Studies on the thermal and mechanical behavior of PLA-PET blends

• Published in: Journal of applied polymer science 2016-11, Vol.133 (43), p.np-n/a
• Main Authors: McLauchlin, Andrew R., Ghita, Oana R.
• Format: Article
• Language: English
• Subjects: amorphous; Biodegradability; biopolymers and renewable polymers; Crystallization; differential scanning calorimetry; Fracture strength; Injection molding; Materials science; Mechanical properties; Mechanical tests; Microparticles; Polyethylene terephthalate; Polyethylene terephthalates; Polylactic acid; Polymer blends; Polymers; properties and characterization; Thermal degradation
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.44147

ABSTRACT The increasing use of bio‐sourced and biodegradable polymers such as poly(lactic acid) (PLA) in bottle packaging presents an increasing challenge to the polyethylene terephthalate (PET) recycling process. Despite advanced separation technologies to remove PLA from PET recyclate, PLA may still be found in rPET process streams. This study explores the effects of PLA on the mechanical properties and crystallization behavior of blends of PET containing 0.5–20% PLA produced by injection molding. SEM indicates an immiscible blend of the two polymers and TGA confirms the independent behavior of the two polymers under thermal degradation conditions. Temperature‐modulated DSC studies indicate that adding PLA to PET increases the rigid amorphous fraction of the PET moiety. Critical amounts of PLA induce stress oscillation behavior during mechanical testing. The mechanical behavior of the samples is explained by antagonistic interaction between increased rigid amorphous fraction and decreased fracture strength arising from an increased population of PLA microparticles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44147.