Advanced Materials Research Vols. 550-553

Abstract: A soluble polyimide with high molecular weight was synthesized from 4, 4'-(hexafluoroiso propylidene) diphthalic anhydride (6FDA) and 2, 2’-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (BAPAF) via two-step polycondesation procedure involving the preparation of poly(amic acid) (PAA) followed by chemical imidization. Effect of synthesis parameters on polyimide molecular weight involving material ratio, imidization temperature and imidization catalyst were studied. Synthesized PI was analyzed with respect to their molecular weights, chemical structures and solubility through GPC, FTIR, XRD and solubility tests respectively. The results showed that a high-molecular-weight PI was successfully synthesized from 4, 4'-(hexafluoroisopropylidene) diphthalic anhydride and 2, 2’-bis (3-amino-4-hydroxyphenyl) hexafluoropropane with imidization at 80°C for 3h, material ratio of n(BAPAF):n(6FDA) equal to 1:1 and catalyst of n(triethylamine):n (pyridine) less than1:3. The obtained PI showed excellent solubility in polar aprotic organic solvents such as NMP, DMAc, DMSO, THF and Acetone. Poly(6FDA-BAPAF) PI, with high molecular weight and excellent solubility, which was synthesized under lower imidization temperature that was equal to 80°C,could be easily obtained and convenient to process, thus it is a potential material for membrane separation.

Abstract: The graft copolymerization of maleic anhydride (MAH) onto ground rubber tire (GRT) was investigated through solvothermal synthesis route using free radical initiator. The effects of solvents, initiators and their concentration, and GRT mesh size on the grafting yield (GY) were studied, and the optimal conditions were concluded. The results showed that the high GY was obtained by using toluene as solvent, 1% azobisisobutyronitrile as initiator, and GRT fine powder as raw material. Infrared spectra and X-ray photoelectron spectra confirmed that MAH was successfully grafted onto the GRT molecules. The thermogravimetric analysis revealed that the thermal stability of graft GRT (GRT-g-MAH) is better than that of GRT slightly. The blending experimental results suggest that the GRT-g-MAH can be used as a compatilizer for GRT/HDPE blends.

Abstract: Highly reactive penta-coordinate organic silicon was prepared by the reaction of silica with ethylene glycol and potassium hydroxide, which reacted with 4-vinylbenzyl chloride to synthesize a new 4-vinyl benzyl tetra-coordinate silicate (VBTCS), and the new monomer was homo-polymerized and copolymerized with styrene and methyl acrylate via free radical polymerization, respectively. Tetra-coordinate silicon monomer, homo-polymer, and copolymers were characterized by IR, EA, TG, DSC, GPC etc.

Abstract: Ampholytic Polyphenylene Sulfide (PPS) was prepared from PPS by sulfonation, followed by bromination and then the substitution of bromine by quaternary ammonium group and tertiary amine group.The structure and properties of polymers were characterized by FT-IR, TGA, UV and isoelectric point(IEP) measurement. The degree of sulfonation and the content of bromide were investigated by acid base titration and Mohr Method respectively. The results indicated that 47.6% sulfonation degree at 4h, 105°C and a 15ml/g ratio of oluem and PPS, 35.25% content of bromide at 4h, 40°C and 4% FeCl₃. Bromine is completely substituted by quaternary ammonium groups at a 1:1.2 ratio of P-SO3-Br and volume of trimethylamine,70°C and 4 h,and that by tertiary amine groups at a 1:1.2 ratio of P-SO₃-Br and volume of dimethylamine,80°C and 4 h. Ampholytic PPS shows better solubility and thermostability than PPS.Hyperchromic effect: Br < NH(CH3)2 < N(CH₃)₃. The IEP of P-SO₃-TMA and P-SO₃-DMA are 4.08 and 3.84 respectively.

Abstract: In this paper, the high concentration polymer oil flooding experiments were first carried out on two artificial cores that with different Permeability (1000×10-3μm2 and 1700×10-3μm2) by using various concentrations of the polymer respectively(2000mg/L, 3000mg/L, 4000mg/L, 5000mg/L).The relationship between the polymer concentration and oil recovery was given, the upper limit of the polymer concentration was obtained according to the oil displacement efficiency, and the feasibility of the polymer concentration upper limit was investigated. Then it was found that higher produced water polymer concentrations were needed if the same the oil displacement efficiency was reached compared those fresh water polymer solutions by comparing the oil displacement efficiency that using produced water polymer solutions and fresh water polymer solutions.

Abstract: According to the demanded functions, a novel hardening accelerating and water reducing admixture has been excogitated which is based on a polycarboxylate superplasticizer and cooperated with some other hardening accelerants at the same time, and has many merits such as chloride free、sulfate free、low total alkali content、low dosage、high water reducing rate、high early strength and so on. The performance of this admixture has proved to be outstanding especially in accelerating the early strength of 12 hours and 24 hours age in the concrete tests.

Abstract: Polyethylene wax is prepared from LDPE through orthogonal experiments. It is found that temperature, time and the ratio of solvent to the feed can affect the experiment. The optimal condition is 310°C, 5h and 1 : 1.5. The result of experiment under the optimal condition is better than that in the orthogonal experiments. The color of products is from white to yellow. Finally, PEW is obtained from pyrolyzing waste PE bag under the optimal condition and the best condition in the orthogonal experiments. It can be seen that the former result is better than the later. The average molecular weight of polyethylene wax ranges from 1970 g/mol to 2700 g/mol.

Abstract: The synthesis and characterization of well-dispersed Bi2O3 nanoclusters from diblock copolymer are reported. A diblock copolymer template of norbornene derivatives was synthesized using ring-opening metathesis polymerization. By introducing BiCl3 into the diblock copolymer template, the bismuth oxide nanoclusters within the copolymer micelles were achieved by NaOH soaking and water wash. Finally, FTIR and TEM were used to characterize the nanocomposite morphology and the process of oxide formation

Abstract: HA MIP was prepared in acetonitrile-ethylene glycol mixed solvent ( 20:1，v/v), HA was used as the template, methacrylic acid (MAA) as the functional monomer, azobisisobutyronitrile (AIBN) as the initiator and ethylene glycol dimethaerylate (EGDMA) as the cross-linker. The UV spectrophotometry was used to demonstrate the interaction between HA and MAA. The adsorption characteristics of MIP to HA have been studied by equilibrium binding experiment and Scatchard analysis. The data obtained show that MIP reached equilibrium within 6 h. It is found that within the studied concentration range one HA molecule is entrapped by two MAA molecules The Scatchard chart shows the apparent maximum binding capacity (Bmax) and the dissociation contents (KD) of MIP are 170.5 μmol/g and 0.18 mmol/L, respctively. The MIP synthesized by this method have better binding ability to histamine and can be applied on the separation and detection of histamine.

Abstract: Immobilized lipase Novozym-435 catalyzed regioselective synthesis of glucose and undecylenic acid(UA) to produce glucose mono-ester in Organic solvents was investigated. Reactionconditions were tested in order to produce the mono-ester more rapidly and in higher yield, the optimal conditions were obtained as: temperature at 50°C,mole ratio of glucose toUA of 1:2,concentration of molecular sieves and enzyme used as 0.56mg/mL and 10mg/mL respectively . After the reaction, product was purified, and characterized by MS and 13C NMR spectroscopy, and determined as 6-O-(10-undercylenoyl)-D-glucose, The product was used as the starting material, K2S2O8 as a chemical initiator, to polymerize and form the sugar-containing polymer, which could be used for medicine release agent and other application of biological materials.