last update: August 01, 2000
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STC-ERSP Program Details Principal Investigator: Saad A. Khan Project Title: Rheology of Polymer Melts and Solutions in CO2 (#17) Phone/Fax: 919-515-4519 / 919-515-3465 E-mail: khan@eos.ncsu.edu Research Plan Connectivity Outreach Components Requested Budget Allocation - Year 1 Plans for Additional Funding Research Plan Overall objectives Khan proposes to understand the rheological behavior of polymer melts plasticized with CO2. In particular, the correlation between degree of swelling with CO2 and changes in rheological behavior will be investigated. The effect of surfactants on rheology and swelling will be probed as a function of temperature, pressure and shear rate. Khan also proposes to undertake a systematic study of the rheological behavior of associative polymers (block or comb) in CO2 with and without surfactants. In this regard, experiments will be designed to elucidate relationships between rheological behavior, molecular architecture and polymer/surfactant interactions. Relation to overall objectives of the Center An understanding of the rheological behavior of polymer melts and solutions is critical for enhancing polymer processing and developing new materials. An understanding of the reduction of viscosity of polymer melts can be used to improve/modify its processability, design polymerization schemes to achieve polymers with higher molecular weight and facilitate processing of blends of polymers. Identification of the structure-property relationship in associating system is needed to develop new surfactants and polymers as well as exploring their potential in various applications (e.g. coatings). Approach and Year 1-Year 5 timelines Years 1-2: Develop understanding of the effects of CO2 pressure and temperature on polymer melt viscosity. Investigate the relationship between extent of swelling and rheology of polymer melts. Develop magnetorheometer to study the steady, low shear properties of systems. Year 2-3: Investigate the effects of different surfactants on the swelling properties and rheology of polymer melts. Study the rheology of associative polymers. Year 2-5: Investigate the rheology of polymer blends. Extend the design/capability of the magnetorheometer to incorporate a wider range (e.g. viscosity) and variety (e.g., stress relaxation) of rheological measurements. Determine the rheology of surfactant/associative polymer complexes. Correlate studies with complementary investigations of other PIs (theory of Rubinstein, morphological analysis of Spontak). Thrust area of this proposal Thrust Area C: Rate Processes Connectivity Collaborators, multi-institutional, multi-disciplinary components The rheological studies undertaken will be part of an effort involving several other groups. The surfactant and associative polymers used in this study will be synthesized by DeSimone (UNC-CH) and his group. Spontak (NCSU) will be undertaking morphological analysis of associative systems and blends of polymer melts. Wignall (ORNL) will will use small angle x-ray scattering to study phase behavior of blends of polymer melts. Rubinstein (UNC-CH) will develop theories to predict reversibility and phase behavior of associative systems that will be experimentally probed. Adams (France) will be involved in the magnetorheometer development. Related work in other thrust areas Researchers in Thrust Area A (Interfacial and Colloid Sciences in Compressible Media) will be synthesizing surfactants and associative systems for use in this study. Thus, this study will facilitate characterizing and developing new materials as well as investigating their utility in polymer processing. Researchers in thrust area B (Molecular Thermodynamics and Computer Simulation) will be developing microstructural theories that will facilitate understanding the rheological behavior of associative systems. Sharing of resources (students, supplies, equipment, etc.) The student working in this project will be intimately involved with the PIs outlined above. A post-doctoral associate will be shared with one of the PIs The equipment used in this study and the results obtained will be shared with other groups, and vice versa, to fully comprehend the macroscopic behavior of systems in terms of their molecular architecture and microstructure. Outreach Components Suggested K-12 Outreach Ideas Khan and student funded through this project would be available to demonstrate in schools fundamental concepts of rheology through experiments (e.g rod climbing, tubeless siphon). The next step they would like to take is to present in teacher workshops opportunities for the use of CO2 in rheology and polymer processing, including making new blends. Requested Budget Allocation - Year 1 Personnel salaries
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