Biodegradable PVOH-based foams for packaging applications

Biodegradable poly(vinyl alcohol) (PVOH) based foams were prepared through an eco-friendly methodology. Different amount of recycled multilayer cartons (MC), composed of cellulose and low-density polyethylene (80/20 wt/wt), were added as a direct cellulose source to PVOH. Foams were realized through a modified overrun process without using chemical agents or promoting chemical reactions. In particular, the air entrapped during the high-speed mixing of the PVOH/MC water dispersion was able to create a porous morphology. The effects of the addition of MC on microstructure, swelling behavior, and mechanical and thermal properties of foams were investigated. Materials were characterized by a dual-pore structure. Improvements of the swelling behavior, mechanical properties, and thermal stability were recorded as a function of MC content. These findings can be considered as a result of a good interaction between filler and polymer.