attenuated Total Reflection Infra-Red (ATR-IR) spectroscopy. In general, solvent stability is excellent for both types of composite, even for low cross-linking degree of the polymer. Our data reveal that a treatment of mesoporous PHEMA-SBA-15 with chloroform or toluene has a minor, but reproducible, effect on the composite material in terms of porosity. Here, a reorganization of the polymer layer-silica interface seems to occur to some extent, which is leading to slight variation of the intrawall porosity. As a consequence, an increase of the thermal stability is clearly observed, with, however, no marked difference in the mean mesopore diameter. On the other hand, the PS-SBA-15 composite treated with the same solvents shows higher specific surface area values and an improved homogeneity in terms of polymer coating compared to untreated materials, especially for composites synthesized using benzoyle peroxide as the polymerization initiator. However, no increase in thermal stability is observed in this case.
机译：介孔聚合物-二氧化硅复合材料是有吸引力的新材料，因为这些系统可以在一个坚固的结构中结合高孔隙度二氧化硅的优点和有机聚合物的广泛功能多样性。该贡献涉及有机溶剂处理对介孔结构聚合物-SBA-15二氧化硅纳米复合物的物理化学性质的影响。对于本研究，使用先前报道的表面受限聚合技术制备了两种不同的参比介孔纳米复合材料，例如，聚（苯乙烯）（PS）-SBA-15复合材料和聚（甲基丙烯酸2-羟乙酯）（PHEMA）-SBA-15综合。将所得材料在加热下用氯仿或甲苯处理较长时间（24小时）。两种材料在溶剂处理之前和之后均通过-196 A摄氏度的氮物理吸附，热重分析和衰减全反射红外（ATR-IR）光谱进行表征。通常，即使对于聚合物的低交联度，溶剂稳定性对于两种类型的复合物都是优异的。我们的数据显示，用氯仿或甲苯处理中孔PHEMA-SBA-15对复合材料的孔隙率影响较小，但可重现。在此，似乎在某种程度上发生了聚合物层-二氧化硅界面的重组，这导致壁内孔隙率的轻微变化。结果，清楚地观察到热稳定性的增加，但是平均中孔直径没有显着差异。另一方面，与未处理的材料相比，用相同溶剂处理的PS-SBA-15复合材料在聚合物涂层方面表现出更高的比表面积值和更高的均质性，尤其是对于使用过氧化苯甲酰作为聚合引发剂合成的复合材料而言。但是，在这种情况下，没有观察到热稳定性的提高。

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