Time-resolved SAXS on crystallization of a low-density polyethylene/high density polyethylene polymer blend
Time-resolved SAXS on crystallization of a low-density polyethylene/high density polyethylene polymer blend
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DOI：
10.1021/ma00182a057
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发表时间：
1988-07
期刊：
影响因子：
5.5
通讯作者：
H. Song;R. Stein;D. Q. Wu;M. Ree;J. C. Phillips;A. Legrand;B. Chu
中科院分区：
文献类型：
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作者：
H. Song;R. Stein;D. Q. Wu;M. Ree;J. C. Phillips;A. Legrand;B. Chu
小角 X 射线散射 (SAXS) 已成功用于研究聚合物共混物的结构。 1" 5 一个自然的延伸是使用同步加速器辐射来测量结晶早期阶段的时间分辨结构变化。6" 8 在本文中，我们报告了低密度聚乙烯 (LDPE) 和高密度聚乙烯 (HDPE) 混合物以及各自均聚物的时间分辨 SAXS 图案。 HDPE 的 Mw= 1.60 X10s g/mol，n/= 7.1，每 1000 个碳原子约 1 个短链支化，密度为 0.957 g/mL。LDPE 的 Mw= 2.86 X 105 g/mol，Mw/Mn= 16，每 1000 个碳原子约 26 个短链支化，密度为 0.920 g/mL 的混合物为 50/50 的 HDPE 和 LDPE（按重量百分比计）。这些材料与之前的研究中使用的材料相同，是通过使用适用于纽约州立大学 NSLS 、布鲁克海文国家实验室 (BNL) 同步加速器辐射的改进型 Kratky 准直器进行的。我们使用了约 2.5 厘米窗口长度的光电二极管阵列。作为线性位置敏感探测器，安装在距样品 548 mm 的位置。
Small-angle X-ray scattering (SAXS) has been used successfully to study the structure of polymer blends. 1" 5 A natural extension is to use synchrotron radiation for measurements of time-resolved structural changes during early stages of crystallization. 6" 8 In this paper, we report our time-resolved SAXS patterns of a blend of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) and of the respective homopolymers. HDPE has Mw= 1.60 X10s g/mol,„/= 7.1, ca. one short chain branching per 1000 carbon atoms, and a density of 0.957 g/mL. The LDPE has Mw= 2.86 X 105 g/mol, Mw/Mn= 16,~ 26 short chains branching per 1000 carbon atoms, and a density of 0.920 g/mL. The blend is 50/50 of HDPE and LDPE by weight percentage. These are the same materials as used in a previous study. 5 SAXS measurements were carried out by using a mod-ified Kratky collimator9 adapted for synchrotron radiation at the SUNY beamline, NSLS, Brookhaven National Laboratory (BNL). The wavelength of X-ray used was 0.154 nm. We used a photodiode array of~ 2.5-cm window length as the linear position sensitive detector, which was mounted at a distance of 548 mm from the sample.