High temperature gel permeation chromatography

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Polyethylene and polypropylene are high-tonnage plastics used to make bottles, grocery bags, wrapping films, automotive parts, and several other applications. These plastics, known as polyolefins, are very important because of their versatility, low cost and non-toxicity.    Polyolefins are versatile because their molecules can be altered to make products with properties for different application. By changing the distribution of molecular sizes of polyethylene (formally know as the molecular weight distribution - MWD), it is possible to make plastics that have properties varying from those of waxes (small molecules) to those of very strong materials such as the ones used to make gas pipes (very large molecules). To better understand these materials, it is fundamental to characterize them at the molecular level. This molecular characterization can then be used to enhance the quality of different polyolefin-made products.    The MWD of polyolefins is measured with laboratory instruments called high-temperature gel permeation chromatography (HT-GPC). This instrument is of the utmost importance for understanding polyolefin production and applications. We are currently very active in this area and own an old model HT-GPC that is not reliable anymore. The objective of this grant proposal is to purchase a new HT-GPC for our laboratories with several modern features that will provide significantly more accurate information on the nature of polyolefins we produce.    The knowledge of the MWD of polyolefins is fundamental for the study of polymerization catalysis, kinetics of polymerization processes, polymer processing and structure-property relationships. We have a very active, long-term research program in all these areas, funded by both industry and government; this program will be greatly enhanced by the acquisition of this new GPC instrument.