摘要:

AbstractFür HD PE und LD PE wurden oberhalb der Kristallisationstemperaturen die Löslichkeitsparameter auf der Basis gaschromatographischer Retentionsdaten bestimmt. Als Meßverfahren wurde die Methode der Inversen Gaschromatographie angewendet. Es zeigte sich, daß die Löslichkeitsparameter der untersuchten Polyethylentypen innerhalb der Fehlergrenzen nahezu gleich sind. Aus der Beschreibung der Temperaturabhängigkeit der Löslichkeitsparameter folgt, daß das thermodynamische Verhalten der Polyethylenkomponenten in Mischungen durch ihre unterschiedlichen freien Volumina determini

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520101

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractAus den Löslichkeitsparametern von HD PE und LD PE wurde ihr temperaturabhängiger Flory‐Huggins‐Wechselwirkungsparameter χ12und daraus wiederum nach Flory‐Huggins die spezifische freie Mischungsenthalpie ΔGm/V eines HD PE/LD PE‐Systems berechnet. Unter Zuhilfenahme des „reptation”︁‐Modells und der Einstein‐Relation wurde die Diffusionsgeschwindigkeit der PE‐Moleküle abgeschätzt. Die Triebkraft dieser Diffusion ist proportional der spezifischen freien Mischungsenthalphie. Die Ergebnisse zeigen, daß diffusionskontrollierte Entmischungserscheinungen in einer HD PE/LD PE‐Mischung im Schmelzezustand nicht ablaufen. Das bedeutet, daß die Morphologie der Mischungen im Schmelzezustand nur durch die Mischbedingungen im Zusammenspiel mit den Fließeigenschaften d

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520102

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractA copolymer of 3,3′‐bisitaconimido‐m,m′‐diphenyl sulfone and methacrylic acid was synthesized by free radical polymerization. The copolymer was characterized and the copolymerization parameters were evaluated. The reactivity ratios determined by three different methods were in good agreement and the values suggest an alternating copolymer. The thermal degradation of the bisitaconimide homopolymer and the copolymer were compared and the structural implications on the thermal behaviour are discussed. The activation energies for the different stages of thermal decomposition of both the homopolymer and the copolymer were evaluated from the Coats‐Re

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520103

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe influence of diluent composition on the internal structure of porous copolymers of 1,4‐di(methacryloyloxymethyl)naphthalene (1,4‐DMN) and divinylbenzene (DVB) was studied.A set of copolymers containing 0.5 mole fraction of 1,4‐DMN and 0.5 mole fraction of DVB obtained in the presence of various amounts of toluene in the mixture with n‐decanol was investigated. In order to establish the influence of toluene concentration on the internal structure of 1,4‐DMN and DVB copolymers, surface areas, pore size distributions, and polarities of sorbents were inv

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520104

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractPolyurethanes slightly crosslinked with allophanate and CC linkages have been prepared by reaction of 4,4′‐diphenylmethane diisocyanate with poly(ethylene adipate) and poly(ethylene maleate) as well as with terephthalic‐adipic copolyesterdiol and some low molecular diols.Data obtained from isothermal and dynamic thermogravimetric analysis carried out in an inert atmosphere indicate that the thermal stability of polyurethanes is independent on the crosslinking density and the structural characteristics of crosslinks and hard s

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520105

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractA study with model compounds was made by13C‐NMR in order to confirm the two possible sites of attack on an oxirane ring by a carboxylic acid serie. In all cases the presence of signals corresponding to normal and abnormal opening of the ring was detected. Thus, two different methods to quantify the obtained primary and secondary alcohol amounts were used. It was found that the less primary alcohol was obtained the more nucleophilic the carboxylic acid i

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520106

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe sorption and permeability of tetraalkylammonium chlorides and alkali chlorides in perfluorocarboxylate membranes were determined. The water content and density of the membranes were found to change with treatment in boiling water and with different tetraalkylammonium cations as counterions for the carboxylate fixed charge. This is attributed to a change in the structure of the membrane matrices. DSC measurements suggested the existence of three distinct phases in the membranes, i.e. a free water phase, a bound water phase, and nonfreezable water. The nonfreezable water was assumed to be in the fluorocarbon phase. The permeability sequence of the tetraalkylammonium chlorides was found to be TEACl>TMACl>TBACl. To interpret the results, a parallel permeation model was proposed.

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520107

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThis study is concerned with some kinetic features of the reaction of n‐butyl isocyanate with poly(vinyl alcohol) without any catalyst and using triethylene diamine as catalyst. The structure of the resulting polymers was determined by means of IR,1H‐ and13C‐NMR spectroscopy as well as by chemical analysis. Vinyl alcohol‐vinyl butyl urethane (VAL‐VBU) copolymers were obtained. It has been found a linear dependence of reaction rate on polymer, n‐butyl isocyanate, and triethylene diamine concentrations. Reaction rate constant decreases as reaction time increases. It can be explained by steric hindrance phenomena due to urethane groups incorporated along the polymeric chain. The activation energy was found to be 49.9 kJ/mol. A kinetic study of the homogeneous hydrolysis of VAL‐VBU copolymers has been made as a function of the base concentration, the temperature, and the VBU content. The homogeneous hydrolysis was found to be first order with respect to both hydroxyl ion and VBU contents. The activation energy for the base catalyzed homogeneous hydrolysis was found to be 79.3 kJ/mol. The heterogeneous hydrolysis of VAL‐VBU copolymers in basic medium showed that no hydrolysis takes place under the cond

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520108

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractCellulose‐poly(glycidyl methacrylate) copolymer was reacted with methylamine. Factors affecting the reaction, such as methylamine concentration, liquor‐to‐material ratio, pH, temperature, and time were studied. The general kinetics of the process was reported, and a mechanism of the reaction was suggested. Potentiometric titration of the product showed that it was a weak base anion exchanger having a pKbo

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520109

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractA carbon black filled 50/50 natural rubber (NR)/styrene‐butadiene rubber (SBR) blend is vulcanized using several conventional curing systems designed by varying the amounts of sulphur and accelerator. The cure characteristics and the properties of the vulcanizates are compared. The quantity and quality of crosslinks in each case are evaluated by chemical probes to correlate them with the vulcanizate propertie

ISSN:0003-3146    

DOI:10.1002/apmc.1987.051520110

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY