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首页> 外文学位 >Preparation of water-absorbing deep-groove polypropylene fibers through the use of migratory additives and photografting.
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Preparation of water-absorbing deep-groove polypropylene fibers through the use of migratory additives and photografting.

机译：通过使用迁移添加剂和光接枝制备吸水深槽聚丙烯纤维。

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摘要

To change the surface properties of polypropylene (PP) deep-groove fibers, this research applied two different surface modification methods: the use of migratory additives and photografting. To identify effective additives for PP, the molecular weight and architecture of the additives were studied in a film system. Hydrophilic additives under investigation included linear polyethylene glycol (PEG) and four-arm polyethylene oxide (4-PEO) of different molecular weights, and a commercial hydrophilic additive (CHA) Irgasurf HL560. ATR-FTIR detected concentration increases for all additives in the near-surface region, but there was no significant improvement in surface hydrophilicity for the PEGs and 4-arm PEOs by water contact angles measurements. Among the linear additives, low MW PEG (1 kDa) was found to migrate faster than the high MW varieties. The linear PEG and 4-arm PEO with MW higher than 2 kDa did not exhibit significant migration to the surface within 1 month. The CHA was effective in rendering PP surfaces hydrophilic in a relatively short time, and demonstrated an ability to replenish the surface after it had been washed in methanol.; To measure the diffusivity of the CHA in PP, an experiment was designed based on a standard 1-D diffusion model. Experimentally, two cases were compared: (1) washing additive off the film surface with limited contact with the solvent. (2) immersing the film in solvent with continuous stirring. Diffusivity measured by the surface-washing method was 10-14 ∼ 10-12 cm2/s, and 10-12 ∼ 10-10 by the immersion method. It is clear that the continuous immersion method more closely matched the zero boundary condition used in the model and thus gave more accurate diffusivity values than did the surface-washing method. Activation energy for diffusion was in the range of 30-100 kJmol -1.; Deep-groove fibers were spun from the mixture of PP and the CHA migratory additive. A novel dynamic contact angle (DCA) analysis method was designed to measure DCAs on single fibers. Results showed decreased advancing and receding contact angles with longer ageing time. Spontaneous water uptake from these modified fibers was observed.; Upon photografting the deep-groove PP fibers with polyacrylamide (PAAm) and polyacrylic acid (PAA) through a two-step photopolymerization, decreased dynamic water contact angles on single fibers and spontaneous water adsorption into fiber bundles were observed. An increase in monomer concentration was found more effective than longer UV exposure time in creating higher graft density on deep-groove PP fibers. Compared with acrylamide (AAm), acrylic acid (AA) penetrated into the fiber and polymerized below the surface. DCA results showed that advancing water contact angle on single fibers decreased from 100° on plain PP to 55° upon modification with PAAm and PAA, and the wicking amount of vertically placed fiber bundles was a linear function of the square root of time at early wicking times.
机译：为了改变聚丙烯（PP）深沟纤维的表面性能，本研究应用了两种不同的表面改性方法：使用迁移添加剂和光接枝。为了鉴定用于PP的有效添加剂，在膜系统中研究了添加剂的分子量和结构。正在研究的亲水性添加剂包括不同分子量的线性聚乙二醇（PEG）和四臂聚环氧乙烷（4-PEO），以及市售的亲水性添加剂（CHA）Irgasurf HL560。 ATR-FTIR检测到近表面区域中所有添加剂的浓度均增加，但是通过水接触角测量，PEG和4臂PEO的表面亲水性没有明显改善。在线性添加剂中，发现低分子量PEG（1 kDa）的迁移速度快于高分子量品种。分子量高于2 kDa的线性PEG和4臂PEO在1个月内未表现出明显的向表面的迁移。 CHA在相对短的时间内有效地使PP表面亲水，并显示出在甲醇中洗涤后能够​​补充表面的能力。为了测量CHA在PP中的扩散率，基于标准的一维扩散模型设计了一个实验。实验上比较了两种情况：（1）在与溶剂接触有限的情况下，从薄膜表面清洗添加剂。 （2）在连续搅拌下将膜浸入溶剂中。通过表面洗涤法测得的扩散率为10-14〜10-12cm 2 / s，通过浸没法测得的扩散率为10-12〜10-10。显然，连续浸入法与模型中使用的零边界条件更加匹配，因此比表面洗涤法具有更准确的扩散率值。扩散的活化能在30-100kJmol -1的范围内。从PP和CHA迁移添加剂的混合物中纺出深槽纤维。设计了一种新颖的动态接触角（DCA）分析方法来测量单根光纤上的DCA。结果表明，随着老化时间的延长，前进和后退接触角减小。观察到这些改性纤维自发吸收水。通过两步光致聚合，用聚丙烯酰胺（PAAm）和聚丙烯酸（PAA）将深沟PP纤维光接枝后，观察到单根纤维上动态水接触角减小，并且自发的水吸附到纤维束中。发现在深槽PP纤维上产生更高的接枝密度比增加紫外线暴露时间更有效。与丙烯酰胺（AAm）相比，丙烯酸（AA）渗透到纤维中并在表面以下聚合。 DCA结果表明，单根纤维的前进水接触角从普通PP的100°降低到PAAm和PAA改性后的55°，垂直放置的纤维束的芯吸量是早期芯吸时的时间平方根的线性函数次。

著录项

  • 作者

    Zhu, Siqiang.;

  • 作者单位

    Clemson University.$bChemical and Biomolecular Engineering.;

  • 授予单位 Clemson University.$bChemical and Biomolecular Engineering.;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 182 p.
  • 总页数 182
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化工过程（物理过程及物理化学过程）;
  • 关键词

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