摘要:

AbstractDie Synthese eines Celluloseaustauschers mit 8‐Oxa‐2,4,12,14‐tetraoxopentadecan als chelatbildende Ankergruppe wird beschrieben. Für die Kupplung des Chelatbildners an die polymere Matrix werden optimale Bedingungen angegeben. Eine allgemein gültige Gleichung für die sukzessive Ermittlung des Substitutionsgrades in jeder Reaktionsstufe der Synthese an einer makromolekularen Gerüstsubstanz wird vorgestellt. Charakterisiert wird der Austauscher durch reversible Beladungen mit Kupfer, Eisen und Uran, Ermittlung der Verteilungskoeffizienten für UO 2+2‐, Cu2+‐, Fe3+‐ und Ni2+‐Ionen in Wasser und simuliertem Meerwasser sowie durch radiochemische Bestimmung der Austauschgeschwindi

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120101

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCopolymerisation of tributyl tin methacrylate (TBTM) with methyl methacrylate (MMA), styrene (ST) and vinyl acetate (VAC) has been studied at 60°C. TBTM‐MMA behaves almost ideally and the product of reactivity ratios (r1r2) is close to unity. The TBTM‐ST pair is non‐azeotropic throughout the concentration range whereas TBTM‐VAC shows azeotropic behaviour at about 80 mol‐% of TBTM.When properly dried, the copolymers are amorphous solids. Copolymers of TBTM and VAC are hydrolyzed easily and become insoluble but can be made soluble again by treatment with tributyl tin oxide. The IR spectra of the copolymers have also bee

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120102

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe triethylamine‐bromine (TEA‐Br2) charge transfer complex was employed as photoinitiator in the photopolymerization of methyl methacrylate under light of 440 nm. The initial rate of conversion was 0.418%/min with an induction period of 56 min. The initiator and monomer exponents were 0.5 and 1.0, respectively. The polymerization was inhibited in the presence of hydroquinone but oxygen had a very little inhibitory effect. The value of k 2p/ktwas 5.13 · 10−2l/mol · s and the activation energy was 19.18 kJ/mol. The rate constant for the decomposition of the charge transfer complex (kε) was 4.61 · 10−61/s. Kinetic data and other evidence indicate that the overall polymerization takes place by a radi

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120103

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractEpoxidharze lassen sich mit einer haftfesten Metallschicht überziehen, wenn sie zuvor mit einem metallisierbaren Haftvermittler beschichtet worden sind. Ein solcher Haftvermittler besteht z.B. aus einem partiell epoxidierten Styrol‐Butadien‐Styrol‐Triblockcopolymeren, einem Epoxidharzvorprodukt und einem Aminhärter.Das Mischungsverhältnis dieser Komponenten sowie die Art des Amins beeinflussen die Abzugsfestigkeit der galvanisch aufgebrachten Metallschicht. Der höchste Wert wurde bei der Verwendung eines niedermolekularen Amins mit ca. 45 N/25 mm erreicht, während beim Einsatz von höhermolekularen Aminen nur Werte bis ca. 10 N/25 mm erzielt wer

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120104

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of thermal history on the glass transition temperature (Tg) of poly(vinyl chloride) was studied. The parameters like the hole energy (Eh), the activation energy for the disappearance of holes (Ej), the activation enthalpy for the structural relaxation (Δh1* and Δh2*) and the activation energy for the glass transition process (E) were calculated. The increase of Ehvalue with the increase in Tgvalue shows that there exists a holesize distribution. The Ej(26.9 ± 0.5 kcal/mol) value calculated according to Wunderlich's treatment, the Δh1* (27.8 ± 0.6 kcal/mol) value obtained by Moynihan's procedure and the E (35.3 kcal/mol) value from Barton‐Critchley's method agree well with one another in the poly(vinyl chloride) system. The Δh2* quantity, obtained through Moynihan's formulations, increase as the rate of heating was increased, a result similar to the variation of Ehvalue with the rate of

