Study On Preparation And Performance Of Functionalized Conductive Wood Film Based On Temperature-responsive Phase Change Element

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.