| Polyhedral oligomeric silsesquioxane (POSS) are emerging as a new chemical technology for nanoreinforced organic-inorganic hybrids. POSS monomers possess the structure of cube-octameric frameworks with reactive organic corner groups. The polymers incorporating POSS monomers have become the focus of many studies in recent twenty years due to the simplicity in processing and the excellent comprehensive properties of this class of hybrid materials, such as mechanical properties, thermal stability, and flame retardation etc. Recent efforts have focused on well-defined cubic silsesquioxane frame-works, including a wide variety of frameworks with synthetically functional groups. This paper describes, for the first time, a facile method for synthesis of octa(aminophenyl)silsesquioxane (OAPS) prepared from octa(nitrophenyl)silsesquioxane (ONPS) by using the stable, inexpensive and readily available hydrazine hydrate as the reducing agent in yield around86%, offering a low cost alternative to the conventional Pd/C catalyst method. The product was characterized by FT-IR, GPC,’H NMR,13C NMR,29Si NMR and XRD. It was also found that the time period for preparation of ONPS from octaphenylsilsesquioxane could be considerably shortened from20h to6h, reaching the complete nitration reaction and avoiding the double nitration of aromatic rings.Bismaleimides are a type of thermosetting resin, with high temperature stability, hot-wet strength, and mechanical properties. They suffer, however, from brittlesness. One of the important modifications is the use of diamine, but leads to the decrease in Tg of resulting materials. We describe here the preparation of novel polyimides prepared by reaction of1,1’-(methylene-di-4,1-phenylene)bismaleimide (BMI) with OAPS and4,4’-diamino-diphenyl ether (DDE). The structure of resulting organic-inorganic hybrid nanocomposites was characterized by FT-IR and XRD. The decomposition temperature and char yield of resulting materials increased with increasing OAPS loading. The DSC data showed that the Glass transition temperature of nanocomposite was enhanced by36℃with the content of OAPS around15wt%. As the feed amount of OAPS increased further, the decrease in Tgs could be observed.Polybenzoxazine is a new kind of thermosetting resin, and has some excellent characteristics. However, with the developing of the society and the increasing of the requirement of the properties of the materials, the comprehensive properties of the polybenzoxazine should be improved further. One of the attempts is modifying polybenzoxazine with POSS monomer. In previous paper, however, POSS monomer is poorly miscible with benzoxazine. The difficulty lies in that the inorganic silica structure of the cages does not permit the POSS monomer disperse well in the organic matrix. In this paper, the novel poly-benzoxazinyl functionalized polyhedral oligomeric silsesquioxane macromonomer (BZ-POSS), containing7.6benzoxazine groups per molecule on average was synthesized from octaaminophenylsilsesquioxane, p-cresol and paraformaldehyde. BZ-POSS was well miscible with bisphenol A-based benzoxazine (BBZ) melt. The transparent BBZ/BZ-POSS organic-inorganic hybrid nanocomposites were prepared through ring-opening polymerization under conditions similar to that used for polymerization of neat BBZ. The nano-scale dispersion of POSS cages in the nanocomposite was verified by powder X-ray diffraction and transmission electron microscopy studies. Dynamic mechanical analyses and thermal gravimetric analysis indicated that thermal stabilities, cross-link densities and the flame retardancy of the nanocomposite were increased in comparison with neat PBBZ resin, although only small amounts of inorganic POSS cores were incorporated into the systems. The structure analyses of BZ-POSS and BBZ/BZ-POSS nanocomposites were discussed herein.Vegetable oil is a renewable, cheap and biodegradable natural source dominating today’s food oil market. With the environment being overwhelmed by non-biodegradable petroleum-based polymeric materials, the study on conversion of vegetable oil to high molecular weight polymer has been increasing recently. We reports here the free radical copolymerizations of regular soybean oil (SO) or tung oil (TO) with styrene (ST) initiated by BPO provides polymer ranging from soft rubbers to hard plastics, depending on the reagents, stoichimetry amd initiators used. By terminating the reaction before gelation, non-crosslinked soluble copolymers were obtained. GPC results showed that the Mn of TO/ST and SO/ST could reach7-8×104. Nuclear magnetic resonance spectroscopy indicated that the TO was more reactive than the ST when copolymerized, and double bonds remained in the copolymer chain. All these results reveal the benefit for further processing and modification of the copolymer. The Cross-linked copolymers of TO/ST was prepared by the gelation at120℃. Dynamic mechanical analysis showed that the modulus of the bulk polymer is that of a approximately109Pa at room temperature, which are comparable to those of conventional plastics. |
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