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Controlled Surface Modifications of Synthetic Polymers via Radical Graft Polymerization
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Controlled Surface Modifications of Synthetic Polymers via Radical Graft Polymerization. |
| 개인저자 | Tamizifar, Maryam. |
| 단체저자명 | University of California, Davis. Agricultural and Environmental Chemistry. |
| 발행사항 | [S.l.]: University of California, Davis., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 135 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-03B. Dissertation Abstract International |
| ISBN | 9781085746236 |
| 학위논문주기 | Thesis (Ph.D.)--University of California, Davis, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
Advisor: Sun, Gang. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Synthetic polymers such as polyethylene terephthalate (PET), polyamide (PA), polyacrylonitrile (PAN) and polypropylene (PP) possess many advantages such as high mechanical strength and elasticity, good chemical and abrasion resistance, however, also exhibit hydrophobic behavior and poor wettability, causing them limitations in comfort and application properties. Radical graft polymerization has been considered as a possible and effective method for surface modification of the synthetic polymers to improve surface properties or introduce new functionalities. However, having proper control of conventional free-radical polymerization to increase the grafting efficiency is challenging and critical due to the nature of radical reactions, limited fiber surface area, and lack of surface reactive groups. Therefore, having an appropriate method of control is critically important to achieve high grafting yields on synthetic fiber surfaces.As an effort to control radical graft polymerization on surfaces of synthetic fibers with focus on PET fibers, the Hansen Solubility Parameter (HSP) has been successfully employed to quantify mutual affinities of different reaction components in the grafting reaction system (vinyl monomers, radical initiators, solvents, crosslinkers, and fiber) through calculation of distances between different materials. Calculated HSP distance (R) values can serve as an effective measure to predict, increase and in other words to control the fate of the graft polymerization reaction on polymer (PET) surfaces. The competency of HSP in this regard has been investigated using several different vinyl monomers, initiators, solvents, and crosslinkers on PET surfaces. Successful graft polymerizations on PET surfaces were confirmed by FTIR analysis, and supported quantitatively by different measures such as gravimetric analysis (grafting yield), surface elemental analyses, relative moisture regain values, active chlorine content of grafted samples with N-H containing monomers, and dye uptake of the grafted products. Scanning electron microscope (SEM) was employed to examine surface morphologies of the grafted PET samples. Results indicate that for the selected grafting systems, in general, hydrophilic functional monomers show higher grafting values on PET surfaces compared to hydrophobic vinyl monomers without any crosslinkers. Disregarding the nature and properties of monomers (and other reaction components) HSP can successfully justify grafting values based on mutual affinities (HSP distances) between reaction components and provides effective control on surface radical graft polymerization of PET fibers. HSP can inform selection of solvents and initiators with suitable affinities between monomers and PET polymer. It appears that four major distances, initiator-PET, initiator-solvent, monomer-PET, and monomer-solvent, in the grafting reaction system have major roles in the fate and result of the grafting reaction efficiency.In order to increase the grafting values for hydrophobic monomers studied in the research, another component, a multi-vinyl crosslinker (CL), was added to the graft polymerization reaction system and the new interaction system was analyzed using HSP. As expected, results indicate addition of crosslinkers increased the grafting values of all six different monomers including hydrophobic monomers that had significantly low grafting values in absence of a crosslinker. Using HSP it was enlightened that although the monomer-PET, crosslinker-PET, and monomer-crosslinker interactions impart significant roles in controlling the radical graft polymerization on PET surfaces, monomer/crosslinker-solvent and monomer/crosslinker-initiator interactions are determining factors and affect the grafting values. Dyeing properties and active chlorine contents of the grafted samples with N-H containing monomers in presence of crosslinkers, show increased values that confirm positive control of the crosslinker in enhancing the grafting efficiency. Obvious morphological alteration in surface structure of grafted PET surfaces in presence of PEGDIA crosslinker is observed for all monomers by scanning electron microscopy. The significance of this research lies in the fact that, HSP can be an efficient tool to analyze different interactions (affinities) in the grafting system which enables one to effectively control (enhance) surface modification of inert polymers such as PET. |
| 일반주제명 | Polymer chemistry. Textile research. Materials science. |
| 언어 | 영어 |
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