Saturated Thermoplastic Elastomers via One-Step Copolymerization.

Copolymerization of a lower alpha-olefin monomer system and a C(16) to C(50) alpha-olefin comonomer yields a thermoplastic elastomer with an amorphous backbone and crystalline side chains that features good flexibility and softness and a relatively high melting point. The copolymerization uses a transition metal catalyst. A conventional t..

Radical Copolymerization of Various Vinyl Esters and the Cotacticities of the Copolymers.

Researchers conducted radical copolymerization of vinyl acetate (Vac) with vinyl butylate (VBu), vinyl isobutylate (ViBu), vinyl trifluoroacetate (VTFAc), and vinyl benzoate (VBz), and vinyl pivalate (VP) with VTFAc at 0 degrees centigrade by ultraviolet irradiation. Hydrogen nuclear magnetic spectra of polyvinyl alcohols obtained by sapo..

Predicting Phase Diagrams of Polymer/Clay Composites: The Role of Grafted Organic Modifiers.

Research on phase behavior in polymer/clay composites combined the density functional formalism for the ordering of the clay sheets with the self consistent field calculated potential for the effective clay-clay interactions within a polymer melt. The potential was integrated into the Somoza-Tarazona free energy functional for anisotropic..

Chlorination of Polyamides and Characteristics of the Chlorinated Polymers.

Researchers studied the chlorination and dechlorination of nylon 66 and poly-m-phenyleneisophthalamide (PMPIPA). Chlorine analysis, infrared and deuterium neutron magnetic resonance spectroscopy, viscometry, and wide angle X-ray diffraction determined the chemical structures and properties of the chlorinated polymers. Nylon 66 chlorinatio..

Entrap-Immobilization of Cells (S. cerevisiae) on Titanium Iso-Propoxide-Cellulose Gel Fiber and Its Properties.

Gel formation entrapped and immobilized S. cerevisiae cells on titanium iso-propoxide-cellulose acetate fiber and compared them with native cells for ehtyl alcohol fermentation and beta-keto ester (ethyl acetoacetate) biotransformation. The entrapped fibers can be used in phosphate media, in which conventionally entrapped alginate dissolv..

Miscibility in Saturated Polymer Blends.

Metallocene catalysis yields commodity grade polymers with a low level of chain defects and achieves controlled incorporation of a wide range of comonomers and a very narrow molecular weight and short chain branching distribution. These properties enable the rational design of miscibility windows in blends of these polymers, resulting in ..

Record World Consumption Boosted by Recovery in Brazil and Russia and Strong Growth in China and Pakistan.

The July 1999 United States Department of Agriculture world cotton consumption estimate for the 1999-2000 market year indicated growth of approximately 3.5 percent from the previous year. A continued strong world economic performance fueled a strong demand for cotton products. Initial cotton consumption estimates showed substantial growth..

Outlook for Cotton Prices.

Cotton prices have fallen for four consecutive seasons and are now as low s they were in 1985-1986. The average Cotlook A Index declined 38 percent between 1994-1995 and 1998-1999. Cotton prices will not increase over the next two years due to weak demand, changes in cotton policy in the People's Republic of China, and government subsidie..

53rd Annual Conference Report on Cotton Insect Research and Control.

An overview of cotton insect infestation in the United States in 1999 describes crop and arthropod pest conditions and research developments in Alabama, Arizona, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, new Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia. Arthropod pests re..

Weed Control in Ultra Narrow Row Cotton in Arizona.

Field studies in 1999 evaluated the use of the pre-emergence herbicides Prowl and Treflan and the postemergence herbicides Staple and Roundup Ultra (in conjunction with Roundup Ready cotton) for weed control in ultra narrow row cotton in Arizona. Prowl at 2.4 pints per acre or Treflan at 0.75 pound active ingredient per acre followed by R..