In Situ Dispersion of Lignin in Polypropylene via Supercritical CO Extrusion Foaming: Effects of Lignin on Cell Nucleation and Foam Compression Properties.

Supercritical CO (scCO) extrusion foamed high-melt-strength (HMS) polypropylene (PP) often suffers from low cell density, large cell sizes, and poor cell structure uniformity due to the poor nucleation rates of CO in the PP. To remedy this, various inorganic fillers have been used as heterogeneous nucleation agents. Although their efficient nucleation effects have been demonstrated, the preparation of these fillers causes some adverse effects on the environment/human health or involves relatively expensive processes or non-eco-friendly chemicals.