Effect of Lignin Content on Properties of Flexible Transparent Poplar Veneer Fabricated by Impregnation with Epoxy Resin

Abstract

In this work, poplar veneer (PV) rotary-cut from fast-growing polar was delignified to prepare flexible transparent poplar veneer (TPV). Lignin was gradually removed from the PV and then epoxy resin filled into the delignified PV. The study mainly concerns the effect of lignin content on microstructure, light transmittance, haze, tensile strength, and thermal stability of the PVs impregnated with epoxy resin. The results indicate that the lignin could be removed completely from the PV when the delignification time was around 8 h, which was proved by FTIR spectra and chemical component detection. Moreover, according to SEM observation and XRD testing, the porosity and crystallinity of the PVs were gradually increased with the removal of lignin. Also, the optical properties measurement indicated that the light transmittance and haze of the TPVs gradually increased, and the thermal stability also became more stable as shown by thermogravimetric analysis (TG). However, the tensile strength of the TPVs declined due to the removal of lignin. Among them, TPV8 exhibited excellent optical properties, thermal stability, and tensile strength. Consequently, it has great potential to be used as a substrate in photovoltaics, solar cells, smart windows, etc.

In-Situ Cross-Linking of Waterborne Epoxy Resin Inside Wood for Enhancing Its Dimensional Stability, Thermal Stability, and Decay Resistance

“…It is worth noting that the slight shoulders owing to the decomposition of hemicellulose displayed in the DTG thermograms were significantly smaller than those of the untreated wood. As displayed in Table , the T 10% values of WEP30-Wood and WEP60-Wood, respectively, around 34.4 and 35.7 °C were higher than those of the untreated wood because the pyrolysis processes of the wood components were delayed by the protection of the cured epoxy resin . The next stage from 300 to 500 °C was ascribed to the pyrolysis of cellulose, lignin, and remaining epoxy resin.…”

“…As displayed in Table 1, the T 10% values of WEP30-Wood and WEP60-Wood, respectively, around 34.4 and 35.7 °C were higher than those of the untreated wood because the pyrolysis processes of the wood components were delayed by the protection of the cured epoxy resin. 42 The next stage from 300 to 500 °C was ascribed to the pyrolysis of cellulose, lignin, and remaining epoxy resin. Both the T 50% and the T max values of the WEP60-modified wood (WEP60-Wood) during this stage were slightly higher than those of the untreated sample.…”

Enhanced Modification of Fast-Growing Wood: Application and Evaluation of Castor Oil-Based Unsaturated Polyester Resin

“…It is worth noting that the modified wood has a higher thermal decomposition starting temperature than the log because the protection of CO-UPR delays the pyrolysis process of the wood components and increases the thermal stability of the wood by about 40 °C. 54 In the fourth stage, the remaining materials in the original and modified woods continue to decompose until carbonization. The thermal decomposition of the cured UPR resin can be explained by three main steps.…”

Preparation and properties of a kind of high conductivity flexible wood with light switch characteristics

“…Transparent wood (TW) composite has the function of light guide and can effectively daylighting, which is of great significance for energy‐saving and comfortable green energy‐saving buildings. Recently, the manufacture and functionalization of TW have attracted extensive interest 3–7 . Direct delignification of wood can produce graded micron and nanometer cellulose fibers with diameter smaller than the visible wavelength.…”