摘要:

AbstractThe dynamic loss energy measurements for characterizing adhesion using Vibron DDV‐II have been applied to the tire cord–rubber composite system, and the relationships between these dynamic measurements and static adhesion test (H‐block pull test and strip peeling test) were also investigated. Tested samples were the commercial nylon 66 tire cord and poly(ethylene terephthalate) tire cord with two adhesive systems. The degree of adhesion (adhesion factor) was obtained as the energy dissipation at the tire cord‐to‐rubber interface as measured by dynamic testing. It was shown that energy dissipation is increased at the filament–matrix interface when the composite is subjected to continuous cyclic loading if a condition of poor adhesion exists. The test was based upon the separation of the total energy dissipation in a composite under cyclic loading into a portion associated with viscous properties of the constituent materials and a second portion resulting from the lack of perfect bonding in the interfacial regions. The strip peeling measurement of adhesion exhibited an approximately linear correlation with the dynamic loss energy measurement of adhesion. The dynamic energy loss measurement is suggested as a potential source of information on the rheological characteristics of the interfacial region

ISSN:0021-8995    

DOI:10.1002/app.1973.070170301

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

年代:1973

数据来源: WILEY

摘要:

AbstractMorphologic studies of gas‐filled polyethylene show a characteristic void structure, with an interior region containing distinct gas bubbles surrounded by a surface layer of void‐free polymer. The voids in the bubbled region frequently show an elongated shape with the long dimension oriented parallel to the surface of the specimens. The gas–polymer interface within individual voids is composed of fibrils of the polymer extending into the interior of the void. Studies of the annealing temperatures required to obtain gas bubbles in the material and of the melting range of the ungasified polymer indicate that melting of the crystalline component of polyethylene is required for void form

ISSN:0021-8995    

DOI:10.1002/app.1973.070170302

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe mechanical properties of gas‐filled polyethylene have been studied for material with density greater than about 0.85 g/cm3. The effect of gasification on the tensile properties of both high and low density polyethylene beyond a certain critical density reduction is to cause a general weakening of the material. The yield stress falls by about 25% over the range of density investigated, while the elongation to fracture decreases by an order of magnitude. A mechanism is proposed to this weakening and for the yielding and fracture phenomena observed for gasified polyethylen

ISSN:0021-8995    

DOI:10.1002/app.1973.070170303

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

年代:1973

数据来源: WILEY

摘要:

AbstractBirefringence–temperature behavior at constant stress during cooling and heating of styrene–butadiene and ethylene–propylene copolymers between −120°C and +60°C was investigated. Copolymer composition, thermal treatment, and stress levels were shown to have a pronounced effect on the photoelastic p

ISSN:0021-8995    

DOI:10.1002/app.1973.070170304

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe efficacy of oxidatively crosslinked starch xanthate for improving wet‐ and dry‐strength properties of paper prompted the present study of an alternative, interpolymeric crosslinking procedure. Sodium starch xanthate of degrees of substitution 0.05–0.25 was reacted with a commercial paper additive (a polyamide–polyamine–epichlorohydrin wet‐strength resin) which was found to contain 3‐hydroxyazetidinium chloride, epoxy‐propyl, and chlorohydrin groups (3:1:1) to give an interpolymer crosslinked by both ionic and covalent bonds. Model systems, in conjunction with nuclear magnetic resonance, infrared, and ultraviolet spectral data, served to elucidate reaction mechanisms and structures of the interpolymer and the commercial resin. Reaction conditions that favored formation of either ionic (polysalt) or covalent (xanthate ester) crosslinks were investigated. In preliminary evaluations, incorporation of the interpolymer into paper handsheets resulted in excellent wet‐ and dry‐st

ISSN:0021-8995    

DOI:10.1002/app.1973.070170305

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

年代:1973

数据来源: WILEY

摘要:

AbstractA study of the crystallization of poly(vinylidene chloride) from dilute solution in various solvents was carried out. The temperature at which the polymer dissolved was dependent on crystallization history. The minimum solution temperature obtained by recrystallization at high undercooling and redissolving is the preferred parameter for characterizing solvents for poly(vinylidene chloride).

ISSN:0021-8995    

DOI:10.1002/app.1973.070170306

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe incorporation of electron‐donating components such as mono‐, di‐, and triethanolamines into the thionine photoredox system was tried (1) by copolymer preparations containing the acrylamidomethylthionines and triethanolamine monoacrylic ester as components, (2) by the reaction of triethanolamine and thionines with the N‐hydroxy‐methyl group in polymer in an acid medium, and (3) by the reaction of mono‐ or diethanolamine and thionines with the N‐hydroxymethyl group. The photochromic behavior incorporated into the polymer chain are as effective as their monomeric equivalents, to the extent that the sensitivity is among the highest so far

ISSN:0021-8995    

DOI:10.1002/app.1973.070170307

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

年代:1973

数据来源: WILEY

摘要:

AbstractA differential conductimetric apparatus allowing the continuous titration of HCl carried by a stream of gas with a limit sensitivity of 40 nanograms is described and applied to study the initial steps of poly(vinyl chloride) thermal degradation. The powdered sample is placed in a quartz cell which may be closed and detached and placed at a chosen time interval in a reflexion diffuse UV spectrometer. The dehydrochlorination process begins just aboveTg; the isotherms under argon show, after a variable time, a steady state with a zero order and an activation energy of 22 kcal. For a dehydrochlorination ratio (DR) less than 1000 ppm, the shape of the UV visible spectrum does not depend on the DR, and for the same DR it does not depend on the degradation temperature. A plot of the reflectance ratio versus the DR shows a coloration process in two steps: a rapid step followed by a slower step. The phenomenon, which does not depend on the physical state of the sample, tends to disappear if the amount of polymer is lowered and if the rate of flow of the gas is increased. It suggests that the HCl formed upon the dehydrochlorination process remains partly dissolved in the polymer. Further proof of the dissolution of HCl in the polymer is given, and a through method of titration is proposed. It is suggested that the initial steps of the dehydrochlorination follows an ionic mechanism, and might be partially reversible and diffusion controlled, although the autocatalysis which involves a rather high dehydrochlorination ratio and the presence of a large amount of dissolved HCl might initiate the radical process.

ISSN:0021-8995    

DOI:10.1002/app.1973.070170308

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe anisotropic characteristics of injection‐molded flat rubber sheets were investigated. The shrinkage and mechanical properties were measured in two directions: parallel and perpendicular to the flow direction. The results showed that (1) the shrinkage in the parallel direction is larger than that in the perpendicular direction, (2) such anisotropic shrinkage increases with the increase of vulcanization temperature and flow distance, (3) similar anisotropy was also noticed in 300% modulus, tensile strength, and elongation. Two kinds of orientation, “shear orientation” and “expanded orientation,” were observed. The former occurs by plug flow, and the latter by the expansion of the materials. The shrinkage was independent of the expanded orientation but was strongly associated with the shear orientation, while the mechanical properties were affected by the expanded or

ISSN:0021-8995    

DOI:10.1002/app.1973.070170309

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

年代:1973

数据来源: WILEY

摘要:

AbstractThe effects of the depositing condition in column fractionation of isotactic polypropylene were studied in detail. A good fractionation was accomplished not only in selective but also in nonselective deposition. Furthermore, it was found, in opposition to Kenyon's opinion, that the polymer was not spread uniformly over the support, but deposited onto the support in the state of particles and that fractionation was not successful in the case of large particles. From these facts, the particle size is regarded as an important factor to attain good fractionation of isotactic polypropylene.

ISSN:0021-8995    

DOI:10.1002/app.1973.070170310

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

年代:1973

数据来源: WILEY