Mechanical and thermal properties of polylactic acid blended with recycled polymethyl methacrylate

Dehghani, Samaneh; Salehiyan, Reza; Pholharn, Dutchanee; Srithep, Yottha

Abstract

This study investigates the effect of incorporating recycled polymethyl methacrylate (r-PMMA) into polylactic acid (PLA) and further modifications with a bio-based compatibilizer (epoxidized soybean oil [ESO]). Various PLA:r-PMMA ratios were evaluated, with and without ESO. Blending r-PMMA into PLA significantly influenced mechanical properties. The 10PLA90r-PMMA blend showed enhanced elongation at break (6.10%) and tensile toughness (1686 kJ/m3) compared to pure PLA (3.34% and 737 kJ/m3, respectively), addressing PLA's inherent brittleness. The 30PLA70r-PMMA composition exhibited a tensile strength (TS) of 51.44 MPa and significant tensile toughness (1237 kJ/m3). Thermal analysis revealed an increase in the glass transition temperature (Tg) with higher r-PMMA content, reaching 124°C for 100r-PMMA, and a decrease in crystallinity percentage from 68.17% (pure PLA) to 30.43% (50PLA50r-PMMA). Incorporating ESO into a 50 PLA50r-PMMA blend modified its properties. Adding 3 parts per hundred resins (phr) ESO improved elongation at break (5.68%) and tensile toughness (1302 kJ/m3) while reducing TS (35.03 MPa). At 6 phr ESO, flexibility was maximized with an elongation of 6.37%, but TS decreased to 26.89 MPa. These findings highlight the synergy between r-PMMA and ESO in enhancing PLA's performance for sustainable applications and balancing mechanical and thermal properties while addressing environmental challenges.

Citation

Dehghani, S., Salehiyan, R., Pholharn, D., & Srithep, Y. (2025). Mechanical and thermal properties of polylactic acid blended with recycled polymethyl methacrylate. Polymer Engineering and Science, 65(4), 2119-2132. https://doi.org/10.1002/pen.27141

• Journal Article Type: Article
• Acceptance Date: Feb 3, 2025
• Online Publication Date: Feb 14, 2025
• Publication Date: 2025
• Deposit Date: Feb 18, 2025
• Publicly Available Date: Feb 15, 2026
• Journal: Polymer Engineering & Science
• Print ISSN: 0032-3888
• Electronic ISSN: 1548-2634
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 65
• Issue: 4
• Pages: 2119-2132
• DOI: https://doi.org/10.1002/pen.27141
• Keywords: biocompatibilizer, mechanical properties, phone screens, polylactic acid, recycled polymethyl methacrylate
• Public URL: http://researchrepository.napier.ac.uk/Output/4122354