In order to obtain melt-processable wholly aromatic crystalline polymers, twenty-six new aromatic polyetheresters were synthesized by means of melt-polymerization and their thermal properties (m. p., glass transition temperature, etc.) were measured by DSC. Among these polymers, sixteen crystalline polymers were obtained, which melted in the temperature range of about 260_??_340°C without thermal degradation. These include (1) polymers containing appropriate meta-oriented components and (2) polymers consisting of only para-oriented components and having benzene ring linked with one ester bond. These polymers could be melt-spun and heat-drawn and the tensile properties and thermal stabilities of these fibers were evaluated. It was observed that tenacity and elongation decreased with increase of the crystallinity caused by heat treatment and the degree of this physical deterioration depended on the polymer species and affected the apparent thermal stability.
Polaris™ unsaturated polyester resins provide fabricators with resin options that fit any cast polymer need. Polaris resins are designed for high filler loading, fast green strength development and quick de-mold times without cracking or warping. Polaris resins have excellent batch-to-batch consistency in color and liquid properties. For cultured marble and onyx fabricators, Polaris resins also have excellent thermal shock resistance and low color.
Poly(methyl methacrylate) was also used as a ZnO surface modifier by Hong []. Nanoparticles of zinc oxide with a diameter of approximately 30 nm were synthesized by means of homogeneous precipitation followed by calcination. In order to introduce reactive groups onto the ZnO surface, a reaction was carried out between the hydroxyl groups and a silane coupling agent (3-methacryloxypropyltrimethoxysilane). Graft polymerization was effected by means of a reaction between the ZnO, containing silanol groups, and the monomer. Tests showed that the polymerization does not alter the crystalline structure of the ZnO nanoparticles. Their dispersion in the organic solvent can greatly improve the graft polymerization of PMMA, and further improvement can be achieved by the addition of other surfactants. Modification of ZnO nanoparticles by grafted PMMA increases the degree of lyophilicity of the inorganic surface and reduces the formation of aggregates. The work of Hong , showed that ZnO nanoparticles grafted with PMMA can increase the thermal stability of polystyrene.
Xiong [] synthesized a new nanocomposite ZnO(PEGME), in which the ZnO nanoparticles and polymer groups (PEGME—poly(ethylene glycol) methyl ether) are linked by covalent bonds. The compound was analyzed in terms of composition, structure, fluorescence and specific conductance. The tests showed that the polymer nanocomposite synthesized by means of a chemical reaction has better properties than its equivalent obtained through physical mixing. The lasting stability of the properties of ZnO(PEGME) results from the strong chemical bond between the polymer and the nanoparticles. The hybrid ZnO(PEGME) has the capability of tuning luminescence spectra and has stable ionic conductance. These properties mean that the obtained compound can be used in luminescent devices and in electronic apparatus.
In order to solve this problem, surface modification techniques are applied to improve the interaction between the nanoparticles and the polymer. In the work of Yuan [], in order to prepare the silicone rubber with high thermal conductivity, pristine and surface-modified ZnO nanoparticles containing the vinyl silane group are incorporated into the silicone rubber via a hydrosilylation reaction during the curing process. The corresponding structure, morphology and properties of the silicone rubber/ZnO (SR/ZnO) and silicone rubber/SiVi@ZnO (SR/SiVi@ZnO) nanocomposites were investigated. Yuan synthesized ZnO nanoparticles (with an average size below 10 nm) by a sol-gel procedure. Next the silicone coupling agent VTES was successfully incorporated onto the surface of the nanoparticles. The SR/SiVi@ZnO nanocomposites showed better mechanical properties and higher thermal conductivity due to the formation of a cross-linking structure with the silicone rubber matrix and better dispersion in that matrix.
XxtraDura™ GMA multipurpose additive provides numerous direct and indirect benefits in oil well cement slurries. It is an anionic synthetic co-polymer available as a concentrated aqueous solution and free-flowing powder use to provide outstanding gas migration, filtration and free water control properties in a wide range of operating of temperature (80-350 °F) and salt (36 percent NaCl).