【摘要】 以杉木和落叶松的木粉为研究对象,测定其三大化学组分的含量,利用瞬态平面热源法(TPS)导热系数仪测定植物纤维素、半纤维素和木素以及不同粒径木粉的导热系数,全自动压汞仪测定不同粒径木粉内部的孔隙结构,通过场发射电子显微镜观察两种木粉表面的形貌,并与多种常用真空绝热板(VIP)芯材原料的导热系数和成本进行对比。结果表明:纤维素、半纤维素和木素的导热系数分别为86.1、55.7和50.7 m W·(m·K)-1;杉木木粉的木素含量相对较高,纤维素和半纤维含量相对较低;杉木木粉开孔较多,孔径较小;在粒径为106～150μm时,杉木木粉的孔隙率为88.2%,总孔体积为7.876 cm3·g-1,平均孔径为18.1μm,导热系数较低,为48.4 m W·(m·K)-1,并且芯材成本较其他材料低,制备所得VIP导热系数为10.6 m W·(m·K)-1。更多还原

【Abstract】 Chinese fir and larch wood powders were used to study the thermal conductivity of the major chemical components of plants( cellulose,hemicellulose,and lignin). Different wood powder sizes were measured using the transient plane heat source( TPS) technique and a thermal conductivity tester,and the composition of the wood powders were compared. The pore structure of different sized wood powders was measured using an automatic mercury porosimeter. The surface morphology of the two wood powders was observed using a field emission scanning electron microscope( FESEM). After comparing the thermal conductivity and cost of several common vacuum insulation panel( VIP) core materials,the cost performance of the wood powders was determined. The thermal conductivities of cellulose,hemicellulose,and lignin were 86.1,55.7,and 50.7 m W·( m·K)-1,respectively. The lignin content of the fir powder was relatively high,whereas the content of cellulose and hemicellulose was relatively low. The FESEM results indicated that the fir powder was more porous with smaller pore sizes. The porosity of the fir powder in the 106-150 μm was88.2%, total pore volume was 7. 876 cm3· g-1, average pore size was 18. 1 μm, thermal conductivity was lower at48.4 m W·( m·K)-1,and core material cost was lower than that of other materials. For comparison,the thermal conductivity of VIP is 10.6 m W·( m·K)-1.更多还原