Volume 46 Issue 5, May 2014

A hydrophilically modified poly(dimethylsiloxane) (HPM-PDMS) bearing quaternized amino groups on the side chains was dissolved in mixtures of methanol (MeOH) and water, and studied by light scattering and small-angle x-ray scattering. According to the ternary phase diagram of polymer + solvent + non-solvent, MeOH-rich and water-rich solutions are in the one-phase and biphasic regions, respectively. In the latter solutions, the concentrated phase exists as colloidal droplets, which coagulate gradually. The multiplet structure in the melt HPM-PDMS sample may be responsible for the tentative dispersion of HPM-PDMS even in the biphasic region.

Dynamic viscoelasticity and dynamic birefringence of phenolic resins having different cross-linking density were examined to clarify the relationship between structure and viscoelastic properties. Dynamic modulus was found to be insensitive to cross-linking density at a high cross-linking density, where molar mass between the cross-linking points was smaller than the viscoelastic segment size of phenolic resin, whereas the complex strain-optical coefficient reflects more sensitively the cross-linking density.

Conventional preformed particle gels (PPGs) of homo-polyacrylamide have been improved by incorporating an optimized ratio of functional groups, AMPS and NVP. The improved PPG shows acceptable viscoelastic properties, thermal and ionic strength stability when they are exposed and aged under high-temperature (130 °C) and high-salinity (225 000 p.p.m. of TDS) conditions. According to the experimental results obtained, these improved PPG can be used for water control purposes under harsh reservoir conditions.

A nanocomposite of polyurethane (PU) containing 8.78 vol% chemically bonded copper phthalocyanine oligomers (CuPc) was developed. At 100 Hz, the nanocomposite film exhibits a dielectric constant of 391. Under an electric field of 10 V μm⁻¹, a strain of 17.7% and an elastic energy density of 0.927 J cm⁻³ can be achieved. CuPc particle size had a very important role in the enhancement of the electric properties.

Drug can be loaded into the silica nanoparticle-crosslinked thermosensitive hydrogels while preparing the hydrogels by mixing the silica nanoparticle suspension and copolymer solution at room temperature. These hydrogels can then be used for release study without any other processing like washing, purification, etc., as the copolymer and other chemicals were purified in advance. The simplicity of this preparation method allows a great control of drug loading. Because of the high swelling ratios of these hydrogels, cumulative release is high (more than 90%) in both higher and lower temperature than lower critical solution temperature.

A novel plant oil-based green composite was developed using a porous bacterial polyester, poly(3-hydroxybutyrate) (PHB). The porous PHB prepared by thermally induced phase separation was impregnated via immersion with epoxidized soybean oil (ESO), and the subsequent acid-catalyzed curing of ESO afforded a full bio-based composite. The resulting composites exhibited relatively good transparency due to the nanoscale fibrous structure of PHB. The mechanical properties of the composites improved without sacrificing toughness.

This study demonstrates a low amount of halloysite nanotubes modified by a CVA process remarkably improve the thermal stability of PC nanocomposites. The n-octadecyltrimethoxysilane modifier bearing a longer alkyl tails shows stronger affinity with the matrix than the N-(2-aminoethyl)-3-aminopropyltrimethoxysilane modifier bearing shorter alkyl tails with amino group.