Preparation And Properties Of Copolymers Of Aromatic Sulfonate And Plant Polyphemol With HRP Catalysis

Leather tanned by vegetable tannins has many advantages such as fullness,elasticity, and resistance abrasion, good permeability and water vaporpermeability. But there are also many defects such as poor solubility, dark colorand poor hydrothermal stability of leather, so vegetable tannin need to beimproved to make the performance of leather achieve the requirements.Traditional modification methods contain sulfite modification, hydrolysiscoordination modification, graft copolymerization modification, amphotericmodification, degraded modification and so on. The solubility of vegetabletannin has improvement with these methods, but the structure of vegetable tanninis destroyed, greatly reduce the tanning performance of vegetable tanninsbecause of the acid, alkali, salts and oxidizer in the solution.Enzyme is a kind of green and efficient biological material. It can simplifyprocesses, save the equipment, no risk of traditional craft in the process ofchemicals production. Enzyme is widely used in organic synthesis because of itshigh catalytic efficiency, selectivity and specificity, and without by-products inpolymerization process. HRP is commercialized earlier and widely used invarious fields such as food industry, light industry, medicine, perfume,environmental protection and energy. HRP has unique catalytic properties,meanwhile leave the ortho-H+and para-H+of phenols and anilines to form ionintermediates in the presence of H₂O₂. Then monomer of aromatic polymerizesto form a special structure polymer with π-π conjugated system in manner ofbenzene side by side.Plant polyphenols was modified by aromatic sulfonate with HRP catalysisin this research. Firstly, the preparation and application of gallic acid witharomatic sulfonate （4-hydroxybenzenesulfonate （SHBS） and sulfamic acid（SAA）） graft polymers was prepared. Explored the graft copolymerization reaction system by means of HRP/H₂O₂, and GA-SAA/GA-SHBS graftcopolymer was synthesized. The main factors were discussed and the optimumreaction conditions were determined as follows:100g distilled water,5.1g GAand5.2g SAA or7g SHBS （the molar ratio of GA and SAA/SHBS was1:1）.Control the system pH7.5with sodium bicarbonate and sodium bisulfatesolution, add3mg HRP and6.8g30%H₂O₂, the dropwise time was1.5h,reaction temperature was35℃after3h, GA-SAA/GA-SHBS were obtained.And the mechanism of polymerization between GA and SHBS was advanced.The structure and properties of GA-SAA and GA-SHBS were characterized byFTIR and NMR, the results showed that the expected structure of graftcopolymer was obtained. Application test indicated that the optimal amount ofretanning agent GA-SAA was12%, the tanning liquid was fully absorbed after2h. The average thickening rate of leather was25%. The softness, fullness, lightcolor effect, fine grain and mechanical property of leather retanned by GA-SAAwere ideal.Secondly, the preparation and application of tannic acid （TA） and sulfamicacid （SAA） copolymer catalyzed by HRP/H₂O₂were explored. The effects ofmolar ratio and reaction time on Ts of leather were investigated. The optimumcondition was150g deionized water,17g TA and3.4g SAA （molar ratio of TAand SAA was1:2）, reaction pH7.5, reaction time for3.5h, TA-SAA wasobtained under such conditions. The structure and properties of the copolymerwere characterized by FTIR, and the results showed that the expected structurewas obtained. Applied results showed when the amount of TA-SAA was8%,aluminium tanning agent was10%，Ts of leather was102℃. Meanwhile,8%TA-SAA and1.5%chrome tanning agent was used, Ts of leather was108℃, theaverage thickening rate of leather was30%. The leather got excellent softness,mechanical property, light color effect and fine grain, which due to phenolichydroxyl, carboxyl, amino combined with collagen by means of multiplehydrogen bonds, electrovalent bonds and covalent bonds.