聚丙烯腈表面改質之探討

Abstract

在研究論文中，以聚丙烯腈(polyacrylonitrile，PAN)不對稱膜做為薄膜基材，在第一階段表面改質中，利用矽烷(silane)胺丙基三乙氧基矽烷((3-aminopropyl)triethoxysilane，APTES)在無水(anhydrous)狀態下使與PAN上的-CN官能基鍵結，以產生後續改質中的接枝點(grafting point)，在第二階段表面改質中，利用silane 四乙氧基矽烷(tetraethylorthosilicate ， TEOS)將第一階段分散的接枝點連結起來，在PAN_A表面產生一緻密立體網狀的二氧化矽(SiO2，silica)無機層，在第三階段表面改質中，利用不同種類silane(包括APTES 、3-環氧丙醇三甲氧基矽烷((3-glycidoxypropyl)trimethoxysilane，GPTMS)、與(3-巰基丙基)三甲氧基矽烷 ((3-mercaptopropyl)trimethoxysilane，MPTMS))，經水解(hydrolysis)反應後，在第二階段改質後的PAN_A_T薄膜表面二氧化矽無機層上鍵接，以製備新型奈米過濾(nanofiltration，NF)薄膜。由實驗結果分析重點主要得包括：(1)PAN基材製備時PAN厚度的過高會造成低層結構過於疏鬆，而透過SEM的截面分析可以決定成膜的最適厚度；(2)第一階段表面改質中，反應時間會對PAN表面化學結構與機械強度的影響，必須分析改質後薄膜特性以找出適當的反應時間；(3)分析第二階段和第三階段表面改質後，PAN表面緻密性，以及表面接上官能基特性；(4)分析PAN厚度與其表面親水性的改變，對於過濾水通量的影響。

In this research thesis, asymmetric polyacrylonitrile (PAN) membrane as supporting material, in the first-phase surficial modification, (3-aminopropyl)triethoxysilane (APTES) is bonded with -CN on PAN under anhydrous state, to provide the grafting points for condensation reaction in subsequent surficial modification, in the second-phase surficial modification, reaction of tetraethyl orthosilicate (TEOS) will crosslink the scattered grafting points to become a tight, steric-mesh, inorganic silica (SiO2) film on PAN_A surface, in the third-phase surficial modification, silanes (including APTES, (3-glycidoxypropyl)trimethoxysilane (GPTMS), and (3-mercaptopropyl)trimethoxysilane, (MPTMS)), after hydrolysis and condensation, and are grafted onto SiO2 film on PAN_A_T surface, to prepare a new type of nanofiltration (NF) membrane. By mainly focused on analysis of experimental results include: (1) The preparation of PAN thickness is thick that will cause the lower substrate structure is very friable, and through cross-sectional SEM analysis can determine the optimum thickness of a membrane; (2) At first-phase surficial modification, chemical structure and mechanical strength are affected by reaction times, analysis relations between reaction times and membrane properties can find appropriate reaction times; (3) After the second-phase and three-phase surface modification, surface analysis of PAN membranes shows where density increase, and new functional groups change surface properties; (4) Analysis thickness and hydrophilicity of PAN membranes change, for filtered water flux influence.