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120105

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractIn einer Reihe von Polyestern aus Diolen und aromatischen Dicarbonsäuren wurden die cyclischen Oligomeren isoliert und mit Hilfe der Hochdruckflüssigkeitschromatographie quantitativ bestimmt.Der Gehalt an cyclischen Oligomeren hängt von der chemischen Struktur der Polyester und vom Kondensationsverfahren ab. Hauptkomponente ist das cyclische Dimere, bei Poly(ethylenterephthalat), Poly(1,4‐dimethylencyclohexanterephthalat) und Poly(1,4‐dimethylenbenzolterephthalat) aus Ringspannungsgründen das cyclische Trimere.Bei technischem Poly(1,4‐dimethylencyclohexanterephthalat) gelang eine Auftrennung der stereoisomeren cyclischen Oligomeren, die durch die Verwendung eines trans/cis‐1,4‐Cyclohexandimethanol‐Gemisches entstehen.Die cyclischen Oligomeren der Copolyester mit Diolethern enthalten bei niedrigem Modifizierungsgrad nur eine

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120106

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThermal Properties of methyl methacrylate (MMA), ethyl methacrylate (EMA) and n‐butyl methacrylate (n‐BMA) grafted onto nylon 6 fibre with various graft levels were investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) and the results compared with that of parent nylon 6 fibre. It was found that the initial decomposition temperatures (IDT) of the grafted samples were lower than that of the parent nylon 6 fibre. On the other hand with all the three monomers, there was an increase in overall thermal stability followed by subsequent decrease with increase in the graft level. Among the grafted samples both the IDT and IPDT (initial procedural decomposition temperature) followed the order MMA‐g nylon>EMA‐g nylon

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120107

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractMill scoured and bleached cotton fabric, alkali treated cotton and partially carboxymethylated cottons having 34, 50 and 68 milliequivalent/100 g cellulose were subjected to thermal treatments. The latter were carried out at different temperatures for different durations of time. Chemical degradation of the substrates brought about by thermal treatment was assessed by copper number, carboxylic groups and degree of polymerization whereas deterioration was measured by tensile strength and elongation at break. It was found that the partially carboxymethylated cottons underwent higher degradation than the original (mill scoured and bleached) cotton, that the magnitude of deterioration of the substrate was determined by the previous chemical treatments and that the higher the carboxymethyl content the greater the degradation and deterioration of the substrate.

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120108

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractAn isothermal calorimeter for studying radical polymerization in heterogeneous systems is presented. The calorimeter was used for investigation of suspension and emulsion polymerization of vinyl chloride at 50°C. The results from the suspension polymerization experiments showed that the termination rate constant in the PVC phase was diffusion controlled and very sensitive to the vinyl chloride activity. During suspension polymerization the pressure started to drop at a much lower conversion than in emulsion polymerization. Mass balance calculations showed that this was due to entrapment of a large amount of liquid vinyl chloride in the fine capillary system of the suspension particles. The results from emulsion polymerization experiments in which the particle number spanned the range from 0.094.1018to 1.7.1018dm−3, were analyzed according to the kinetic model developed by Ugelstad et al. Using the concentration‐dependent termination rate constant obtained from the suspension experiments and assuming proportionality between the radical adsorption and desorption rate constants, this model gave a very good fit of the experimental rate over the entire interval II and most of interval III. The results strongly indicated that termination in the aqueous phase was of measurable importance during interval II and became the dominating termination in interval

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120109

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractEs wird eine Näherungsformel für die bei chemischen Reaktionen von vernetzten makromolekularen Stoffen gewonnenen Zeit‐Umsatz‐Kurven mit Hilfe der Beziehung α = 1 − exp (a1τa2) vorgeschlagen. Es wird die Berechnung der Geschwindigkeitskonstanten und der Diffusionskoeffizienten angegeben, die sich auf die Diffusion der reagierenden flüssigen Komponenten ins hydrophobe Polymergerüst beziehen. Die Berechnung wird für Kugel‐, Tafel‐ und Zylinder‐Formen des reagierenden, vernetzten makromolekularen St

ISSN:0003-3146    

DOI:10.1002/apmc.1983.051120110

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY