Comparative Study of Organic and Inorganic Modification of Chinese Fir Wood Based on the Respiratory Impregnation Method

Abstract

To compare The effects of organic and inorganic impregnation on the properties of unmodified, phenol formaldehyde oligomer-modified (PFOMCF), and sodium silicate-modified Chinese fir wood (SSMCF) were compared using samples prepared using the respiratory impregnation method. Impregnation and reinforcement effects and water resistance of PFOMCF and SSMCF were compared and the results was showed that the weight percentage gain, density increase rate, bending strength, and compressive strength of SSMCF were clearly higher than those of PFOMCF and had a lower water absorption rate within 60 h. The impregnation and reinforcement effects and dimensional stability of SSMCF were better than those of PFOMCF. FT-IR, XRD, CONE, and TGA examinations were used to test and analyze the chemical structure, crystalline structure, flame retardancy, and heat resistance of these modified woods. The results indicated that SSMCF possessed more hydrogen bonds than PFOMCF and that Si–O–Si chemical bonding with high bond energy was formed. Meanwhile, the weakened degree of the diffraction peak of SSMCF was much less than that of PFOMCF. These results explained that the mechanical properties and water resistance of SSMCF were better than PFOMCF. Compared with PFOMCF, SSMCF had a lower heat release rate (HRR), peak-HRR, mean-HRR, total heat release, smoke production rate, and total smoke production as well as higher thermal decomposition temperature and residual rate. Inorganic sodium silicate was shown to be a better flame retardant, while SSMCF had good smoke suppression effects, thermal stability, and safety performance in the case of fire.

Research Progress of Reinforced Modification of Fast-Growing Wood

“…Most of the studies on organic modifiers focus on urea-formaldehyde resin (UF) [17,18], phenolic resin (PF) [19][20][21], melamine formaldehyde resin (MF) [22] and isocyanate resin. Inorganic salts, inorganic oxide nanoparticles and natural mineral soil are used as inorganic modifiers [23]. Both organic modification and inorganic modification show great potential for the enhancement of fast-growing wood, but there are some shortcomings such as a high cost of organic modification, toxic substances, poor binding stability of inorganic modification and easy moisture absorption.…”

Study on Microwave Pretreatment Technology to Improve the Effect of Shellac Impregnation of Fast-Growing Chinese Fir

“…These deficiencies result in wood that is easily deformed and damaged during use and rendered unsuitable for use as materials in furniture, floors, wooden structures and construction [5]. Therefore, to improve the properties of Chinese fir, expand its range of uses and increase the added value of its products, researchers have thoroughly studied modifications of the wood by impregnation with synthetic resin to increase its density and improve its physical and mechanical properties [6]. The synthetic resins that are commonly used to impregnate wood are urea formaldehyde resin [7], phenol formaldehyde resin [4], melamine-urea formaldehyde resin, phenol-melamine-urea formaldehyde resin [8], and unsaturated polyester resin [5] among others.…”