Wood-polymer composites prepared by in situ polymerization of methyl methacrylate using bi-functional additives

Abstract

We prepared wood/polymer composites by in situ polymerization of methyl methacrylate (MMA) using glycidyl methacrylate (GMA) and methacrylic acid (MAA) as cross-linkers and coupling agents. The guapuruvu wood samples were impregnated in a vacuum/pressure system and polymerized at 90 °C for 10 h, using benzoyl peroxide at 1.5 wt % as catalyst. We characterized the composites through water uptake, dimensional stability tests, wettability, ATR-FTIR spectroscopy, TGA, SEM, and WPG. ATR-FTIR spectra showed an increase of the peaks at 1746, 1460, and 1145 cm^-1, corresponding to the chemical structures of the polymers into the pores and capillaries of the wood. This was further confirmed in the SEM images. TGA curves showed evidences for a chemical interaction between the copolymer and the wood cell wall in the composites with GMA and MAA. Hygroscopicity and dimensional stability properties of the composites prepared with MMA improved by 50%. Nevertheless, the addition of GMA and MAA resulted in additional increases for hydrophobicity and dimensional stability of the samples, ~ 66 – 90%.

Keywords:
free-radical polymerization; Schizolobium parahyba; heat catalyst; cross-linkers; coupling agents