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Investigation and characterization of oxidized cellulose and cellulose nanofiber films.

机译：氧化纤维素和纤维素纳米纤维薄膜的研究与表征。

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摘要

Over the last two decades, a large amount of research has focused on natural cellulose fibers, since they are "green" and renewable raw materials. Recently, nanomaterials science has attracted wide attention due to the large surface area and unique properties of nanoparticles. Cellulose certainly is becoming an important material in nanomaterials science, with the increasing demand of environmentally friendly materials.;In this work, a novel method of preparing cellulose nanofibers (CNF) is being presented. This method contains up to three oxidation steps: periodate, chlorite and TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) oxidation. The first two oxidation steps are investigated in the first part of this work. Cellulose pulp was oxidized to various extents by a two step-oxidation with sodium periodate, followed by sodium chlorite. The oxidized products can be separated into three different fractions. The mass ratio and charge content of each fraction were determined. The morphology, size distribution and crystallinity index of each fraction were measured by AFM, DLS and XRD, respectively.;In the second part of this work, CNF were prepared and modified under various conditions, including (1) the introduction of various amounts of aldehyde groups onto CNF by periodate oxidation; (2) the carboxyl groups in sodium form on CNF were converted to acid form by treated with an acid type ion-exchange resin; (3) CNF were cross-linked in two different ways by employing adipic dihydrazide (ADH) as cross-linker and water-soluble 1-ethyl-3-[3-(dimethylaminopropyl)] carbodiimide (EDC) as carboxyl-activating agent. Films were fabricated with these modified CNF suspensions by vacuum filtration. The optical, mechanical and thermo-stability properties of these films were investigated by UV-visible spectrometry, tensile test and thermogravimetric analysis (TGA). Water vapor transmission rates (WVTR) and water contact angle (WCA) of these films were also studied.
机译：在过去的二十年中，大量的研究集中在天然纤维素纤维上，因为它们是“绿色”和可再生的原材料。近来，由于纳米颗粒的大表面积和独特性能，纳米材料科学引起了广泛的关注。随着对环境友好材料的需求不断增长，纤维素无疑已成为纳米材料科学中的重要材料。在这项工作中，正在提出一种制备纤维素纳米纤维（CNF）的新方法。该方法最多包含三个氧化步骤：高碘酸盐，亚氯酸盐和TEMPO（2,2,6,6-四甲基哌啶基-1-氧基）氧化。在这项工作的第一部分中，对前两个氧化步骤进行了研究。通过用高碘酸钠，然后用亚氯酸钠的两步氧化，将纤维素纸浆氧化至不同程度。氧化产物可以分为三个不同的部分。确定各部分的质量比和电荷含量。通过AFM，DLS和XRD分别测量了每个级分的形态，尺寸分布和结晶度指数。在第二部分中，CNF是在各种条件下制备和修饰的，包括（1）引入各种量的醛基通过高碘酸盐氧化形成CNF; （2）通过用酸型离子交换树脂处理将CNF上的钠形式的羧基转化为酸形式。 （3）通过使用己二酸二酰肼（ADH）作为交联剂和水溶性1-乙基-3- [3-（二甲基氨基丙基）]碳二亚胺（EDC）作为羧基活化剂，CNF以两种不同的方式交联。通过真空过滤将这些改性的CNF悬浮液制成薄膜。通过紫外可见光谱，拉伸试验和热重分析（TGA）研究了这些薄膜的光学，机械和热稳定性。还研究了这些膜的水蒸气透过率（WVTR）和水接触角（WCA）。

著录项

  • 作者

    Yang, Han.;

  • 作者单位

    McGill University (Canada).;

  • 授予单位 McGill University (Canada).;
  • 学科 Polymer chemistry.;Materials science.
  • 学位 M.Sc.
  • 年度 2012
  • 页码 111 p.
  • 总页数 111
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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