Recently, consumer markets have shown great interest in sustainable products. Considerable research efforts are headed towards developing biodegradable and recyclable polymers and composites. In this study, the fabrication of a wood–plastic composite (WPC) via solid state compounding has been examined. Polyethylene terephthalate (PET) and wood sawdust waste as major components of waste and challenging materials for the manufacturing of WPCs have been explored. Furthermore, the addition of poly(ε-caprolactone) as a biodegradable plasticizing agent was investigated. Composite powders were prepared by cryogenic solid-state milling (cryomilling) according to a statistical mixture design. Mechanical and water absorption properties were inspected on film samples obtained by hot pressing. Different formulations resulted in a variety of colors, textures, water interactions and mechanical properties. A sawdust content of approximately 25 vol.% was optimal for the best combination of properties. The results indicated that cryomilling is technically advantageous in the production of WPCs.

The present study explores solid-state cryomilling for the compounding of green composites. Herein, wood plastic composites (WPCs) composed of sawdust (SD) and poly(ε-caprolactone) (PCL) with various compositions were prepared. Two compounding techniques, namely, extrusion and cryomilling, were utilized to prepare WPC raw material pellets and powders, respectively, for comparison purposes. Flat pressing was further utilized to prepare WPC films for testing. Morphological, structural, thermal, mechanical, and surface wettability properties were investigated. Results indicate the advantages of cryomilling in producing WPCs. Scanning electron microscopy (SEM) along with optical micrographs revealed well ground SD particles and uniform distribution in the PCL matrix. Tensile strength and elongation at break of the composites declined with increasing SD content, however, the modulus of elasticity significantly increased. Water contact angles averaged less than 90°, implying partial wetting. Visual observations and thermo-gravimetric analysis (TGA) indicated thermal stability of composites during processing. In conclusion, PCL/SD WPC is a potential candidate to replace conventional plastics for packaging applications. This would also provide a much better utilization of the currently undervalued wood waste resources.

Cryomilling is a promising method for fabricating polymeric blend and composite powder raw materials for various subsequent manufacturing processes. In this study, biodegradable porous membranes were fabricated from poly (ε-caprolactone) (PCL) using the cryomilling/hot pressing/porogen leaching approach. Powder mixtures of six different model compositions were compounded by cryomilling; thereafter, films were fabricated by hot-pressing. Poly (ethylene-oxide) (PEO) and salt were utilized as eco-friendly porogens in these mixtures, which were dissolved in water to introduce porosity in the films. Wood sawdust (WSD) and alum were investigated as fillers potentially capable of manipulating the hydrophilicity, mechanical and antimicrobial properties of the membranes. The morphological, hydrophilicity, mechanical, and filtration efficiency properties were explored and compared to those of commercial laboratory microfiltration (MF) membranes. SEM analysis revealed dense membrane skins for all compositions, along with lamellar porous structures. Mean pore radius ranged from 0.15 to 0.21 μm, which is within the MF pore size range. Water contact angle measurements averaged 70° and decreased with the addition of WSD and alum, indicating increased hydrophilicity. Tensile test results showed a decrease in mechanical properties, with higher porosities and with the addition of WSD. Adding alum (≥10 wt%) resulted in embrittled membranes. Filtration performance was evaluated in terms of pure water flux and turbidity reduction for textile wastewater, and it compared favorably to commercial membranes. In conclusion, this study has successfully introduced a new facile and versatile membrane fabrication approach.