9530403 Freed Theoretical research will continue on developing theories for calculating the thermodynamic properties of polymer melts, blends, block copolymers, glasses and liquid crystals. A main and novel feature of this theoretical approach involves the combined treatment of monomer molecular structures, local correlations, and compressibility. The principal investigator will continue this work by extending his lattice cluster theory to include semiflexibility in order to describe polymer glasses and liquid crystals. Another aspect of the proposed research will involve continued studies of the influence of short chain branching (and semiflexibility) on the miscibility of polymer blends (with special focus on polyolefin blends) and, if time permits, on their interfacial properties. Other phenomena to be studied include the pressure dependence of polymer blend miscibility and glass transition temperatures. The accurate description of polymer blends and of polymer liquid crystals with models containing complex monomer structures will require the inclusion of contributions from long range correlations, contributions that only can be evaluated with the aid of sophisticated computer-based combinatorial algorithms which will be devised and applied to this project. %%% This theoretical research involves both analytical and computational components. The research will determine a variety of properties of polymers and their mixtures using a formalism developed by the principal investigator. Modifications to this formalism will be made in order to model more realistic situations. ***
