摘要:

AbstractThe polymerization of 6‐caprolactam by various mechanisms was investigated in the presence of poly(oxyethylene) (POE) of moleculare mass 1000 and 3000 terminated with hydroxyl or methoxy groups. Whereas the rate of hydrolytic polymerization (6‐aminocaproic acid as initiator) is not affected by addition of POE, the acidolytic polymerization (initiator: lauric acid) and spontaneous polymerization (without initiator intentionally added) are pronouncedly accelerated. The equilibrium content of polymer decreases with the increasing of POE concentration in initial reaction mixture in all mechanisms. A block copolymer probably results; the content of chemically bound POE is highest in the acidolytic polymerization and lowest in the hydrolytic polymerizat

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210101

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractEs wurde Polyvinylchlorid mit Aluminiumpulver als Füllstoff untersucht. Es wurde der spezifische elektrische Volumenwiderstand im Temperaturbereich von 293–373 K bestimmt und die Aktivierungsenergie als Funktion der Konzentration des Metallfüllstoffs berechnet.Es wurde die Dicke der dielektrischen Schicht, die auf den Metallteilchen adsobiert ist, bestimmt und die Feldstärke berechnet, bei der das System vom hochohmigen in den niederohmigen Zustand umschaltet. Im niederohmigen Zustand wurden die stati schen Strom‐Spannungskennlinien bei verschiedenen Temperaturen aufgenommen. Es wurde eine S‐Typ Kurve bei der Umschaltung in den niederohmigen Zustand und eine Hysteresis beobachtet.Es werden einige allgemeine theoretische Betrachtungen über die vorliegenden Mechanismen der Leitfähigke

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210102

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractVernetzte Copolymere aus Acrylnitril oder aus Acrylnitril und Acrylsäure wurden mit N‐Methylolmaleinimid zu maleinimidgruppenhaltigen reaktiven Trägern umgesetzt. Enzyme mit SH‐Gruppen oder solche, in die in einer Thiolierungsreaktion SH‐Gruppen eingeführt worden waren, konnten an diesen Trägern erfolgreich immobilisie

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210103

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractPoly(acrylonitrile‐co‐acrylic acid) films containing 1.8 percent acrylic acid as comonomer units in the copolymer were oxidized in air isothermally at different temperatures for periods of 1 and 5 hours. The physico‐chemical properties such as thermogravimetry, differential scanning calorimetry, infrared spectral absorption and intrinsic viscosity were analysed for the oxidized films. The intrinsic viscosity shows that the molecules of the polymer crosslink at temperature as low as 100°C. TGA spectrum shows two regions of steep weight losses in the range of temperatures studied, one is at 275–300°C and the other at 395–485°C. The first region is the formation of ladder polymer with the elimination of NH3, HCN and CO. The second region is due to the formation of aromatic structures with the elimination of HCN, NH3, water vapour and higher hydrocarbons. DSC spectral analysis shows an endothermic effect up to 205°C and exothermic processes from 205–300°C with a peak at 276°C. The exothermic processes continue up to 360°C. The exothermic effect is reduced for the films oxidized at 242 and 275°C. A marked endothermic effect is noticed at 120°C for the films oxidized at 242 and 275°C. This shows that the cyclization accompanying with exothermic effect sufficiently advanced during isothermal treatment leaving less room for rapid cyclization occurring upon further heating. IR spectral data show the negative environment with a shoulder at 2210 cm−1which is associated with uptake of oxygen during oxidation. Distinct peaks at 810 and 1550–1700 cm−1are noticed for the oxidized films oxidized at 275°C which are due to the presence of conjugated double bonds of the type C  NC  N. This type of conjugatio

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210104

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe compatibility and the mechanical properties of the blends of polyurethane (PU) elastomer and poly(vinyl chloride) (PVC) were studied. The results showed partial compatibility between PU and PVC. When the portion of PVC in blends exceeded 75%, the compatibility decreased. On the other hand, increasing the molecular weight of the glycol in PU improved the compatibility. The elongation decreased and the Young's modulus increased as the proportion of the weight of PVC in blends was increased. The tensile strength reached a minimum when PU/PVC was 50/50.

