Manufacture of environmentally friendly plywood bonded with plastic film.

摘要

The main objective of this study was to evaluate the feasibility of using unmodified plastic film as a novel wood adhesive in the plywood production, which is done to eliminate formaldehyde release during plywood production and use. The bondability of plastic film was determined by testing the shear strength of plywood. In addition, physical-mechanical properties, including thickness swelling, water absorption, modulus of elasticity, and modulus of rupture under the optimal pressing conditions, were also considered. Results showed that the plywood could meet the requirements for Grade 2 plywood according to Chinese National Standard (GB/T 17657-1999) and that the highest strength was obtained under hot-pressing conditions (pressure, 0.7 MPa; temperature, 160 degrees C; time, 1 min.mm-1; and film dosage of two layers), which was comparable to that of commercial urea-formaldehyde plywood as determined by Liu (Master's thesis, Zhejiang Agric. and Forestry Univ., Hangzhou, China, 2010). Pressing temperature had a notable effect on adhesive penetration and bonded joints formed. Mechanical interlock, as observed by scanning electron microscopy, formed between nonpolar plastic film and porous poplar veneer.