Study On The Synthesis,Surface Properties And Application Of Fluorosilicone Block Copolymers

The fluorosilicone polymer is a polymer which contains both the structure of the silicone ?PDMF?and the fluorinated group?PF?. It is a new material not only with thermal stability, weather resistance and molecular flexibility, but also the characteristics of oil resistance, solvent resistance and low surface tension. It can be applied for aerospace, aviation, automobile, bridge building, durable self-cleaning coatings, triple-proofing finish agent, optical fiber and cable surface coating materials etc. The researches on the fluorosilicone polymer are concentrated on the siloxane fluorinated polyacrylate and the side chain fluorosilicone polymer recently. There are few studies on the synthesis of fluorosilicone block copolymer and its raw material.In this study, a three block copolymer with PF-PDMS-PF structure was designed and synthesized. The preparation methods of 1,3-bis?3-hydroxypropyl?-1,1,3,3-tetramethyl polysiloxanes?BHTPS?, macroinitiator?Cl-PDMS-Cl? and fluorosilicone block copolymer ?PHFBMA-b-PDMS-b-PHFBMA? were studied in detail. The relationship between the length of the block, the ratio of the segment and the surface microphase separation behavior and the surface properties were discussed. With the synthesized copolymer as a film forming material, low surface energy anti fouling coating was prepared with the aid of several assistants. The preparation, characterization of the raw materials and fluorosilicone block copolymers had been studied deeply. The surface properties and application of the fluorosilicone block copolymers had been discussed too. The main results were described as follows:1. The synthesis of BHTPS was studied systematically under microwave radiation. With the vinyl alcohol and hexamethyl disilylamine as the starting materials, the synthesis technology of BHTPS was obtained under microwave radiation by hydroxyl protection, hydrosilation, ring-opening polymerization and hydrolysis reaction. The synthetic parameters of four steps were optimized by single factor and response surface experiments respectively. Six different hydroxyl contents of BHTPS were prepared. The amplification researches were carried out. The results showed that The yield of hydroxyl protection and silicon hydrogen addition was 95.50% and 94.46% respectively, the measured molecular weights of ring opening polymerization and hydrolysis reaction were close to that of the designed with narrow molecular weight distribution. It could reduce the synthesis time to 21h, and the catalyst dosage was deceased to 19mg/kg. The reaction had good applicability, and the amplification effect was not obvious. This study could provide reference for the industrialization of BHTPS synthesis.2. The synthesis of PHFBMA-b-PDMS-b-PHFBMA was studied intensively by atom transfer radical polymerization?ATRP?. PHFBMA-b-PDMS-b-PHFBMA was designed and synthesized for the first time. The structure, reaction kinetics and reaction mechanism were discussed. It was proved that the polymerization kinetic curve was a first order reaction and the polymerization was active. The synthesis processes of Cl-PDMS-Cl and PHFBMA-b-PDMS-b-PHFBMA were optimized. A series of fluorosilicone block copolymers with different fluorine content were synthesized under the optimized processing parameters. The results indicated that the conversion rate and yield were higher?above 80%?, the measured molecular weight was close to that of the designed with narrow molecular weight distribution. The amplification of PHFBMA-b-PDMS-b-PHFBMA prepared by ATRP was studied. It showed that the amplification effect was not obvious, and the magnify experiment results were close to those of laboratory scale test. It was found that the dropping time, ambient temperature and the stirring rate were of some influence on the reaction. This study could provide basic data for the industrial production of the product, as well as offering a reference for the amplification experiment of ATRP.3. The surface properties of the PHFBMA-b-PDMS-b-PHFBMA block copolymers films with different fluorine content and different length of block were investigated. It was showed that when the number of DMS was 88, the number of HFBMA was 20, the hydrophobic and hydrophobic properties of the copolymer was the best. With water and glycerol as the reference solution, the static contact angles were determined. The surface energy of the triblock copolymer could reach as low as 10.43mN/m and the fluorine content was only 19.2wt%. The microstructure of PHFBMA-b-PDMS-b-PHFBMA was investigated by differential scanning calorimetry ?DSC? and transmission electron microscopy ?TEM?. Scanning electron microscopy ?SEM?, atomic force microscopy ?AFM?, and X-ray photoelectron spectroscopy ?XPS? were used to reveal the surface morphology and phase composition of the films. The factors which might affect the surface properties were explored. The effects of the length of the chain, the solvent and the filming temperature on the size of the micelles, the surface microtopography and hydrophobic/oleophobic property of the coating were studied. The HFBMA₁₀DMS₈₈HFBMA₁₀ was applied to construct the hydrophobic/oleophobic fabric. The surface morphology and hydrophobic/oleophobic property of the copolymers were evaluated. The results showed that:the contact angle of the treated fabric with water increased to 145.50°, and for the oil droplets, the contact angle was 129.25°. The effects of concentration of fluorosilicon block copolymer solution and treatment time on the property of the fabric were tested. The results showed that:the contact angle was the maximum when the fabric was treated with the 0.3% solutions for 20 minutes.4. With the synthesized HFBMA₁₀DMS₈₈HFBMA₁₀ as a film forming material, Low surface energy anti fouling coating was prepared with the aid of several assistants. The optimized formula and process were found by uniform design method. The low surface energy anti fouling coatings with extraordinary properties was prepared. The performance of the coatings was systematically evaluated also. The results showed that the water/oil contact angle was about 159.55°/139.32° respectively, and other performance of the film was excellent.