Date of Award

Fall 12-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Materials Science

First Advisor

Dr. Ram K. Gupta

Second Advisor

Dr. Serif Uran

Third Advisor

Dr. Tim Dawsey

Keywords

Cellulose, Bio-based, Castor oil, Adhesive, Recycle

Abstract

The increasing consumption of paper towels generates significant waste, necessitating sustainable recycling solutions. This study investigates the extraction of cellulose from waste paper towels and its application in bio-based polyurethane (PU) adhesives. The extraction process includes alkali treatment, bleaching, and acid hydrolysis to obtain recycled cellulose (rCL). The extracted cellulose is then used in PU synthesis alongside castor oil polyol (COP) and methylene diphenyl diisocyanate (MDI), with performance compared to industrial cellulose-based PU. The obtained rCL and synthesized PU adhesives have been characterized with FT-IR spectra for structural confirmation. In addition, the synthesized PU adhesives demonstrated improved mechanical and thermal properties. At room temperature, tensile testing showed that rCL -5wt.% exhibited a higher tensile strength of 7.37 MPa as compared to 6.36 MPa for CL-5 wt.%, indicating better mechanical strength of PU adhesives with rCL. Differential scanning calorimetry (DSC) analysis showed an elevated glass transition temperature (Tg) of 82.24°C for the rCL-5wt.% and 72.26°C for the CL-5wt.% as compared to 68.74°C for the control sample, indicating improved rigidity. Gel swell analysis confirmed a lower swelling and higher gel content for rCL-5wt.% as compared to CL-5wt.%, reflecting a denser, more robust polymer network structure with high crosslinking with rCL. These results suggest that recycled cellulose is a viable alternative to industrial cellulose for sustainable polymer applications. The study contributes to eco-friendly material development by promoting waste utilization and reducing reliance on petrochemical-based adhesives.

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