Performance comparison of HDPE plywood with UF resin plywood

In order to evaluate the feasibility of using HDPE film as wood adhesives, physical-mechanical properties, thermal properties and interface morphology of two kinds of poplar plywood, made with HDPE film and UF resins as adhesives respectively, were investigated by mechanical testing machine, dynamic mechanical analysis (DMA), thermal gravimetric analysis (TG), and scanning electronic microscope (SEM). Results showed that HDPE film had comparable bonding ability to UF resins and possesed better water-resistance than UF resins. Seven days water absorption and thickness swelling values of the plywood bonded with UF resins were 23。5% and 5。1% higher than those with HDPE film respectively. Storage modulus of HDPE bonded plywood reached a minimum value near 130 0 Cwhile plywood bonded with UF resins remained a slow reduction of modulus in the whole period. However, it presented almost the same dynamic mechanical properties as UF composites when temperature was lower than 60 0 C. Similar pyrolysis characteristics were found in HDPE plywood and UF plywood except an additional weak peak at 420 0 Cfor HDPE plywood. Both HDPE film and UF resins can form mechanical interlock structures with poplar veneers.