Advanced Materials Research Vols. 311-313

Abstract: A new selenium-containing curcumin polymer was synthesized by polycondensation of curcumin with dihydride, polyethylene glycol, and selenium amino acid monomers. The polymer was stable, water soluble, and injectable with a molecular weight of 6.1x10⁴ Da. The in vivo anti-liver fibrosis efficacy of the polymer was investigated with Sprague Dawley rats. The results showed the curcumin polymer had strong anti-hepafibrosis activity.

Abstract: In this article, the thermal stability of PU/PVDF blend was investigated by thermogravimetry (TG), and their rheological property was studied through testing and analyzing the rheological curves. The results showed that, with the increase in PVDF content, the thermal decomposition temperature of PU/PVDF blend increased, and by fitting relevant data to thermal decomposition dynamic equations, it was found that thermal decomposition activation energy of the blend increased gradually, i.e. the thermal stability of the blend increased gradually. Meantime, based on the curves of shear stress vs. shear rate of the blend at 180°C and 200°C, it was shown that for PU/PVDF blend, with the decrease of temperature and the increase in PVDF content, the non-Newtonian index decreased, while the viscosity of the blend increased.

Abstract: The thermoplastic polyurethane elastomer (TPU) was firstly synthesized by using polybutylene adipate (PBA) as soft segments, methane-4-4’-diisocyanate(MDI) and 1,4–butanediol(BDO) as hard segments. The polyurethane hot-melt adhesive was then prepared by adding the tackifying resin, filler and other auxiliaries into the TPU matrix. The structure of the synthetic products was characterized by Infrared Spectrum and the thermal properties and microstructure of polyurethane hot-melt adhesive was tested by the thermogravimetric(TG) and the scanning electron microscopy(SEM), respectively. The results showed that the thermoplastic polyurethane elastomer had the expected structure, the shear strength of polyurethane hot-melt adhesive increased with the pentaerythritol abietate content increasing when the addition of the pentaerythritol abietate is less than 20 wt%, and decreased with the content of CaCO₃ filler and petroleum resin increasing, respectively; the thermal stability was improved, and the char yields of the polyurethane blends increased with adding the filler CaCO₃. When the molar ratio of PBA:MDI:BDO was 1:2:1, the addition of pentaerythritol abietate and filler CaCO₃ was 20 wt% and 30 wt%, the comprehensive performance of PU hot-melt adhesive was better and the shear strength was 7.37 MPa.

Abstract: Effects of initial concentration of Ag(І), concentration of HNO₃, contact time and adsorption temperature on adsorption capacities of a novel polystyrene modified ethoxycarbonyl thiourea resin were investigated, and the maximum adsorption capacity of Ag(І) reached 4.11 mmol·g^-1. The adsorption kinetics was well fitted Boyd’s diffusion equation of liq·uid film, so the adsorption was controlled by liquid film diffusion. The experimental date fitted Langmuir equation, and the correlation coefficient was close to 1. The positive value of adsorption enthalpy ΔH is indicative of an endothermic process. FT-IR characteristic peaks of ethoxycarbonyl and thiourea groups changed obviously fore-and-aft adsorption, which means that the corresponding functional groups coordinate with Ag during the adsorption process.

Abstract: The temperature sweep tests at defferent frequencies and heating rates, and frequency sweep tests at various temperatures for the samples of poly(methyl methacrylate) are carried out on a dynamic mechanical thermal spectrometer EPLEXOR® 500N-Gabo. The effects of temperature, frequency and heating rate on dynamic mechanical properties of poly(methyl methacrylate) are investigated. The results indicate that the glass transition temperature of poly(methyl methacrylate) increases with increasing frequency from 1 to 100Hz, and increases with increasing heating rate from 3 to 8°C/min as well. The temperature sweep curves at various heating rates suggest that the storage modulus of poly(methyl methacrylate) is non-sensitive at heating rate 3°C/min or 8°C/min, while heating rate is 5°C/min, there exists a critical temperature, within which the storage modulus versus temperature curves depart from each other, and beyond which the curves overlap one another. The glass transition temperature determined by the peak of loss modulus curve is smaller than that defined by the peak of loss tangent. The frequency sweep curves at a constant temperature show that a drop in storage modulus and a peak in loss tangent appear at a certain critical frequency, and the critical frequency increases with increasing temperature. For amorphous polymer, a competitive mechanism between frequency and temperature is observed. Higher temperature accelerates molecular motion, while higher frequency restrains molecular motion, so that the critical frequency corresponding to the peak of loss tangent shifts toward the direction of high temperature.

