[CCoE Notice] Dissertation Defense: Understanding Structure/ Property Relationships for Impact Polystyrene

[Grayson, Audrey A]

PhD DEFENSE STUDENT: Jason Clark
DATE: January 14, 2016
TIME: 10:30 AM
PLACE: Mechanical Engineering Conference Room
DISSERTATION CHAIR: Dr. Ramanan Krishnamoorti
________________________________
TITLE:
Understanding Structure/Property Relationships For Impact Polystyrene

The understanding of impact polystyrene structure-property relations was previously limited to ex situ analysis. Developing in-situ analysis methods for morphology development and interfacial tension characterization would enhance fundamental understanding of the multi-component, multi-phase impact polystyrene system and would facilitate the development of online analysis tools to improve product quality and process control.
Diffusing wave spectroscopy measurements and analysis coupled with microfluidic capillary viscometry was verified as a quantitatively accurate tool using polystyrene standards and prepared solutions of well-characterized impact polystyrene samples. The diffusing wave spectroscopy analysis and microfluidic capillary viscometer were then extended as in situ tools to monitor polymerizing systems and thereby follow the morphology development.  Ex situ rheological methods were then employed on post-phase inversion samples to extract interfacial tension using well-established quantitative rheological models.
The effect of block copolymer and random copolymer compatibilizers on controlling the structure and viscoelasticity of impact polystyrene was investigated using these in situ tools. The behavior during polymerization of the structure and viscoelasticity indicated the effectiveness of block copolymers as compatibilizing agents and providing a quantitative mechanism to control the structure of impact polystyrene. Quantification of the compatibilization effect of the copolymers was measured by rheological methods.
Adaptations to capture the complete form of the viscoelastic relaxation time have been proposed and observation of behavior at phase inversion of the impact polystyrene system is recommended for future study. Use of the microfluidic capillary viscometer coupled with the diffusing wave spectroscopy analysis was demonstrated for in situ use on the impact polystyrene polymerizing system, but is readily applicable to other multiphase systems where morphology development and knowledge of shear dependent viscosity behavior during processing is beneficial. The principals demonstrated in this work can be extended readily to inline quality control and quality analysis by the adaptations proposed.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://Bug.EGR.UH.EDU/pipermail/engi-dist/attachments/20160112/94b821e9/attachment.html