聚乙烯醇的氟化疏水改性及性能研究

发布时间：2018-03-10 07:45

本文选题：聚乙烯醇　切入点：氟化改性　出处：《太原理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：聚乙烯醇(PVA)是一种重要的化工原料,由于其优良的成膜性、无毒性、热化学稳定性等优点而被广泛应用于各种功能性膜材料。聚乙烯醇侧链含有大量亲水性羟基,使其表现出超强的亲水的性质,如吸湿性大、耐水性差等缺点,在一定程度上限值了其应用,因此对聚乙烯醇的疏水改性研究也引起了关注。本课题以PVA为基体材料,分别通过微波辅助合成法引发含氟丙烯酸单体进行侧链接枝聚合和含氟硅烷偶联剂水解接枝并复合二氧化硅(SiO2)两种不同的氟化方法来对PVA进行疏水改性。采用含氟有机化合物对PVA进行改性是因为有机氟含有更多的氟原子且氟的原子半径小电负性大、形成的C-F键短、键能高,因而低的表面能可降低材料的亲水性。微波辅助合成法引发含氟丙烯酸单体对PVA进行侧链接枝聚合是利用微波这种高效、省时、加热均匀的清洁能源作为驱动力,以过硫酸钾作为引发剂,在PVA侧链生成自由基进而引发甲基丙烯酸十二氟庚酯(DFMA)的双键链增长,进行侧链自由基聚合,将含氟的低表面能物质接枝到PVA上,制备具有疏水性能的接枝聚合物(PVAF)。傅立叶红外、固体核磁及XRD对接枝聚合物的化学组成及分子结构分析表明DFMA在微波辐照下双键引发得以聚合,氟原子被引入到PVA侧链上;热重分析研究了接枝聚合物的热分解状况,结果显示侧链接枝DFMA有助于提高PVA的稳定性,且随着DFMA含量的增大,接枝聚合物的稳定性逐渐升高;利用吸水性实验研究了接枝聚合物的疏水性,结果表明含氟物质引入越多PVA的疏水效果越好。但由于微波法合成的氟化接枝聚合物PVAF为固体,且侧链氟原子过多致使PVAF不易溶解,难于后处理及成膜进行接触角测量。所以为了制备以PVA为基体的超疏水薄膜,本论文在第二个研究体系里将PVA/SiO2旋涂在玻璃表面后,再将复合膜经含氟硅烷偶联剂十七氟癸基三甲氧基硅烷(C13H13F17O3Si,FAS)进行水解接枝,制备具有粗糙表面的含氟超疏水薄膜。研究了PVA与SiO2复合的比例及FAS修饰对薄膜疏水性的影响。用傅里叶红外光谱、X射线能谱对超疏水表面进行了结构分析和形貌表征,研究表明所制备的超疏水薄膜的表面成功自组装了氟硅烷,由于氟元素在薄膜表面富集,F含量在薄膜表面高达41.57%;通过扫描电子显微镜可以知道该薄膜表面有很多大小相近的球状凸起,粒径约在30-50 nm之间,形成了微纳米粗糙结构;用接触角测量仪观察了水滴在薄膜表面的润湿性,结果显示当PVA/SiO2为1:5时,氟化PVA/SiO2薄膜表面具有较好的超疏水功能,静态接触角可达151.24°,滚动角约为4°。这主要是薄膜表面含有低表面能氟原子及其具有纳米粗糙结构共同作用的结果。以PVA为基底制备的疏水及超疏水薄膜在日常生活中有广泛的用途,如可用在玻璃、木材、轮船等的表面起到防水、防污甚至实现自清洁等效果。本课题对氟化聚乙烯醇进行研究可以提高PVA的耐水性,扩大其应用领域。
[Abstract]:Polyvinyl alcohol (PVA) is an important chemical raw material, because of its excellent film-forming properties, non-toxic, chemical stability and other advantages and is widely used in various functional membrane materials. Polyvinyl alcohol side chain containing a large number of hydrophilic hydroxyl groups, which shows the nature of super hydrophilic, such as hygroscopicity, disadvantages poor water resistance, the value of its application in a certain degree limit, so the hydrophobic of Modified PVA research has also attracted attention. This paper adopts PVA as matrix materials, respectively by fluorine-containing acrylic monomer graft polymerization and side chain fluorinated silane hydrolysis and graft composite silica synthesis by microwave assisted (SiO2) two different fluoride method for hydrophobic modification of PVA. Using fluorinated organic compounds on PVA was modified because organic fluorine containing more fluorine atoms and fluorine atoms with small radius of electronegativity, the formation of C- The F key is short, high bond energy and low surface energy can reduce the hydrophilic material. By fluoro acrylate monomer grafted polymerization is the use of microwave time of PVA the efficient synthesis method of microwave assisted heating, clean energy as the driving force, using potassium persulfate as initiator, free base triggering twelve fluorine methacrylic acid heptyl ester side chain at PVA (DFMA) double bond chain growth, side chains of free radical polymerization, low surface energy materials will be grafted onto PVA containing fluorine, the grafted polymer with hydrophobic properties. Fu Liyehong (PVAF), DFMA analysis showed that under microwave irradiation with double bond lead to polymerization of chemical composition and molecular structure of solid state NMR and XRD on graft polymer, fluorine atoms are introduced into the PVA side chain; thermogravimetric analysis on the thermal decomposition of the grafted polymer, results showed that the grafted DFMA helps to improve PVA The stability, and with the increase of DFMA content, the stability of the grafted polymer increased gradually; hydrophobic graft polymer was studied by water absorption experiment, results show that the better effect of hydrophobic fluorinated substances into more PVA. But because the fluoride grafted by microwave polymerization of PVAF is solid, and the side chain of fluorine atoms resulting in too much PVAF is not easy to dissolve, processing and membrane contact angle measurement is difficult. So in order to prepare PVA super hydrophobic film matrix, in this thesis second research system in PVA/SiO2 spin coated on the glass surface, and the composite film by fluorine containing silane coupling agent seventeen fluorine decyl trimethoxysilane (C13H13F17O3Si, FAS) were prepared by hydrolysis of grafting, with rough surface fluorinated superhydrophobic films. The effects of PVA and SiO2 composite ratio and the effects of FAS modification on the hydrophobic film. By Fourier transform infrared spectroscopy, X ray Spectrum structure analysis and morphology characterization of super hydrophobic surface, the results indicated that the surface of super hydrophobic films prepared successfully self-assembled fluorine silane, the fluorine element in the film surface enrichment, the content of F on the surface of the films is up to 41.57%; by scanning electron microscopy that the surface of the thin film have many spherical protrusions of similar size in 30-50, the diameter of about nm, the formation of micro nano rough structure; observe the water droplets in the wettability of the film surface by contact angle measurement, the results showed that when the PVA/SiO2 is 1:5, the surface fluorination of PVA/SiO2 thin film with super hydrophobic function better, the static contact angle up to 151.24 degrees, the rolling angle is about 4 degrees. This is the main surface of the thin film containing fluorine atoms and the low surface energy with nano rough structure interaction. With PVA as the hydrophobic substrate preparation and super hydrophobic films are widely used in daily life, such as It can be used for waterproofing, antifouling and even self cleaning on the surface of glass, wood, ship and so on. Our research on fluorinated polyvinyl alcohol can improve the water resistance of PVA and expand its application area.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O632.31

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