对初始含水率分别为0 %、12 %、18 %、30 %、50 %、80 %、100 %和水饱和8种速生杨木试件进行动态黏弹性分析,采用动态热机械分析仪（DMA）进行测定，其操作参数为:温度范围35~350 ℃,升温速度5 ℃/min,测量频率1、10、50 Hz。储能模量的变化趋势表明: 含水率为0 %的试件在95 ℃附近其储能模量出现极大值; 含水率为12 %、18 %、30 %试样的储能模量在75 ℃之前下降缓慢,在温度75～130 ℃之间迅速下降,含水率为12 %试样的降幅最小; 含水率为50 %、80 %、100 %和水饱和试件的储能模量变化点在135 ℃之后,随含水率的增大储能模量转变点的温度增加,并在转变点处出现储能模量最小值。损耗模量的变化表明:在试验温度范围内含水率为0 %的试件不发生玻璃化转变;在所有含水试件中,含水率为12 %试件的初始损耗模量和发生次转变时的损耗模量均为最低,同含水率为18 %和30 %试件相比,发生次转变时温度最高,含水率为30 %试样在所有含水试样中具有最大的黏性。损耗因子的变化表明:所有含水试样均发生玻璃化转变过程,含水率为30 %试样的玻璃化转变温度最低。在1～50 Hz之间,不同频率对储能模量、损耗模量及损耗因子影响较小, 随着测量频率的升高，各力学松弛过程的描述曲线向高温方向有微小移动。

The dynamic viscoelastic properties of fastgrowing poplar samples with difference initial moisture content were studied by DMA at the following conidition of temperature range from 35 ℃ to 350 ℃, heating rate with 5 ℃/min, measuring frequency with 1,10,50 Hz. The storage modulus results showed that the sample with 0 % moisture content got maximum elasticity at 95 ℃. With increasing temperature, the elasticity of samples with 12 %,18 %,30 % moisture content decreased slowly before 75 ℃,and decreased rapidly between 75 ℃and 130 ℃, for the sample with 12 % moisture content(equilibrium moisture content), the elasticity decreasing range was the smallest in all water content samples; For the samples with 50 %,80 %,100 % and watersaturated, the elasticity variety points happened after 135 ℃, the temperatures of elasticity variation points got increased with increasing moisture content，and had minimums elasticity at variation points. The loss modulus results showed that the glass transition never happened in the whole temperature range with 0 % moisture content sample; in all water content samples, 12 % moisture content specimens had the lowest initial loss modulus and secondary transition loss modulus, compared with the samples of 18 % and 30 % moisture content, the sample with 12 % moisture content had the highest temperature of secondary transition; the sample with 30 % moisture content (fiber saturation point) had the maximum viscosity in all water content samples. The data of loss factor also showed all the samples with water content had the process of glass transition, and the sample with 30 % moisture content got the lowest temperature when the glass transition happened. The measuring frequency with1, 10 and 50 Hz less affected on the storage modulus, loss modulus and loss factor, with the measuring frequency increased, the described curve of mechanical relaxation process moved slightly to high temperature.