Exploring Polymer Dynamics in Solutions and Blends

Case Western Reserve University, Cleveland OH

Investigators

Abstract

Systematic work will be carried out to elucidate how the component dynamics of A and B in a miscible A/B blend depend differently on temperature and composition, i.e., to uncover how friction factors associated with A and B each vary with the temperature and composition, and to determine whether A and B experience glass transition at significantly different temperatures. The concept of polymer plasticization is yet to proven as the origin of the negative intrinsic viscosity observed in solutions where the polymer component has a significantly different temperatures. It remains a fundamental question whether dynamics of polymer A in a solution or blend depend are completely determined by inter-chain (extrinsic) interactions or are further influenced by intra-chain (intrinsic) interaction so that they are from those of B and whether A undergoes the glass transition at a different temperature from that where B experiences its glass transition.. A novel Solution Rheology Approach (SRA) will be applied to probe these topics. To depict the separate component dynamics operative in miscible blends (e.g., made of species A and B), corresponding "object" and "mirror" solutions (e.g., made of polymeric A in oligomeric B and polymeric B in oligomeric A) will be investigated respectively to resolve the component dynamics of A and B. The protocol studying solution dynamics to gain explicit information about the component dynamics of corresponding blends represents a new attractive approach to the subject, to which few experimental techniques have been successfully and effectively applied. This SRA has the advantage of being able to determine the component dynamics with minimal concentration fluctuations as well as to probe component dynamics in immiscible blends. %%% The objective of the proposed research is to achieve new understanding of polymer dynamics in solutions and blends that are pertinent to rheology and processing of polymeric materials. The subject of the proposed work is at the heart of polymer science and engineering and is a very active area of polymer materials research. One central question is how to predict the overall viscoelasticity and individual component dynamics of a molecularly mixed polymer blend knowing the glass transition and viscoelastic properties of each component.