PHBV/TPU/cellulose compounds for compostable injection molded parts with improved thermal and mechanical performance

Abstract

Poly(hydroxybutyrate-co-valerate) (PHBV) is a biopolymer that has gained a lot of attention because of its biodegradability, good thermal resistance, and balanced mechanical properties with respect to some commodity plastics. However, it presents two big limitations that hinder its potential application in replacing plastics for rigid injected parts: high cost and low toughness. Aiming at overcoming these limitations, the use of two additives in a PHBV matrix was explored: thermoplastic polyurethane (TPU) as an impact modifier and cellulose as reinforcing filler. Compounds of PHBV with different TPUs and cellulose contents were prepared by extrusion and, subsequently, injection molding. The morphology, thermal, and mechanical properties of the so-obtained materials were analyzed. Also, the biodisintegrability under standard composting conditions of the studied compositions was also assessed. The results of this work show that the obtained PHBV/TPU/cellulose compounds are biodisintegrable and show balanced properties in terms of thermal resistance–stiffness–toughness. These properties point these compounds as potential candidates to replace commodities in rigid part applications that require biodisintegration in their end-of-life, being able to be processed in a conventional injection molding industrial facility.