02/15/2024
By Danielle Fretwell

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Mansour Alotaibi on "The Impact of Compounding Systems and Parameters on Polymer Degradation."

Candidate Name: Mansour Alotaibi
Degree: Doctoral
Defense Date: Thursday, Feb. 29, 2024
Time: 1 to 3 p.m.
Location: Perry Hall 215

Committee:

  • Advisor Carol Barry, Professor and Chair, Plastics Engineering, University of Massachusetts Lowell
  • Amir Ameli, Assistant Professor, Plastics Engineering, University of Massachusetts Lowell
  • Akshay Kokil, Assistant Teaching Professor, Plastics Engineering, University of Massachusetts Lowell

Brief Abstract:

The machine type, screw or rotor design, and processing parameters (e.g., screw or rotor speed, processing temperatures) play a crucial role in determining the level of degradation and the resulting changes in properties when melt compounding polymers. Therefore, it is important to understand how processing systems and variables affect polymer molecular weight to minimize degradation with good end product quality. Most commercial melt processing is performed with co-rotating twin screw extruders. This research, however, focused on evaluating the performance of other compounding systems which can provide better mixing and greater throughput than twin screw extruders. The first part of this work investigated the impact of reprocessing with a quad screw extruder (QSE) and comparable twin screw extruder (TSE) on the degradation of polypropylene material. In this work, a polypropylene reprocessed multiple times at different screw speeds; the reprocessed materials were characterized for their rheological, chemical, mechanical, thermal, and morphological properties. The second part of this work focuses on the effects of rotor design, single screw design, rotor speed, feed rate, and orifice setting in a Farrel continuous mixer (FCM). This fundamental study seeks to understand the effects of these parameters on the residence time and melt temperature of a very stable polymer – i.e., high density polyethylene. The third part of this work will investigate the impact of rotor configuration, single screw design, and processing in a FCM on the degradation of a biopolymer polymer, polylactic acid (PLA). The final part of this work will study the influence of rotor design and single screw design of a continuous mixer system on the performance of blending PLA and amorphous polyhydroxyalkanoate (aPHA).