The homogeneous non-catalytic hydrogenation of cis-1,4 poly(isoprene), isotactic cis-1,4 poly(1,3-pentadiene) and syndiotactic cis-1,4 poly(1,3-pentadiene) with diimide, formed by thermal decomposition of para-toluenesulfonylhydrazide, is examined. Perfectly alternating ethylene/propylene copolymers having different tacticity (i.e., isotactic and syndiotactic), which are difficult to synthesize...

a series of ethylene-propylene-2-ethylidenebicyclo [2.2.1] hept.5-ene terpolymers (epdm) have been prepared using a vocl3/al2et3cl3 catalyst under various al/v ratios and diene concentrations via solution polymerization and characterized by ftir, mooney viscosity (ml1+4,125oc), and thermal gravimetery analyzing. the polymerization yield was seen to increase with augmentation of the al/v ratio a...

Poly(propylene adipate)-block-poly(ɛ-caprolactone) copolymers were synthesized using a combination of polycondensation and ring-opening polymerization of ɛ-caprolactone in the presence of poly(propylene adipate). Gel permeation chromatography was used for molecular weight determination, whereas hydrogen-1 nuclear magnetic resonance and carbon-13 nuclear magnetic resonance spectroscopy were empl...

New step-growth graft block copolymers were synthesized. These two-sided comb copolymers consisted of a poly(amic ester) (PAE) backbone and pendant poly(propylene oxide) (PPO) grafts. The copolymers were made via a macromonomer approach, in which the 4,6-bischlorocarbonyl isophthalic acid bis[poly(propylene oxide)] ester macromonomer was synthesized through the reaction of hydroxyl-terminated P...

Amphiphilic poly(ethylene oxide)–poly(propylene oxide) (PEO–PPO)-based copolymers are thermoresponsive materials having aggregation properties in aqueous medium. As hydrosolubilizers of poorly water-soluble drugs and improved stability of sensitive agents, these materials have been investigated for improvement in solubility, stability, release and bioavailability of drugs. The goal of the prese...

Mean-square unperturbed dimensions {r2)0 and their temperature coefficient d In{r2)0/dT have been calculated for ethylene-propylene copolymers by means of the rotational isomeric state theory of chain molecules. Conformational energies required in the analysis are shown to be readily obtained from previous analyses of polyethylene and polypropylene, without additional approximations. Results th...

Triblock, diblock and random copolymers of poly(ethylene oxide) and poly(propylene oxide) are used as molecular templates in poly(methyl silsesquioxane) (MSQ) matrices to fabricate ultra low-k dielectric materials (kp2:0). Solidstate NMR shows that polymer architecture plays an important role in the polymer domain size and the polymer– matrix interface in the nanocomposites. Positronium annihil...