Facile Side-Chain Functionalization of Polybutadiene and Its Use of Prepare Graft Copolymers.

A better preparation of graft copolymers would combine free radicals displaying high selectivity in the abstraction reaction along with radicals that can act as growth moderators during grafting to reduce termination by coupling. Researchers employed stepwise growth moderated by reversible termination in the preparation of polydiene based..

Synthesis of Oxide-Supported Vanadium Catalysts and Their Activity in Ethylene Polymerization

Researchers studied the activity of oxide supported vanadium based catalyst systems (VOCI(3)/Et(2)AICI) in low pressure ethylene polymerization and the properties of the resultant polyethylenes in relation to the type and mode of modification of the oxide support. Alumina, silica, and an unconventional silica type material prepared by the..

Spin-Label Investigation of the Dynamic Behavior of Stearic Acid Additives in Poly(vinyl chloride)

An experiment added three kinds of spin label compounds having a DOXYL-radical substituent at different positions on the hydrocarbon chain of stearic acid to polyvinyl chloride (PVC) with dioctyl phthalate (DOP) as plasticizer. ESR measurements determined the order parameter (S) of each radical in the PVC resin. An increase in the quantit..

Initiator-Free Photo-Graft Polymerization of Various Vinyl Monomers into Solubilized Collagen Films and Characterization of Grafted Films.

Researchers observed a marked solvent effect on initiator-free photo-graft polymerization of methyl methacrylate (MMA). The order of solvent for increasing grafting was the same as the order of swelling of collagen: methanol > ethanol > n-propanol > acetone = toluene. Polymerization of n-butyl methacrylate (BMA), 2-hydroxyl ethyl methacry..

Synthesis of Poly(ester ether)s by the Reaction of gamma-Butyrolactone with Diols and Their Application to Polyurethanes.

A reaction of gamma-butyrolactone (BL) with diols in the presence of acidic catalyst under reflux in xylene yielded polyester ethers. Researchers attempted to correlate the molecular weight of the resultant polyester ethers with such polymerization conditions as the amount of activated clay and starting glycol components. Reaction conditi..

Plastics in Medicine -- Current Status and Prospectives.

A review of the applications of polymers in medicine focuses on the requirements and criteria of biopolymers, examples of unsatisfactory results of applications, and future research projects. Homeostasis and the contact of biopolymers with blood and their biodegradation are described. 10 refs.

New Avenues in Ethylene Synthesis

United States consumption of ethylene for commodity plastics in 1998 totalled 23.6 billion kilograms. Processing industries are exploring new methods of transforming abundant, inexpensive feed materials into higher value fuels and chemicals. Recent research involved the development of a reactor that would allow a single-stage synthesis of..

RHEOLOGICAL PROPERTIES OF FIBER-FORMING PETROLEUM PITCHES

The rheological properties of high-temperature, carbon fiber-forming petroleum pitches with investigated in the temperature range of 230 to 350 degrees Centigrade. The pitches were prepared from benzene pyrolysis resin. A rotary viscometer with a chromel-alumel thermocouple was used to measure the rheological properties of samples in a he..

HIGH-MODULUS, HIGH-STRENGTH CARBON FIBER BASED ON POLYACRYLONITRILE

A high-mo dulus, high-strength carbon fiber based on polyacrylonitrile was prepared by heat treatment and boronizing at 2800 degrees Centigrade. The heat treatments consisted of oxidation, carbonization, and/or graphitization. Dynamic elastic modulus and strength in extension were measured. The optimal heat treatment was preliminary carbo..

DEGRADATION OF CU(II)-PARTLY ALKYLATED WOOL KERATIN COMPLEX BY HYDROGEN PEROXIDE

Hydrogen peroxide caused the degradation of wool keratin fibers when the Cu(II) ion was bound to the wool keratin. S-B-(2-pyridylethyl) cysteine residue and the tyrosine content in the wool fiber residue increased as the degradation proceeded. These results suggest that the high-sulfur proteins were easily degraded in the peptide bond cle..