Efficient Simulation of Melt Viscoelasticity of Architecturally Varied Polymer Mixtures

点击翻译按钮获取中文摘要

1067707DorganIn this project, non-equilibrium molecular scale simulations are used to advance the understanding of flow of plastic materials during manufacturing operations. The proposed new modeling technique allows profound insight into the flow properties of different types (linear vs. branched) polymers and their mixtures. Such an understanding has been long sought in order to address issues in materials design and polymer processing. Ultimately, such understanding will lead to the best combination of polymer types that achieve a desired technical objective. Improved understanding of polymer flow properties provides a means of designing optimized additives capable of delivering desired properties. For validation, results from the new simulation techniques will be held against existing experimental data for novel polymer architectures and then used to design polymer mixtures having desirable processing characteristics. The intellectual merit of the work lies in developing the computer codes and in generating rheological data for complex polymeric systems. The work builds on existing success in accurately and completely describing the melt rheological properties of linear architectures using these same simulation techniques. In addition to the effects of chain architecture, confinement effects on flow are studied. The results generated can shed insight into novel confinement effects that are being exploited in emerging areas of nanotechnology. The activities pursued integrate research and teaching while promoting discovery; to successfully complete the project several subjects must be mastered including polymer science, statistical mechanics, computer science, and molecular visualization. Computer programs for performing the simulations will be shared via posting on the CSM Chemical Engineering web pages. Additional dissemination of the results will be accomplished through publication in widely available scientific journals (J. Chemical Physics and Macromolecules) and presentations at national (ACS, APS, AICHE, and SoR (Society of Rheology) and international meetings (Polymer Processing Society, International Congress of Rheology). The commitment to diversity evidenced by past performance by the PI will be continued. In addition to direct support of underrepresented groups as graduate students, outreach activities will be continued. Supported graduate students all participate in MentorNet as a means of providing role models to younger students. The Denver, Colorado region is particularly rich for recruiting Hispanic and Native American students. The PI has worked extensively with students from varied backgrounds, particularly in the context of the NSF supported Research Experience for Undergraduates (REU) program.