Hybrid recycling approaches for PLA, PHA, and related composite blended films

Overview

This research program addresses two linked challenges in sustainable packaging: improving the performance of biodegradable PLA and PHA films and creating viable end-of-life recycling pathways for these polymers and their composites. Melt blending PLA with PHA, copolymers, plasticizers, and biomass-based nanofillers is used to tune crystallinity, stiffness, flexibility, hydrophobicity, and barrier properties (oxygen permeability and water vapor transmission rate). A hybrid recycling strategy combining enzymatic and chemical depolymerization is then applied to recover monomers from the blended and composite films, enabling repolymerization into new polymers and films. Together, these approaches offer a circular route for green polymer packaging that reduces reliance on composting and addresses limitations of thermal cracking of polyesters.

Technical specifications

• Film formulation: PLA melt-blended with PHA, copolymers, and plasticizers to improve processability and flexibility for film extrusion
• Nanocomposite reinforcement: Small amounts of biomass-based nanomaterials such as lignin and cellulose nanocrystals added to tune hydrophobicity, optical clarity, UV barrier, and mechanical performance
• Performance targets: Increased crystallinity, improved mechanical resistance, low oxygen permeability, low water vapor transmission rate, and transparency suitable for packaging applications
• Characterization: Thermal, mechanical, crystallization, hydrophobicity, optical, and barrier properties measured by standard methods; degradation tracked through structural analysis, weight loss, and microscopy
• Hybrid depolymerization: Sequential enzymatic followed by ambient-temperature chemical depolymerization to overcome the slow kinetics of enzymatic-only PLA degradation
• Monomer recovery and repolymerization: Quantitative monitoring of monomer and byproduct formation, isolation of monomers by standard methods, and repolymerization to produce recycled films

Technology readiness level

The work is at an early-to-mid research stage. Film formulations are being prepared via industrially viable melt blending, with planned characterization of thermal, mechanical, crystallization, hydrophobicity, optical, and barrier properties. The hybrid enzymatic-chemical depolymerization approach is being validated through quantitative analysis of monomer and byproduct formation, followed by monomer isolation, repolymerization, and film production from recycled polymers. Further validation is needed to demonstrate scale-up, consistent monomer yields, and parity of properties between recycled and virgin films before commercial deployment.