Thermal tools in the evaluation of decayed and weathered wood polymer composites prepared by in situ polymerization

Abstract

This study aims to apply thermal tools in the evaluation of decayed and weathered wood polymer composites prepared by in situ polymerization with and without cross-linkers. Pinewood samples were impregnated with methyl methacrylate using glycidyl methacrylate and methacrylic acid as cross-linkers by vacuum/pressure. The polymerization was carried out in an oven at 90°C for 10 h using benzoyl peroxide as catalyst. All samples were exposed to decay and artificial weathering tests. The characterization was performed by mass loss, color changes, optical images, wettability, thermogravimetric analysis (by means of DTG) and differential scanning calorimetry analyzes. The mass loss was higher in untreated wood in comparison with the composites, *2.5-10 times. Crosslinked composites showed the highest resistance to fungal biodeterioration. The reduction in L*, chroma and b* confirmed loss of original yellow tones and increase in dark and dull tones of samples. The wettability was very affected by irregularities of the samples' surface. Only DTG showed a shifting in the temperature of thermal events related to polysaccharides and lignin after exposure to decay and weathering. DTG was the best thermal technique for evaluation of decaying and weathering of wood composites.

Wood biomass characterization by DSC or FT-IR spectroscopy

“…410-430°C, respectively. As the main components of wood are cellulose, hemicelluloses and lignin [26,27], it can be concluded that obtained exotherms refer to the thermal decomposition of mentioned components and inform about interactions occurring between them. Position of DSC curve maximum of pure hemicellulose sample is according to the literature data [28] located at 268°C, while data obtained in current study locate it at over 280°C.…”

Termite Resistance of a Fast-Growing Pine Wood Treated by In Situ Polymerization of Three Different Precursors

“…Methyl methacrylate (MMA) is also an important vinyl monomer, and has shown great performance when applied to modifying PW, including increases in mechanical, hygroscopic, thermal and biological properties [17,28]. According to Mattos and co-workers, the in situ polymerization and copolymerization of the poly(methyl methacrylate) (PMMA) into PW converts a low-quality wood product into a high-performance material, and then diverse applications become possible [28]. This WPC allies an ease of processing (associated with the low time for wood production since the PW presents a fast growth) with the low cost of the involved chemicals.…”

Thermochemical and Mechanical Properties of Pine Wood Treated by In Situ Polymerization of Methyl Methacrylate (MMA)

“…These characteristics facilitate the impregnation, flow and polymerization of the MMA within the wood, making the JV more susceptible to present a high WPG. Depending on anatomical features, it is well known that monomer loading directly influences WPG [24,25].…”