摘要:

AbstractPoly(tetramethylene adipate)diol having a molar mass of 2000 was stored at temperatures of 60 and 80°C in the presence of water or 1,4‐butanediol and a common PUR‐catalyst like 1,4‐diazabicyclo [2.2.2]octane (DABCO) or dibutyltindilaurate (DBTL) and the solvolysis was investigated. The rate of solvolysis is low at 60°C except for DBTL and shows a drastic increase at 80°C. In the alcoholysis reaction DBTL is a much more active catalyst than DABCO. The rate of hydrolysis is slower probably because the catalysts are deactivated by the acidic products formed in this process. The mechanical properties of polyurethanes made from the degraded polyols are in good correlation with the decrease in mo

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600101

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe paper deals with the effect of addition of bis(allylphenyl) type (TM 120) monomer on the properties of unidirectionally carbon fibre reinforced 4,4′ bismaleimidodi‐phenyl methane (BM) – 2,4‐tolylene diamine (A) (1:0.3 molar ratio) (BM‐A) composites. The curing and thermal behaviour of the blends was investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) in air atmosphere. A marginal decrease in thermal stability was observed with increasing concentration of TM 120. Flexural, interlaminar, and impact strength of the laminates increased in the presence of this monomer. Optimum mechanical properties were observed at ∼ 20 ph

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600102

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper examines the effects of deformation amplitude, temperature and frequency on the dynamic properties of SBR‐short fiber composites. The presence of the fiber increases the storage modulus at any deformation amplitude. Depending on the nature of the fiber, the linear response zone of the modulus versus deformation either diminishes or disappears. The loss factor tan δ is higher in fiber composites. Although the peaks do not vary in magnitude, they occur at different deformation amplitudes.Temperature increase causes the moduli to decrease, the gradient, however, being less pronounced for fiber composites. The relaxation spectra show a damping peak which correlates to the principal relaxation process in the elastomeric matrix. The temperature at which this peak appears is displaced towards higher values with increasing excitation frequency. This allows the determination of the apparent relaxation activation energy, which is higher in fiber plus adhesive composites (225 – 275 kJ/mol), as compared to the fiber‐free composite (194 kJ/mol), as a consequence of stronger fiber‐matrix int

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600103

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA new type of a UV‐curable polyurethane acrylate resin based on hydroxyterminated polydimethylsiloxane (PDMS) soft segments with molecular weight 1800 and 2,4‐toluene diisocyanate (TDI)/2‐hydroxyethyl methacrylate (HEMA) hard segments were synthesized. The reactivity of 2,4‐TDI with the hydroxy groups of silanol and HEMA was discussed by means of IR measurements. The characteristic absorption peaks of the —NCO groups of 2,4‐TDI in the para‐ and ortho‐position should decline with increasing the reaction time. The measurements of fundamental physical properties of this type of UV‐curable materials had been widely studied in addition to the effects of using various reactive diluents and some pigments. This kind of resin with good optical, electrical insulating, and adhesive properties on various matrices, could be improved in chemical properties and reduced in viscosity while promoting the coating processability by mixing with various reactive diluents. The excellent adhesive properties on glass plates can be attributed to the similar structure between the PDMS soft segments and glass which makes the application in the coating

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600104

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractNew Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) coordination polymers of Schiff base ligand derived from terephthalaldehyde and S‐benzyldithiocarbazate have been synthesized in DMF media. The coordination polymers have been characterized by their elemental analysis, magnetic susceptibility, and by electronic and infrared spectral measurements.The thermal stability of each polymer was found out by thermogravimetric analysis. The thermal stability of coordination polymers obtained from thermograms has the following order:\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Zn} \simeq {\rm Fe}>{\rm Co}>{\rm Ni}>{\rm Min} \simeq {\rm Cu}$\end{document}Mn(II), Fe(II), Co(II), and Ni(II) coordination polymers are of a six‐coordinated octahedral structure while Cu(II) and Zn(II) coordination polymers are found to be four‐coordinated square planar and tetrahedral structure, respectively. The ligand‐field and nephelauxetic parameters have been determined from the spectra, using ligand‐field theory of spin‐allowed transitions which are found consistent with six‐coordinate structure for Mn(II), Fe(II), Co(II), and Ni(II) coordination polymers. Elemental analyses indicates a ligand: metal ratio of 1 : 1 in all the coordination polymers and the association of water molecules with central metal atom in case of Mn(II), Fe(II), Co(II), and Ni(II) coordina

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600105

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe reaction of polymers containing carbonyl groups such as poly(methyl vinylketone), poly(methyl vinyl ketone‐co‐styrene) and acetylated polystyrene with phenol in the presence of HCI or H2SO4has been studied in order to produce bisphenol A type structure on the polymer chain. Poly(methyl vinyl ketone) shows intramolecular aldol condensation and acetylated polystyrene results in bisphenol A type struct

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600106

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe emulsions of aromatic polyamic acids (PMPE and PBPPM) in DMF and methanol were used to coat uniform films on conductor surfaces by electrodeposition. The deposition yield and quality of the deposited films are dependent on sort of polyamic acid, solvent (DMF), precipitant (MeOH), surfactant (TEA), pH value and solid content. To get maximum deposition yields from PMPE and PBPPM, the best conditions of electrodeposition were required as follows: pH value 5.7 and 5.58, MeOH/DMF weight ratio 3.0 and 2.8, solid content 3.5 and 2.4 wt.‐%. Deposition yield was found to obey Faraday's law of electrolysis, and the higher the equivalent weight of the polyamic acid, the higher the coulombic yiel

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600107

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA simple model of double associates is used to represent bilayer sorption of binary gas mixtures on a flexible linear chain of a polymer. The isotherm equation derived in terms of this model is a simple product of the isotherm equation describing bilayer adsorption of binary gas mixtures on a homogeneous solid surface and a function reflecting specific features of sorption on polymers.

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600108

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractFor anionic polymerization with slow initiation and rapid propagation step analytical expressions are presented to calculate average molecular weights and molecular weight distributions for a semi‐batch process, in which a monomer solution contaminated by impurities is fed to an initiator solution in the reactor. The validity of the model was checked for the case of the polymerization of isoprene by n‐butyllithium in n‐heptane. The differences observed between theoretical and experimental values are explained by the changes in the rate constants of the initiation and the propagation step caused by the change in the polarity of the reaction solution by the continuously fed impurities. Furthermore it is shown that polymers with bimodal molecular weight distributions are formed if the semi‐batch procedure is followed by a batch one to increase the monomer con

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600109

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractFür ein Polymersystem Schwefel‐Styrol mit 10% Styrol wird die Abhängigkeit der Morphologie von der Polymerisationstemperatur und ‐zeit beschrieben. Neben der charakteristischen orthorhombischen Phase wurden röntgenographisch eine monokline und eine pseudoorthorhombische Phase nachgewiesen. Außerdem liegt, abhängig von den Polymerisationsparametern, ein amorpher An

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051600110

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY