Form I′ crystal formation in random butene-1/propylene copolymers as revealed by real-time X-ray scattering using synchrotron radiation and fast scanning chip calorimetry
Form I′ crystal formation in random butene-1/propylene copolymers as revealed by real-time X-ray scattering using synchrotron radiation and fast scanning chip calorimetry
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DOI：
10.1016/j.eurpolymj.2014.08.011
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发表时间：
2014-11
影响因子：
6
通讯作者：
I. Stolte;D. Cavallo;G. C. Alfonso;G. Portale;M. Drongelen;R. Androsch
中科院分区：
文献类型：
--
作者：
I. Stolte;D. Cavallo;G. C. Alfonso;G. Portale;M. Drongelen;R. Androsch
在273 ~ 343 K的较宽温度范围内，研究了无规全同1-丁烯/丙烯共聚物的结晶行为与丙烯浓度和结晶温度的关系，着重考察了I′型晶体的形成。如果丙烯含量大于约10摩尔%，则在无规丁烯-1/丙烯共聚物中形成I′型晶体。对于具有11.4mol%丙烯的无规丁烯-1/丙烯共聚物，发现仅在低于310 K时形成I′型晶体，且相对量随着结晶温度的降低而增加。在273 K下结晶时，观察到最大I′型晶体分数约为总晶体分数的1/3。无论其形成温度如何，如果在相同温度下形成，亚稳I′型晶体的热稳定性明显低于不稳定II型中间相和稳定I型晶体的热稳定性。
The crystallization behavior of random isotactic butene-1/propylene copolymers has been investigated as a function of the propylene concentration and as a function of the crystallization temperature in a wide temperature range from 273 to 343 K, with emphasis placed on the detection of formation of Form I′ crystals. Form I′ crystals in random butene-1/propylene copolymers develop if the propylene content is larger than about 10 mol%. For a random butene-1/propylene copolymer with 11.4 mol% propylene it was found that Form I′ crystals only form below 310 K, with the relative amount increasing with decreasing crystallization temperature. A maximum Form I′ crystal fraction of about 1/3 of the total crystal fraction has been observed on crystallization at 273 K. Regardless the temperature of its formation, the thermal stability of metastable Form I′ crystals is distinctly lower than the thermal stability of unstable Form II mesophase and stable Form I crystals, if formed at identical temperature.