title: Nanoalloys based on clays: intercalated semicrystalline blends of syndiotactic polystyrene with poly(2,6-dimethyl-p-phenylene oxide).
abstract: Nanoalloys of syndiotactic polystyrene with poly(2,6-dimethyl-p-phenylene oxide) clay were prepared by a solution intercalation technique using 1,1,2,2-tetrachloroethane. A mixed intercalated/exfoliated morphology in the nanoalloys containing organo-clays is evinced by transmission electron microscopy. Thermal stability is found to improve with 5% by weight of organo-clays, but a reverse trend is observed by increasing the concentration of clay. The influence of montmorillonite clays in isothermal melt-crystallization behavior of blends was thoroughly investigated by using differential scanning calorimetry and wide-angle X-ray diffraction. A considerable change in polymorphic behavior of syndiotactic polystyrene is observed by the incorporation of different clays into the blends, and the temperature window of isothermal crystallization for the formation of a-crystals of syndiotactic polystyrene is found to broaden in the presence of organo-clays. In contrast, the pristine clay is found to induce only the beta-crystal of syndiotactic polystyrene at all the crystallization temperatures studied in this work. The amorphous component poly(2,6-dimethyl-p-phenylene oxide) affects the crystallinity of syndiotactic polystyrene adversely and favors the beta-form of syndiotactic polystyrene in blends; a-crystals are observed in the nano-alloys containing 20 wt% of poly(2,6-dimethyl-p-phenylene oxide). The crystalline morphology, as characterized by polarized optical microscopy, clearly indicates rapid formation of the alpha-form induced by the nanoscale dispersion of organo-clays in spherulites of smaller dimension.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan 701-01, Taiwan
authors.forename: Arup K
authors.initials: AK
authors.lastname: Ghosh
authors.forename: E M
authors.initials: EM
authors.lastname: Woo
authors.forename: Chean C
authors.initials: CC
authors.lastname: Su
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D000077215:Clay; D003460:Crystallization / Q000379:methods*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000379:methods*; D010087:Oxides / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D000538:Aluminum Silicates; D010087:Oxides; D011137:Polystyrenes; D000077215:Clay