07/19/2022
By Sokny Long
Ph.D. Candidate Name: Thamer Aldhafeeri
Defense Date: Monday, August 02, 2022
Time: 9 to 11 a.m. EDT
Location: ETIC-445
Committee Chair (Advisor): Carol Barry, D.Eng., Professor, Department of Plastics Engineering, University of Massachusetts Lowell
Committee Members:
Amir Ameli, Ph.D., Assistant Professor, Plastics Engineering, Department of Plastics Engineering, University of Massachusetts Lowell
Davide Masato, Ph.D., Assistant Professor, Department of Plastics Engineering, University of Massachusetts Lowell
Brief Abstract:
Melt compounding of polymers enhances polymer performance by mixing other polymers or additives with the base polymer. Most commercial melt compounding is performed with twin screw extruders. This research focused on evaluating the performance of the newer compounding systems which provide greater throughput than twin screw extruders. First, polypropylene and glass fibers were compounded using a quad screw extruder and critical processing parameters (i.e., screw speed, fiber content, feed rate, screw configuration, and feed location). The resultant fiber degradation and dispersion were compared to those for a similar twin screw extruder. Second, the twin screw extruder and quad screw extruders were evaluated for their effect on the degradation of a biodegradable polymer, polylactic acid (PLA). When the PLA was processed using different screw speeds, feed rates, and screw configurations, the critical factor affecting degradation was found to be extruder residence time, rather than the melt temperature suggested by prior work. Third, screw speed and rotor design) in a continuous mixer with tangential twin screws were investigated for their effects on the degradation of neat PLA and the blending of PLA with polybutylene succinate (PBS).
All interested are invited to attend the in-person defense.