Today, most plastics are still manufactured based on fossil resources. Against the background of global climate change, “Two Carbon Goals”— carbon peaking and carbon neutrality goals — have become a consensus. All industrial sectors across the globe are pursuing self-revolution, trying to find, manufacture and promote an alternative to fossil-based plastics. 

1. Biodegradable E-PLA will reduce carbon footprint

As a bio-based and biodegradable polyester with mechanical properties similar to polystyrene (PS), including excellent thermal insulation and impact resistance, PLA is commonly used as a polymer foam for packaging and insulation. PLA foams will be an alternative to EPS foams in packaging sector to reduce carbon footprint.

This new foaming material has obtained the Cradle to Cradle Certificate, and different from EPS, it can be used for industrial composting. What’s more, it can also be chemically recycled to produce new raw materials of PLA polymers. E-PLA is stable under normal atmospheric conditions, biodegradable within 50 days in industrial composts, and within 48 months in water. At the same time, with a lifespan of 2-3 years, it also has such performances as good transparency, anti-mildew, and anti-bacteria.

2. Modification and enhancement of E-PLA

In practice, the low melt strength of PLA is a disadvantage for processes involving melt elongation or stretching (e.g., foaming). Therefore, the modification and enhancement of PLA is necessary before the foam molding process. As more technological breakthrough has been made in the foaming process of PLA, many advanced techniques have come into being and continuously led the industrial development, such as Ingeo, PLAneo® of Uhde Inventa-Fischer, PARALOID™ of Dow.

During the process of transforming raw materials to foams, various methods need to be adopted to improve the mechanical properties of PLA through adjusting the structure, density, cell distribution and size. Researchers found that producing nanoparticle reinforced materials is also an option, such as composites with MWNTs, CNF and wood fibers. Nanoparticles can improve the mechanical properties of foam structures.

3. Manufacturing microcellular PLA foams with supercritical fluid

In recent years, there have been many studies on foam extrusion with supercritical fluids as physical foaming agents. Due to the plasticization of physical foaming agents, high-performance supercritical microcellular foamed polymer can be obtained under proper conditions, including proper saturation pressure, saturation temperature and foaming time.

As physical foaming agents, supercritical fluids (inert gases C02 and N2 are commonly used) are cost-efficient and accessible, environment-friendly, pollution-free and residue-free. At present, major preparation methods with supercritical fluids as foaming agents include intermittent foaming, injection foaming, continuous extrusion foaming, and bead foaming.