Complex Fluids from Model Polyolefins

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9307098 Balsara This research is a study of the thermodynamic properties of blends of polymethylbutene (PMB) and polyethylbutene (PEB) containing polymethylbutene-polyethylbutene (PMB-PEB) block copolymers to examine the possibility of forming complex fluids. Small angle neutron scattering and light scattering will be the primary tools for this study. The required model polymers will be synthesized by "living" anionic polymerization of dienes under high-vacuum and subsequent hydrogenation, or deuteration for creating neutron scattering contrast. The proposed study will consist of two stages. First, the thermodynamics of mixing of PMB/PEB/PMB-PEB mixtures will be obtained from small angle neutron scattering measurements on homogeneous, single-phase mixtures. These data will provide the thermodynamic basis for the rational design of the dispersed phase in phase-separated systems. The second stage will consist of examining such systems. The evolution of the two-phase structures which will be studied by time resolved small angle neutron scattering and light-scattering measurements on thermodynamically unstable mixtures. The experiments are designed so that the transition temperatures from single-phase to two-phase systems are experimentally accessible (in the vicinity of 170 C). The scattering experiments will determine the shape and size of the dispersed phase, the interfacial activity of the block copolymer, and whether or not the morphology is at equilibrium. These polymers belong to one of the largest and most important polymer blend family, namely that arising from polyolefins- polyethylene, polypropylene, polybutene and their copolymers. In spite of their commercial importance, there is virtually no data on the thermodynamics of mixing of these multi-component systems. ***