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Improvements in the mechanical properties of some biodegradable polymers & bimodal poly(dimethylsiloxane) hydrogels and surface hydrophilic treatments.

机译：改善了一些可生物降解的聚合物和双峰聚二甲基硅氧烷水凝胶的机械性能以及表面亲水性处理。

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摘要

The first part presents the improvements in the mechanical properties of a couple of biodegradable polymers, the first one is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) by introducing several nano-fillers (clay, mica, talc, expanded graphite) to prepare nanocomposites. Solution mixing and melt bending are the two preparation methods used. The resulting nanocomposites were characterized by X-ray diffraction measurements (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and INSTRON measurements. The results showed that PHBHx/clay and PHBHx/graphite nanocomposites were obtained with remarkable improvements in mechanical properties even at very low filler content. The improvements were mostly attributed to the intercalated, even exfoliated state of the clay in PHBHx.;Another Biodegradable polymer was studied in this work is glycerol-derived alkyd resin. One set of the resin/clay nanocomposites was successfully prepared by melt blending the resin precursors with organoclays. The clay using here is clay30B, and clay30BT (further treated ones of clay30B). Mica and talc were also used to prepare nanocomposites for comparison. The morphologies, thermostabilities, and mechanical properties of the resulting nanocomposites were investigated, indicating that resin/clay nanocomposites were obtained with remarkable improvements in thermostability and mechanical properties even at very low loadings.;The second part focused on the preparation and characterization of silicone hydrogels based on poly(dimethylsiloxane) (PDMS) and hydrophilic block copolymer, and some surface modifications of PDMS.;The first two series of bimodal silicone hydrogels successfully prepared are PDMS-poly(ethylene glycol) (PEG) hydrogels, which were prepared by end-linking a combination of long and short chains and a couple of hydrophilic functional crosslinker respectively. In both cases longer hydrophilic chains clearly migrated to the surfaces of the resulting PDMS-PEG hydrogels to give decreases of static contact angles (CA) from 105° to 80° for the first series, and to 40° for the second. The longer hydrophilic chains were found to give larger decreases in CA values and larger equilibrium water contents as expected.;Several other series of PDMS amphiphilic conetworks (APCNs) were prepared including by bonding a hydrophilic macromer, hydroxyl-terminated linear PEG, hydroxyl-terminated linear PDMS with the crosslinker bis[(3-methyldimethoxysilyl)propyl]-polypropylene oxide (BMPPO), which also functioned as a compatibilizer. The CA values decreased significantly from 105° in PDMS to 55° in the PEG/PDMS APCN (10/1 mol ratio), and the swelling degrees of the APCNs increased from about 0 to 60% when the mol ratio was larger than 4/1. A couple of other series APCNs with very high and long lasting hydrophilicity and good mechanical properties were also obtained.;Secondly, several surface treatments methods were applied to make PDMS networks surface hydrophilic, including (1) introduction of an ultra thin layer of silica on the surfaces through the sol-gel process, (2) a UV/ozone method for bimodal networks consisting of some vinyl-substituted chains, poly(vinylmethylsiloxane) (PVMS), along with those of PDMS; (3) treatment of PDMS networks by UV/ozone, followed by grafting of polyethylene glycol based silane directly onto the surfaces, (4) grafting a hydrophilic monomer, N-isopropylacrylateamine by the UV radiation, (5) plasma polymerization of acrylic acid (AA) onto the surface of the PDMS.;Keywords. poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); clay; expanded graphite; carbon nanotube; poly(dimethylsiloxane); poly(ethylene glycol); amphiphilic conetworks; hydrophilicity; mechanical properties; end-linking; alkoxy silanes; Hydrogels; surface properties; contact angles; swelling; surface treatments.
机译：第一部分介绍了几种可生物降解的聚合物在机械性能方面的改进，第一个部分是通过引入几种纳米填料（粘土，云母，滑石粉，膨胀粉）的聚（3-羟基丁酸酯-co-3-羟基己酸酯）（PHBHx）石墨）以制备纳米复合材料。溶液混合和熔融弯曲是所使用的两种制备方法。通过X射线衍射测量（XRD），扫描电子显微镜（SEM），透射电子显微镜（TEM），热重分析（TGA），差示扫描量热法（DSC）和INSTRON测量来表征所得的纳米复合材料。结果表明，即使在非常低的填料含量下，仍获得了机械性能显着改善的PHBHx /粘土和PHBHx /石墨纳米复合材料。改善主要归因于PHBHx中粘土的插层，甚至剥落状态。这项工作中研究的另一种可生物降解的聚合物是甘油衍生的醇酸树脂。通过将树脂前体与有机粘土熔融共混，成功制备了一组树脂/粘土纳米复合材料。这里使用的黏土是黏土30B和黏土30BT（黏土30B的进一步处理的黏土）。云母和滑石粉也用于制备纳米复合材料进行比较。研究了所得纳米复合材料的形貌，热稳定性和力学性能，表明所获得的树脂/粘土纳米复合材料即使在非常低的负载量下，其热稳定性和机械性能也得到了显着改善。以聚二甲基硅氧烷（PDMS）和亲水性嵌段共聚物为基础，并对PDMS进行了一些表面修饰。;成功制备的前两个系列的双峰有机硅水凝胶是PDMS-聚乙二醇（PEG）水凝胶，它们是通过最终制备的-分别连接长链和短链的组合以及一对亲水性功能交联剂。在这两种情况下，更长的亲水链显然迁移到所得PDMS-PEG水凝胶的表面，从而使静态接触角（CA）从第一个系列的105°减小到80°，而第二个系列减小到40°。发现更长的亲水链可按预期提供更大的CA值降低和更大的平衡水含量。；还制备了PDSM的其他两个系列的两亲共网络（APCN），包括通过键合亲水大分子单体，羟基封端的线性PEG，羟基封端的方法具有交联剂双[（3-甲基二甲氧基甲硅烷基）丙基]-聚环氧丙烷（BMPPO）的线性PDMS，它也起增容剂的作用。 CA值从PEG / PDMS APCN中的105°显着下降到PEG / PDMS APCN中的55°（摩尔比为10/1），并且当摩尔比大于4 /时，APCN的溶胀度从大约0％升高到60％。 1。还获得了其他两种具有很高的亲水性和持久的亲水性以及良好的机械性能的系列APCN。其次，应用了几种表面处理方法使PDMS网络表面具有亲水性，包括（1）在硅上引入超薄二氧化硅层。通过溶胶-凝胶法制得的表面，（2）双峰网络的UV /臭氧法，该方法由一些乙烯基取代的链，聚（乙烯基甲基硅氧烷）（PVMS）和PDMS组成。 （3）用UV /臭氧处理PDMS网络，然后将聚乙二醇基硅烷直接接枝到表面上，（4）通过UV辐射接枝亲水单体N-异丙基丙烯酸胺，（5）丙烯酸的等离子体聚合（ AA）到PDMS的表面上；关键字。聚（3-羟基丁酸酯-co-3-羟基己酸酯）;粘土;膨胀石墨碳纳米管聚二甲基硅氧烷聚乙二醇）;两亲网络亲水性机械性能末端连接烷氧基硅烷；水凝胶；表面性质接触角肿胀;表面处理。

著录项

  • 作者

    Zhang, Xiujuan.;

  • 作者单位

    University of Cincinnati.;

  • 授予单位 University of Cincinnati.;
  • 学科 Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 209 p.
  • 总页数 209
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 高分子化学（高聚物）;
  • 关键词

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