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...

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...

In the past few years, an increasing number of in situ-forming systems have been reported in the literature for various biomedical applications, including drug delivery, cell encapsulation, and tissue repair. There are several possible mechanisms that lead to in situ gel formation: solvent exchange, UV-irradiation, ionic cross-linkage, pH change, and temperature modulation. The thermosensitive ...

Pluronic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers are grafted with poly(vinyl pyrrolidone) by free radical polymerization of vinyl pyrrolidone with simultaneous chain transfer to the Pluronic in dioxane. This modified polymer has both thermal responsiveness and remarkable capacity to interact with a wide variety of hydrophilic and hydrop...

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...

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...

Data were obtained on the copolymerization of ethylene with α-olefins over supported titanium–magnesium catalysts (TMC) prepared same magnesium dichloride support but differing in composition and oxidation state titanium. The kinetics 1-hexene TMC different compositions studied. produced ethylene–1-hexene copolymers, their molecular weight distribution, thermophysical characteristics, branching...

This review presents some examples obtained by molecular techniques in the study of non-ionic reverse micelles of poly(ethylene oxide) type surfactants: tetraethylene glycol mono-ndodecyl ether (C12E4), Triton X-100, and triblok copolymers poly(ethylene oxide)-blockpoly(propylene oxide)-blockpoly(ethylene oxide) (L62 and L64 Pluronics). By using specific spectral parameters of spin, fluorescenc...