摘要:

AbstractAn attempt is made to provide a simple and inexpensive method for the lamination of polyamides. A new application of a known reaction – methoxymethylation of polyamides – is proposed: creation of chemical bonds at the interfacial boundary between two contacting surfaces, i. e. welding and lamination of polymides. Commercial polyamide‐6 films are used in this study. As a result of the creation of methylene bridges between neighboring amide groups welding of the films takes place. After the pressing for 30 h of films coated in a methoxymethylation solution, the welding is so strong that during the mechanical tests, instead of delamination, breaking of the films outside the overlapped area o

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790101

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractEs wird eine neuartige spektroskopische Methode zur Messung der Ammoniak‐Permeabilität in transparenten Polymerfilmen vorgestellt. Sie beruht auf dem quantitativen Nachweis des den Testfilm durchdringenden Ammoniaks in einer darunter befindlichen Sensorschicht mit Hilfe der NH3‐empfindlichen Sonde 4‐Nitrophenol. Aus dem Anstieg der Extinktion mit der Zeit (ΔE/Δt) in der Sensorschicht wird die Permeabilität (P) und aus der Verzögerungszeit (lag time (t1)) der Diffusionskoeffizient (D) berechnet. Die Eignung der Methode wird durch Vergleich mit Literaturwerten belegt. Die aus t1zugänglichen Diffusionskoeffizienten stimmen sehr gut mit denen überein, die mit der Sorptionsmethode gefunden werden.Die Temperaturabhängigkeiten von P und D in mehr als fünf verschiedenen Polymeren (CDA, PVB, PVAc, PVC und in verschiedenen Polyvinylalkoholen) zeigen, daß Besonderheiten im Temperaturgang der Permeabilität aus dem vom Aufbau des Polymeren stark abhängigen Verhalten der NH3‐Löslichke

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790102

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractUrease was covalently immobilized on a new acrylic enzyme carrier: aminated butyl acrylate‐ethylenedimethacrylate copolymer. The enzyme retained 56% of its original activity. The properties of the free and immobilized urease were determined and compared. The Michaelis constant was found to be higher for the immobilized urease than for the free one, while maximum reaction rate was lower for the immobilized enzyme. The stability of urease against change in pH was considerably improved by the immobilization. The immobilized urease showed very good storage stability and reusability. Resistance of the enzyme against heat inactivation at 70°C, however, was not found to be improv

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790103

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe morphology of polypropylene plaques containing a weld line, has been investigated by x‐ray wide and small angle scattering, light scattering and polarization microscopy. The results are correlated to mechanical values obtained from tensile tests. While the lamellar morphology is of neglectable influence, it is found, that the mechanical properties of the samples are strongly influenced by the spherulitic structure. Clustering of β‐type spherulites and strong morphological inhomogeneities in the vicinity of the weld line are the primary reason for the mechanical weakening of the plaques. The temperature of the mould has a strong effect on the spherulitic structure and thus on the tensile properties of the sam

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790104

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractSeveral families of UV‐autocurable benzophenone tetracarboxylic dianhydride (BTDA)‐based polyester multiacrylate oligomers containing pendant glycidyl methacrylate (GMA) were synthesized and the effects of acrylic functionality and polyol type on their properties were investigated. The obtained autocurable oligomers possess good pot life and are cured rapidly when exposed to ultraviolet (UV) radiation without the addition of photoinitiator or photosensitizer. Different polyols were used to obtain wide range properties of cured multiacrylate oligomers with a glass transition temperature (Tg) range of 84–130°C. A further modification of the multiacrylate oligomers was obtained by mixing them with reactive monomers having different molecular structure and methacrylic functio

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790105

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractFillers for PVC and PP compounds have been treated by microwave plasma. FT‐IR photoacoustic spectroscopy studies show that the plasma polymer sheath on filler's surface contains CC, CH2, CH3groups, etc. X‐ray photoelectron spectroscopy studies reveal that interfacial chemical bondings exist between silica and the organic coating. Application of plasma‐treated fillers in PVC and PP compounds gives rise to materials of good mechanical proper

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790106

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractTraces of potassium acetate present in commercial poly(oxyethylene) diols (Fluka) were shown to catalyze the cyclotrimerization reaction of isocyanates. This reaction interferes with the determination of hydroxy groups by using the phenylisocyanate method. After the removal of potasium acetate (e. g. by means of ion exchangers) the phenylisocyanate method gives reproducible results which can be compared with those obtained by other methods. Reaction conditions suitable for the determination of OH groups in poly(oxyethylene) diols were found.

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790107

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe grafting of 4‐vinyl pyridine (VP) onto styrene‐butadiene‐styrene triblock copolymers (SBS) by homografting irradiation with dissolved oxygen was studied. Homograft membranes of various degree of grafting were prepared from a casting solution of grafted copolymer in benzene. The mechanical properties of membranes, gas permeability, and the effect of operating temperature on gas permeation were investigated.The degree of grafting of 8.4% was the largest at an irradiation time of about 15.5 h. It was smaller at both shorter and longer duration because of the interference of dissolved oxygen. It was found that the tensile strength and elongation of SBS‐g‐VP were similar to those of SBS. The stress relaxation of SBS‐g‐VP was slower than that of SBS, and this might be due to the formation of rigid microphase separation domain of poly(4‐vinyl pyridine), which acted as permanent crosslinking points to reduce the stress relaxation.Using the properties of high flux of SBS and high O2/N2selectivity of poly(4‐vinyl pyridine), the performance of gas permeation of 4‐vinyl pyridine homografted SBS membrane was studied. The selectivity of SBS‐g‐VP membrane increased with increasing degree of grafting. However, it was done at the expense of a decrease in the gas permeability.When the operating temperature of gas permeation increased, the permeability of oxygen and nitrogen increased, and the O2/N2permeability ratio decreased. The activation energy (Ep) for gas permeation through different degree of grafting of SBS‐g‐VP membrane (obtained by the Arrhenius law) increased with increasing degree of grafting. For ungrafted SBS membrane, Ep was 5.5 kcal/mol for oxygen and 7.2 kcal/mol for nitrogen. For 8.4% grafting degree SBS‐g‐VP membrane, Ep for oxygen and nitrogen, were 6.5

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790108

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractDie Oberflächenrauheit ist eine der wesentlichen Eigenschaften textiler Materialien, die sowohl deren Gebrauchs‐ als auch Verarbeitungsverhalten beeinflußt. Die vorgestellten Specklemeßmethoden sind kohärent‐optische Streulichtmeßmethoden, die zur integralen, berührungslosen und zerstörungsfreien Erfassung von Oberflächenstrukturen herangezogen werden. Die Untersuchungen werden mit Verfahren der Specklekontrastmessung und der Korrelation dichromatischer Specklemuster durchgeführt. Sie erstrecken sich auf transparente Dielektrika (Mattglas, Plexiglas und Polyester folie), um zunächst sicherzustellen, daß die Eigenschaften der Specklefelder auch für Hochpolymere erhalten bleiben. Als Ausblick wird die Anwendung von Specklemeßmethoden auf textile Werkstoffe in den drei Ebenen Filament bzw. Faser, Garn und G

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790109

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPoly(alkylene adipate)diols having molar masses of 1500, 2000 and 3000 were stored at temperatures of 25 and 60°C in the presence of low amounts of different alcohols and some polyurethane (PUR) catalysts, such as dibutyltindilaurate (DBTL), dibutyltindiethoxide (DBTEO), dibutyltinoxide (DBTO), and 1,4‐diazabicyclo[2.2.2]octane (DABCO). Alcoholysis was studied using either ethyl acetate (EA) or toluene as solvent. The results were compared with those obtained by examining the behaviour of several dialkyl adipates and ethyl acetate under identical conditions. The alcoholysis in the presence of the tin catalysts proceeds at the same reaction rate without significant decomposition of the catalyst, whereas DABCO is practically inactive. The nucleophilic activity of the alcohols depends on their bulk size rather than their basicity. The resistance of polyalkylene adipates to transesterification increases with the increasing alkyl chain length of diol units in polyester. A partial transesterification of dialkyl adipates takes place too, in spite of ethyl acetate being present in exce

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051790110

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY