Advanced Materials Research Vols. 554-556

Abstract: Cationic polyacrylamides modified with fluorinated methacrylate (FPAM) were prepared with acrylamide, dodecafluoroheptyl methacrylate (DFM) and methacryloxyethyl trimethylammonium chloride by free radical micellar copolymerization. The solution properties of FPAM were investigated. The results show that there are strong hydrophobic associations in the FPAM aqueous solution. The intrinsic viscosity decreases and Huggins constant increases with the increase of DFM content. The apparent viscosity of FPAM solution increases with increasing the FPAM concentration both in water and salt solution. There are maximum values of the apparent viscosity of FPAM with addition of sodium chloride, CTAB and sodium dodecyl sulfate (SDS), respectively. Additionally, the FPAM has higher surface activity in salt solution than in water.

Abstract: Thermal degradation of Ethylene Propylene Diene Rubber (EPDM) and PVC have been investigated and compared by means of TG/DTA in air or N2 atmosphere with the heating rate of 10K/min and gas chromatography-mass spectrometry (GC-MS). The occurrence of primary and second thermal degradation stages of EPDM in air have been recognized, while in N2 it was only one stage. The total weight loss ratio in air and N2 was 61.3%, 60.7%, respectively. Three degradation stages of PVC occur in both air and N2 and the total weight loss ratio was 72.5%, 72.6%, respectively. The thermal degradation of EPDM are all endothermic reaction, while of PVC are mainly exothermic reaction. Combustion products heated by laser in the same experimental conditions have been analyzed by GC-MS, the amount of toxic substances differ greatly, the amount of dimethylmethane of PVC are 2.55 times more than EPDM, dimethylbenzene and styrene of PVC are 6.2 and 5.5 times more than EPDM, toluene and benzene of PVC differ greatest with EPDM, are 24.2 and 35.7 times, respectively. EPDM can significantly reduce toxic products generation compared with PVC.

Abstract: Cardiovascular disease is one of important problems that the world countries face to. Especially for atherosclerosis and its concerned vascular diseases, they needs to be cured via bypass surgery. Consequently, developing small-diameter vascular grafts becomes important. This study aims to fabricate the tubular braid, and then evaluate its manufacturing methods and properties. In this paper, PET/Spandex hybrid yarn was braided into the tubular braid by braider. By repeated braiding, the layers of the tubular braid increases, producing multi-group tubular braids with varying thickness. After by the thickness and tensile strength tests, the physical properties of braids were estimated. The result demonstrates that, as increase of layers, the tensile strength also increases.

Abstract: Capillary rheometer was used to conduct preliminary study on the rheological behavior of SKYPEL thermoplastic polyester elastomer (TPEE). SKYPEL TPEE is a kind of non-Newtonian fluid and displays typical shear thinning behavior. Non-Newtonian index of the three samples varies from 0.69 to 0.77. With increasing temperature, the structure viscosity of the sample decreased and among them G172D is the smallest one under the same temperature.

Abstract: The terpolymer was synthesized by maleic anhydride (MA), acrylic acid (AA) and methyl acrylate (MAC) and the structure was also conformed. Its scale inhibition effect was also studied in high barium and strontium ion concentration aqueous medium and simulated formation water (Ca2+, Mg2+, Ba2+, Si2+) condition. The results indicate that when additive amount of AA/MAC/MA is 60 mg/L, the inhibition rate is up to 100% and 80% for BaSO4 scale and SrSO4 scale respectively, but only 50% for calcium scale. And the scale inhibition rate moderately increases with the dosage increasing. The scale inhibition effect of AA/MAC/MA is also very obvious in simulated formation water containing low calcium ions (400 mg/L) and high barium ions (500 mg/L) as well as strontium ions (500 mg/L). It can satisfy the need of restraining composite scale (BaSO4 scale and SrSO4 scale as well as CaSO4 scale) in high calcium and barium strontium ion aqueous medium when compounded with calcium scale inhibitors CY and CX respectively.

Abstract: Five different multifunctional nitro octaphenyl silsesquioxane (NPS) were Synthesised and reduction was carried out to obtain amino octaphenyl silsesquioxane(APS). These compounds were characterized with elementary analysis, fourier transform infrared(FTIR), nuclear magnetic resonance (NMR, ²⁹Si), wide-angle X-ray diffraction(XRD) and thermogravimetry (TG). Experiental results showed that the longer the nitration time, the more nitro connected to the OPS, but not positively, nitro number remained unchanged after five hours. NPS has good thermal stability than corresponding APS under 450°C, and the thermal stability of APS are decrease with the increase of amino number.

Abstract: Aging performances of polyester oxford with different weaving parameters were analyzed. Filament fineness and fabric density were key parameters. The filaments’ tensile strength, the characteristic groups on the fiber surface by FTIR and the determination of terminal carboxyl group were tested, and then the changes of characteristic groups were analyzed by internal standard working curve methods. It was resulted that during the former aging, the orientation of fibers were destroyed, meanwhile the ester bonds on carboxyl decreased and ester bonds on (C-O-C) formed, and during the later aging, etching on the surface of fibers made the ester bonds sharp decreasing. Compared with different fineness, thicker fibers with one more stretch process have the higher degree of orientation, and then prolong the aging. Then compared with different fabric density, the higher density can prolong the aging, provided of no frictions harm fibers during weaving.

Abstract: In this paper, we studied the influence of the amount of alkyl glycosides emulsifier, reaction temperature and the amount of initiator on emulsion polymerization kinetics. The results show that when we apply the new alkyl glycosides emulsifier in acrylic emulsion polymerization, the relationship between polymerization rate Rp and emulsifier concentration [S] is Rp∝[S]0.70 and the correlation coefficient is 0.93; the relationship between polymerization rate Rp and the initiator concentration [I] is Rp∝[I]1.00 and the correlation coefficient is 0.86; the apparent activation energy of polymerization is 32.34KJ/mol and the correlation coefficient is 0.93. We got good results after applying the new type emulsifier in acrylic emulsion polymerization.

Abstract: The thermo-responsive hydrogels poly(N-isopropylacrylamide) (PNIPAm) were synthesized by frontal polymerization (FP) in dimethylsulfoxide (DMSO) and ethanol mixture. The effects of composition of synthesis-solvent on FP feature and porous morphologies as well as their response behavior of the final products were studied. PNIPAm hydrogel synthesized in mixture exhibited a porous structure, which was responsible for its higher swelling ratio. Moreover, an improvement in swelling capability of the final PNIPAm hydrogel was found when the ethanol content in mixed media was elevated. The approach, frontal polymerization in mixed solvent, reported here provides a promising option to synthesize porous intelligent hydrogels PNIPAm.

Abstract: Homogeneous derivatization of cellulose was investigated with succinic anhydride (SA) in a solvent system containing 1-butyl-3-methylimidazolium chloride ionic liquid ([C₄mim]Cl) and dimethylsulfoxide (DMSO) using iodine, N-bromosuccinimide (NBS), and 4-dimethylaminopyridine (DMAP) as a catalyst. The results showed that the high degree of substitution (DS) of modified cellulose significantly increased from 0.24 without any catalysts to 0.84, 2.31, and 2.34 under same conditions except with I2, NBS, and DMAP, respectively, as a catalyst. The possible mechanism of succinoylation catalysed with different catalysts was discussed. Fourier transform infrared and solid-state cross-polarization/magic angle spinning 13C NMR spectroscopies also provided evidences of catalyzed homogeneous succinoylation reaction. The results indicated that iodine, NBS, and DMAP could effectively improve the succinoylation efficiency of cellulose in [C₄mim]Cl/DMSO.