Physical and Mechanical Properties of Eco-Friendly Composites Made from Wood Dust and Recycled Polystyrene

The development of alternative wood composites based on the use of waste or recycled materials can be beneficial due to over exploitation of natural resources.Under this frame,an option for the successful utilization of waste polystyrene which avoids environmental problems that formaldehyde adhesives cause and also reduces waste dis-posal,is its potential application as a binder for the production of value-added environmentally friendly and low cost wood composites.Two types of panel were successfully made,consisting of wood dust and two recycled poly-styrene contents,namely,15%and 30%.Both physical properties,water absorption and thickness swelling,and mechanical properties,modulus of rupture,shear strength parallel in the plane of the board and glue line shear strength,were significantly improved as the recycled polystyrene content increased from 15%to 30%.Water absorption and thickness swelling after 24 h immersion in water were improved by 165%and 750%as the recycled polystyrene content increased from 15%to 30%.The magnitude of the improvement in mechanical properties however,was less pronounced than of the physical properties since modulus of rupture,shear strength parallel in the plane of the board and glue line shear strength were increased by 43.6%,50%and 61.5%,respec-tively.The low viscosity of the recycled polystyrene caused more mobility inside the panel matrix and therefore,an improved penetration took place into adequate depth of the compressed dust particles.It is concluded that boards can be successfully produced using these waste raw materials,wood dust and recycled polystyrene in organic solvent as a binder,and therefore it can reduce waste disposal and provide cleaner production for the development of wood-based boards.

Water Repellency of Cellulosic Fibrous Mats Impregnated with Organic Solutions Based on Recycled Polystyrene

Recycled polystyrene in combination with paraffin wax,alkyd resin,and gum rosin were used as components in formulations to investigate their water repellency when applied to cellulosic filter paper substrates.Polystyrene was used in concentration of 5,10,15 and 20%,alkyd resin and gum rosin of 5%each and paraffin wax of 0.5%.Totally,twenty four water repellent solutions were prepared.Water repellency was evaluated in terms of water absorption of the cellulosic fibrous mats.The relations between retention of solid substances of the formulations and grammage and water absorption of filter paper samples were also determined.The results showed that all the water repellent formulations exhibited a degree of water repellency.Water absorption decreased by increasing the polystyrene concentration in the solution and polystyrene retention by the impregnated filter paper samples.The incorporation of 0.5%paraffin wax improved the hydrophobicity of treated samples.The best of the three water repellent formulations including paraffin wax was found to be the“polystyrene+gum rosin+paraffin wax”solution followed by the“polystyrene+alkyd resin+paraffin wax”and“polystyrene+paraffin wax”solution.The inclusion of 5%gum rosin in polystyrene solutions compared to that of 0.5%paraffin wax was found more effective in almost all cases.