Phase change energy storage wood (PCESW) was prepared by using microencapsulated phase change materials (MicroPCM) as thermal energy storage (TES) materials and wood as the matrix.
Thermal energy storage wood (TESW) was fabricated by using graphene aerogel encapsulated polyethylene glycol (PEG) as phase change material and wood as the matrix. The microstructure of TESW was investigated by scanning electron microscope (SEM), the thermal properties of TESW was determined by differential scanning calorimetry (DSC), thermal gravimetric analysis (TG) and laser flash diffusivity apparatus (LFA). The results showed that: (1) graphene aerogel (GA) encapsulated PEG composite was founded in the lumens of wood, there was no apparent interface between PEG and graphene aerogel; (2) the melting and freezing enthalpy of TESW were 11.81 and 27.91 J g−1, respectively. The melting and freezing point were 20 °C and 15 °C, respectively, which were suitable for human comfortable temperature; (3) incorporation of graphene aerogel improved the thermal conductivity of TESW apparently. Thermal conductivity of TESW was 0.374 W (m*K)−1, which increased about 274% compared to pure wood; (4) TG and hygroscopicity test indicated that the TESW had excellent thermal and dimensional stability. The TESW was suggested as energy conservation building material for indoor temperature regulating due to its comfortable phase change temperature and prior latent heat.
To improve the hydrophobicity of precious hardwood, a facile sanding pretreatment and alkyl ketene dimer (AKD) modification were performed. After the AKD modification, the wood was highly hydrophobic, and the contact angle was 143°. The increased hydrophobicity could be attributed to the ester bond formed between the wood hydroxyl groups and AKD, which was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy. Sanding pretreatment could further greatly increase the wood hydrophobicity and render it superhydrophobic, not only in a cross-section but also in the tangential and radial sections. The changed wood surface roughness could be responsible for the increased hydrophobicity, which was confirmed by characterization with a scanning electron microscope (SEM) and a three-dimensional optical microscope. Apart from the improved hydrophobicity, the AKD-modified wood exhibited excellent water, acid, and toluene resistance. After a 12 h immersion, the contact angle did not change significantly, and the acid immersion contributed to an improvement in the hydrophobicity of the wood. Furthermore, the resultant AKD-modified wood exhibited an excellent self-cleaning effect.