Transitions and Phases of Polytetrafluoroethylene
Transitions and Phases of Polytetrafluoroethylene
复制标题
聚四氟乙烯的转变和相
DOI：
10.1143/jjap.8.635
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发表时间：
1969
影响因子：
1.5
通讯作者：
T. Takemura
中科院分区：
文献类型：
--
作者：
S. Hirakawa;T. Takemura
用超声波、热膨胀、差热分析和X射线衍射法研究了聚四氟乙烯的相变行为和高压相的性质。在1atm的压力范围内得到了相图。在室温到165°C的温度范围内，发现三个相：高于30°C的阶段I和低于20°C的阶段II，两者都在1个大气压下。第三阶段，5000公斤/平方厘米以上。三相点位于75°C和5,000公斤/平方厘米。在低压下，20°C和30°C的转变温度与压力的关系分别为每1,000 kg/cm2 15度和9度，在中压范围内，这两种转变的转变温度分别为每1,000 kg/cm2 9度，II-III和III-I转变分别为-13度和50度。结果表明，高压相(III相)可能是紧密堆积的无序相。
Behavior of transitions and the nature of high-pressure phase in polytetrafluoro ethylene are studied using methods of ultrasonic waves, thermal expansion, differential thermal analysis and X-ray diffraction. A phase diagram is obtained in pressure range from 1 atm. to 6,500 kg/cm2 and in temperature range from room temperature to 165°C. Three phases are found; phase I above 30°C, phase II below 20°C, both at 1 atm. and phase III above 5,000 kg/cm2. The triple point is located at 75°C and 5,000 kg/cm2. Pressure dependence of transition temperatures is obtained as 15 and 9 degrees per 1,000 kg/cm2 for the 20°C and 30°C transitions at low pressure, 9 degrees per 1,000 kg/cm2 for both transitions at intermediate pressure range from about 3,000 to 5,000 kg/cm2, -13 and 50 degrees per 1,000 kg/cm2 for the II–III and the III–I transitions, respectively. It is suggested that the high-pressure phase (phase III) may be a closely packed but disordered phase.