Advanced Materials Research Vols. 634-638

Abstract: Functional macromolecule polyethyleneimine (PEI) is grafted onto the surface of silica gel particles with the “graft to” method using γ-chloropropyl trimethoxy silane as coupling agent, and the grafted composite adsorption material PEI/SiO₂ is prepared. The adsorption abilities and mechanism of PEI/SiO₂ towards p-nitrophenol are also studied. The results show that PEI/SiO₂ possesses very strong adsorption ability for p-nitrophenol by hydrogen bond interaction. The adsorption amount can reach to 78.6mg•g⁻¹. The adsorption is physical adsorption of a monomolecular layer and conforms to the Freundlich adsorption model. The pH and temperature have great influence on the adsorption capacity. As sodium hydroxide solution is used as eluent, and the adsorbed phenol is eluted easily from PEI/SiO₂.

Abstract: With Pd(AcO)2DPPP as catalytic precursor of CO/C2H4 alternating copolymerization. The main factors which affect the molecular weight of polyketone were studied. The results showed that: Temperature was the most important factor in copolymerization. The polyketone molecular weight lower faster with increasing temperature, have a decrease of 53% when system temperature rise from 70°C to 80°C, and the palladium-catalyzed progenitor easy to decomposition and become deactivation. Adding pressure was in favor of the increase of copolymerization rate and molecular weight. Water content in methanol solvent was sensitive to copolymerization rate, as far as molecular weight was concerned, it made no difference. HClO4 and other strong acids in the catalytic system will help improve the molecular weight of the polyketone.

Abstract: Polydichlorophazene is a colloidal ivory inorganic polymer with high elastic and an important intermediate that synthetizes polyphosphazene derivatives. By means of substituting the chloridion on polydichlorophazene by nucleophilic group, new functional materials with various different performance are fromed. The paper present research progress of synthetizing polydichlor- ophazene methods which are consist of two steps: the first step is synthesis of hexachlorocyclo- triphosphazene, the second step is synthesis of polydichlorophazene.

Abstract: In order to further improve the anti-aging properties of polypropylene (PP), the polypropylene (PP) was modified via Supercritical carbon dioxide (SC CO₂) grafting copolymerization with AN. PP-g-AN characterized by FT-IR. Polypropylene grafted acrylonitrile (PP-g-AN) / polypropylene (PP) / silica (SiO₂) were blended. The influence of the contents of PP-g-AN on the anti-aging property was discussed. At the same time, the anti-aging mechanism was studied. After the artificial accelerated ageing test, the result shows that the anti-aging properties of PP were improved greatly which due to the addition of PP-g-AN and SiO₂．

Abstract: High polymer active functional groups can be grafted on the surface of carbon fibers so as to adjust the interface effect between fibers in the composite material and resin and improve the performance of composite material, by controlling the structure of grafted high polymer, the interface layer with intended performance can be well designed. Heat treatment does not affect the fiber strength, the content of functional groups on the surface of the fibers reaches the max. value around 1h. There are no macromolecules polymerized and grafted on the surface of carbon fibers not subjected to isocyanate grafting treatment. Through isocyanate treatment after heat treatment, it can be obviously seen that the nylon molecules are grafted on the fiber surface. When no activating agent is added in the polymerized monomers, the resin grafting percent of fiber surface can reach 18.8%; when 0.003 activating agent (mole ratio of it to monomers) is added in the monomers, the grafting percent of PA6 on surface of carbon fibers is only 7.65%, this is the result of reactive competition on the interface between monomer matrix and fibers.

Abstract: The thermoplastic composite material with general plastics and high-performance engineering plastics as the matrix has become the hot spot of current research, because of big viscosity of thermoplastic resin melt, the focal point of research has been long concentrated on the aspect of impregnation technology, therefore, it is of particular importance to theoretically build the percolation model for fibers impregnated with thermoplastic resin. In this paper a theoretical model for fibers impregnated with thermoplastic resin melt through percolation is established, this model characterizes the influential laws of process parameters, melt viscosity and fiber structure on impregnation time. The model shows that theoretical volume fraction of fibers of the molten nylon resin composite material is hard to reach over 70%; for the nylon resin melt after viscosity reduction treatment, the time for complete impregnation is still very long, and raising temperature or increasing pressure can only improve the impregnation effect to a certain degree.

Abstract: High polymer active functional groups can be grafted on the surface of carbon fibers so as to adjust the interface effect between fibers in the composite material and resin and improve the performance of composite material, by controlling the structure of grafted high polymer, the interface layer with intended performance can be well designed. The surface of carbon fiber has great influence on the nylon generated through in situ polymerization and modified nylon crystallization, and little transcrystallization on the surface will be formed when the fiber carbon without grafting; after grating of carbon fiber, large quantity of crystalline texture can be seen near the fiber, and the crystal with high density is helpful for the improvement of material performance.

Abstract: Metal Reinforced Polyethylene Spiral Pipe (MRPSCP) is an innovative product of underground sewer. This product is a combination of the high stiffness and strength of steel and the better flexible and corrosion resistance of polyethylene. This paper mainly discussed some production technology and the product quality control of MRPSCP.

Abstract: 2-Hydroxy-6-naphthoic acid is an main raw material for the synthesis of polyaromatic ester, it was synthesized from 2-Naphthol by methoxylation, bromization, grignard reaction and demethylation before recrystallization (C2H5OH:H2O=2.8:1 m/m) with an overall yield of 78.5% and content of 99.1%. Furthermore, the results showed that the 6-bromo-2-methoxynaphthalene was prepared using Sn as reducing agent with 96.2% of the yield which is higher than 6-bromo-2-methoxynaphthalene was prepared using solid carbon dioxide and grignard reagent with 23.8% of the yield.

Abstract: A star-shaped cationic polyacrylamide(star-P(AM-DMDAAC)) was synthesized by free radical copolymerization of monomer of acrylamide(AM) and dimethyl diallyl ammonium chloride (DMDAAC) using the redox system of pentaerythritol(PETL) and (NH4)2S2O8 as initiator. And the factor influence the polymer molecular weight were detailed studied. The results indicate that the effects of polymerization temperature, the dosage of initiator, molar ratio of AM to DMDAAC have a greater influence on the viscosity-average molecular weight of the copolymer. and adding urea and ethylenediamine tetraacetic acid(EDTA) for additive and adding ammonia for adjustment the acidity of catalyst system can also increase the polymer molecular weight. The sludge dewatering performance of self-made star-P(AM-DMDAAC) is better than the commercial linear type cationic polyacrylamide flocculants in the market. The structures of the resulting products were characterized by nuclear magnetic resonance(1H-NMR), the PETL as "core" of the star polymer, the AM and DMDAAC as "arms" of the star polymer. And the synthesis mechanism was proposed in this paper.