Effect of maleated polypropylene emulsion on the mechanical and thermal properties of lignin-polypropylene blends

Abstract

The increasing oil rates and environmental concerns of the use of synthetic or petroleum-based polymers has newly led to a growing attention in eco-friendly materials. Lignin has received much attention as a novel eco-friendly material due to its abundant availability and its potential as a low-cost filler. Biobased blends from polypropylene (PP) and lignin were fabricated by extrusion followed by injection moulding. In order to improve the compatibility of the polar lignin and the non-polar matrix PP, three different maleated PP emulsions, namely ME91735 (nonionic PP emulsion), ME42035 (cationic water based emulsion of polyolefin waxes) and PP286 (containing 1-5% N,N-ethylethanolamine) were used as coupling agents. The mechanical properties such as tensile and flexural strength as well as tensile and flexural modulus of the blends were improved by using lignin treated with 2.5 wt.% of the emulsions. However, the elongation at break decreased in the case of the lignin treated with ME91735 and ME42035 as compared to the untreated lignin. The morphological and thermal properties of the blends were also studied.