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210105

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractSecondary fuel cells based on oxygen reduction of platinum electrode modified by polymers and metal‐phthalocyanine (Mt = Fe(III), Co(II), Ni(II), and Cu(II)) were studied. The discharge curves for the platinum electrode modified by poly(2‐vinylpyridine) (or polystyrene) and Co‐phthalocyanine in 30% KOH aqueous solution, for a 30 min charge at 500 μA, followed by a 100 μA discharge showed a stable plateau at about −0.24 V SCE (Saturated Calomel Electrode). The open circuit voltage (vs. Zn) of the cell was 1.2 V, and the discharge capacity was of 46 A · h/kg. For this battery there was no significant decay in its characteristics after more than 30 charge‐discharge cycles. In Mt‐phthalocyanines, the values decreased in the order of Co(II)>Fe(III)>>Cu(II)>Ni(II). From a cyclic voltammogram for the electrode modified by the polymer and Co‐Pc, the cathodic reaction

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210106

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe contribution of jute constituents, namely, water soluble matters, waxes, pectins, lignin, hemicelluloses, and α‐cellulose in the graft copolymerization reaction of jute fabric with some vinyl monomers was investigated. Styrene, methylmethacrylate, and acrylonitrile were used as the monomers and Fe2+/H2O2redox system as initiator. The graft copolymerization reaction was carried out at 80°C using different concentrations of monomer and initiator for different lengths of time. The water soluble matters, pectins, and lignin were found to accelerate the graft copolymerization reaction during the initial stages of the reaction and in the meantime impede termination during the latter stages of the reaction. Generally, the magnitude of grafting is governed by nature of the substrate, nature of the monomer, and the conditions of the polymerization reaction. Grafting decreases the moisture regain of jute and substrates derived thereof irrespective of the monomer used within the range studied. Also, grafting decreases the tensile strength and imparts rot‐proofing properties to the substrates exa

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210107

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractScanning electron microscopy was used to obtain complementary data concerning the surface and inner structure of porous aliphatic‐aromatic methacrylate copolymers. Depending on the amount of a porogenic (toluene and dodecane) or crosslinking agent, the suspension copolymerization of methyl methacrylate and di(methacryloyloxymethyl)naphthalene (DMN) leads to either porous polymers with measurable surface areas or gel type polymers with no measurable surface areas. Porous polymers are visualized as one or two level organization of microglobules within the beads whereas gel type polymers exhibit no pores or microglobules neither in the surface layer nor in the bead interio

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210108

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractParameters of the equivalent pore model of different membranes (NAFION‐125, MRF‐26, and the polyethylene‐polystyrenesulphonic acid membranes (PE/PSSA)) were estimated from measurements of water hydraulic permeabilities. The pore radius calculations were performed according to the modified Ferry‐Elford equation rθ= rFEθ, where rFEis the radius calculated from the Ferry‐Elford relation and Å the tortuosity factor.The PE/PSSA membranes, expanded in hot water, were similar to the MRF‐26 membranes in their equivalent pore model parameters (radius 20 – 24 Å, and specific permeation rate 5.09 and 4.30.10−16cm2, respectively). The NAFION‐125 membrane exhibits the smallest pore radius (14 Å) and specific permeation

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210109

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractAsymmetric addition reaction of n‐butyllithium to aldehydes was studied by using chiral polystyrene derivatives and chiral low molecular model compounds, both of which were derived from cis,endo‐3‐dimethylamino‐2‐hydroxybornane. The higher optical yields were achieved by using low molecular model compounds, and particularly the highest value was obtained in the case when ether was used as the solvent. The effect of reaction temperature, sort of the solvents and the molar ratio of the reagent to aldehyde on the asymmetric addition was also

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051210110

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY