|| SYNTHESIS, MODIFICATION & APPLICATION OF HYPERBRANCHED POLYMER POLYOLS|
|| hyperbranched polymer polyol, synthesis modification, tanning，formaldehyde capture|
According to the theory of macromolecule and organic synthesis, two kinds of hyperbranched polymer polyols were prepared by “one step method”and “one step method with core” respectively. These polymers as follows: hyperbranched poly(acylamide-ester) polyol (HP-I) and hyperbranched poly(amide-ester) polyol (HP-II). According to the theory of molecular design, the synthesized hyperbranched polymer polyols were modified properly which created condition for its use in leather industry. As a result, the novel research field of leather chemicals is widened and the development of leather industry is sustainable.
Using diethanolamine (DEA) and succinic anhydride (SA) as monomers, HP-I was synthesized in appropriate conditions via “one step method”. Then it was modified with glutaraldehyde to obtain a hyperbranched polymer leather retanning agent with terminal aldehyde and hydroxyl (HR-I). On the basis of Single-factor experimental, the optimum synthesis conditions for HP-I were determined as follows: n(DEA):n(SA)=1:1, amidation reaction time was 6h, esterification reaction time was 2.5h, at 130℃, and dosage of catalyst is 5.0% (based on the total weight of reactants). HP-I was tested by IR and GPC; the degree of branch was also estimated. Experiments indicated that HR-I possessed good water-solubility, and were stable in acid, alkaline and salt solutions. Contrast experiments were done between HR-I and phenolic tannin PF-210 produced by Tingjiang Fine Chemicals limitied, by applicating to chromme-tanned pig split. It indicated that the tearing resistance of the leather retanned by HR-I was 30.5% higher than retanned by phenolic tannin PF-210, and both have similar tensile strength. Otherwise, the leather retanned by HR-I was softer and fuller.
The divergent synthesis of a series of hyperbranched poly(amine-ester)s (HP-II) based on trimethylolpropane(as a core molecule) and N,N-diethylol-3-amine-methylpropionate (as AB2 type monomer) synthesized via Michael addition action of methyl acrylate (MA) and diethanolamine, proceeding in one-step procedure in the melt using P-TSA as catalyst. At last hyperbranched polymer with active methylene (HPAM) has been synthesized by transesterification of HP-II with diethyl malonate (DEM) in the presence of catalyst (anhydrous K2CO3). By the method of Single-factor experimental design, some correlative factors how to influence the action were investigated, the appropriate action conditions were optimized. For monomer was: dripping methyl acrylate to diethanolamine, methyl alcohol as solvent, the molar feed ratio of DEA and MA was 1:2, reaction time was 4h and temperature was 35℃; and for HP-II was: dripping monomer to core material, catalyst amount is 2.0%, reaction time was 4~5h and temperature was 120℃. The monomer and polymers were characterized by IR, 1H-NMR, GPC, TG, and DSC and so on. The thermal property, deliquescent property and surface activity of HP-II were also estimated, It was applied to retan wet blue leather of sheepskin, results indicated that: G1 (the first generation of polymer) obtained good bleaching effect on sample, the white degree increased by 19.8%; G3 (the third generation of polymer) could improve tearing resistance of chrome tanned leather obviously, increased by 23.3%, and had some help to tensile strength, increased by 11.3%, at the same time.
The capture effect of HPAM on free formaldehyde was investigated at last. The best capture parameters were optimized through application to capturing experiments of aldehyde-tanned pigskin: the dosage of HPAM was 2.0%, capture time was 5h. In this condition, the capture yield could exceed to 56.3%, the capture effect was obvious.