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Fillers/additives used to produce environmental friendly materials include waste paper sludge (WPS) and ink‐eliminated sludge (IES). These materials are used in high‐density polyethylene (HDPE)/wood flour composites [47]. Research shows that, the flexural properties of the HDPE/wood flour composites increased when WPS was added as an additive. This increase in flexural strength could be further increased by using a compatibilizer such as malleated anhydride grafted polyethylene (MAPE) in between the reinforcement and the matrix. Also, there occurs a decrease in the swelling and water absorption properties when this WPS and IES are added as fillers/additives. It has been found out that the overall mechanical properties of IES‐added composites show better results than that of the WPS‐added composites. The optimum loading condition of IES‐added composites is 60 wt%. These results show a promising outcome that these composites could be used for the preparation of biobased composites.

As these HDPE/wood flour composites find its applications in the exteriors of construction industries, their amount of durability could be calculated by investigating the damage caused due to sunlight and other weathering conditions [48]. Artificial weathering experiments could be carried out on the surface of these composites and by carefully investigating the chemical changes happening on the surface, help in finding out the durability. Further, it has been proved that, when carrying out tests such as X‐ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR), the amount of weathering damage to the wood flour‐reinforced HDPE is increased to 16 times faster than unreinforced plastic. The outcomes confirm that the degradation mechanism is triggered in the polymer chain due to the presence of carbonyl groups and leads to polymer chain scission once the surface oxidation is started. There is an overall reduction in the crystallinity of the polymer as the time increases and when the chain scission mechanism has been initiated.