Abstract: Toluene diisocyanate(TDI), polyethylene glycol(PEG), double-propionic acid(DMPA), hydroxyethyl methacrylate(HEMA) and other raw materials were used to synthesis UV-curable waterborne polyurethane, and the effect of the synthesis condition on the particle size of the emulsion was investigated in this paper. The structure of the polyurethane was identified by infrared spectroscopy (IR), thermal decomposition properties was measured through the thermogravimetric(TG). The results showed that, the target product is expected waterborne UV polyurethane by IR. With DMPA content increasing, the particle size decrease, stability and appearance of the emulsion turn better. With the mole ration of PEG/DMPA decreasing, adhesion and water absorption of the film increase. TG analysis indicates that the thermal decomposition performance of the Waterborne UV Polyurethane （WPUA） is excellent.

Abstract: The cold rolling of slab is analyzed by using elastic-plastic and heat-mechanic coupling FEM with the nonlinear method. The distribution of residual stress was analyzed mainly in this paper. It is indicated by the results that the residual stress in surface layer of slab material is the pressure stress and inside the plate is the tension stress under the smaller press quantity, the residual stress in surface layer is the tension stress and inside the slab is the pressure stress under bigger press quantity, the maximum residual tension stress in the slab becomes bigger with the increment of the reduction.

Abstract: In response to the serious barium / strontium – scale in oilfields, we simulated oilfield conditions and investigated the scale inhibition performance of several common scale inhibitors to barium and strontium, by following the protocol from Evaluation Methods of Anti-Scale Agent for Oilfield Use, Petroleum Gas Standards of People’s Republic of China SY/T 5673. The most effective scale inhibitor CD-1 was screened out. With CD-1 as barium / strontium scale inhibitor in the static anti-scale analytical experiments, the dependence of scale inhibition performance on scale inhibitor concentration, saltiness, temperature, time and the system pH was investigated. The application conditions of barium / strontium scale inhibitor in real petroleum and gas field was obtained. Under the optimized application conditions, the mixture scale inhibitor had better scale inhibition efficiency than CD-1 alone.

Abstract: Ionic liquid was used as the pore-forming additive to design the structure and properties of PVDF membranes. The crystal structure, morphology and the wettability of the membranes was investigated by Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and contact angle measurement. The results of FTIR and XRD suggested that ionic liquid could make α crystal phase in pure PVDF membrane totally transformed into β crystal phase via immersion precipitation process. SEM results also indicated that ionic liquid was a good pore-forming additive, which was in favor of the formation of the pore structure in the membranes. Contact angle results showed that the surface hydrophobic of PVDF membrane increased with the addition of ionic liquid in the casting solution. These results suggested that ionic liquid may be found its further application in the preparation of piezo-electric PVDF films with β crystal phase, and oil/water separation membranes.

Abstract: Directly using L-lactic acid (L-LA) and glucose (Glu) as the starting materials, novel biodegradable material poly(L-lactic acid-co-glucose) [P(L-LA-co-Glu)] was synthesized via direct melt polycondensation. The copolymers P(L-LA-co-Glu)s at different molar feed ratios were characterized by FTIR, ¹H-NMR, GPC, DSC and XRD. All poly(L-lactic acid) modified by Glu was partly crystalline. And their M_w, T_m, and crystallinity basically increased with the increase of the molar feed ratio n(L-LA) : n(Glu). When n(Glu) : n(L-LA) was 1 : 750, the biggest Mw was 5900 Da, and all M_w could meet the requirement for drug delivery application.