The Aging Study Of Bamboo-wood Thermoelectric Composites Prepared By Four Adhesives

Bamboo-wood thermoelectric composites are based on bamboo for the surface material,wooden material forthe substrates,carbon fiber paper for the heating layer,prepared a new type of functional material.Carbon fiber paper as a conductive material when electro-thermal conversion efficiency can be as high as 97%,and infrared radiationhave certain effectsin human health care,which can be prepared as geothermal floor,heating wall panels and other products,these products have excellent features such as clean?energy saving?low cost?easy to install?heating up quickly?comfortable,and so on.However,in the period of practical application,its chemical composition and structure will occur a series of changes,physical and mechanical properties will change,such asdiscoloration,warping deformation,strength degradation,which put forward higher requirements for the safetyand stability of bamboo-wood heating floor.Therefore,by studying the performance ofbamboo-woodthermoelectriccomposites in the process of long-term energization,grasp aging behavior,and then improve the performanceof heating floor,which has important theoretical guiding significance for scientific research and actual production.In this paper,we used water-based polymer isocyanate adhesive(API)?epoxy resin adhesive(EP)?melamine modified urea-formaldehyde resin adhesive(MUF)?phenolic resin adhesive(PF)to prepare bamboo-wood thermoelectric composites,under threeheating power level,tested the resistance,time-temperature effect,surface performance,dipping detachment and dimensional stability,summed up a systematic aging properties of bamboo-wood thermoelectriccomposites and provided a theoretical foundation for developinglong-term application ofbamboo-wood thermoelectricfloor.The main conclusions are as follows:The resistance of four materials showed a tendency of decreasingfirst and then stabilizing under electric power.The greater the power,the more the resistance drops.Relatively,resistance of PF material changed least under power 160W/m2,its resistance dropping rate is 0.7 %.The greaterthe power,the higher the surface steady temperature of the materials,and the faster the heating rate.During the initial 20 min,the surface temperature rises rapidly,and the temperature reaches the steady state within 45 min,and remained stable in 60 min.After power failure,the temperature referred back to the state when the material is not powered on in 60 min.The greater the heatingpower,the higher the surface temperature unevenness,the unevenness of PF materialunder power 160 W/m2 is 3.6?,and the unevenness of API material under power 800 W/m2 is 22 ?.When the energization time is increased and the power is increased,the total color difference of four materials increased,and the gloss is decreased.The warpagein the longitudinal direction is in line withnational standards GB/T 18103-2013,which is not more than 1.00%,meet the floor with the size of the stability of deformation requirements.In the length direction,the API control sample had a moisture swelling rate of 0.25%,the MUF control material had a heat shrinkage rate of 0.32%,and the EP material had a moisture resistance dimensional stability of 0.3%,moisture resistance dimensional stability of the EP material is 0.3% under power 800W/m2,does not meet the standard requirements.Under other conditions,the humidityand heat-resistance dimensional stabilityof four materials meet the requirements of LY / T 1700-2007.In addition to API materialsunder electric power 160W/m2,impregnation stripping performance of othersis perfect.Four materials have superior anti-impregnation peel performance under electric power 320W/m2 and 800W/m2.The elastic modulus and bending strengthbefore and after the power are in line with GB/T 18103-2013.We adopted mathematical fuzzy evaluation method and got following conclusions,the performance ofPF material is excellent,MUF material secondly,EP materials and API materials are relatively poor.Theperformanceof PF material under power 160 W/m2 is best,the greater the power,the worse the performance.