فهرست مطالب saeid reza farokh payam

Although many studies have been done about the application of waste materials such as used plastics but returning of wood plastic products (Regrind) to the production cycle was rarely reported. In this work, the effect of once and twice regrind on the functional properties of WPC made from high density polyethylene (HDPE) has been studied. The specimens were fabricated with powder raw materials and by the flat press under laboratory conditions. HDEP and poplar wood flour were mixed with a weight ratio of 50-50 percent. The estimation of regrind process, physical and mechanical properties of boards were measured after each regrinding and also to evaluate of regrinding on filler particle size and the interface between the polymer and wood flour some Scanning Electron Microscopy (SEM) were prepared. The results of this research showed that regrinding of WPC leads to a decrease in mechanical properties including bending strength, flexural modulus, tensile strength and tensile modulus and on the other hand regrinding process leads to improved physical properties including water absorption and thickness swelling after hours. SEM photographs showed that during the process of regrinding, filler particle size is reduced while matrix surrounding the filler particles better.

In this study the possibility of using canola stalks mixed with poplar wood in the manufacture of particleboard was investigated. Weight ratio of canola particle to poplar particles at five levels (98, 93/75, 87/50, 81/25, 77%), the weight ratio of the urea-formaldehyde/melamine formaldehyde resin as a adhesive at five levels (23, 18/75, 12/50, 6/25, 2%) and moisture content of matt at five levels (10, 12, 15, 18, 20%) were selected as production variables. Mechanical properties of boards consist of MOR, MOE and IB was tested. According to the results, with increasing the canola stalks/poplar particle ratio MOR and MOE of the boards decreased, but all of the values obtained from treatments were higher than standard. Interaction effect analysis of variables showed that the increasing the ratio of melamine formaldehyde/urea formaldehyde resin decreased the bending strength, while the increasing the moisture of mat increased MOR and MOE. IB values of all treatments are lower than the standard. According to the results of response surface methodology (RSM) and interaction effect between studied variables on the mechanical properties of the panels, the best situation for producing the panels was selected as: weight ratio of 84/32 for canola/poplar particle, ratio of 6/25 for UF/MF resin and moisture content of 12% for mattress.

In this study the possibility of using urea formaldehyde and melamine urea formaldehyde with different ratios of formaldehyde and melamine for manufacture lightweight particleboard by expanded polystyrene (EPS) was investigated. Experimental panels were made with 30 percent lighter that common particleboard in 25 millimeters thickness and with wood particles that had been came from a factory. Urea formaldehyde and melamine urea formaldehyde with two ratios different of melamine to urea، 40 to 60 and 20 to 80 were types of adhesive. Analysis of data and obtained averages on physical and mechanical properties indicated the best combination of EPS and used resins. Amino plastics adhesives showed good compatibility result with expanded polystyrene. As reducing of the weight of the panel was the most important target in this work، internal bonding (IB) result showed it was done. Because there was no any chemical reaction between EPS and phenolic resin as adhesive، it’s using was unsuccessful. Preliminary results especially internal bonding and physical properties revealed this lightweight panel is proper for defined applications. Furthermore، using melamine urea formaldehyde as adhesive was positive effects on IB and the highest IB was for the panel made with this resin and minimum EPS content. In comparison of common panels، this new panel with maximum melamine content and hydrophobic EPS showed better results on IB and physical properties.