Supercritical CO2 composite foams as durable alternatives to melamine foams

Overview

This technology uses supercritical CO2 blowing to produce multicellular composite foams from both synthetic polymers (such as poly lactic acid, polyurethane, and poly vinyl alcohol) and biodegradable materials (including high molecular weight cellulosic polymers). The approach aims to create viable replacements for melamine foams with controlled cellular structures, improved mechanical durability, and tunable wetting characteristics. By incorporating fillers such as silica and poly methyl methacrylate with varying surface morphologies, the foams achieve enhanced fracture strength through multiscale stress propagation pathways. The resulting materials offer low density, tunable friction and wear properties, and adjustable interfacial energy depending on foam structure and the presence of lubricants.

Technical specifications

Key features:

• Supercritical CO2 batch foaming process operating at 2000-4000 psi and 60-200C, followed by rapid depressurization to generate solid foams
• Compatible with generally recognized as safe (GRAS) polymers including cellulosic diacetate, poly vinyl alcohol, and poly methyl methacrylate
• Achievable pore sizes below 20 micrometers and densities below 0.05 g/cm3
• Composite formulations incorporating smooth and rough fillers to enhance fracture toughness
• Tunable hydrophilicity and water transport properties, demonstrated in poly dimethyl siloxane sponges with significantly reduced contact angles
• Analytical characterization via compressive DMA, Instron mechanical testing, microscopy, goniometry, and micro-CT

Technology readiness level

The technology has been validated through initial proof-of-concept experiments. Cellulose-based multicellular foams have been successfully synthesized using high-pressure batch setups, and poly dimethyl siloxane sponges with enhanced hydrophilicity have been produced. Compressive DMA and Instron testing have demonstrated an order of magnitude increase in fracture energy when rough-surface fillers are incorporated. Current efforts focus on optimizing the foaming process for additional GRAS polymers, incorporating poly methyl methacrylate fillers with varied morphologies, and benchmarking composite foams against melamine foams using industry-relevant performance testing protocols. The technology is advancing toward pilot-scale validation and pre-commercial readiness.