报告题目：Selection criteria for three different commercial applications
报 告 人：Prof. Shaw Ling Hsu
报告时间：2019年6月22日（周六）下午4:00
报告地点：化学楼一号会议室
邀 请 人：解孝林教授
报告人简介：
Prof. Shaw Ling Hsu received his BSc in 1970 from Rutgers University and his PhD in 1975 from University of Michigan. Then, he worked in Allied-Signal Corporation as a research chemist during 1976-1978. In 1978, he joined the Department of Polymer Science and Engineering of University of Massachusetts Amherst and has been a full professor since 1987. He was the head of the department during 2003 and 2013. Hsu’s main research interests are the development of environmentally appropriate materials, development of new polymer morphologies for controlled drug delivery, development of multiphase reactive blends, structural characterization of polymer structure in restricted geometry (surfaces/interfaces), deformation behavior of polymers, aging behavior of polymers, residual stress in coatings. He has published over 350 papers including 80+ in Macromolecules. Among the awards and honors Hsu received, he won Phi Beta Kappa, Danforth Foundation Fellow, Sigma Xi Honorary Research Society, National Science Foundation Creativity Award, American Physical Society Fellowship, University of Massachusetts Faculty Fellowship, University Outstanding Faculty Leadership Award, USDA National Panel Manager, Bioenergy Production and Byproducts, Chair of Advanced Materials Platform Panel of Taiwan
报告简介：
This talk addresses the physical characteristics of polymers that played a crucial role in achieving commercial success in three different applications. The first example deals with polyolefin based hot melt adhesives. Here the crystallization kinetics of various copolymers is crucial in the development of green strength of this class of adhesives. Clear elucidation of the nucleation process and subsequent crystal growth of specific copolymers were the necessary components in the commercial achievement. Similarly, in the second example, chain configuration also played a crucial role in the success of flexible polyurethane foams. It can be said that polyol design is the single most important aspect to achieve high mechanical properties of flexible foams. The elasticity of such polyols no doubt is important. However, a factor that is commonly overlooked is the dispersion property of the polyol in order to achieve the blowing process effectively. We have shown that successful mathematical modeling of mass spectroscopic data of polyols was essential in determining both mechanical properties and affinity for water, an essential element in the PU blowing process. Lastly, crosslinking is a crucial structural component in raising mechanical properties and stability at elevated temperatures. Surprisingly even for such structures, moisture significantly affects physical properties. The explanation for this type of relaxation is often nebulous. Our study has focused on crosslinked phenolics. Our study presents the possibility that separate relaxation mechanisms are at work with very different physical origins. We have cleanly and quantitatively separated the magnitude of each moisture absorption mechanism and assigned their relative importance. Our results will alter the view of the polymer community on moisture absorption effects in polymers.
