Melamine Formaldehyde Modified Furfurylation to Improve Chinese Fir’s Dimensional Stability and Mechanical Properties

Abstract

Melamine formaldehyde modified furfurylation (MFMF) was developed in this investigation to overcome the issues encountered by traditional wood furfurylation, the strong acidic reaction condition and the high cost of furfuryl alcohol. In this study, the optimum ratio of melamine, formaldehyde, and furfuryl alcohol constituents and the optimum curing conditions were explored. Then, MFMF was applied to Chinese fir modification and its performance was evaluated by the weight gain rate (WGR), equilibrium moisture content (EMC), dimensional stability (anti-swelling efficiency [ASE]), and parallel-to-grain compressive strength. The results showed that MFMF took place at a pH close to neutral (6.8) and the formulas had good penetration of cell walls. The best stability and improvement to mechanical properties achieved by MFMF were: a WGR of 158.9%; a low EMC of 11.5% under 96% relative humidity conditions; an ASE in high humidity and water-soaked conditions of 58.5% and 64.2%, respectively; and an increase in parallel-to-grain compressive strength by 81.9%, when compared with the control.