Comparing the performance of acrylate and vinyl cross linkers on the properties of Populus deltoides / styrene wood-polymer composite

Along with the advancement of synthetic polymer industries, monomers are widely used for wood modification. Coupling agents play an important role in bonding non-polar monomers and wood hydroxyl groups. In the study of the effect of trimethoxysilyl polypropyl methacrylate (TMSPM) and triethoxy vinyl silane (TEVS) as coupling agents on the physical properties of poplar wood-polymer, the test specimens were divided into control and groups containing styrene (with and without silane coupling agents). Fourier-transform infrared spectroscopy (FTIR) results confirmed the presence of silane and monomer in the wood structure. Levels containing acrylate silane showed the carbonyl group, as well as the ketone carbonyl group of the wood structure. The absorption of monomer increased in samples containing vinyl silane more than acrylate ones. In spite of determining the highest absorption in vinyl silane, the highest weight gain was measured in the level that contained TMSPM, TEVS and styrene. Despite the higher reactivity of acrylate silane, the vinyl silane with a lower molecular weight resulted in the greater penetration of the compound into the wood structure which, in turn, resulted in a better polymerization with styrene at this level. The linkage of the modified cell wall with silane compounds to the polymer led to a decrease in weight gain and porosity and eventually improved dimensional stability, water repellency efficiency and anti-swelling efficiency of the product.