Foam-laid thermoplastic composites based on kraft lignin and softwood pulp

This article presents a new method of producing thermomoldable nonwoven materials based on kraft lignin (KL) and softwood kraft pulp (KP). A mixture of starch acetate (SA) and triethyl citrate (TEC) was used as a water insoluble plasticizer for KL. The thermoplastic lignin (TPL) material with the optimized ratio of KL, SA and TEC was prepared in a twin-screw extruder. The TPL compound was ground and mixed with KP fi bers to produce thermoformable sheets using foam-laid technology. The formed webs were compression molded (CM) into plates and mechanically tested. The foam-laid composites had tensile strengths and modulus of 67 MPa and 5.2 GPa, respectively. Scanning electron microscopy (SEM) was used to analyze the dispersion of the fi bers and the matrix in the composites. As a comparison, injection molded (IM) TPL-KP composites were also prepared.