摘要:

AbstractStudies of interchain excimer interaction in semi‐dilute and concentrated solutions of polystyrene (PS) in a good solvent have been extended to polystyrene/polyvinylmethylether (PS/PVME) polymer‐polymer compatible blends. The constant fluorescence intensity ratio R ≡ IE/IMfor blends with a PS content lower than 5 wt.‐%, which is smaller than the value of PS in a dilute solution implies a mixing of PS and PVME chain segments down to molecular level in the compatible blend. The fluorescence intensity has been found to serve as sensitive criterion for phase separation. The cloud point curve for the used PS/PVME system has been obtained showing an LCST at 113°C at ca. 20 wt.‐% PS. It was shown that the one‐phase PS/PVME system is thermodynamically stable at room temperature presumably over the entire concent

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410101

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe Huggins constant k′ was measured for sodium carboxymethyl cellulose (NaCMC) solutions by an isoionic dilution technique for various ionic strengths. The value of k′ is found to increase with decreasing ionic strength. The electrostatic potential at the effective surface of the macromolecule was calculated due to the method of Mason et al. and that of Lifson and it has been observed that there is an agreement between the two methods of deriving the potent

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410102

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe electrical conduction was investigated in different rubber composites, subjected to various values of longitudinal extension. The study involves styrene‐butadiene‐rubber (SBR), butadiene‐rubber (BR), acrylonitrile‐butadiene‐rubber (NBR), butyl‐rubber (IIR), and natural rubber (NR). Each type was separately blended with 100 phr of fast extruding furnace black. The parameters of the model of Polley and Boonstra are recalculated for a specific example and good fitti

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410103

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe low molecular weight polyimides (PI) end‐capped with bismaleimide or amine terminated monomaleimide of six different compositions were synthesized by reacting benzophenone tetracarboxylic dianhydride, hexamethylene diamine, and maleic anhydride. These low molecular weight reactive imide prepolymers were characterized by infra‐red spectra,1H‐NMR, elemental analysis, vapour pressure osmometry (VPO) technique, solution viscosity (0.5 g/dl in NMP), density and X‐ray measurements. With these resins carbon cloth reinforced laminates were fabricated by the hot press moulding method. These laminates were evaluated by their flexural strength, interlaminar shear strength, density, void content, and fibre content. Optimization studies in mechanical and thermal behaviour of such composites were also carr

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410104

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe crystalline content in high pressure compacted polymeric powders has been investigated as a function of moulding pressure. It has been noted that the crystallinity Cpvaried with the pressure as [C0— βPα] where α and β were material dependent constants. There also appears a correlation between α, β, and an empirically defined factor which is related to the glass transition temperature, melting point, and compressive yield strength for all the polymers studied. The results have been discussed in terms of various processes taking place during the high pressure compacti

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410105

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA new flocculation agent is prepared by reaction of polyacrylonitrile with dicyandiamide in alkaline solution, followed by acid hydrolysis. The polymer contains guanamine‐, N‐carbimidoyl‐N′‐cyanoguanidine‐, amido‐, hydronaphthiridine‐, and carboxylic‐groups. In consequence of the alkaline and acidic groups present, the polymer shows polyampholytic properties and can be used as a primary flocculation agent. Fields of application are removal of contaminants dispersed in water, like waste, algae, bacteria and also in some cases dissolved substances like dyes, etc. Concepts of the flocculation activity and suggestions of applicat

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410106

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractFolien von Poly(tetrafluorethylen) (PTFE) und Poly(ethylen‐co‐tetrafluorethylen) wurden in Gegenwart von Luftsauerstoff der Einwirkung von Gammastrahlen ausgesetzt. Die IR‐analytische Untersuchung nach der MIR‐Technik (multiple innere Reflexion) zeigt, daß bei PTFE nur Kettenspaltung eintritt; eine oxidative Veränderung konnte nicht festgestellt werden. Die thermomechanische Analyse (TMA) zeigt, daß die Glasübergangstemperatur durch die Bestrahlung sinkt, offenbar als Folge einer Dichtezunahme der amorphen Phase. Im Gegensatz dazu unterliegt Poly(ethylen‐co‐tetrafluorethylen) einer Oxidation mit Ausbildung von Carbonylgruppen bis zu einer Strahlendosis von etwa 3 · 106Gy, danach erfolgt Kettenabbau. Die Bildung der Carbonylgruppen ist eine Reaktion de

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410107

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractPoly(phenylene sulphide) was synthesized by a direct method. Benzene and elemental sulphur were used as substrates, and aluminium chloride as a catalyst. The obtained final product was characterized by IR, VIS‐UV, wide angle X‐ray and mass spectroscopy, thermal, and elemental analyses. On the base of the analytical methods the molecular structure of the obtained polymer was discus

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410108

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe influence of different retarders on the conversion and the molecular weight distribution of initiated styrene polymerization in a continuous stirred tank reactor (CSTR) was investigated. The retarders used were nitrobenzene, tert‐butylpyrocatechol (tBC) and tert‐butyl‐o‐quinone. The inhibition constant of the nitrocompound was taken from literature to test the mathematical model. For the other two substances the inhibition constant was determined experimentally. The effectiveness of tBC increases in the presence of oxygen. Our results indicate that oxygen transforms the normal alkyl radicals of the polymerization into peroxy radicals having a higher reactivity towards the retarder thus leading to an overall increase in eff

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410109

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractEmpirical relationships, describing the change in mechanical properties of polyolefins at natural ageing in a seaside climate at middle geographic latitudes are derived on the basis of experimental data collected in a long exposure period — more than 10 years. The empirical equations describe the experimental data with a good accuracy. A constant is introduced accounting for the period in which the properties remain unchanged (induction period). The empirical equations derived may be used in predicting the change in mechanical properties of the investigated polymers in outdoor application

ISSN:0003-3146    

DOI:10.1002/apmc.1986.051410110

出版商:Hüthig&Wepf Verlag    

年代:1986

数据来源: WILEY