利用超臨界二氧化碳進行聚丙烯腈薄膜表面改質之研究

Surface Modification of Polyacrylonitrile Membrane Using Supercritical Carbon Dioxide

袁振邦(Chan-Pong Iun)

指導教授 ： 陳延平

國立臺灣大學/工學院/化學工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01265

摘要

本研究利用超臨界二氧化碳為溶劑，取代一般有機溶劑，進行聚丙烯腈薄膜之表面改質。本研究以兩段式操作，利用自由基聚合法，把親水性單體接枝在聚丙烯腈表面上。在第一段操作中，超臨界二氧化碳把自由基起始劑帶進高分子薄膜中。第二階段再利用超臨界二氧化碳把親水性單體帶至高分子表面上，進行自由基接枝反應，令親水性單體接枝在高分子表面上，形成親水性區域。以超臨界二氧化碳為溶劑進行接枝反應，可利用操作温度與壓力之改變，調整單體在高分子上之接枝重量百分比。除兩段式操作外，也可以經由單一步驟完成接枝反應，本研究比較兩段式與單一步驟程序所得到的不同接枝效率。反應後之聚丙烯腈，利用霍氏轉換紅外光譜儀，測定接枝後之化學性質改變；利用差式掃瞄熱量分析儀，鑑定薄膜之熔化與結晶性質改變；利用掃瞄式電子顯微鏡，觀察薄膜表面之形態改變；再利用液滴法，測量薄膜靜態接觸角之改變，求出接枝後薄膜表面親水性之改變。本研究並利用相同方法，製備鐵氟龍混材，和進行聚氟乙烯和聚碳酯之表面改質。

關鍵字

超臨界二氧化碳 ； 聚丙烯腈表面改質

並列摘要

Supercritical carbon dioxide (SCCO2) was used as the solvent and swelling agent to modify the surface of polyacrylonitrile (PAN) membrane. A two-stage process was used to graft 2-hydroxyethyl methacrylate (HEMA) by free radical polymerization onto PAN. The composite polymer was prepared by first infusion of initiator, 2,2’-azobisisobutyronitrile (AIBN) into the swollen substrate by SCCO2. The next step involved the grafting of HEMA by absorbed AIBN on the surface of PAN, making the surface to be coated with hydrophilic domains of HEMA. Using SCCO2 as the solvent has the advantage to control the effectiveness of grafting by variation in operating temperature and pressure. In stead of using two-stage process, one stage process could also be used. The procedures of preparation were varied to compare the effectiveness of grafting by each procedure. The chemical changes of PAN were characterized by Fourier transfer infrared (FTIR) spectroscopy. The hydrophilicity and hydrophobicity of membrane surface was characterized by static contact angle measurement using sessile drop method. The changes in melting and crystalline behavior of the polymer were characterized by differential scanning calorimetry (DSC). The change in surface morphology was characterized by scanning electron microscope (SEM). In order to test whether this method could be applied for the modification of other polymers, this method was used further to prepare polymer blend of polytetrafluoroethylene–poly(2-hydroxyethyl methacrylate), and the grafting of HEMA onto other polymers like poly(vinyl fluoride) and polycarbonate.

並列關鍵字

supercritical carbon dioxide ； polyacrylonitrile ； surface modification

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