摘要:

AbstractSurface properties of a number of commercial thermoplastic polymer films were investigated before and after brief exposures to RF induced, low temperature gas plasmas. Water wettability and adhesion of vapor deposited aluminum to thin films (8–12 micron) of polyethylene, polypropylene, polyester, polysulfone, polycarbonate, and polyvinylidene fluoride films were studied before and after treatments with oxygen, 96% CF4/4% O2, and helium plasmas. Treatment with oxygen plasmas showed the greatest change in water wettability for polyvinylidene fluoride and polypropylene films, while treatment with 96% CF4/4% O2showed dramatic changes in wettability of polycarbonate, polysulfone, and polystyrene. Excellent adhesion of aluminium was found for polymers that had been previously exposed to gas plasma

ISSN:0021-8995    

DOI:10.1002/app.1991.070430901

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

年代:1991

数据来源: WILEY

摘要:

AbstractA polystyrene‐polycaprolactone diblock copolymer was extrusion blended with polystyrene and polyethylene terephthalate. The morphologies of the resultant blends were studied using differential scanning calorimetry and scanning electron microscopy. In all compositions studied, the polystyrene and polyethylene terephthalate phases exhibited discrete glass transitions indicative of the immiscibility of these components. However, addition of the copolymer increased the extent of dispersion of the homopolymer components within one another quite effectively. Blend specimens were tested with respect to tensile, flexural, impact, and thermal performance characteristics to study the effects of morphology and composition on these factors. In general, the blends were rigid, brittle materials with some‐what enhanced thermal characteristics. Addition of polystyrene‐block‐polycaprolactone polymer to the blends resulted in increased brittleness, slightly reduced thermal performance, and, in some instances, greatly increased r

ISSN:0021-8995    

DOI:10.1002/app.1991.070430902

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe polyesterification reaction of maleic anhydride and 1,4‐butylene glycol was carried out, usingp‐toluensulphonic acid as catalyst. The resulting material was characterized by IR and H1‐NMR spectroscopy, end group analysis, and gel permeation chromatography. It is shown that there is a relationship between maleate to fumarate isomerization and steric interaction among condensed groups on the one hand and the tendency of the reacting system to crosslink o

ISSN:0021-8995    

DOI:10.1002/app.1991.070430903

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

年代:1991

数据来源: WILEY

摘要:

AbstractA number of polycarboxylic acids have been used successfully as new nonformaldehyde cross‐linking agents for cotton fabrics. In our previous research, Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS) demonstrated the ability for characterizing ester cross‐linkages in the finished cotton fabrics. In this research, the effects of different acid concentrations, different catalyst concentrations, different curing temperatures, and different curing times on the ester cross‐linking of the cotton fabrics were determined by FTIR/PAS. The infrared spectroscopic data were also correlated to durable press (DP) ratings. FTIR appears to be useful for evaluating the effectiveness of polycarboxylic acids as cross‐linking agents for cotton fabrics. FTIR definitely complements the existing methods for evaluating finished textile

ISSN:0021-8995    

DOI:10.1002/app.1991.070430904

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe area under the linear loss modulus‐temperature curves, LA, has been shown to be related to the chemical composition of the material. In addition, it can be significantly affected by morphology in multicomponent polymer systems. To characterize LA quantitatively, base‐line corrections for instrumental contributions to LA were evaluated by several different methods and the results compared. In some instances, the calculation method affects only the LA magnitude, while general trends are unchanged; whereas in others, qualitative differences also become important. Not all of the methods described can be utilized universally. However, a straight‐line‐type of base line, similar to that which is used in infrared spectroscopy and differential scanning calorimetry, provides a widely applicable means of quantifying the lo

ISSN:0021-8995    

DOI:10.1002/app.1991.070430905

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

年代:1991

数据来源: WILEY

摘要:

AbstractPlasma treatment of poly(p‐phenylene sulfide) (PPS) doped with I2is found to increase both the electrical conductivity and the stability of the material. The average conductivity of plasma‐treated samples reaches an apparently saturated value of 1.7 × 10−3s cm−1, which is about six orders of magnitude higher than that of the same material without plasma treatment, and this conductivity remains practically unchanged under exposure to ambient environment for 10 days. Infrared and secondary ion mass spectra of the samples before and after plasma treatment suggest that the charge‐transfer complexes are formed in PPS doped with I2after plasma treatment. This is also consistent with the temperature dependence of conductivity results which show that the activation energy for electrical conduction decreases from 2.0 eV for pure PPS to 0.2 eV for plasma‐treated I2‐doped PPS. Using isothermal potential and current decay techniques, we have also measured the trap density distribution. Plasma treatment, on the one hand, does create more traps in PPS, but, on the other hand, it enhances conductivity. The mechanism of electrical conduction is bri

