| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 92 === In this investigation, we attempt to improve the peel strength of ePTFE membrane by plasma treatment followed by grafting with hydrophilic monomers, such as Acrylamide (AAm)、Glycidyl methacrylate (GMA) and 2-Hydroxyethyl methacrylate (HEMA). The adhesion properties of the PTFE membrane were significantly improved by using plasma graft polymerization of AAm、GMA、and HEMA onto the surface of ePTFE membrane. The surface properties of the modified membrane were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total refraction–Fourier transform infrared (ATR-FTIR), contact angle meter (CA), scanning electron microscopy (SEM) and Instron.
In this study, it was found that heavy degradation was happened by the oxygen plasma treatment. Small molecular weight segments such as –CFx were formed due to the etching phenomenon on the ePTFE surface. By increasing the power of plasma, this phenomenon was more significantly. These -CFx segments might be re-deposition on to the ePTFE surface by physical adsorption and lead to the decrease of peel strength from 3.65 N/cm to 1.05 N/cm (peel strength between original ePTFE and adhesive is 2.47 N/cm). Optimum peel strength was obtained using an oxygen plasma treatment followed by grafting with 20 wt% AAm at 80 oC for 3 hr, giving a [N]/[C] ratio: 0.208 and improvement of peel strength to 6.22 ± 0.55 N/cm.
In addition, the adhesion properties of the ePTFE membrane were significantly improved by oxygen plasma pretreated and followed by post grafting with AAm onto the surface of ePTFE membrane from 2.47 to 6.22 N/cm. On the other hand, the adhesion strength is lower by the argon plasma pretreated ePTFE membrane followed by post grafting with AAm than oxygen plasma pretreated one under the same condition. It suggests that due to the surface pore of ePTFE membrane were filled up with the homopolymer, the mechanical inter locking force between the ePTFE and adhesion was decreased, resulting in the drop of peel strength.
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