摘要
采用示差扫描量热仪研究了稀土顺式聚丁二烯（PB）等温过程的结晶及其熔融行为。结果表明,在等温结晶的后期存在晶型完善的过程,而且随着等温结晶温度的提高,结晶速率均下降。PB的熔融总是在比等温结晶温度高约2℃处开始,而且在10℃/min的升温速率下,DSC曲线不仅显示出很宽的熔融温度范围,而且在低温处还出现了小肩峰,说明等温结晶后体系中具有在该升温速率下不同稳定性的晶体。通过不同温度下的等温结晶曲线,分别采用结晶度趋于零（Xc=0）时的熔点和结晶时间无限长（tc-1=0）时的熔点,用Hoffman-Weeks方法得到顺式聚丁二烯的平衡熔点Tm^∞位于9-17.6℃之间。
The isothermal crystallization process and subsequent melting behavior of a cis-1,4-polybutadiene（PB） sample were investigated by differential scanning calorimetry（DSC）.It was found that there existed a perfection process of crystals at the late stage of the isothermal crystallization process.In addition,the rate of crystallization decreased with an increase of the crystallization temperature.Melting of the PB crystals always starts at about 2 ℃ above the crystallization temperature.At a heating rate of 10 ℃/min,DSC thermogram shows a broad distribution of melting temperatures with a smaller shoulder on the low-temperature side,indicating that this sample possesses crystallites with different stabilities after isothermal crystallization.By extrapolating the melting points to zero crystallinity（Xc=0） or infinite long crystallization time（t-1c=0）,we determined the equilibrium melting point Tm^∞ of this PB specimen to be in between 9 and 17.6 ℃ according to the Hoffman-Weeks approach.
出处
《应用化学》
CAS
CSCD
北大核心
2008年第10期1233-1236,共4页
Chinese Journal of Applied Chemistry
关键词
DSC
顺式聚丁二烯
结晶
熔融
DSC,cis-polybutadiene,crystallization,melting
