方案摘要
方案下载| 应用领域 | 其他 |
| 检测样本 | 其他 |
| 检测项目 | |
| 参考标准 |
Modulated thermomechanical analysis is shown to be a useful tool for determining thermodynamic and kinetic, reversing and nonreversing length changes in materials when these thermally induced events take place simultaneously. This ability to separate thermodynamic from kinetic events aids in the interpretation of the thermal curve, measures expansion and contraction taking place at the same time and provides a more accurate estimation of the glass transition temperature than the softening temperature. MTMA may have applications in other measurements where thermodynamic and kinetic length changes occur simultaneously. Such examples may include the softening of organic or inorganic glasses, heat set films and fibers, and shape memory alloys.
ABSTRACT
In modulated thermal analysis, a sinusoidally varying temperature program is added to an underlying linearly changing or static temperature program. Fourier transformation of the oscillatory temperature “forcing function” and the result dependent variable provides the deconvolution of these signals into reversing and nonreversing components. The reversing signal is associated with properties dependent upon the temperature rate of change while the nonreversing signal defines kinetic events (that is, those associated with both time and temperature). Thus for modulated thermomechanical analysis (MTMA™), coefficient of thermal expansion is observed in the reversing signal and stress relaxation, softening and heat shrinking are observed in the nonreversing signal. The ability of MTMA to measure both expansion and contraction simultaneously is demonstrated on samples including thermoset composite printed circuit boards and heat-shrink packaging film.
利用微量热技术研究病毒结构与宿主细胞受体结合反应
等温量热法研究水泥水化
等温微量热法研究生物制品长时间稳定性评价
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