当前位置: X-MOL 学术ACS Macro Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Resolving Segmental Polymer Dynamics in Nanocomposites by Incoherent Neutron Spin–Echo Spectroscopy
ACS Macro Letters ( IF 5.1 ) Pub Date : 2020-06-04 , DOI: 10.1021/acsmacrolett.0c00369
Dafne Musino 1 , Julian Oberdisse 1 , Bela Farago 2 , Angel Alegria 3 , Anne-Caroline Genix 1
Affiliation  

The segmental dynamics of styrene–butadiene nanocomposites with embedded silica nanoparticles (NPs, ca. 20 vol. %) has been studied by broadband dielectric (BDS) and neutron spin–echo spectroscopy (NSE). It is shown by BDS that overlapping contributions only allow us to conclude on a range of distributions of relaxation times in simplified industrial nanocomposites formed with highly polydisperse NPs. For comparison, structurally similar but less aggregated colloidal nanocomposites have a well-defined distribution of relaxation times due to the reduced influence of interfacial polarization processes. This distribution is widened with respect to the neat polymer, without change in the position of the maximum and at most a small slowing down visible in the average time. We then demonstrate that incoherent NSE can be used to resolve small modifications of segmental dynamics of the industrial samples. By carefully choosing the q-vector of the measurement, experiments with fully hydrogenated polymer give access to the self-dynamics of the polymer in the presence of silica on the scale of approximately 1 nm. Our high-resolution measurements show that the segmental motion is slightly but systematically slowed also by the presence of the industrial filler NPs.

中文翻译:

通过非相干中子自旋回波光谱解析纳米复合材料中的节段聚合物动力学

已通过宽带电介质 (BDS) 和中子自旋回波光谱 (NSE) 研究了嵌入二氧化硅纳米粒子 (NPs, ca. 20 vol. %) 的苯乙烯-丁二烯纳米复合材料的分段动力学。BDS 表明,重叠的贡献只能让我们得出结论,在由高度多分散的 NPs 形成的简化工业纳米复合材料中,弛豫时间的分布范围。作为比较,由于界面极化过程的影响减少,结构相似但聚集较少的胶体纳米复合材料具有明确的弛豫时间分布。相对于纯聚合物,该分布变宽,最大值的位置没有变化,并且在平均时间内至多可见小幅减慢。然后,我们证明了非相干 NSE 可用于解决工业样品分段动力学的小修改。通过仔细选择测量的 q 向量,使用完全氢化聚合物的实验可以在大约 1 nm 的尺度上获得在二氧化硅存在下聚合物的自动力学。我们的高分辨率测量结果表明,工业填料 NP 的存在也略微但系统地减慢了分段运动。
更新日期:2020-06-04
down
wechat
bug