Crystallization-Induced Confinement Enhances Glassy Dynamics in Star-Shaped Polyhedral Oligomeric Polysilesquioxane–Isotactic Polystyrene (POSS–iPS) Hybrid Material,Macromolecules

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Crystallization-Induced Confinement Enhances Glassy Dynamics in Star-Shaped Polyhedral Oligomeric Polysilesquioxane–Isotactic Polystyrene (POSS–iPS) Hybrid Material
Macromolecules ( IF 5.1 ) Pub Date : 2018-01-10 00:00:00 , DOI: 10.1021/acs.macromol.7b02137
Martin Tress _{1,

2} , Maximilian Vielhauer ₃ , Pierre J. Lutz _{3,

4} , Rolf Mülhaupt _{3,

5} , Friedrich Kremer ₂

Affiliation

In semicrystalline polymers, the segments around the crystallites typically relax significantly slower than in the purely amorphous phase. This results in an, on average, slower dynamics. Here we present a contrary effect in a star-shaped polymer based on a polyhedral oligomeric silesquioxane (POSS) molecule as center and isotactic polystyrene arms. Measurements by means of broadband dielectric spectroscopy reveal a reduction of the mean relaxation time by up to 1 decade. Analyzing the relaxation time distribution unravels three moieties of different dynamics beyond the crystalline fraction. These are assumed to form respective domains: a rigid amorphous fraction around crystallites, a mobile amorphous fraction, and a confined amorphous fraction of enhanced dynamics presumably located around the POSS centers. Probably, the crystallites in combination with the starlike architecture stabilize the average volume which balances the higher density of the growing crystallites by an increase in free volume in the amorphous domains.

中文翻译：

结晶诱导的禁闭作用增强了星形多面体低聚聚倍半硅氧烷-全同立构聚苯乙烯（POSS-iPS）杂化材料的玻璃态动力学

在半结晶聚合物中，微晶周围的链段通常比纯无定形相中的弛豫要慢得多。平均而言，这会导致动态变化变慢。在这里，我们在以多面体低聚倍半硅氧烷（POSS）分子为中心和全同立构聚苯乙烯臂的星形聚合物中呈现相反的作用。通过宽带介电谱法进行的测量表明，平均弛豫时间最多可减少10年。分析弛豫时间分布可揭示结晶部分以外的三个不同动力学的部分。假定它们形成了各自的畴：微晶周围的刚性无定形部分，流动性无定形部分和大概位于POSS中心附近的增强动力学的受限无定形部分。大概，

更新日期：2018-01-10

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