Papers by Author: Xiao Liang Yan

Abstract: A graft copolymer was synthesized by copolymerization of degraded starch and acrylamide using horseradish peroxidase (HRP)/H2O2/acetylacetone (ACAC) as initiator. The structure of the copolymer was confirmed by FTIR and NMR. The copolymer can be used as retannage in leather making substitute for chrome retannage and contribute to decreasing pollution. The applied results show that the retanned leather possesses merits of excellent soft feeling, good elasticity and uniform thickness.

Abstract: A copolymer of vanillin and gallic acid was synthesized using HRP/H2O2 as initiator. The chemical structure of the copolymer was characterized by means of FTIR, NMR and GPC. The copolymer was applied in making leather as a tanning agent and the shrinkage temperature (Ts) of tanned leather reached 82.5°C. The average thickness increment ratio (E) of retanned leather was 19.4%. It has also excellent assisting dyeing and soft leather fibers properties. The application leather has desired dyeing effect and excellent softness.

Abstract: Citrate-hydroxypropyl acrylate (CA-HPA) was prepared by esterification of citric acid and hydroxypropyl acrylate. Then a graft copolymer was synthesized by copolymerization of degraded starch and CA-HPA using a complex initiation system of horseradish peroxidase (HRP)/H₂O₂/acetylacetone (ACAC). The effects of amount of CA-HPA, HRP, ACAC and reaction temperature on grafting efficiency (GE) and grafting percentage (GP) were investigated. The results showed that the graft copolymer with higher grafting level could be prepared by grafting copolymerization of 50 g degraded starch (wt 15%) with 13.9 g CA-HPA in the presence of 6.4 mg HRP/4.7mL H₂O₂/1.2g ACAC at 35 °C for 5h under system pH 8. The graft copolymer can be used as retannage. The structure of the copolymer was characterized by FTIR, and the mechanism of polymerization was advanced. The retanned leather has the merits of good uniformity fullness softness, strong selecting filling properties and good elasticity.

Abstract: The chitosan was degraded by hydrochloric acid and the effects of concentration of chitosan, amount of hydrochloric acid, reaction temperature and reaction time on the viscosity of chitosan were investigated. The results showed that the degraded chitosan with low viscosity could be prepared when chitosan (wt 6%) was dissolved in acetic acid solution and hydrochloric acid (wt 3%) at 90°C for 6 h to decrease the viscosity from 7.52 mPa·s to 2.48 mPa·s. Then, a graft copolymer was synthesized by copolymerization of degraded chitosan with methacrylic acid (MAA) and acrylamide (AAM) by using horseradish peroxidase (HRP)/H₂O₂/acetylacetone (ACAC) as initiator. The structures of original chitosan, degraded chitosan and the copolymer were characterized by FTIR. The copolymer was applied to the leather industry as an amphoteric retanning agent. The applied results showed that the retanned leather had the merits of good uniformity fullness softness, strong selecting filling properties, good dyeing ability and antimicrobial activity.

Abstract: Modified starch tannage was synthesized by two steps. First step, a graft starch was synthesized by graft copolymerization of degraded starch with p-aminobenzene sulfonic acid and nekal using horseradish peroxidase (HRP)/H₂O₂ catalyze system. The effects of system pH, reaction temperature and amount of HRP on the graft efficient (GE) and graft percent (GP) were investigated and the maximum GE and GP of modified starch were obtained using 4 mg HRP/2.24 g H₂O₂ as catalyst at 35 for 3h under pH 7. The second step, the graft starch was oxidized by periodic acid to prepare modified starch tannage with dial dehyde.The effect of periodic acid on aldehyde groups content of graft starch was studied and it was found that the maximum content was at periodic acid concentration of 4 mol/L. The structure of modified starch tannage was characterized by FTIR, NMR and GPC. The shrink temperature (T_s)of tanned leather is 80.6 °C and the retanned leather has distinctive style of softness and flexibility.

Abstract: A modified polycarboxylate superplasticizer was synthesized by copolymerization of polyethylene glycol monomethyl ether methacrylate (MPEG-MA), β–Cyclodextrins grafted maleic anhydride (MAH-β-CD), methacrylic acid (MAA) and methallyl sulfonic acid (MAS). The excellent superplasticizer was obtained at the molar ratio of n(MAH-β-CD) : n(MAS) : n(MAA) : n(MPEG-MA) was 0.05:0.1:3:1 using ammonium persulfate (APS) as initiator at 90°C for 5 h. The applied results show that the product had many advantages, such as lower dosage, longer setting time, better flow-keeping ability and better compatibility with different cement. Meanwhile, the structure and relative molecular weight were characterized by FTIR and GPC respectively.

Abstract: Degraded starch was reacted with 4-phenolsuflonate (PHS) in water in the presence of horseradish peroxidase (HRP) catalyst/H2O2/acetylacetone (ACAC) to give starch and PHS graft copolymers. The structure and properties of the graft copolymer are characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear　Magnetic　Resonance (NMR). The retanned leather exhibits excellent increased thickness and softness, good dyeing ability and eligible mechanical properties.