Abstract
Honeycomb paperboard is an important wood-derived product and also an emerging new material to combine with wood panels. It is commonly applied as cushioning materials with excellent mechanical performance, and high demands in packaging market. The aims of this study were to enhance the durability of honeycomb paperboard using PF resins of various molecular weights (Mw 200, Mw 500, Mw 700), particularly examining the difference between vacuum-assisted and atmospheric impregnations. The entire experiments were designed and analysed through response surface methodology (RSM). Our results show vacuum-assisted impregnated specimens exhibited a smaller coefficient of variation and a higher weight percentage gained, demonstrating their superiority. Different molecular weights of PF resin significantly affected the impregnation results, samples treated with Mw 500 resin showing the best weight percentage gained. The impregnation duration and humidity also are significant factors. At 55%RH, samples treated with Mw 500 and Mw 700 resin showed highest weight percentage gained compared to the other two humidities, but specimen treated with Mw 200 had greater impregnation performance at 95%RH. The optimal experimental parameter combination was suggested to be conducted at a relative humidity of 55% (55.16%), a reagent concentration of 40% (39.99%), and an impregnation duration of 60 minutes (61.02 minutes).