Study On The Tanning Mechanism Of Vinylpolymer/Montmorillonite Nano-Composite Tannage

In this paper, the reaction mechanism of vinyl polymer/montmorillonitenano-composite tannage with collagen were studied by nano-composite tannagereacted respectively with collagen models, gelatin, hide powder and hide blockand then contrasted with vinyl polymer.Polyamide and polyvinyl alcohol were selected as the collagen models,simulating peptide bonds and hydroxyls in the structure of skin collagen. In thecondition of different tannage dosages and pH values, Vinylpolymer/montmorillonite nano-composite tannage reacted with collagen models,the response method and extent between nano-composite tannage and collagenmodels were tested by the binding capacity of nano-composite tannage. In thesame conditions, it was compared with vinyl polymer. Nano-composite tannagereacted with gelatin, and the molecule structure changes of gelatin solutionreacted with nano-composite tannage were researched by UV and FTIR spectrum.In the condition of different dosages and pH value, Vinylpolymer/montmorillonite nano-composite tannage reacted with hide powder, andchecked the effects of different nano-composite tannage dosages and pH valueson the binding capacity, as well as the ideal dosage and proper pH value werefound. In the condition of ideal dosage and proper pH value, the nano-compositetannage reacted with deamino hide powder, esterified hide powder and chromedhide powder, how the amino group and carboxyl group of collagen and chromereacted with nano-composite tannage were studied. Under the same conditions, itwas compared with vinyl polymer. Hide powder and modified hide powderreacted respectively with nano-composite tannage and vinyl polymer, thechanges of shrinkage temperature, cooperating units and thermodynamic factorsof various hide powder tanned back and forth were studied by DSC. Compositetannage reacted with hide block, deamino hide block, esterified hide powder andchromed hide powder, the changes of shrinking temperature of hide block tannedback and forth were tested, and it was compared with vinyl polymer, themechanism of composite tannage reacted with collagen was explained again.The results of the study show that the composite tannage reacted best withcollagen models and hide powder when the pH value is 3.95 and the dosage isabout percentage of 30. The amino group of collagen is the main groupcombined with composite tannage, but the function of carboxyl group ofcollagen is relatively less, the hydroxyls and peptide group are the least.Composite tannage is combined with peptide group of collagen by hydrogenbond, united with hydroxyl of collagen by ester linkage that is formed betweencarboxyl group of composite tannage and hydroxyl of collagen, linked withamino group of collagen by amido bond which is built by ionized carboxyl groupof composite tannage and ionized amino group of collagen side chain, coalescentwith carboxyl group of collagen by electrovalent band made between aminogroup of TECB in composite tannage and carboxyl group of collage. In additionto, carboxyl group of collagen can integrate with chrome complex bycoordination bond. By analyzing DSC spectrograms, we know that the shrinkagetemperature, cooperating units, reaction order and activation energy of shrinkagereaction of tanned hide powder bigger than untanned hide powder,nanocomposite tannage and vinyl polymer have certain tanning function, and thetanning function of nanocomposite tannage better than vinyl polymer.Comparison the results of composite tannage and vinyl polymer reacted withcollagen, it was shown that the complex of montmorillonite and vinyl polymerhas certain cooperative effects. Nano particles can improve efficiently thereaction activity of vinyl polymer.The innovations of this paper are: 1. this is the first time to study thetanning mechanism of vinyl polymer/montmorillonite nano-composite tannagefrom all-sides. The results obtained have certain theoretic guiding significance tofurther impove the properties of tanning agent;2. the changes of manyparameters of hide powder before and after taned were studied by DSC. Themechanism of vinyl polymer/montmorillonite nano-composite tannage wereexplained further from thermodynamics and dynamics angle;3. in the study ofthe tanning mechanism of organic tannage, it was firstly proved that thecarboxyls and hydroxyls of tanning agents can combined with hydroxyls andcarboxyls of collagen by ester bond.