摘要:

AbstractA systematic study of the well‐known indophenin reaction between isatin and thiophene was extended to embrace bithiophene. The products of the reactions were isolated and characterized by FT‐IR, UV,1H‐NMR,13C‐NMR, and GPC. The values of the thus determined molar masses and molar mass distributions differed from the data given in the literature. The reaction conditions – solvent, temperature, and concentration – are of crucial importance for the course of the reaction and the products obtained.New structures suggested for the oligomeric reaction products agree with all the analytical data. The reactions between isatin and thiophene (bithiophene) are explained sc

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780101

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractAls Vorstufe zur Teilchengrößenanalyse von Farbstoffbädern mittels Photonen‐Korrelations‐Spektroskopie werden Latexsuspensionen untersucht. Eine Simulation einer Färbung von Polyestermaterial mit Dispersionsfarbstoffen wird durch eine ‘Modellblindfärbung’ unter Benutzung von Latexsuspensionen bei unterschiedlichen Farbbadtemperaturen nachgestellt. Die sich innerhalb des ‘Färbebades’ ergebenden Partikelgrößenverteilungen werden mit Hilfe der Photonen‐Korrelations‐S

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780102

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA Novolac p‐fluorophenol‐formaldehyde (NFF) resin was prepared by condensation of p‐fluorophenol with formaldehyde. DSC showed the glass transition effect or coinciding endothermal peak depending upon the thermal history of samples. It is supposed that the peaks are caused by breaking of the intermolecular bondings in the resin during the glass transition. The bondings are formed in the resin during the storage at room temperature. Thermally stimulated depolarization current (TSDC) measurements were carried out in the temperature range of 290 to 350 K, with the samples having an average number molecular weight M̄nof 375 and 434. TSDC curves mainly showed the dipolar relaxation α peaks. The influence of poling temperatures, the influence of M̄n, the activation energy Ea, and the physical ageing of the samples were investigated. Physical ageing was determined as the reciprocal polarizability Rpvs. time of ageing. Samples. with higher M̄nshowed a higher glass transition temperature, a lower Ea, and a higher increase in Rpthan the sample with lower M̄n. The increase in M̄nincreased the rigidness of NFF samples. The effects are attributed to the strong hydrogen bonding. The comparison with analogous results in novolac phenol‐formaldehyde resin without fluo

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780103

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractDynamic mechanical properties of bounded joints—stainless steel/epoxy adhesive—are investigated as a function of the thickness of the adhesive and aging conditions. The viscoelastic properties of the bounded joints have been investigated by Dynamic Thermo Mechanical Analysis (DTMA).The glass transition temperature (Tg) showed a dependence on both the chemical/electrochemical pretreatments of the substrate and the thickness of the adhesive in the bounded joint. The crosslinking density in the adhesive thus seemed more important in the interfacial region than in adhesion bulk.The water uptake induces a plasticization of the adhesive and a decrease in Tg. The most stable bounded joints were obtained by carrying out sulfochromic acid anodization as a pretreatment step. The most important stability of the bounded joints was obtained with the sulfochromic anodization of the substr

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780104

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractN,N'‐Dibenzyl‐3,6‐dioxaoctandiamin‐1,8 und drei analoge sekundäre Diamine mit langen aliphatischen Ethergruppierungen (EDA) sind hergestellt und mit Bisphenol‐A‐diglycidylether DGEBA polymerisiert worden. Der lineare Charakter der Additions‐polymerisation wurde durch die Molmassenverteilung, Mw/Mn= 2, sowie elementaranalytische und spektroskopische Untersuchungen der Additionspolymeren und ihrer Hydroxylderivate (Acetate, Dicarbonsäurehalbester, Urethane) belegt.Durch ein verbessertes Reaktionsmodell wurde die Epoxid‐Amin‐Reaktion in ausgezeichneter Übereinstimmung mit dem Experiment (Zeit‐Umsatz‐Kurve und dynamische Wärmekapazitätsmessung) bis zum höchsmöglichen Umsatz beschrieben. Das Reaktionsmodell berücksichtigt die nichtkatalysierte Reaktion und eine durch Addukt‐OH‐Grup

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780105

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe preparation of block copolymers from 6‐caprolactam and a liquid amine terminated butadiene‐acrylonitrile copolymer Hycar ATBN 1300X21 having higher notched impact strength than ordinary poly(6‐caprolactam) was studied. In the polymerization of 6‐caprolactam initiated by an adduct of phosphoric acid with 6‐caprolactam the influence of initiator concentration (0– 50 mol‐%) and Hycar ATBN 1300X21 concentration (0–5 wt.‐%) in the polymerization charge, of polymerization time (4 – 72 h) and of temperature (200–280°C) on the 6‐caprolactam conversion and on the properties of the copolymers formed were followed. Notched impact strength of the block copolymers prepared under optimized conditions wa

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780106

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractNatriumcarboxycellulose mit einem Substitutionsgrad bis 0,8 kann durch Oxidation von Cellulose mit einem Polymerisationsgrad im Bereich von 170 bis 1500 mit NaNO2/H3PO4und anschließender Behandlung mit NaBH4hergestellt werden. Das Ausmaß der Oxidation steigt mit wachsender Molmasse des Ausgangsmaterials. IR–und NMR‐Untersuchungen zeigen, daß nur das C‐6‐Atom der Anhydroglucoseeinheit oxidiert ist. Die Natriumcarboxycellulosen weisen eine hohe Tendenz zur ionotropen Gelbildung auch in sphärischer Form mit Calciumionen auf. Die mechanisch stabilen Gele werden durch Quellungsuntersuchungen und REM char

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780107

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA study was made of the time affecting the ceric ion induced grafting of 4‐vinylpyridine (4‐VP) onto partially carboxymethylated cotton (PCMC) having different degrees of substitution (D.S.). For comparison the same monomer was grafted onto cotton and mercerized cotton. The grafting parameters of these copolymerization reactions were determined. The graft yields for PCMC were significantly higher than those for unmodified cotton and mercerized cotton. The degree of crystallinity of the graft copolymers and of the unmodified cotton and PCMC samples was determined by the X‐ray method. The crystallinity index decreased with the presence of grafted polymer. The reaction time effect of the grafting of 2‐VP on cotton was also

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780108

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of pH on the graft polymerization of 4‐vinylpyridine (4‐VP) onto cellulose and on partially carboxymethylated cotton (PCMC) initiated by ceric ammonium nitrate (CAN) in dilute nitric acid was examined. The grafting parameters grafting efficiency (GE), graft yield (G), graft frequency (GF), and ceric ion consumption (Ce(IV)c) were studied as a function of nitric acid concentration. Also the effect of pH on the graft polymerization was examined and the total nitrate ion concentration was maintained high and constant at 0.86 mol/1 by addition of sodium nitrate. Maximum grafting and total conversion occurred at pH 1, but these values were smaller than the ones obtained in the previous case. For comparison some experiments were carried out using ceric sulfate as initia

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780109

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPhotocalorimetry, differential scanning calorimetry and ESR‐spectroscopy were used to analyse the photoinduced polymerization of multifunctional acrylic esters in various polymeric binders. Limiting conversion, maximal polymerization rate, inhibition time, and the time necessary to reach the maximum of the polymerization reaction rate were used to compare the reactivity of the photopolymer systems investigated in this work. Significant correlations exist between the limiting conversion and chemical structure of the acrylic esters used. A relation was also found between the glass transition temperature and oxygen permeability of the binder and the limiting conversion measured calorimetrically. A good correlation does not exist for the other reactivity parameters, because other factors such as phase change and changing diffusion conditions can have a complex influence on those value

ISSN:0003-3146    

DOI:10.1002/apmc.1990.051780110

出版商:Hüthig&Wepf Verlag    

年代:1990

数据来源: WILEY