KraussMaffei and its partner have developed a new process to reinforce polylactic acid (PLA) by incorporating lignin, resulting in a 100 percent bio-based reinforced thermoplastic. Through modification, KraussMaffei's technical team has incorporated lignin as a filler into the PLA matrix, creating a composite material with outstanding performance.

Lignin is a 100 percent natural substance that is second to cellulose as the most abundant organic material on Earth. Around 50 million tons of lignin, including hydrolysis lignin, are produced annually worldwide as a waste product from wood processing in the paper and bioethanol industries, 98 percent of which is incinerated.

The team incorporated up to 30 percent lignin into the PLA matrix, producing a compound with natural antioxidant capacity, enhanced mechanical properties, and controlled biodegradability. The material exhibits a biodegradation rate exceeding 90 percent within 99 days.

Experimental results have shown that compared to pure PLA, the lignin reinforcement enables flexural and tensile modulus to be increased by around 30 percent. It can be useful in packaging applications where the material needs to be stiff enough to hold its shape under load.

Another advantage is that lignin adds sufficient antioxidant capacity that can help prevent oxidation of the food and maintain its quality and safety by preventing the formation of off-flavors, odors, or toxic compounds. The material could be applied to biodegradable plastics for agricultural purposes, to protect them from oxidative degradation.