文中建立了超声波和PVT同步检测装置，检测了聚丙烯（PP）的凝固行为。测得了不同压力下超声波振幅或波速与温度关系的曲线，曲线具有相似性，能够定量分析特征结晶温度和压力对结晶的影响。按照温压等效原理，对波速曲线按照固态和液态分别进行归一化处理，发现两态下平移因子不同，结晶区接近固态的；绝对结晶峰温度相对熔融峰温度随压力变化接近指数衰减规律。相对于动态扫描量热学（DSC），超声波扫描热学（USC）直接测量物料，可在高压条件进行测试。
The instrument was designed for the simultaneous characterization of the ultrasonic wave and pressure- volume-temperature in the solidification of polypropylene. Ultrasonic amplitude and velocity versus temperature at different pressures quantitatively exhibited the effects of pressure on crystallization. The similar velocity curves were normalized for obtaining the master curve in solid state and melt state respectively in terms of pressure-temperature equivalence principle. The shift factors in two states were different when the crystallization shifting was close to the solid state. The peak temperature in amplitude curve dropped in the exponential decay. Unlike dynamic scanning calorimetry (DSC), ultrasonic scanning calorimetry( USC) can perform high pressures measurement directly.
参考文献
| [1] | P.D.Coates;S.E.Barnes;M.G.Sibley;E.C.Brown;H.G.M.Edwards;I.J.Scowen .In-process vibrational spectroscopy and ultrasound measurements in polymer melt extrusion[J].Polymer: The International Journal for the Science and Technology of Polymers,2003(19):5937-5949. |
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