ISSN:0021-8995    

DOI:10.1002/app.1961.070051418

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

年代:1961

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1961.070051420

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

年代:1961

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1961.070051421

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

年代:1961

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1961.070051422

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

年代:1961

数据来源: WILEY

摘要:

AbstractAn instrument for the measurement of the adhesion of organic coatings has been developed. It is based on the formation of a blister by injecting a liquid (generally mercury) under pressure between the coating and the substrate. The work of detachment, i.e., the energy needed to detach 1 cm.2of coating, is determined by recording the liquid pressure as a function of the injected volume and computing the area under this curve. Extraneous factors such as deformation of the film and compressibility of the liquid are eliminated through a blank run. The design and operation of the instrument are described, an evaluation of its performance and limitations is given, and examples of its application are presented. The method should be useful for accurate measurement of adhesion of many types of surface coatings to metal and, possibly, to other substrates, as well as for studies of the various factors that influence adhesion.

ISSN:0021-8995    

DOI:10.1002/app.1961.070051401

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

年代:1961

数据来源: WILEY

摘要:

AbstractIn the present work a wide variety of nonionic emulsifiers and anionic/nonionic blends of emulsifiers were evaluated in the emulsion polymerization of vinyl acetate and styrene. It was found that the emulsion stability and other polymer emulsion properties are often dependent upon a certain property of the emulsifier known as the HLB value. It has been shown elsewhere that the HLB value can be correlated with a fundamental physical property of the system oil–water–emulsifier, namely, the spreading coefficient of the internal phase liquid on the surface of a 1% solution of the emulsifier in the external phase. In the emulsion polymerization of styrene, good emulsion stability coupled with adequate conversion rate was obtained in an emulsifier HLB range of 13 to 16. For certain emulsifier blends it was found that emulsion viscosity and emulsion particle size were strongly dependent on the HLB of the emulsifier. Similar comments apply to vinyl acetate polymerization, except that the most stable emulsions were obtained with emulsifiers in an HLB range from 14.5 to 17.5. These observations on preferred HLB range apply only to nonionic emulsifiers and anionic/nonionic emulsifier blends, which were the emulsifier types screened in the present investigation. For both styrene and vinyl acetate the most generally satisfactory emulsion properties were obtained in the present work by the use of an anionic/nonionic emulsifier blend (G‐3300/G

ISSN:0021-8995    

DOI:10.1002/app.1961.070051402

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe dependence of grafting on the type of initiator has been examined in the case of three polymer–monomer systems: polystyrene–methyl methacrylate, polymethyl methacrylate–vinyl acetate, and polyethyl α‐chloroacrylate–vinyl acetate. The different initiators used in these experiments were benzoyl peroxide (Bz2O2), azobisisobutyronitrile (AIBN), di‐tert‐butyl peroxide (DTBP), andtert‐butyl hydroperoxide (TBHP). In each case the graft copolymers were separated from the homopolymers by fractional precipitation or by extraction. In the case of the system polystyrene–methyl methacrylate, an appreciable degree of grafting as well as formation of graft copolymer occur in the presence of Bz2O2; in contrast, the grafting is low with DTBP and doubtful with AIBN. For the other two systems no noticeable differences occurred as function of the initiator. In the case of polyethyl α‐chloroacrylate the amount of graft copolymer is exceptionally high owing to the sensitivity of this polymer to a radical attack; this sensitivity results in the partial insolubility of the graft copolymers in the presence of TBHP and DTBP, but not in

ISSN:0021-8995    

DOI:10.1002/app.1961.070051403

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe relationship of intrinsic viscosity [η] to the weight‐average molecular weight M̄wof polydimethylsiloxane in toluene at 25°C. has been determined. The modified Staudinger equation, [η] =KM̄wa, withK= 2.43 × 10−5anda= 0.84, describes the relationship for the above polymers in the range of weight‐average molecular weight from 18,900 to 124,500 (as determined by light‐scattering measurements). These constants differ from the values reported by Barry, whereK= 2 × 10−4anda= 0.66 were obtained. The difference is attributed to the fact that Barry dealt with number‐average rather than weight‐aver

ISSN:0021-8995    

DOI:10.1002/app.1961.070051404

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

年代:1961

数据来源: WILEY

摘要:

AbstractA new synthetic elastomer has been obtained based on an ethylene‐propylene copolymer prepared using an organometallic catalyst system. Reactive sites (phosphonyl dichloride groups) are placed on the copolymer chain by treating the polymer with phosphorus trichloride and oxygen. After hydrolysis or alcoholysis of the phosphonyl dichloride groups to phosphonic acid or phosphonic acid esters, vulcanization may be carried out by reaction with metallic oxides, particularly lead oxide. Vulcanizates of the polyolefin elastomer have outstanding resistance to heat, ozone, and oxygen, and have excellent electrical properties. This combination suggests the use of this material in high temperature electrical application

ISSN:0021-8995    

DOI:10.1002/app.1961.070051405

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe cellulose of cotton yarns was reacted with acrylonitrile under conditions preventing their longitudinal contraction. Changes taking place in the fine structure of the fiber were studied by means of optical microscopy, density measurements, x‐ray diffraction, and thermal stress behavior measurements. The results indicate that in spite of the strong tensions developed in the yarns, the reaction proceeds in both the accessible and the crystalline regions with considerable volume expansion and eventual disappearance of crystalline structure. Suggestions of a glass transition temperature appear at substitutions slightly above D.S. = 1. Annealing becomes possible at substitutions above D.S. = 2 with the development of the cyanoethyl cellulose crystal structure and over 40% increase in tensile strength. Changes in tenacity, ultimate elongation, energy of rupture, and immediate elastic recovery were also observe

ISSN:0021-8995    

DOI:10.1002/app.1961.070051406

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

年代:1961

数据来源: WILEY