摘要
利用动态热机械分析仪检测了落叶松和白桦试材在不同含水率下的玻璃化转变温度(tg),研究了二者的关系及不同初含水率下储能模量随温度变化的规律。结果表明:落叶松和白桦试材玻璃化转变温度均随含水率升高而线性降低,表征二者关系的两个线性方程之决定系数分别高达0.996 46与0.979 86;含水率每增大1%所引起的玻璃化转变温度的降低值,落叶松为6.71℃,大于白桦的6.64℃。落叶松和白桦的储能模量均随其温度、初含水率的升高而减小。落叶松的储能模量以约70 MPa/℃的平均幅度随温度的升高近似呈线性减小趋势。白桦储能模量在初含水率6%~13%时,约以146.9 MPa/℃的平均幅度随温度的升高呈近似线性减小趋势;初含水率在15%~22%,随温度的上升产生了较为明显的突变点,在100℃左右急剧减小。所得落叶松和桦木储能模量与温度及含水率关系的两个数学表达式的决定系数分别达到0.910 43和0.886 54。
Dynamic mechanical analysis (DMA) of the White Birch and Larch were performed using a TAQ800 analyzer. The effect of moisture content on the glass transition temperature and the effect of temperature and initial moisture content on the storage modulus for White Birch and Larch were acquired. The glass transition temperature of larch and birch decreased linearly with the increase of moisture content, and the coefficient of determination of the two linear equations were 0.996 46 and 0.979 86, respectively. Each percent of moisture content increase cause the reduction of glass transition temperature for 6.71 ℃ on larch which is greater than that of birch for 6.64 ℃. The storage modulus of White Birch and Larch decreased with the increase of temperature and initial moisture content. The storage modulus of larch decreased approximately linearly with the increase of temperature at the average amplitude of about 70 MPa/℃. As for larch, the storage modulus was decreased with the decreasing temperature at the average amplitude of about 146.9 MPa/℃ when the initial moisture content was between 6% and 13%, and decreased drastically at 100 ℃, when the initial water content was between 15% and 22%. The correlation coefficients of the two mathematical expressions of the relationship of the storage modulus including temperature and water content of larch and birch were 0.910 43 and 0.886 54, respectively.
出处
《东北林业大学学报》
CAS
CSCD
北大核心
2017年第8期66-69,共4页
Journal of Northeast Forestry University
基金
国家自然科学基金项目(31270595)
关键词
变定处理
木材含水率
玻璃化转变温度
储能模量
Drying set
Moisture content of wood
Glass transition temperature
Storage modulus