Advanced Materials Research Vols. 455-456

Abstract: A starch-polyacrylamide graft copolymer has been synthesized in water by means of horseradish peroxidase (HRP)/H₂O₂/acetylacetone (ACAC). It is discussed through single factor experiment that the effects of system pH, reaction temperature and amount of HRP on the residual acrylamide (AAM) content. The results show that the ideal copolymer was synthesized when mass ratio of starch and AAM was 2:1, and catalyst was HRP/H₂O₂ at 30 °C for 3.5 h. The residual AAM content was about 1.0%. The structure and properties of the graft copolymer are characterized by FTIR, NMR. The graft copolymer is used as retannage.

Abstract: The modified starch surfactant was synthesized by grafting copolymerization of methoxy polyethylene glycol methacrylate (MPGM) with starch. The effects of monomers composition and side chain length on surface activity of starch surfactants were investigated. The modified starch surfactant was synthesized when the molar ratio of AGU (starch) and MPEGMA was 1: 0.3 at 85 °C for 2h. The FTIR result shows that starch had successfully reacted with MPGM. Modified starch surfactants are poor foam surfactant with excellent surface activity. The modified starch surfactants are biodegradable and environmentally friendly and may be extensively used in various fields in future.

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: Maleic anhydride modified polycarboxylates superplasticizes (MPC) was synthesized from allylic poly (ethylene oxide ether) (APEG), maleic anhydride (MAH), sodium methylallyl sulfonate (SMAS) using ammonium persulfate (APS) as initiator. The optimal MPC with best fluidity was got at 90 °C when molar ratio of MAH, APEG, SAMA was 2.75∶1∶0.4 in the present of 4.5 mol% APS of all the monomer molars. MPC which possessed hydroxyl terminated side chains shows some difference in fluidity retarding related to the conventional superplasticizers possessed methoxy terminated side chains.

Abstract: A new polycarboxylate superplasticizer (NPC) was synthesized by radical copolymerization of maleic anhydride (MAH), sodium methylacryl sulfonate (MAS), allyl polyethylene glycols (APEG), and β-cyclodextrins grafted maleic anhydride (MAH-β-CD) using ammonium persulfate (APS) as initiator. The effect of feeding mode and molar ratio of monomers, contents of MAH-β-CD and reaction temperature on fluidity was discussed. The results show that the excellent properties of NPC were obtained when molar ratios of MAH, MAS, APEG and MAH-β-CD were 2.5: 0.5 : 1 : 0.1 in the presence of 1 mol% APS of all molar of vinyl monomers at 90 °C for 5 h. Meanwhile, the molecular structure was characterized by FTIR spectrum.

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.

Abstract: The vortex impinging streams technology (VIS) has good micromixing in the precipitation processes. The experiments were loaded with two reactants, BaCl₂ and Na₂SO₄, using ethylene diamine tetraacetic acid (EDTA) as complexing agent, to prepare BaSO4 in the vortex impinging streams reactor at Re=2500, comparing with those in the stirred tank reactor (STR). The products were characterized by XRD, TEM, BET and FTIR. The results indicate barium sulfate superfine particles are crystallized in the orthorhombic structure with lattice parameters a=7.156 Å, b=8.881 Å, and c=5.454 Å. The size of the ellipsoidal particles from VIS is about 386 nm, with narrower distribution and finer dispersity than that from STR. The specific surface area of the particles from VIS is 29.25 m²/g, comparing to 11.95 m²/g from STR. The infrared spectra decades the surface of the prepared BaSO₄ absorbs the functional group of EDTA.

Abstract: There is an introduction of the synthesis principles and extraction performance of several kinds of germanium extraction agents including Lix63, Kelex100, and 7815. In addition, the general procedures and technical advantages of the extraction agents for germanium recycling are analyzed and compared. Finally, recommendations for the synthesis of a new generation of germanium extraction agent are proposed.

Abstract: China is a big industrial energy consuming country. The largest proportion of energy consuming is the operations of separation in chemical industry, and the energy consumption of the distillation is the highest in separation. Therefore, it is very important to research energy-saving issues of the process of distillation in today's circumstances of the energy shortage. This article describes the model of heat pump distillation column,and its characteristics, uses static simulation programs to simulate operating conditions in the atmospheric pressure for the benzene-toluene material system, and studys effects of the different feed states on the energy-saving of heat pump distillation column. The results will be compared with the conventional distillation column, and it was showed that for benzene-toluene system, the heat pump distillation column is more remarkable than the conventional distillation column in energy savings, and its energy saving rate can reach 46%.

Abstract: L-Azetidine-2-carboxylic acid, the first known example naturally occurring azetidine, was synthesized in a novel, simple, clean and improved procedure. It was synthesized from γ-butyrolactone through four steps: bromination and esterification, cyclization, hydrogenation and resolution. The overall yield could reach 13.2%.