This paper investigates the perforation treatment of polyvinylchloride (PVC) plastic films and their plywood composites.

Wood fibers were prepared as core materials for a vacuum insulation panel (VIP) via a dry molding process. The morphology of the wood fibers and the microstructure, pore structure, transmittance, and thermal conductivity of the wood fiber VIP were tested. The results showed that the wood fibers had excellent thermal insulation properties and formed a porous structure by interweaving with one another. The optimum bulk density that led to a low-cost and highly thermally efficient wood fiber VIP was 180 kg/m3 to 200 kg/m3. The bulk density of the wood fiber VIP was 200 kg/m3, with a high porosity of 78%, a fine pore size of 112.8 μm, and a total pore volume of 7.0 cm3·g-1. The initial total thermal conductivity of the wood fiber VIP was 9.4 mW/(m·K) at 25 °C. The thermal conductivity of the VIP increased with increasing ambient temperature. These results were relatively good compared to the thermal insulation performance of current biomass VIPs, so the use of wood fiber as a VIP core material has broad application prospects.

The main production process parameters of ultra-low-density fiberboard (UDF) were selected by use of response surface methodology, and then the properties of UDF were improved by adding a coupling agent. Microstructures and chemical bonding in UDF were analyzed by scanning electron microscopy and infrared spectroscopy. The results showed that the desirable process parameters for UDF production were the amount of urea-formaldehyde resin adhesive (18%), the hot pressing temperature (170 °C), the hot pressing time (200 s), and the amount of KH560 coupling agent added (1%). The main physical and mechanical properties of UDF obtained included internal bond strength (0.59 MPa), modulus of rupture (19.8 MPa), and 24h thickness swelling (10.0%). These properties exceeded the requirements of ISO 16895 (2016).