摘要:

AbstractAlthough it has been reported that aminated poly(propylene glycols) react with isatoic anhydride to cleanly yield the correspondingo‐aminophenyl amide (II), this paper shows that a competing reaction leads to the formation of about 10% of the corresponding urea carboxylic acid (III). This impurity (unreactive toward polyisocyanates) limits the use‐fulness of (II) in urethane/urea polymers. A procedure has been developed to quantify (II) and (III). Based on the insight gained, a process has been developed to produce the correspondingo‐aminophenyl amide derivatives of aminated poly(propylene glycols) in a state of high purity (˜100%). A given aminated poly(propylene glycol) is added dropwise to a siurry of isatoic anhydride in an inert fluid (such as toluene or a previously prepared product) at a temperature (60–100°C) at which reaction is rapid. Local excesses of unreacted amine are minimized to prevent formation of urea carboxylic acid impurities. This process has been applied to the preparation of the corresponding derivatives of a variety of aminated poly(propylene glycols). © 1993 John Wiley

ISSN:0021-8995    

DOI:10.1002/app.1993.070500401

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

年代:1993

数据来源: WILEY

摘要:

AbstractPreparation ofin situ‐modified cyclohexanone‐formaldehyde and acetophenone‐formaldehyde resins with compounds such as diphenols, melamine, andp‐toluene sulfonamide were studied. Modification of acetophenone‐formaldehyde resins with hydroxylamine, semicarbazide, phenylhydrazine, phthalic anhydride, and acetic anhydride was also studied. Melting points, solubilities in organic solvents, and FTIR and NMR spectra of modified resins were determined. © 1993 John Wiley

ISSN:0021-8995    

DOI:10.1002/app.1993.070500402

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

年代:1993

数据来源: WILEY

摘要:

AbstractFor making the surface hydrophobic, poly(ethylene terephthalate) (PET) films were subjected to treatment by CF4and CF4/CH4plasmas, and the PET fabrics, to impregnation (padding) with Oleophobol S for comparison. The electronic structure of the modified surface was differenentiated by XPS (ESCA). The surface dynamics upon heating and dipping into water was investigated by the angle‐dependent XPS technique. Application of the XPS technique to these topics gave a wealth of information. © 1993 John Wiley&Sons, I

ISSN:0021-8995    

DOI:10.1002/app.1993.070500403

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis article includes the doping and dedoping behaviors, the electrical conductivity, and the spectral properties of poly(2‐ethynylpyridine) and iodine‐doped poly(2‐ethynylpyri‐dine). The doping ability of poly(2‐ethynylpyridine) having a pyridine substituent was greater than that of polyphenylacetylene having a phenyl substituent. The electrical con‐ductivty of iodine‐doped poly(2‐ethynylpyridine) increased with doping time and reached the value of about 5×10−3Ω−1cm−1when the mol ratio of iodine to poly(2‐ethynylpyridine) repeating unit was above 0.7. The spectral properties of poly(2‐ethynylpyridine) and iodine‐doped poly(2‐ethynylpyridine) were also studied by infrared and UV‐visible spectroscopies and thermogravimetric anal

ISSN:0021-8995    

DOI:10.1002/app.1993.070500404

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe formation, textures, and optic characteristics of the ethyl‐cyanoethyl cellulose [(E‐CE)C]/acrylic acid (AA) mesophase were studied using polarizing microscopy, spectro‐photometry, and small‐angle light scattering (SALS). The disklike, oily streak, planar, pseudoisotropic, polygonal textures and the texture of domains gathered randomly were observed in the mesophase. The polygonal texture in unitary mesomorphic solutions can be regarded as the texture from the combination of deformed mesophase aggregates with the disclike texture. The mesomorphic solution exhibits vivid colors when the concentration is about 42‐52 wt % because of its selective reflection to visible light. The wavelength of the light that is selectively reflected shifts to the shorter wavelength, with increasing concentration. © 1993 John Wiley

ISSN:0021-8995    

DOI:10.1002/app.1993.070500405

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe deformation and fracture behaviors of hybrid‐particulate epoxy composites have been examined. These materials were based on a DGEBA/DDA matrix with various volume fractions of glass beads and different rubber contents. Young's modulus, yield stress, dynamic mechanical spectra, and fracture energy have been determined at room temperature. The Kerner model fits well the Young's modulus for the hybrid complexes with various glass bead contents. The analysis of the relaxation peak recorded from viscoelastic measurements allow us to discuss the influence of the introduction of the glass beads on the mobility of macromolecular chains and the characteristics of the rubber‐separated phase. The fracture energy displays a strong improvement and a synergism effect due to the presence of both kinds of particules. The toughening mechanisms were discussed. © 1993 John Wiley&Sons,

ISSN:0021-8995    

DOI:10.1002/app.1993.070500406

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

年代:1993

数据来源: WILEY

摘要:

AbstractPreparation and characterization of novel cycloaliphatic epoxy resins, which are derived from octadienyl compounds, were studied. From a model peracetic acid epoxidation reaction using 2,7‐octadienyl acetate‐1, the structure of the liquid resins is estimated to be mainly terminal epoxides and some amount of inner epoxide depending on the epoxide content. The epoxy resins offer lower toxicity and lower vapor pressure. The reactivity of the resin with acid anhydrides is moderate but faster than that of traditional cyclohexane epoxide‐type resins and slower than that of the glycidyl ester‐type resins. This reactivity was also examined using model compounds. The heat deflection temperature of the hexahydro‐phthalic anhydride‐cured resins is shown to be directly proportional to the number of epoxy groups in the molecules. The flexural strength of the cured resins is nearly equivalent to that of the commercial resins, although the flexural elongation of the resins is larger than that of the rigid cyclohexane epoxide‐type resins. The thermal stability of the cured resins is comparable to typical rigid cycloaliphatic resins; furthermore, high water resistance of the cured resins is suggested to be attributed to the hydrophobic character of the C8chain by cross‐linking. © 1993 John

ISSN:0021-8995    

DOI:10.1002/app.1993.070500407

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

年代:1993

数据来源: WILEY

摘要:

AbstractThermal shrinkage and the mechanical properties of oriented polypropylene‐polystyrene (PP‐PS) composites obtained byin situpolymerization of styrene in the oriented PP matrices were examined by the analysis of shrinkage stress curves and dynamic mechanical data. It has been shown that by changing the structure of the oriented matrices it is possible to control the properties of the obtained oriented composites. Some composites reveal an increased stability of the obtained oriented composites. Some composites reveal an increased stability of the molecular network at higher temperatures and the modulus of the material obtained from the matrix drawn at 90°C to the natural draw ratio is significantly increased. It is also shown that the differences between the untreated matrices and the PP component of the respective composites observed in the relaxation of the shrinkage stresses correspond very well with the differences seen in the mechanical loss in the frequency range of about 0.02 Hz. Such behavior suggests that similar molecular motions are involved both in the relaxation of shrinkage stresses and in this part of the mechanical loss. © 1993 John Wiley&Sons

ISSN:0021-8995    

DOI:10.1002/app.1993.070500408

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

年代:1993

数据来源: WILEY

摘要:

AbstractPreliminary investigations have been conducted on the graft copolymerization of meth‐ylmethacrylate onto Caesarweed fiber, initiated by potassium permanganate and the toluene redox system. The percentage graft yield increased with permanganate up to 132% in the concentration range, 1.0×10−2to 5.0×10−2M at 40°C. The effects of varying concentrations of toluene, acids, and monomer on graft yield were also investigated. Graft yield increased initially and then decreased on varying the concentrations of toluene from 2×10−2to 20×10−2M. The graft yield increased with temperature between 20 and 50°C. At 60°C, the graft yield decreased considerably by up to 60% of the value at 50°C. The calculated activation energies for the overall reaction, and for the initiation process, are 9.15 and 9.30 Kcal mol−1, respectively. © 1993

ISSN:0021-8995    

DOI:10.1002/app.1993.070500409

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

年代:1993

数据来源: WILEY

摘要:

AbstractHydroxytelechelic polybutadienes carrying covalently bound quaternary ammonium salts were successfully synthesized in three steps. The first one was the preparation of 1‐(N, N‐dimethylaminopropyl) 1,1,3,3‐tetramethyldisiloxane (M′2A) by hydrosilylation. The addition occurred mainly in the terminal position of the double bond, but isomers were formed in small proportion (an isomer resulting from an inverse addition and an isomer resulting from an isomerization of the double bond). The proportion of these isomers increased with the concentration of catalyst (H2PtCl6). Similar results were obtained with a Pt (0)‐di‐vinyltetramethyldisiloxane complex (Pt,DVDS). The second step was the grafting of M′2A onto the 1,2‐units of a hydroxytelechelic polybutadiene by hydrosilylation. The yield of the reaction was higher than 90% and the OH functionality decreased slightly. Here again, different platinum catalysts were compared: initial rates were higher with Pt,DVDS, but the final yields were better with H2PtCl6. The last step was the quaternization of the pendant tertiary amino groups in methanol with alkyl bromides from C8H17Br to C16H33Br. The yield of the reaction was higher than 90% and the OH functionality was not modified. © 1993 John

ISSN:0021-8995    

DOI:10.1002/app.1993.070500410

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

年代:1993

数据来源: WILEY