Properties of nanofibrillated cellulose from different raw materials and its reinforcement potential

Five commercial wood and wheat straw fiber sources with different morphologies were mechanically disintegrated into nanofibrillated cellulose (NFC). The processing times for disintegration varied, depending on the sizes and the moisture content of the starting materials. A decrease in polymerization degree (DP) for the fibrillated materials between 15% and 63% could be observed. Nevertheless, all isolated NFC materials showed homogenous network structures. They were used for the production of composite films with hydroxypropyl cellulose (HPC) as matrix and different proportions of NFC and two commercial fibrillar-fibrous celluloses as reinforcing components. Films with the commercial, more inhomogeneous fibrillated celluloses showed up to 2.5 times lower strength and up to four times lower stiffness. It appeared that homogeneity of the NFC material is more important for its reinforcement potential than the DP. A proper pre-treatment and choice of starting cellulose materials can reduce energy consumption, a key issue for industrial up-scaling.