05/06/2022
By Sokny Long

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Akanksha Patel on “Improving enzymatic depolymerization of post-consumer polyethylene terephthalate (PET) waste via pretreatment methods.”

Ph.D. Student: Akanksha Patel
Proposal Defense Date: Thursday, May 19, 2022
Time: 9 to 11 a.m. EST
Location: This will be physically at ETIC 445 and a virtual defense via Zoom. Those interested in attending should contact akanksha_patel@student.uml.edu and committee advisor, margaret_sobkowiczkline@uml.edu, at least 24 hours prior to the defense to request access to the meeting.


Committee Chair Advisor: Margaret J. SobkowiczKline, Associate Professor, Plastics Engineering, University of Massachusetts Lowell

Committee Members:

  • Ramaswamy Nagarajan, Professor, Plastics Engineering, University of Massachusetts Lowell
  • Stephen Johnston, Professor, Plastics Engineering, University of Massachusetts Lowell
  • Dongming Xie, Associate Professor, Chemical Engineering, University of Massachusetts Lowell

Brief Abstract:
Polyethylene terephthalate (PET) is an omnipresent material used in numerous applications such as bottles, textiles, food packaging and automotive parts, etc. Its unique properties like high transparency, strength-to-weight ratio, and chemical resistance make it a desirable material for many household applications. High demand for PET results in more waste, leading to a need for more efficient recycling strategies. Enzymatic recycling of PET is a new recycling method that uses enzymes to treat various types of PET wastes in an ecologically acceptable manner. It offers several benefits including the involvement of less harmful chemicals and lowers energy costs compared to other commonly used recycling technologies such as mechanical, chemical, or thermal recycling. Enzyme efficiency and effectiveness are the main limiting factors, but straightforward improvements can be made by altering the structural properties of materials (e.g., Tg, crystallinity, Mw, IV, specific surface area, etc.). In this work, we introduce a pretreatment method for post-consumer PET waste via an ultra-high-speed twin-screw extruder using different chemical reagents. The main aim of these pretreatments was to disrupt the molecular packing of PET substrate with increased binding sites for enzymes to react further. These pretreated samples have shown a decrease in molecular weight, glass transition temperature as well as crystallinity, and improved specific surface area after the milling process. Unpurified Leaf-branch compost cutinase (LCC) enzyme was used for the further enzymatic reaction, where higher depolymerization was observed with low crystallinity and improved specific surface area. This work has given a significantly faster and energy-efficient method for post-consumer PET depolymerization using unpurified LCC enzymes.

All interested students and faculty members are invited to attend the online defense via remote access.