ISSN:0021-8995    

DOI:10.1002/app.1991.070430906

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

年代:1991

数据来源: WILEY

摘要:

AbstractIodine was incorporated into poly(N‐vinylcarbazole) (PVK) films by exposing the films to saturated iodine vapor at 100°C for 10 h. The content of iodine in the films was 2.3% by weight. The films were stable at room temperature. The infrared spectra indicate that no chemical reaction has taken place during the incorporation process. The dark conductivity of these films is about two orders of magnitude greater than that of pure PVK films. Carriers can be photogenerated in the films by light illumination from the UV region to the entire visible region. The most significant feature of these films is that the photoconductivity has a peak at the photon energy of 1.8eV. This is attributed to the charge transfer from the carbazole to I2. The results of thermally stimulated currents (TSC) indicate that there are deep traps in pure PVK films, but after iodine incorporation, these deep traps disappear or are replaced by a large quantity of shallow tra

ISSN:0021-8995    

DOI:10.1002/app.1991.070430907

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

年代:1991

数据来源: WILEY

摘要:

AbstractSuspension Copolymerization of glycidyl methacrylate (GMA), phenyl methacrylate (PhMA), 2,4,6‐tribromophenyl acrylate (TBPA), and 4‐acetylphenyl acrylate (APA) with divinyl benzene (DVB) was carried out at 80 ± 1°C in aqueous medium, as basic supports for possible applications in polymer‐supported chemistry. The resulting copolymer heads were characterized with various techniques. The identification of monomers in the copolymer was attempted using FTIR and13C‐CP/MAS‐NMR spectroscopic techniques. The optical and scanning electron microscopic methods were used to study the shape, size, and surface morphology of the beaded copolymers. The particle‐size distribution was measured, and the average particle size of the particulate copolymers were carried out using a Malvern particle‐size analyzer. The decomposition temperatures and energy of activation involved in the thermal degradation were studied with thermogravimetry. The solvent imbibition of the polymer supports in various solvents was carried out with a ce

ISSN:0021-8995    

DOI:10.1002/app.1991.070430908

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

年代:1991

数据来源: WILEY

摘要:

AbstractPolystyrenes, polyacrylates, and poly(3,4‐isoprenes) incorporating the hexafluorodimethylcarbinol functionality have been synthesized, characterized, and tested as microsensor coatings on a surface acoustic wave (SAW) device for dimethyl methylphosphonate (DMMP) vapor absorption sensitivity. The syntheses involved monomer functionalization and polymerization or hexafluoroacetone reaction with preformed polymer. All fluoroalcohol functionalized polymer coatings displayed sub parts per million level sensitivity with the slope of the absorption isotherm steepest at low DMMP concentrations. The order of sensitivity for the isomeric polystyrene fluoroalcohols (meta>para≫ortho) paralleled that of the relative free hydroxyl to hydrogen‐bonded hydroxyl content. Strong hydrogen bonding between the fluoroalcohol polymers and DMMP vapor was observed by IR spectroscopy. Acylation of the fluoroalcohol group markedly reduced the DMMP sensit

ISSN:0021-8995    

DOI:10.1002/app.1991.070430909

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

年代:1991

数据来源: WILEY

摘要:

AbstractAn attempt is made to develop a novel series of cable sheathing compounds with variation in chlorine content and sufficient fire retardance and unique low‐smoke characteristics. These are prepared by blending PVC and functionalized polyolefins in different compositions. PE and EPDM have been functionalized by grafting dibutyl maleate (DBM) using DCP as initiator. FRLS compounds made from PVC‐functionalized polyolefin blends possess the special characteristics of low‐smoke, low‐acid‐gas generation, increased fire retardance, and improved volume resistivity, which are much better in comparison with a typical PVC sheathing compound. Thermoplastic elastomer (TPE) based nonhalogen FRLS compounds are also reported. The mechanisms for grafting, polymer‐polymer and polymer‐filler interactions have b

ISSN:0021-8995    

DOI:10.1002/app.1991.070430910

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

年代:1991

数据来源: WILEY