摘要:

AbstractFour pyridazine derivatives were synthesized and evaluated as accelerators in natural rubber (NR) mixes. The rheological characteristics were determined by a Monsanto Rheometer 100. The kinetic constants for the vulcanization reaction in the presence of the synthetic compounds were calculated using the rheometric data. The compounds showed a good accelerating efficiency compared with mercaptobenzothiazole (MBT), which is widely used in rubber industry.

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680101

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe results of investigations of the supermolecular structure of the mixture of a semicrystalline polymer polyamide‐6 (PA‐6) and of an amorphous one, poly(methacrylic acid) (PMA), are presented. The determination of the supermolecular structure was realized using the correlation functions and the interface distribution functions calculated from SAXS patterns. It was stated that the introduction of poly(methacrylic acid) results in a transformation of the γ‐type crystalline structure into the α‐type structure. Until the PMA content is less than 46%, the blend has a lamellar structure, and an increase in the PMA content causes an increase in the long period. PMA and the amorphous phase of PA‐6 form a homogeneous phase, there are no microdomains of PMA.An increase in the PMA content results in a decrease of the crystallinity index. Simultaneously, the thickness of the transition layers between the crystalline regions and the phase composed of PMA and of the amorphous phase of PA‐6 increases. When the content of PMA is large, the lamellar structu

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680102

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractN‐substituted maleimides have been investigated as thermal stabilizers for rigid polyvinylchloride (PVC) at 180°C in air by measuring the rate of dehydrochlorination and the extent of discoloration of the polymer. The results reveal the higher stabilizing efficiency of these products relative to basic lead carbonate, dibutyl tin maleate, and cadmium‐barium stearate stabilizers commonly used in industry. The induction period (Ts) increases as a function of the positive resonance effect of the substituents (+R). Moreover, the investigated stabilizers impart better color stability for the degraded samples as compared with the stearate stabilizer. The stabilizer efficiencies are attributed to their radical trapping potency which intervenes with the radical degradation process of PVC, while the good color stability is due to the ability of the stabilizer to interact with the conjugated double bonds formed on the PVC chains as a result of degradation. A mechanism illustrating the stabilizer's action is prop

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680103

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractKraft‐Dehnungs‐Graphen von Filamentgarnen für die Dehngeschwindigkeiten zwischen 10−1und 105%/s werden ermittelt. Für die niedrigen Dehngeschwindigkeiten bis 10%/s wird eine übliche Zugprüfmaschine benutzt, die höheren Dehngeschwindigkeiten werden mit einer Fallschlagapparatur durch Variation der Fallhöhe und der Fadenlänge erreicht.Aufgrund der hohen Dehngeschwindigkeit und der Meßzeiten bis minimal 10−4s sowie der Variation der Fallhöhe zwischen 0,6 und 166 cm treten Fehler auf, die eingehend d

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680104

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractUntersucht werden Polyethylenterephthalat (PETP)‐Multifilamentgarne mit unterschiedlicher thermischer Vorgeschichte.Die Kraft‐Dehnungs‐Kurven für die Dehngeschwindigkeit von 0,1 bis 100 000%/s zeigen, daß die Höchstzugkraft mit der Dehngeschwindigkeit zunimmt und die Höchstzugkraftdehnung abnimmt. Für die Garne mit unterschiedlicher thermischer Vorgeschichte bestehen jedoch Unterschiede, was die Änderung der Höchstzugkraftund Höchstzugkraftdehnungswerte mit der Dehngeschwindigkeit betrifft. So weist ein spannungslos thermisch behandeltes Material eine geringere Änderung der Höchstzugkraft mit steigender Dehngeschwindigkeit auf als ein bei gleicher Temperatur, aber unter Spannung thermofixiertes Material. Die Höchstzugkraftdehnungswerte zeigen dagegen ein umgekehrtes Verhalten. Mit wachsendem Einfluß der Dehngeschwindigkeit auf die Bruchkraft nimmt das Verhältnis von Höchstzugkraft zu Höchstzugkraftdehnung stärker zu.Die Anfangssteigung, d. h. der Anfangsmodul der K‐D‐Kurven des Fadenmaterials, nimmt für alle Fixierspannungen und ‐temperaturen mit der Dehngeschwindigkeit zu. Das lokale Minimum der ersten Ableitung der K‐D‐Kurven (lokales Modulminimum) verlagert sich mit zunehmender Dehngeschwindigkeit zu höheren Modulwerten, die Lage des Minimums als Funktion d

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680105

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractNew esterimide and ketoimide polymers containing a biphenyl group have been synthesized and characterized by spectral techniques. Their thermal properties have been studied by thermogravimetric (TGA) measurements, showing a different stability with regard to the imide structure. The analogous amide imide compounds have been tested as monomers, but their polymerization has not taken place as we expected and side reactions have been detected by13C‐NMR spectroscop

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680106

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe copolymerization of acrylonitrile (AN) with glycidyl methacrylate (GMA) has been investigated in tetrahydrofuran (THF). The reactivity ratios were estimated and the thermal behaviour of the homo‐ as well as the copolymers, both in air, and under nitrogen atmosphere was investigated using differential thermal analysis (DTA) and thermogravimetry (TG) techniques. GMA was found to initiate the nitrile oligomerization reaction in the copolymers upon heating. The dyeing ability, as well as the colour fastness towards UV light have also been investigated. It was found that the copolymers showed better affinity towards basic dyes compared to homopolyacrylonitrile. This affinity increases with increasing the GMA content in the copolyme

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680107

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractMelting, recrystallisation and remelting of undrawn and drawn linear polyethylene with different molecular weight were studied by differential scanning calorimetry before and after oxidation with nitric acid.

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680108

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThermal properties of polyurethanes based on 4,4′‐diphenylmethane diisocyanate and poly(ethylene adipate) crosslinked only by CC linkages were studied by isothermal and non‐isothermal thermogravimetry carried out in nitrogen atmosphere. Previously studied polyurethanes crosslinked only with allophanate groups were used for comparison.It was found that the structure of crosslinks determines the initial stage of degradation

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680109

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe reaction product of cyclohexanone‐formaldehyde resin with an acid chloride of a radical initiator, 4,4′‐azo‐bis(4‐cyano pentanoic acid) was used as initiator for styrene polymerization to form a cyclohexanone‐formaldehyde resin/polystyrene copolymer. The copolymer showed similar solubility as

ISSN:0003-3146    

DOI:10.1002/apmc.1989.051680110

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY