By a News Reporter-Staff News Editor at Science Letter -- Research findings on Halogens are discussed in a new report. According to news originating from Gainesville, Florida, by NewsRx correspondents, research stated, "The crystallization of a polyethylene with precise chlorine substitution on each and every 15th backbone carbon displays a drastic change in crystalline structure in a narrow interval of crystallization temperatures. The structural change occurs within one degree of undercooling and is accompanied by a sharp increase in melting temperature, a change in WAXD patterns, and a dramatic increase in TG conformers around the Cl substitution while the main CH2 sequence remains with the all-trans packing."
Our news journalists obtained a quote from the research from the University of Florida, "These changes correlate with the formation of two different polymorphs characterized by a different packing and distribution of Cl atoms in the crystallites. Under fast crystallization kinetics, the chains assemble in an all-trans planar packing (form I) with a layered Cl distribution that presents some longitudinal disorder, while slower crystallization rates favor a more structured intermolecular halogen staggering consistent with a herringbone-like nonplanar structure (form II). The drastic change in morphology is enabled by the precise halogen placement in the chain and appears to be driven by the selection of the nucleus stem length in the initial stages of the crystallization."
According to the news editors, the research concluded: "Exquisite kinetic control of the crystallization in novel polyolefins of this nature allows models for generating new materials based on nanostructures at the lamellar and sublamellar level not feasible in classical branched polyethylenes."
For more information on this research see: Kinetic Control of Chlorine Packing in Crystals of a Precisely Substituted Polyethylene. Toward Advanced Polyolefin Materials. Macromolecules, 2014;47(1):236-245. Macromolecules can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society - www.acs.org; Macromolecules - www.pubs.acs.org/journal/mamobx)
The news correspondents report that additional information may be obtained from P. Kaner, University of Florida, Dept. of Chem, Gainesville, FL 32611, United States. Additional authors for this research include C. Ruiz-Orta, E. Boz, K.B. Wagener, M. Tasaki, K. Tashiro and R.G. Alamo (see also Halogens).
Keywords for this news article include: Florida, Alkenes, Chlorine, Halogens, Polyenes, Gainesville, Hydrocarbons, United States, Polyethylenes, Organic Chemicals, North and Central America
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC