| Wood is the most abundant bio-based material in nature.The multi-layered structure and p-orous structure of wood provide conditions for the preparation of multifunctional wood composit-e materials.Transparent wood is prepared by impregnating resin with a delignified wood substr-ate.This material has both high light transmittance and high haze.With excellent mechanical p-roperties,functionalized transparent wood has a wide range of application prospects in the field-s of smart windows and optoelectronics.In this paper,balsa wood is used as raw material,oct-adecyl methacrylate（ODMA）and polyethylene glycol diacrylate（PEGDA）are used as phase c h-ange primitives to design and synthesize temperature response,phase change energy storage,a-nd ultraviolet shielding functions.The transparent conductive wood film.The main research wo-rk and results are as follows:（1）Using acrylamide（AM）as the modified monomer and ODMA as the phase change unit,the delignified wood template was impregnated by vacuum impregnation,and thermally cured t-o obtain poly（acrylamide-octadecyl methacrylate）（P（AM-ODMA））wood film.Experiments hav-e found that the ODMA content has a greater impact on the material properties.When the O DMA content is 2.0wt%and 2.4wt%,along the fiber direction,the wood film achieves the ma-ximum elongation at break and tensile strength,which are 10.69%and 5.86MPa,respectively.;ODMA content increased from 0wt%to 3.0wt%,at a wavelength of 550nm,the transmitance o-f wood film decreased from 61.20%to 2.96%.The wood film has temperature response perfor mance.The wood film sample of 1.0wt%ODMA will increase the transmittance as the tempera-ture rises within the temperature range of 0℃～80℃.The maximum transmittance of the wood film is 5.50 of the initial transmittance.The transmittance of wood film has the largest change in the range of 0～50℃.The DSC test showed that the wood film phase transition temperature was 7.16℃.The concentration of Na Cl affects the conductivity of the wood film.As the conc-entration of Na Cl increases,the conductivity first increases and then decreases,and the conduct-ivity shows anisotropy,along the fiber direction（x direction）and perpendicular to the fiber dire ction（y direction）ion conductivity Higher,0.0031S/m and 0.0032S/m,respectively.The conduc-tivity of wood film in the direction perpendicular to the x-y plane is much lower than in the x and y directions.（2）Using AM as the modified monomer,PEGDA as the phase change element and crossly-nking agent,after impregnating the delignified wood template by the vacuum impregnation met-hod,poly（acrylamide/polyethylene glycol two Acrylate）（PAM/PEGDA）wood film.The infrared spectrum showed that the delignification template was successfully introduced into PAM,PEGD A and other components.The mechanical properties test found that the wood film has a maxi-mum tensile strength of 2.85MPa when the PEGDA content is 2.5wt%,and the maximum elon-gation at break is 6.06%when the PEGDA content is 0.5wt%;when the PEGDA content is 2.0wt%,the wood film The crystallinity has a maximum value of 47.70%,and the wood film ha-s a maximum phase change latent enthalpy value of 25.60J/g at this time.Ion species have an effect on the conductivity of wood film.Soaking in 0.50mol/L Fe Cl3 solution is higher than i-mmersing in Al Cl3 and Na Cl solutions of the same concentration;the conductivity of wood fil-m is anisotropic and soaking in 0.50mol/L When the Fe Cl3 solution is 15min,the conductivity in the x direction is 2.99S/m,which is better than the conductivity in the y direction of 2.10S/m.（3）Using AM as the modified monomer,ODMA as the phase change element,and adding polydopamine nanoparticles（PDA-NPs）as the photoprotective agent.PDA-NPs are prepared by oxidative self-polymerization,and PDA-NPs are obtained after purification using acetone precip-itation method.Disperse PDA-NPs into the dipping solution and heat curing to obtain polydop-amine/poly（acrylamide-octadecyl methacrylate）（PDA-NPs/P（AM-ODMA））wood film.It was obse-rved by SEM that the prepared PDA-NPs were spherical in shape and uniform in size.The m echanical performance test found that with the increase of PDA-NPs content,the tensile strengt-h and elongation at break of wood film increased first and then decreased.The maximum and elongation at break and strength were obtained when the content of PDA-NPs was 0.4wt%,Th at is 9.40%and 3.20MPa respectively.The conductivity of wood film with PDA-NPs added in t-he x direction and y direction is increased compared with wood film without PDA-NPs.The xdirection and y direction are 3.00 times that of wood film without PDA-NPs.3.07 time-s.The wood film with PDA-NPs as the photoprotective agent has full absorption in the ultravi-olet reg-ion,has good ultraviolet shielding performance,and has potential applications in anti-ultraviolet products. |
