Study On The Synthesis Of Hyperbranched-Linear Polymer And Its Effect On Leather As Fatliquor

Hydroxyl terminated hyperbranched-linear polyesters of generations 1-3 (CHBPx category) which can be used as fatliquor were synthesized by one-pot method using coconut-oil fatty acid diethanolamide (CDEA) as a core, dimethylol propionic acid (DMPA) as monomers and p-toluenesulfonic acid (p-TSA) as catalyst. Next, carboxyl terminated hyperbranched-linear polyesters of generations 1-3 (MHBPx category) which can also be used as fatliquor were synthesized by grafting maleic anhydride. Hydroxyl terminated hyperbranched-linear polyethers (HBPG-X category) were synthesized using glycerol, epoxypropane and oleic acid as materials at the same time. Then, the structures and emulsion characteristics of CHBPx category, MHBPx category and HBPG-X category were studied. Finally, their effects on retanned or tanned leather as fatliquor were analyzed by measuring softness and mechanical properties of fatliquored leather.The appropriate reaction conditions were optimized by both single factor experiments and orthogonal experiments. The results are as follows:The reaction temperature is 160℃, the reaction time is 4h and the quantity of catalyst is equal to 1% of feedstock CDEA. The molecular structures of the products were confirmed by FT-IR,1H NMR. Surface activities were measured by surface tension meter. It was shown that CHBPx category performs good surface activities and their surface tensions decrease with the generations. In addition, CHBPx category has better emulsifying properties and higher hard water resistance compared with CDEA. Orthogonal experiment showed that at temperature of 40℃, time in 60min and mass of CHBPx equal to 10% of tanned leather, fatliquored leather showed higher flexibility. The softness and mechanical properties of CHBPx treated leather were measured with the help of softness tester and multi-function material testing machine. The results showed that softness of the fatliquored leather decreases with growing generations of CHBPx, so do thickening rates. While tensile strength and tearing strength of the fatliquored leather are higher than that of non-fatliquored.In order to improve stability and solubility of the products, maleic anhydride was used to modify CHBPx. Orthogonal experiments showed the most appropriate reaction conditions are as follows:The reaction temperature is 90℃, the reaction time is 4h and the molar ratio of quantity of hydroxyl groups in CHBPX with maleic anhydride is equal to 1:1.4. The molecular structures of the products were confirmed by FT-IR. Orthogonal experiment again was introduced to optimize the most suitable conditions of fatliquor process of MHBPx, with the finding that at temperature of 50℃, time in 40min and mass of MHBPx equal to 8% of tanned leather, fatliquored leather showed higher flexibility. Other rules of the results using MHBPX as fatliquor were almost the same with that of CHBPx.Quantity of linear chains in a molecule is another important factor for the softness of the treated leather, hyperbranched polyglycerol (HBPG) of generation three was synthesized by ring-opening multibranching polymerization method using glycerol and glycidol as materials and sodium methoxide as catalyst. Oleic acid was then used to modify HBPG with different content to obtain a series of products named HBPG-X. The structures of the products were confirmed by FT-IR and 1H-NMR. Then the products were used as fatliquor on tanned leather. Particle size measurement results showed that the molecular volume increases with the increment of the quantity of linear chains. More linear chains can not improve the flexibility of the leather because of the larger molecular size of the products. Furthermore, polyethers perform better fatliquor function than polyesters.