To evaluate the effects of chemical changes during thermal modification on the resistance of wood against photodegradation, heat-treated specimens of rubber wood (Hevea brasiliensis) were exposed to ultraviolet light for 384 h. The color changes in the exposed wood surfaces were analyzed using a colorimeter; the chemical changes were monitored using Fourier-transform infrared spectroscopy (FTIR). The photoweathering performances of rubber wood treated at 155 °C for 2 h, 155 °C for 6 h, and 185 °C for 2 h were similar to that of untreated wood, as the lignin did not undergo profound chemical transformation under mild modification conditions. However, compared to untreated rubber wood, the photoaging performances of rubber wood treated at 185 °C for 6 h and 215 °C for 2 h were notably changed. The transformation process was confirmed by FTIR. A good linear relationship between color change and lignin degradation was observed after mild, but not severe, heat treatment. The concentration of carbonyl groups in the wood specimens generally increased during photoaging, although not all samples showed a good correlation between color change and the concentration of carbonyl groups. Only the photochromic performance of wood changed notably when lignin was extensively modified under severe heat-treatment conditions.

Recent advances addressing the development of anti-mildew and UV-resistance microcapsules for wood. IPBC is enclosed in the drug-loaded carriers, through slow release, resulting in the anti-mildew process. Anti-mildew experiments showed that the control effectiveness of 1.25wt% nano SiO2-IPBC microcapsules was 78.125% against Botryodiplodia theobromae. In addition, a novel angle of view is discussed, which is the UV-resistance, including different mass fraction of nano SiO2-IPBC microcapsules, IPBC and the control group. Different FTIR characterizations and surface color related to impregnated wood samples are discussed. Nano SiO2-IPBC microcapsules had better bonding performance and UV-resistance than IPBC due to the synergistic effect of nano SiO2 and IPBC in the microcapsules. Color measurements showed that the UV-resistance of microcapsules was better than 1.25wt% IPBC impregnated wood samples. It helps us open new horizons to anti-mould agent, which offers multi-function of great anti-mildew effect and excellent UV-resistance. The simple and green method for the preparation of microcapsules would have tremendous potential for the extensive development of wood protection.