Use of black locust/poplar wood as filler in thermoplastic composites

Wood plastic composites (WPCs) were produced from different mixtures (up to 45% by weight) of poplar (Populus alba L.) and pruning branches of black locust (Robinia pseudoacacia) wood flours, polypropylene (53 wt.%), and maleic anhydride-grafted polypropylene (2 wt.%). Weight loss, flexural strength (MOR), flexural modulus (MOE), notched impact strength (IS), water absorption (WA), and thickness swelling (TS) of WPCs after 24 h of immersion in distilled water were determined before and after incubation with white-rot fungus (Trametes versicolor) for 7 weeks. The MOR and MOE increased with an increase in poplar wood in the WPC. The notched IS decreased with an increase in black locust wood and poplar wood in the WPC. The weight loss in WPCs exposed to white-rot fungus was minimal for WPCs with a high amount of black locust pruning branch flour. The MOR and MOE declined after incubation with fungus. Fungal decay had a significant influence on the notched IS. Furthermore, the results indicated that the WA and TS of whiterotted WPCs for all the WPC formulations were significantly higher than those of unrotted WPCs.