SGER: A New Approach to Composition Separation in Crystalizable Copolymers

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9812261 Harrison The proposed research in this SGER Award represents a new approach to speeding up crystallization-dissolution processes in copolymers. Speed is necessary to increase the rate at which similar-composition materials can be separated. Temperature- Rising Elution Fractionation (TREF) is currently used to separate crystallizable copolymers based on relative crystallizabilities, and to obtain a distribution of compositions within the copolymer. Results from TREF were key in developing the latest class of polyolefins using so called `single-site catalysts'. However, like other composition separation techniques, TREF is slow. The proposed research uses TREF as a starting point to identify those fundamental parameters that control separation in such systems. An outcome of the proposed study would be to reduce TREF analysis times in crystallizable copolymers from days, to an hour. One approach to increasing separation speed is to turn TREF into a true chromatographic technique where separation between components increases as material moves along a column. This undertaking has never before been attempted and represents a dramatic departure from the norm. A zone refining type modification of TREF will be used to introduce chromatographic character into the separation process. The final form, as described in the proposal, is neither zone refining nor TREF but could potentially reduce analysis time by a factor of 50. Supplementary methods may aid in separation and other routes to the chromatographic approach also exist. These will be evaluated as required. %%% If successful, composition distribution in crystallizable polymers by `zone TREF' can become as standard as molecular weight distribution by GPC, or melting-crystallinity evaluation by DSC. Given the potential impact which rapid composition analysis could have on the plastics industry in general, and the polyolefin segment in particular, early evaluation of this proposed methodology through a SGER grant is desirable. ***