Extracting and investigating the accuracy of granulation and molecular weight of lignin based biological polyols for the production of polyurethane coating

Recently, interest in studying lignin as the second most abundant biopolymer in advanced applications has increased. In particular, micro and nano-lignin materials have high value-added applications. The present study investigated the path of lignin synthesis to nano-lignin materials. Subsequently, through performing different tests, the microstructures of these nano-lignin materials were compared with normal lignin.
At first, the GPC test results of lignin and milled lignin showed that the average molecular weight for lignin was 16814.16 Daltons and the average molecular weight for milled lignin was 265 Daltons.
The results of the DLS test also indicated that the average size of the milled lignin particles when dissolved in ethylene glycol is about 0/520 µm. Next, coatings based on milled lignin were synthesized and applied on steel substrates. Finally, FE-SEM and roughness measurement images of the surface of polyurethane coatings based on milled lignin were prepared, and the results clearly indicated the formation of nano-lignin particles during the ultrasonic and ball mill process.