Advanced Materials Research Vols. 781-784

Abstract: A new cocrystal (3,4-Hbpt)-(H₂oba) (3,4-Hbpt =3-(3-pyridyl)-5-(4-pyridyl)- 1-H-1,2,4-triazole and H₂oba=4,4-oxybis (benzoic acid)), was prepared via self-assembly in the presence of cobalt acetate as template by hydrothermal reactions. The title complex was characterized by single-crystal X-ray diffraction, elemental analysis and IR spectroscopy. Structural analysis reveals that the complex belongs to monoclinic system, space group P2₁/c. The two carboxylate groups from H₂oba are not deprotonated and form two kinds of strong intermolecular hydrogen bonds with 3,4-Hbpt, which linking the molecules into one-dimensional chains. Furthermore, the one-dimensional chains are connected by the hydrogen bond interaction to form two-dimensional lamellar structures. Intermolecular hydrogen bonds may be effective in the stabilization of the crystal structure.

Abstract: A novel intelligent hydrogel of poly(Humic acid - Nisopropylacrylamide - Acrylic acid) (P(NIPAAm-HA-AA)) was prepared at 70°C by inverse suspension polymerization. The reactions include uses N,N-methylene-bis-acrylamide (MBA) as a cross-linking agent, ammonium persulfate (KPS) as an initiator, cyclohexane as a continuous phase and span-65 as dispersant. The influence such as concentration of monomers and cross-linking agent, mole fraction of span-65 in mixed monomers, and temperature of polymerization on the property of resulting P(NIPAAm-HA-AA) hydrogels was investigated in detail. Fourier transform infrared (FTIR) demonstrated that NIPAAm, HA and AA was synthetized successfully. The results showed that the swelling ratio (SR) of modified hydrogel was improved significantly with the dosage of NIPAAm. It was also observed that the thermosensitive and pH sensitive characteristics was strongly affected by concentrations of NIPAAm. At last, we choose NIPAAm: HA=0.3.

Abstract: Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/CaCO₃ blends were prepared by solution blend method. The effect of CaCO₃ on the thermal and crystalline morphology properties was studied by differential scanning calorimetry (DSC), thermogravimetry (TG) and polarizing optical microscopy (POM) analyses. DSC showed the CaCO₃ affected the crystallization behavior of PHBV as heterogeneous nucleation agent. TG results indicated better processability of the blends with 3wt% CaCO₃ than that of pure PHBV. Integrated Maltese crossed spherulitic morphologies were revealed for both pure PHBV and PHBV/CaCO₃ blend. While small-sized PHBV spherulites were formed when CaCO₃ added to PHBV.

Abstract: Polyvinyl alcohol/silk fibroin blend membrane obtained by adding different components of polyols to the ternary solvent of CaCl₂ / C₂H₅OH / H₂O ,makes up for the brittleness of sf and increases its potential properties.Electronic microscope,strength tester and other equipments are used to text the structure and performances of blend membrane. The tests of performances such as moisture content rate,loss rate in hot water, the tensile strength and elongation at break shows that: the blend membrane added by glycerol improves in thermal and mechanical performance to some extent.

Abstract: A crosslinking core-shell structured polyacrylate emulsion polymer was synthesized by semi-batch seeded emulsion polymerization with methyl methacrylate and butyl acrylate as main monomers, and pentaerythritol tetraacrylate as a cross-linking agent. Chemical structure and micro morphology structure of the obtained polymer emulsion particles were characterized by Fourier transform infrared spectra (FTIR) and transmission electron microscope (TEM), respectively. Influences of cross-linking agent content on water resistance, thermal property, and mechanical property of the emulsion films were investigated. Compared to the film of the unmodified polyacrylate emulsion, water absorption capacity of modified polyacrylate emulsion film with 1.0% PET4A declined to 4.7%, tensile strength at break increased from 1.35MPa to 3.03MPa, and elongation at break increased to 171.7%; 5%,10% and 50% weight loss temperature of the modified emulsion increased 17°C,32°C and 45°C, respectively.

Abstract: A water-soluble graft copolymer, which was used to improve the dispersion properties of kaolin slurry with high solid content , was synthesized from sodium humate (HA), acrylic acid (AA), starch (St) and potassium persulfate (KPS) by aqueous solution polymerization. The influence of raw material ratio, dosage of initiator, temperature and reaction time to poly-dispersant properties, which was measured by kaolin slurry viscosity, was studied in detail. It was observed that poly-dispersant prepared in this study exhibited good dispersion properties for kaolin slurry. This is most probably due to high electrostatic repulsion force and steric stability between kaolin particles, which is fully covered by poly-dispersant with suitable molecular weight, molecules contain appropriate side chains and charge density. The optimum conditions are as follows: the mass ratio of St/(AA&HA) is 1:30, the mass ratio of HA/AA is 3:1, and the reaction temperature is 70°C, the dosage of KPS is 7%, reaction time is 2h. It was also observed that viscosity of kaolin slurry was strongly affected by concentrations of Poly(Starch-Acrylic acid-Sodium humate) (P(St-AA-HA)). The optimal content of the poly-dispersant is 0.5%. Fourier transform infrared (FTIR) proved that the product was a graft copolymer of St-AA-HA.

Abstract: A non-ionic copolymer PAMA which has two functions of flocculation and surface activity was synthesized in aqueous solution. The copolymer was also characterized by means of infrared spectroscopic and unclear magnetic. The application performance of PAMA were studied, and the results show that the filtration rate of the phosphoric acid can be increased by about 3.8 times,the water content of the filter cake can be reduced by about 9.8%. Meanwhile, PAMA may increase the cake porosity by 25.82%,increase the mean void area about 7 times ,increase the surface contact angle of phophogypsum by 9.8°and decrease the surface tension by 7.4 mN·m^-1 according to the SEM photos and hydrophobic experiment. All this confirms that PAMA is useful for vacuum filter system of wet process phosphoric acid.

Abstract: The monomer of 2,3-di (thiophen-2-yl) quinoxaline (M1) and 2,3-di (thiophen-2-yl) 1,4-pyradiazine (M2) have been synthesized in moderate yields over two steps from readily available starting materials. The π-conjugated Polymer based on 2,3-di (thiophen-2-yl) quinoxaline was synthesized by Electrochemical workstation which was carried out in DCM/ Bu₄NBF₄ (0.1M) as the solvent/electrolyte couple. The new π-conjugated Polymer can slightly soluble in organic solvents such as methylene chloride and acetonitrile.

Abstract: A new coordination polymer based on cobalt nitrate and 2-4-pyridyl-1H-benzimidazole- 5,6-dicarboxylate (H₂pbd), namely [Co (pbd)₂·(H₂O)₂]_n·n (H₂O)₂, have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The crystal of the complex crystallizes in triclinic, space group P-1 with a=7.6708(6)Å, b=8.0009(8)Å, c=12.8348(12)Å, α=96.4040(10) o, β=102.9480(10) o, γ=112.142(2) o, V=694.11(11)ų, Z=1, C₂₈H₂₂CoN₆O₁₂ and F(000)=376.0. The H₂pbd ligand links the Co (II) atoms into a double stranded chain.

Abstract: This work studied the influence of different molecular structure of polycarbonate on its properties. Different types of polycarbonate molecular chain models were built by molecular simulation method. By combining experimental and molecular dynamic simulation results, it is concluded that the polycarbonate-OQ2720 has better thermal stability, mechanical properties and optical performance, which is a better choice for aviation materials and manufacturing process.