通过SEC/MALS/VISC/DRI来表征烯单体和寡聚物
1Chemical Sciences Division, National Institute of Standards and Technology (NIST), 100 Bureau Drive, MS 8390, Gaithersburg, MD 20899-8390, USA.
Chromatographia
|March 4, 2024
概括
准确的聚合物分析需要了解烯寡合物的特定折射率增量. 这项研究量化了这一参数,改善了聚合物表征和聚乙烯生产的监管合规性.
科学领域:
- 聚合物化学 聚合物化学
- 分析化学 分析化学
- 材料科学 材料科学 材料科学
背景情况:
- 全球聚乙烯 (PS) 产量每年超过2700万,国际贸易也很大.
- 商业PS通常含有寡合物,影响加工,最终用途特性,健康影响和监管分类.
- 通过大小排除色谱 (SEC) 精确量化寡合体,由于寡合体区域的变量特定折射率增量 (
∂ n / ∂ c ) 受到阻碍.
研究的目的:
- 准确地确定一系列聚合度的烯寡合体的特定折射率增量 (
∂ n / ∂ c ). - 为了研究不同
∂ n / ∂ c 对聚合物表征的影响,包括质量分数和摩尔质量平均值. - 评估色谱参数对分辨率的影响,并确定寡合物的内在粘度和粘度半径.
主要方法:
- 使用了多探测器尺寸排除色谱 (SEC) 系统,包括差分折射计,多角度静态光散射和差分粘度计.
- 测量了从单体到六体和一个六体的基终结烯寡合体的∂/c.
- 研究了注射量,流量和温度对染色体分辨率的影响.
主要成果:
- 在
∂ n / ∂ c 参数中观察到显著的变化,聚合度越来越高. - 发现,在相同的条件下, styrene 单体的 C 值小于 polystyrene 聚合物的一半.
- 通过使用集成粘度计,成功确定了单体和小分子的内在粘度和粘度半径.
结论:
- 寡合区中
∂ n / ∂ c 的不稳定性显著影响了聚乙烯的表征. - 精确地确定
∂ n / ∂ c 对于精确量化寡合物和可靠地确定聚合物特性至关重要. - 多探测器SEC方法为改善聚乙烯分析,加工和监管合规提供了必要的数据.
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