Papers by Author: Sheng Hua Lv

Abstract: A novel amphoteric polycarboxylate superplasticizer (APCs) was prepared by solution copolymerization from acrylic acid (AA), allyl polyethylene glycol (APEG), diallyldimethyl ammonium chloride (DMDAAC). Effects of DMDAAC dosage and monomers ratio on performance of APCs were investigated by tested of zeta potential of cement particles and adsorption on cement. Results indicated that introducing of cationic monomer can increase the saturation adsorption amount and dispersibility of APCS. When the molar ratio of AA and APEG and DMDAAC is 5:1:0.5, the dispersibility of APcs has the best adsorptivity and disersibility. The synergistic effects of Zeta potential and steric repulsion of the cement particles surface is the main mechanism for dispersion.

Abstract: The mono polyethylene glycol maleate (MPEGM) was prepared by direct esterification of maleic anhydride (MAH) and polyethylene glycol (PEG). The yields of monoester (YM) could reached to 96% when the molar ratio of MAH and PEG was 1.2 using 2 wt% p-toluene sulphonic acid (PTSA) as catalyst at 95°C for 3 h. The amphoteric retaning agent (ARA) with excellent retanning properties was synthesized by copolymerization when the molar ratio of methacrylic acid (MA), MPEGM and dimethyl diallyl ammonium chloride (DMDAAC) was 3 : 1 : 0.2 using 3 wt% ammonium persulfate (APS) as initiator at 90°C for 4 h. The applied results showed that retanned leather by ARA had excellent selective filling and can improve remarkable the flexiblity and elasticity. The chemical structure of the ARA was characterized by FTIR.

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: Tannic acid (TA) was modified by sulfanilic acid (SAA) using HRP catalysis in aqueous phase. The structure of modified TA was characterized by FTIR. The tanning properties of modified TA have been studied by the tanning test together with aluminum and chrome tannages. The tanning results show that the modified TA is suitable for use as pretannage and in combinaton with chrome and aluminum tannage. The shrink temperature (Ts) of leather tanned using 6% modified TA and 2% chrome tannage can reach to 92.0 oC by the modified TA and and chrome tannage by sequential step. The applied leather has merits of good uniformity, fullness, softness and fine grain. With this method, the dosage of chrome tannage is lessened and environment pollution is alleviated.

Abstract: The radical copolymerization of resorcinol (RSC) and 3,5-dihydroxyl benzoic (DHBA) was carried out in water by the initiator of horseradish (HRP)/H2O2. It was discussed that the effects of monomer composition on the properties of the copolymer. The best monomer mass ratio of RSC:DHBA was 60:40 and the shrink temperature can reached to 88.5oC. The tanning result indicated that the copolymer of RSC and DHPA has particularly excellent tanning properties and can be served as leather tannage substitute for chrome tanning materials. And also the mechanism of the HRP initiated copolymerization was proposed. The structure and molecular weight of the copolymer was characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). The copolymer can be as tannage and retannage in making leather process. The results showed that it has excellent tanning properties and retanning effects.

Abstract: A polycarboxylate superplasticizer (PCs) was synthesized by copolymerization of allyl polyoxyethylene ethers (APE), acrylic acid (AA), sodium methylallyl Sulfonate (SMAS) and ethyl acrylate (EA). The effect of functional groups and branch chain on PCs properties was investigated by the test of fluidity of cement paste, retardation performance and Zeta potential of cement particles. The results showed that carboxylic groups and ethyl ester groups can improve water reducing ratio and fluidity of cement paste, and the sulfonic groups has an important contributiion to retardation performance of PCs.

Abstract: Effect of polycarboxylate superplasticizer (PCs) with different bond between side chain and truck chain on hydration of cement in early period was studied. The performance of PCs in concrete was investigated by setting time, TGA and SEM. PC-based superplasticizer with ester bonding between side chain and truck chain. Although they had the proximate structure parameters in density of side chain and absorption group (carboxyl groups), the setting time of cement paste was significantly different when different PCs were employed in the preparation of cement. Decomposing of this bond in alkali environment may lead to a shorter setting time. On the other hand, same difference in hydration production was observed in early period hydration of cement paste when two different PCs was incorporated, which indicated that the different bond structure in PCs affected the hydration of cement in a different manner. The result of SEM indicated that the morphological phase of hydrated product was different when PC was applied, this may be related with the different result in the TG and TGA

Abstract: Polycarboxylate (PC) superplasticizer was synthesized by radical copolymerization using ammonium persulfate (APS) as initiator at 90 °C for 5 h. The effect of PC on the hydration process and microstructure of hardened cement at different hydration ages (4 h, 1 d and 7 d) was investigated. Hydration of cement paste results show that the nucleation and growth of hydration product of ettringite (Aft) was inhibited by PC at the early hydration ages, and the generation of the hydration products of calcium hydroxide (CH) and calcium carbonate (CaCO3) was promoted at late hydration ages. SEM result indicates that PC can make the structure of hardened cement more homogeneous and more density.

Abstract: The modified starch was prepared by degradation starch with glutaraldehyde. The process conditions of degradation and modification starch were investigation. The result shows that the degradation starch was obtained through 22.5 g cornstarch and 1g ammonium persulfate (APS) in 127.5 g water at 95°C for 1h, and the modified starch was obtained by aldolization reaction of degradation starch and 4 mol/AGU glutaraldehyde at 85°C for 5h. The modified starch can be used as leather tannage. The shrink temperature (T_s) of tanned leather can be increase from 41.6 °C to 85.2°C. It may replace chrome tannage and decrease the pollution produced in chrome tanning processing. Meanwhile, the chemistry structure of modified starch was characterized by FTIR, ¹H-NMR, ¹³C-NMR

Abstract: A phenolic copolymer (GASA) was synthesized from gallic acid (GA) and sulfamic acid (SAA) using horseradish peroxides (HRP)/H₂O₂ as catalyst. The effect of the main factors on yield of the copolymer was discussed. The results showed that the maximum yield of copolymer was obtained when molar ratios of GA and SAA was 1:1 in the presence of 5 mg HRP at 35 °C for 5.5 h. The structure of the copolymer was characterized by FTIR and NMR. The mechanism of polymerization of GASA was pointed out. The phenolic copolymer was used as tannage and retannage to making leather, the results showed that the copolymers has excellent tanning and retanning properties. The T_s of tanned leather reached 75°C and the retanning leather exhibited good service performance and mechanical strength.