Gypsum-based composites was produced using gypsum power(cement), PVA, white latex and sawdust via pouring process. The influences of water/ cement ratio, PVA/ cement ratio and glue/ cement ratio on release time, density and impact strength of the gypsum-based composites were investigated through orthogonal experiment. The results showed that PVA strengthened obviously impact strength, and also delayed the s release time of the Gypsum-based composites. Sawdust as light filler reduced the composites density. Low content of white latex is beneficial to increase the impact strength, while high content of white latex is easy to form micelle in the gypsum crystallization process and is enclosed in crystals, which decreases the impact strength of composite materials.
A novel PPy/PBA-g-PMMA-GMA (copolymer) composites were prepared and the preparation conditions, characterization and properties of the composites were investigated. The results indicate that the oxidant types, molar ratio of oxidant/monomer, polymerization time, PPy content affect greatly the conductivity of the PPy/terpolymer composites. The ultimate elongation of composites decreases with increasing PPy content,while high PPMM content brings forth high tensile strength.
Nanocomposites were obtained by mixing elastomeric copolymer and nanoSiO2 in double-screw extruder at 130-150°C, in which the elastomeric copolymer was prepared by copolymerization of poly (methyl methacrylate (PMMA) macromonomer and butyl acrylate (BA) in benzene using azobisisobutyro-nitrile (AIBN) as initiator. The results indicated that increasing the amount of PMMA, the molecular weight of PMMA and copolymers, nanosilica charged resulted in improving the tensile strength and modulus at 300% elongation of nanocomposites, on the contrary, decreasing ultimate elongation and permanent set decrease. In additions, the tensile strength and the modulus at 300% elongation of nanocomposites reached to a maximum while the mass ratio of nanoSiO2 to copolymer was 3%.
Hydroxyl functional hyperbranched polyester initiators initiated the ring-opening polymerization(ROP) of ε-caprolactone (CL) and the star-shaped polymer with PCL arms using hyperbranched polyester as nuclear was produced. Then, the bromide of star-shaped polymer, initiated the atom transfer radical polymerization (ATRP) of oligo(ethylene oxide) methacrylate (OEOMA) and the star-shaped polymer containing the arms of PCL-b-POEOMA was synthesized ,and the characterization of polymer structure was investigated by NMR.
Nanocomposites were obtained by mixing elastomeric terpolymer and nano-SiO2 in double-screw extruder at 130-150 °C, in which elastomeric terpolymer was prepared by terpolymerization of poly(methyl methacrylate (PMMA) macromonomer, butyl acrylate(BA), and acrylic acid(AA) in benzene using azobisisobutyronitrile (AIBN) as initiator. The results indicated that increasing the amount of PMMA, the molecular weight of PMMA and terpolymers as well as the content of carboxylic acid were favorable to increase the mechanical properties of nanocomposites. In addition, the tensile strength and the modulus at 300% elongation of nanocomposites reach to a maximum while the mass ratio of nano-SiO2 to terpolymer is 3%.
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