摘要:

AbstractA study of the melt rheological behavior of miscible blends of plasticized poly(vinyl chloride) (PVC) and epoxidized natural rubber (ENR) was carried out with a capillary rheometer. Melt viscosity and melt elasticity behavior was determined and surface characteristics of the extrudate was examined by using a scanning electron microscope. Melt viscosity of plasticized PVC increased with ENR content at higher processing temperatures. The melt elasticity parameters such as die swell ratio, principal normal stress difference, and recoverable shear strain at a particular shear stress increased with temperature up to a 50 wt % composition of ENR in blends. For high ENR blends the die swell ratio and recoverable shear strain decreased with temperature, and the principal normal stress difference and elastic shear modulus remained independent of temperature for all values of shear stress. It was noted that the nature of deformation in the surface layer was linear for a smooth extrudate and nonlinear for a distorted extrudate. Moreover, recoverable shear strain was found to have a correlation with the extrudate distortion of the melts.

ISSN:0021-8995    

DOI:10.1002/app.1990.070390201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe copolyesters of poly(butylene terephthalate) and poly(butylene adipate) were prepared by melt polycondensation of 1,4‐butanediol, terephthalic acid, and adipic acid. The thermal stability was important for their use a shot melt adhesives. The thermal degradation of these copolysters and homopolyesters was determined through TGA, change of acid number, IR, GPC, and NMR analyses. It was found that the thermal stability of the copolysters in oxygen decreased as the content of butylene adipate increased at temperature above and belowTm. Thermal degradation occured in oxygen even at temperature lower thanTm, so that degradation would also occur at room temperature in air and embrittlement was found for these copolysters for long term servic

ISSN:0021-8995    

DOI:10.1002/app.1990.070390202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe copolyesters of poly(butylene terephthalate) and polycaprolactone were prepared by melt polycondensation. The charged form of the caprolactone unit was either caprolactone or polycaprolactonediol. The chemical structure of the copolyesters was investigated by proton NMR. It was found that the content of the caprolactone unit in copolyesters was lower than the charged value. The copolyesters prepared from both caprolactone and polycaprolactonediol were found to be random copolymers.Tm,Tg, and crystallinity of the copolyesters decreased as the content of caprolactone unit increased due to the copolymerization effect. The tensile strength, modulus, and hardness decreased as the content of caprolactone unit increased, which was consistent with the trend of crystallinity.

ISSN:0021-8995    

DOI:10.1002/app.1990.070390203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractStyrene–glycidylmethacrylate–divinylbenzene resin beads could be converted to highly hydrophilic resin beads by acid treatment. These resin beads could be modified with isothiocyanato (NCS) groups quite easily using a Friedel–Crafts reaction and a subsequent nucleophilic reaction with KSCN. The resin beads substituted with NCS groups were useful as supports to immobilize enzymes, because they were not only hydrophilic but also bind proteins covalently. The enzymes immobilized onto the resin beads showed sufficiently high catalytic activities for a long p

ISSN:0021-8995    

DOI:10.1002/app.1990.070390204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractNylon fabrics were treated by low temperature fluorocarbon plasmas. All of the fluorocarbon plasmas applied altered the surface of nylon fabrics to be hydrophobic and water‐repellent. The durability of hydrophobicity and water repellency was examined by measurements of the water contact angle, the water droplet rolling‐off angle, and the breakthrough water pressure after plasma‐treated fabrics were washed. It was found that the structure of starting fluorocarbon and the plasma energy input were important factors in the durability. After washing, surface dynamics were investigated on different drying conditions. It was found that chemical composition and water repellency were dependent on drying conditions because of rotation of hydrophobic segments on the surface of fa

ISSN:0021-8995    

DOI:10.1002/app.1990.070390205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe results obtained from ATR FT‐IR and DMA studies of gas/plasma surface modified silicone elastomers are presented. The structural analysis indicates that, upon the plasma treatment in the presence of argon and carbon dioxide gases, the primary components of the surface are short chain layers with carbonyl groups. Their presence significantly influences the viscoelastic properties of the elastomer. The measurements of the storage modulus (E′) indicate a substantial decrease of the crosslink density upon the plasma treatment. Although the glass transition temperature also changes, these changes do not follow the trend observed ofE′values, and primarily depend on the chemical structures that develop upon the treatment. On the other hand, the ammonia–plasma surface modification introduces surface amide groups on the surface of the silicone elastomer, which effectively contribute to the increase of bothTgand storage modulus of the el

ISSN:0021-8995    

DOI:10.1002/app.1990.070390206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIn this study an immiscible blend of polypropylene(PP) and polycarbonate (PC) was examined. Experiments were carried out in an internal mixer and the objective was to examine the influence of the time of mixing, the speed of rotation of the rotors as well as the effect of time under quiescent conditions on the size and size distribution of the minor phase. The morphology was studied by light and electron microscopy and the photographs were quantitatively analyzed by semiautomatic image analysis. The effect of the time of mixing was studied for up to 20 min at three viscosity ratios for PC dispersed in PP. The most significant particle size deformation and disintegration processes take place within the first 2 min of mixing. After 2 min very little reduction in the size of the minor phase is observed up to 20 min mixing time, although some phase size/time dependence was observed at an intermediate viscosity ratio. The influence of rotor speed was also studied and the results indicate that this blend is insensitive to changes in the speed of rotation of the rotor over a three‐ to fourfold range. The effect of time at 250°C under quiescent conditions was studied at 7% and 23% composition (volume fraction) for PP dispersed in PC and also for PC in PP. Coalescence coarsening was observed only for 23% PC in PP where the particle size was found to increase by 75% after approximately 90 min at temperatu

ISSN:0021-8995    

DOI:10.1002/app.1990.070390207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractHPLC columns packed with cellulosic textile materials as stationary phase were examined with respect to their chromatographic parameters. The interaction of the stationary phase with water‐soluble substances (mainly textile chemicals) was also studied. The size‐exclusion effects of the porous material were measured for molecules with MW 20−2 × 106, thus giving further information concerning structural changes during the pretreatment of textile materials. Electrostatic and sorptive interactions were detected simultaneously, but found to exert a minor influence. Using a recently developed mathematical model, the pore volume distribution of swollen celluose could be determined from the size‐exclusion data without the introduction of empirical factors. The applied HPLC method of characterizing cellulosic materials offers an alternative to the previously utilized static and chromatographic methods, especially for studies on pretreated textile m

ISSN:0021-8995    

DOI:10.1002/app.1990.070390208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe deformation of amorphous and isotropic polyester film is studied using a device which simulates on a laboratory scale the continuous stretching between rolls by a drawing under constant load. The kinetics of deformation is compared to the kinetics involved in a conventional drawing at constant speed of elongation. The results of drawing under constant load are applied to the industrial case of stretching between rolls.

ISSN:0021-8995    

DOI:10.1002/app.1990.070390209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe structure development of a PET film is studied during drawings under constant load. The evolution of crystallinity, amorphous orientation, and axial and planar birefringences is described along a deformation path. The influence of the stretching force and stretching temperature is also analysed.

ISSN:0021-8995    

DOI:10.1002/app.1990.070390210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY