摘要:

AbstractThe effect of chemical treatment on the reverse osmosis (RO) separation characteristics of sulfonated poly(phenylene oxide) (SPPO) thin film composite membranes was investigated. The effects of the concentrations of aqueous solutions of formaldehyde, sulfuric acid, hydrochloric acid, phosphoric acid, sodium hydroxide, and treatment time on the RO separation characteristics of the composite membranes with ion exchange capacity (IEC) of 2.14 and 2.50 meq/g in various combinations are reported in detail. The results indicate some enhancement in RO separation characteristics of the SPPO/polysulfone (PS) composite membrane under the best conditions of the chemical treatment.

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630101

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe enhancement effect of the addition of nitromethane into the coating solution of sulfonated sodium poly(phenylene oxide) (SPPONa) polymer for the synthesis of sulfonated poly(phenylene oxide)/polysulfone (SPPO/PS) thin film composite membranes on reverse osmosis (RO) separation characteristic was studied. The effect of gamma‐ray irradiation on the SPPO/PS thin film composite membranes was also evaluated when the membrane samples were in the wet and dry conditions. The composite membranes were also subjected to a chemical treatment combined with gamma‐ray irradiation in both wet and dry conditions in the hope of obtaining the maximum possible enhancement under each treatment. However, the experimental data of this combined treatment indicated the possibility of some degradation of the SPPO/PS composite membra

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630102

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractChlorination of atactic polypropylene (APP) was thermally initiated and carried out in carbon tetrachloride (CCl4) solution. It was found that with the increase in dilution, there is an increase in the extent of chlorination, as measured in terms of % weight‐gain. The reason for this behaviour has been ascribed to a greater degree of opening up and mobility of APP chains thus increasing the accessibility of the replaceable sites to chlorine. The order of the reaction with respect to APP concentration was found to be 0.84, the overall activation energy (Er) being 5.29 kcal/mol. Increase in flow rate leads to an increase in the extent of chlorination and was found to be increasing linearly with a flow rate up to 1 l/h beyond which it levels off. IR spectroscopy and13C‐NMR studies indicate the chlorination occurring in all the three types of replaceable H‐atoms in APP. The mechanism appears to be initial substitution of tertiary H‐atom by free chlorine radical followed subsequently by replacement of secondary and primary H‐atoms via either progressive substitution or elimination‐additio

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630103

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractCompounding of styrene‐butadiene copolymer/polybutadiene, natural rubber/ethylene‐propylene‐diene terpolymer and natural rubber/butadiene‐acrylonitrile copolymer blends was done in three different ways and their curing behaviour and the tensile properties of the vulcanizates are c

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630104

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractMixtures of phenol‐formaldehyde‐resin and pressed olive stones in a weight ratio of 20/80 were cured as small cylinders and then pyrolyzed. Some samples were also activated by steam. For these specimens and for two commercial activated carbons of laboratory or industrial uses the specific surface area, the structure, the adsorption properties, and the adsorption capacity were determined. The results indicate that the carbonaceous material produced by activation has greater values for the examined properties in comparison to the only pyrolyzed and the two commercial activated carbons, respectively. It was found that the Freundlich‐equation is valid for the adsorption of 4‐nitrophenol on all carbonaceous materials examined. The produced carbonaceous materials have different kinds of pores than the commercial activated carbons. The experimental results are explained with regard to the molecular dimensions of the adsorptive substances and the polarization effect of the substituents of the benze

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630105

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractNew acrylic rubbers with a pendant epoxy group were prepared by copolymerization of butyl acrylate (BA) with vinylbenzyl glycidyl ether (VBGE). The modification of an epoxy system (bisphenol‐A diglycidyl ether/p,p′‐diaminodiphenyl sulfone) with the acrylic rubbers was carried out in order to increase the toughness of the cured epoxy resin. The addition of 20 wt.‐% of the copolymer containing 74% of BA and 26% of VBGE units resulted in a 30% increase in the fracture toughness (KIC) of the cured resin at minimal expenses of strength and modulus of the resin. The modified epoxy resin had two‐phase morphology in which the rubber particles with average diameter of 2 μm are dispersed in the epoxy matrix. The copolymer without the pendant epoxy group, prepared from BA and vinylbenzyl methoxyethyl ether, was ineffective as a modifier, indicating that the reaction of the pendant epoxide with the epoxy matrix resulted in good interfacial adhesion between the rubber particles and the matrix, and in the increased toughness. The epoxide‐containing copolymers with 55 or 86% of BA units were also insufficient modifiers. The addition of the former yielded cured resins with homogeneous structure, whereas that of the latter resulted in macroscopic phase separation between the rubber and the

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630106

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractToluene diisocyanate based polyether polyurethane cationomer solutions are prepared and then emulsified by adding water. Properties of films cast from the solutions and emulsions are studied using infrared spectroscopy, dynamic mechanical analysis, differential scanning calorimetry, wide‐angle X‐ray diffraction, and tensileelongation testing. It is found that the use of the asymmetric chain extender, N‐methyl‐diethanolamine, also leads to a polyurethane (PU) with detectable order in the hard domains as in the PU with symmetric chain extender such as 1,4‐butandiol. After quaternization with glycolic acid, the PU cationomers have increased elongation and tensile strength and modulus. These can be attributed to the proper Coulomb interaction between two neighboring hard segments. The emulsification of the PU ionomer solution results in an increased mixing between the soft segments and the hard segments with asymmetric 2,4‐urethane isomers originally located in the hard domains, and therefore make the hard domains containing a higher concentration of symmetric 2,6‐isomer. The hard domains then become more ordered. Such increased order and phase mixing leads to an increase of the three tensile properties. During the emulsification conductivity and viscosity variations show that water is firstly adsorbed on the surface of the hard segment microionic lattices and then enters into the disordered and ordered hard domains

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630107

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractMethyl methacrylate (MMA) was grafted onto starch using ceric ammonium nitrate as initiator. The graft copolymers were isolated by selective solvent extraction in a Soxhlet apparatus. The effects of reaction time, initiator concentration, temperature, monomer, and acid concentrations on the graft yields were investigated. A preliminary kinetic study of the graft copolymerisation reactions shows that they follow the conventional kinetic behaviour of free radical polymerisation.

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630108

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe dispersion and polar surface free energy components, γ SVdand γ SVp, and the critical surface free energy, γc, of polymers were determined from contact angle data by the application of a nonlinear programming method using harmonic mean approximation.The surface free energy components of the probe liquids, γ LVdand γ LVp, which reflect the conditions of the maximized interaction parameter, Φ, were also simultaneously determined b

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630109

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractFormation of intermolecular excimers in polyethersulfone (PES) dichloromethane solutions were observed at a PES concentration about 2.7 × 10−2mol/l by the fluorescence analysis. External light energy irradiation enabled the formation of intramolecular excimers in the PES dichloromethane solution. These chains can gain an access to each other in parallel though the molecular chains are considerably rigid. The electron micrograph of the PES film, heat treated at 200°C for 72 hours, presented a diffraction micrograph, which suggests that the PES molecular aggregation is changed from a randomly coiled amorphous phase to an ordered

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051630110

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY