摘要:

AbstractThe development of crystallinity and orientation during the melt spinning of nylon 66 was investigated. Nylon 66 was found to crystallize in the spinline to form the Bunn‐Garner α‐triclinic structure. This behavior differs from that of nylon 6. Nylon 66 was found to develop lower crystalline orientation than nylon 6 under comparable spinning condit

ISSN:0021-8995    

DOI:10.1002/app.1978.070221201

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

年代:1978

数据来源: WILEY

摘要:

AbstractFormation of peroxides on cellulose derivatives such as fibrous carboxymethyl cellulose, acrylic acid‐grafted cellulose, and aldehyde cellulose with the use of hydrogen peroxide was investigated. Formation of peroxides was observed for each cellulose derivative with the reaction at 25°C and the amount of formation was related closely to the carboxyl or carbonyl contents in the samples. The peroxides were fairly stable in wet samples at low temperatures, but almost all peroxides were decomposed at 60°C. When the cellulose peroxides were warmed with water, hydrogen peroxide separated from the cellulose peroxides into an aqueous medium. The structure of the peroxides formed on the cellulose derivatives is discussed on the basis of the experimental resu

ISSN:0021-8995    

DOI:10.1002/app.1978.070221202

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

年代:1978

数据来源: WILEY

摘要:

AbstractSynthesis of novel metal‐containing cured polyesters was investigated by the reaction of divalent metal salts of mono(hydroxyethyl) phthalate–bisester anhydride–monoepoxide. As the bisester anhydride, ethylene glycol bis(trimellitate) dianhydride (ETDA), diethylene glycol bis(trimellitate) dianhydride (DETDA), and polyethylene glycol bis(trimellitate) dianhydride (PETDA) were used. They were prepared from trimellitic anhydride and glycols. Phenyl glycidyl ether was the monoepoxide used. In the reactions, the Mg salt showed considerably higher catalytic activities than the Ca salt. As for the physical properties of the cured resins, heat distortion temperature, Rockwell hardness, and compressive strength decreased in the order ETDA>DETDA>PETDA. Generally, the resins containing Mg showed better physical properties than those containing Ca. Resistance to chemical attack and boiling water, thermal behavior, and electrical resistances are also disc

ISSN:0021-8995    

DOI:10.1002/app.1978.070221203

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

年代:1978

数据来源: WILEY

摘要:

AbstractGamma‐ray‐induced graft copolymerization of butadiene with vinyl monomers onto PVC was attempted to improve the physical properties of PVC. The Izod impact strength was increased from 2 kg·cm/cm2to more than 100 kg·cm/cm2by grafting ca. 10% butadiene. But the tensile strength and melt flow were decreased by the grafting. The electron micrograph showed that the mass of polybutadiene in the graft copolymer had a convenient diameter (0.1–1 μ) for absorbing the impact energy. The weatherability of PVC grafted with butadiene was improved by cografting of butadiene with acrylates and methacrylates which had long sid

ISSN:0021-8995    

DOI:10.1002/app.1978.070221204

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

年代:1978

数据来源: WILEY

摘要:

AbstractPoly(acrylic acid) and poly(methacrylic acid) homopolymers, copolymers, and 1‐μ‐thick films have been converted in high yield to their corresponding cyclic imide derivatives by anin situgas–solid phase reaction at 200°C with ammonia, methylamine, and ethylamine, respectively. Under similar reaction conditions with H2S or CH3SH as the reactive gas, sulfur was incorporated into the polymers in low yield. Under UV and electron beam irradiation, these cyclic derivatives degraded with main chain scission to eliminate isocyanic acid or alkyl isocyanate and to form olefins and ketenes. Poly(diacrylimide) was the exception and crosslinked. The poor solubility in organic solvents and the very high solubility in aqueous solutions of base limited the use of these films as positive resists. However, poly(methyl methacrylate) copolymers, containing 20%–25% cyclic groups, exhibited adequate solubility and sensitivity to be utilized as lithographi

ISSN:0021-8995    

DOI:10.1002/app.1978.070221205

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

年代:1978

数据来源: WILEY

摘要:

AbstractPhoto‐induced polymerization of methyl acrylate vapors on polyamide and polyester fibers occurred when these fibers were wetted with the polar solvents methanol, N,N‐dimethylformamide, or dimethyl sulfoxide (neat or in aqueous solution). Polymer grafting was accompanied by homopolymer formation, with the amount of grafting and ratio of grafting to homopolymerization being dependent on the fiber type, the solvent used to wet the fiber, and the amount of water present in the wetting solution. Overall deposition of polymer was higher on polyamide than on polyester under all wetting conditions. Water present in the wetting agent had a limited effect on polymerization of poly(methyl acrylate) on polyamide, whereas water caused a rapid decrease in polymerization on polyester. The nature of polymer grafting on the fibers under various wetting conditions was examined by scanning electron microscopy and tensile property measurements, and the mode of polymer deposition was outlined in light of our findi

ISSN:0021-8995    

DOI:10.1002/app.1978.070221206

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

年代:1978

数据来源: WILEY

摘要:

AbstractPolyethylene film synthetized with a randomly distributed14C marker, was exposed to biodegradative impact by cultivated soil, a mixed culture of three wood rot fungi, andFusarium redolens, isolated from soil experiments. The net values of14CO2evolution obtained by scintillation measurements amounted for about 0.5% in two years when calculated as a percentage of the total amount of radioactivity in the test sample. Both the soil and the different mold cultures reflected with very good agreement a definite liberation of14CO2from the14C‐labeled polyethylene film, significantly above that produced abiotically from aging samples. This is interpreted as due to an enzymatic cleavage and oxidative conversion of synthetic polymeric or oligomeric alkanes with limited chain length, accessible for biodegradation. Abiotic parallel experimental series maintained in a similar way, but either on distilled water only, or on media completed with silvernitrate in order to inhibit microbial growth, revealed slow but consequently progressing—evidently nonenzymatic—conversion of14C to14CO2. This is referred to as a borderline case of as unarrestable tardy mineralization process in the absence of light, however, autocatalytic and oxidative, an aging procedure in restricted

ISSN:0021-8995    

DOI:10.1002/app.1978.070221207

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

年代:1978

数据来源: WILEY

摘要:

AbstractIn model experiments based on aerated cultures of molds likeFusarium redolens,14C liberated from randomly labeled pulverized high‐density linear polyethylene (HPDE) with a specific surface of 10 m2/g appeared mainly in the form of respiratory14CO2. The quantity liberated in this case was slightly greater than that stemming from HDPE film, according to our previous report (0.56% by weight against less than 0.40%). Contaminations could be detected, especially after two years aeration in several culture jars. Two unidentified bacterial strains as well asAcremonium kiliense, Aspergillus versicolor, andVerticillium lecaniiwere all thriving on the sparse media and enhanced to some extent the degradative14CO2liberation, especially in mixed cultures together withF. redolens. Repeatedly close coincidence in14CO2development between experiments with somewhat shifting mixed microbial populations point to preference for test with mixed microbial cultures instead of one single pure culture. Such tests should, however, be based on species more likely to utilize hydrocarbons then the celluloses metabolizers often applied for test of plastics according to several internationally accepted prescriptions. Increased liberation of14CO2with decreasing particle size indicate that the accessibility of the metabolizable fractions of polyethylene must affect the degree of biodegradation. This is because with an increased surface/volume ratio in the plastic powders of decreasing mesh, more and more structurally hidden low molecular polyethylene material can be released and thus rendered accessible to the enzymes of attacking fungal hyphae. Also the possibility of an increased autooxidative scission of some of the long polymeric chains due to a “mastication effect,” as well as an autocatalytic type of oxidative deterioration caused by remnants of the silico‐alumina supported CrO3primary polymer catalyst must be considered in this connection, especially with regard to the general phenomenon of abiotic aging in the dark which was consistently registere

ISSN:0021-8995    

DOI:10.1002/app.1978.070221208

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe reaction of metallocenes with solutions of polydienes and halogenated polymers, under Friedel‐Crafts conditions, has now been applied to the surface modification of solid polymer films. The reaction of ferrocene with chlorinated polyethylene films appears to proceed by a fast substitution step followed by a slower diffusion‐controlled step. The stress–strain curves of surface‐modified films, as well as of solution‐cast polymetallocene films, have been examined by means of a bursting‐strength apparatus. The weathering behavior of metallocene‐modified polymers has been studied in both natural and accelerated conditions. Studies on the effect of ageing on composition and properties by spectrophotometric and mechanical measurements indicate that the photooxidative resistance of polymers is improved significantly by metallocene modification. Additionally, modified films have been found to be effective as clear shields for the protection of vulnerable substrates against photodegradation. The observed darkening of the irradiated films could be due to a thermal reaction between metallocene and photolytically generated m

ISSN:0021-8995    

DOI:10.1002/app.1978.070221209

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of internal scattering on the color of dyed fabrics is calculated with the help of a highly simplified model. The predictions agree, at least qualitatively with observation. If an internally scattering fiber is ring‐dyed then at lower values of the product of the coefficient of extinction and dye concentration (25–250) it is lighter than a homogenously dyed fiber but at higher values of that product it is dar

ISSN:0021-8995    

DOI:10.1002/app.1978.070221210

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

年代:1978

数据来源: WILEY