Advisory Committee Chair
Brian Pillay
Advisory Committee Members
Haibin King
Katherine Stewart
Document Type
Thesis
Date of Award
2023
Degree Name by School
Master of Science in Materials Engineering (MSMtE) School of Engineering
Abstract
Recycling of plastics is one of the biggest challenges facing the earth in the 21st century due to the environmental impact they have on the waste stream. One of the biggest challenges in the recycling of these materials are their incompatibility; therefore, the segregation of waste in order to repurpose them back into something useful for a second life is an important barrier to overcome. This study expands on work done in literature to correlate rheological properties of linear virgin plastics to their ��w, which is useful in deducing some mechanical behaviors of the material. The benefit being the impact on industries to run cost-effective and reliable measurements using a Melt Flow Indexer to roughly determine the ratio of HDPE/PP blends if a rough estimate for ��w, is provided. Otherwise, a ��w, can be deduced with a reasonable estimate of the blend of HDPE/PP in the waste stream. This paper employs techniques such as differential scanning calorimetry, thermogravimetric analysis, melt flow indexing, and gel-permeation chromatography to investigate thermal, rheological, and mechanical properties of various blends of both virgin and post-consumer HDPE and PP over five heat histories. The introduction of blends of virgin materials expands on the literature, and post-consumer plastics provide a real-world example of how this relation holds with every day postconsumer plastics such as milk jugs, coffee jars, plastic pottery, and detergent bottles. The results show that the correlation established in literature holds for the virgin materials; however, the post-consumer plastics did not favor this relationship and was more accurately predicted using the raw data plotted against one another. This is an interesting discovery and leads to the investigation of exactly what properties affect this correlation, and if there is a predictable curve depending on the presence of additives or the spread in MFI or ��w, properties.
Recommended Citation
Stonecipher, Ethan, "Analysis of Correlation Between Molecular Weight Distribution and Melt Flow Index of Polyethylene and Polypropyle Blends" (2023). All ETDs from UAB. 405.
https://digitalcommons.library.uab.edu/etd-collection/405