Mechanical behavior and biological resistance of Acrylonitrile wood-polymer modified by alkoxysilan

Wood modification is trying to use eco-friendly materials and methods to improve the wood properties for many applications. Synthetic polymers are widely used for wood modification via impregnation by monomers and the conversion to polymer that was resulted in wood—polymer production. In modification by Acrylonitrile vinyl monomer, the hydroxyl group of cell wall are free and they could absorb moisture exposed to the environmental condition. So, the presence of a modifier with coupling effect between monomer and cell wall could increase the wood service life. In this research, the effect of 3-(trimethoxysilyl) propyl methacrylate on mechanical and biological properties of Acrylonitrile wood-polymer was investigated.
Material and Mechanical and biological test samples of straight grain and no defect timber of dried Poplar wood were prepared according to ASTM-D143 and EN113 standards respectively. Test samples were divided in 7 levels: control, modified with silan compound in subgroups of acidified Ethanol at 110 and 150˚C, ethanol with and without Benzoyl peroxide as initiator at 150°C, Acrylonitrile/ Benzoyl Peroxide and combined level of silan/Acrylonitrile. Samples impregnation was carried out using vacuum-pressure method in the cylinder. A complete randomized design was used to examine the effect of different treatments. Also averages grouping was performed by Duncan multiple range test.
Silan modification and presence of Acrylonitrile in the composite were confirmed by infrared spectroscopy. Samples of silan/Acrylonitrile combination level showed maximum of bending strength, compression strength parallel to grain and hardness. The presence of Acrylonitrile in lumen enhanced the mechanical properties. In reaction between wood and silan, temperature increases due to the intensification of reaction, led to an increase in resistance. Benzoyl Peroxide initiator presence in silan modification resulted in more improvement in mechanical properties due to Cell wall modification and Polymerization some of silan in the lumens. Silan/Acrylonitrile modified samples was showed the significant improvement in decay resistance exposed to Trametes Versicolor
Silan compound enhanced the mechanical and biological properties of Acrylonitrile wood-polymer. The maximum improvement of mechanical properties was observed in combined modification of Silan/Acrylonitrile because of more interaction between silanol of silan compound and hydroxyl group of wood, and the presence of Acrilonytrile in wood cell lumen. Silane/acrylonitrile modification created significant enhancement in the biological resistance against white rot fungi that attributed to filling lumen and cell wall pores, less moisture content, and reduction of hyphae development, enzymes transfer and fungal hyphae access to the wood cell wall.