Structure And Characterization Of Bamboo Fiber Vacuum Insulation Panels

Due to the continuous and rapid economic development in our country,the consumption of a large amount of energy and the increase of emissions of pollutants had put energy and environmental security under tremendous pressure.In order to solve the problem of environmental pollution and energy shortage,Vacuum Insulation Panel(VIP),a thermal insulation material with super thermal insulation performance,had attracted great attentions from energy scientists.But,VIP had such problems as high production cost,non-renewable raw materials and inability to be degraded.Therefore,researching and developing a new type of high-efficiency,energy-saving and environment-friendly green thermal insulation material is an urgent need to solve the problem.This paper studied the thermal conductivity of VIP of preparing of three kinds of pulp,such as dissolved bamboo pulp,bleached bamboo pulp and unbleached bamboo pulp.The results showed that bleached bamboo pulp had better preservation performance and low cost as the core material of VIP.Under the condition of beating degree of 14.9°SR,vacuum degree of 0.05Pa,temperature of 25? and storage time of It,the bamboo fiber of VIP had the smallest thermal conductivity of 12.6mW/(m·k),and it had the best heat insulation performance and good stability.As the beating degree increases,the insulation and air permeability of bamboo fiber of VIP continued to decline,and the strength performance continued to increases.The fiber morphology analysis showed that the mechanical failure during the beating process resulted in an increase in tensile index and solid heat transfer of the core material of VIP.The SEM analysis showed that the surface structure of the core material of VIP became denser with the increase of beating degree,which made the air permeability gradually decrease and the solid heat transfer increases.The AUTOPORE9500 analysis showed that the porosity of core material of VIP was reduced from 75.7%to 49.2%with the increase of beating degree,and the internal structure of core material of VIP tended to be dense.This paper studied the effect of two kinds of insulating particle of A and B for the structure and thermal insulation performance of the bamboo fiber of VIP.The results showed that the insulating particle of A added to the core material of VIP had a better advantage.Under the condition that the amount of insulating particles A added 30%,vacuum degree of 0.05Pa,temperature of 25? and storage time of It,the bamboo fiber of VIP had the smallest thermal conductivity of 11.4mW/(m·k).The bamboo fiber and insulating particle of VIP had the best heat insulation performance and good stability.With the increase of the proportion of insulating particle of A,the thermal conductivity of bamboo fiber of VIP first decreased and then increased.The SEM analysis showed that the three-dimensional network structure of the core material of VIP distributed more insulating particles,when the amount of insulating particle of A was increased from 0%to 30%.Because of good thermal insulation performance of insulating particle of A,the thermal conductivity of VIP was reduced.But the insulating particle was distributed in the three-dimensional network structure,when the added amount is increased from 30%to 50%,resulting the structure of core material of VIP more denser,forming a heat-conducting channel,the solid heat transfer increased.The thermal conductivity of VIP increased.The AUTOPORE9500 analysis showed that the porosity of core material of VIP was reduced from 75.7%to 55.2%with the increase of the ratio of insulating particle of A.The internal structure of the core material tended to be dense,further verifying the analysis results of SEM.This paper studied the effect of adding glass fiber for the structure and thermal insulation properties of bamboo fiber of VIP.The results showed that the thermal conductivity of the bamboo fiber and glass fiber of VIP was 5.13 mW/(m·k)when the glass fiber content,was 45%,which can achieve a good thermal insulation effect,and had a high cost performance,reaching the domestic advanced Level.With the increase of the proportion of glass fiber,the thermal conductivity of bamboo fiber of VIP first decreased rapidly and then declined slowly.The SEM analysis showed that the three-dimensional network structure of the core structure distributed more glass fiber with the increase of glass fiber content.It hindered the fiber interweaving and reduced the interweaving points.The solid heat transfer was reduced in the VIP.The thermal conductivity of VIP was reduced.But the surface morphology of the core material didn't change significantly,when the addition amount increased from 45%to 50%,so that the thermal conductivity of VIP didn't decrease significantly.The AUTOPORE9500 analysis of the internal structure of the core material of VIP further validated the SEM results.