Journal of Applied Polymer Science, Vol.72, No.10, 1321-1326, 1999
Lignin-filled polyolefins
Dry lignin powder was used as a filler in low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) up to 30% w/w. The tensile strength reduced for all polymers. Impact properties were almost unaffected for PP but reduced for the other two polymers, Use of five parts of ethylene acrylic acid copolymer (EAA) and 0.5 parts of titanate coupling agent improved mechanical properties considerably. The melt viscosity increased steadily with increasing amounts of lignin. Electrical properties showed improved electrical resistance. The color of the resulting compound could be evaluated only up to a 10% lignin level, beyond which the compounds became very dark. At lower concentrations, samples of HDPE showed a more reddish tinge, while at higher concentrations, all samples showed a green-blue tinge.