摘要:

AbstractThe stress cracking of polyethylene was studied under various experimental conditions, and the importance of the effect of both crystallinity and molecular weight of the polymer was established. Many of the variables were investigated, such as the thermal pretreatment of the sample, temperature of the sample, surface tension, and concentration of the stress‐cracking agent, and the magnitude of the stress. The importance of this test procedure and the relationship that exists between the stress cracking of polymers and between similar problems affecting nonpolymeric systems have been analyzed. Some microscopic studies of stress cracking have also been mad

ISSN:0021-8995    

DOI:10.1002/app.1962.070061901

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

年代:1962

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1962.070061916

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

年代:1962

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1962.070061917

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

年代:1962

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1962.070061918

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

年代:1962

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1962.070061919

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

年代:1962

数据来源: WILEY

摘要:

AbstractThe reversible reaction with di‐hydrazides in acidic solution or polyamines in alkaline solution is used to cause synthetic polymers containing labile carbonyl groups to gel with sharp thermoreversibility in dilute water solution. Some of the polymers described contain active methylenes, for example, partially acetoacetylated polyvinyl alcohol and polyethylenimine, and copolymer of allyl acetoacetate with acrylamide. These polymers function also as couplers for azo and azomethine dye formatio

ISSN:0021-8995    

DOI:10.1002/app.1962.070061902

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

年代:1962

数据来源: WILEY

摘要:

AbstractThe properties of chlorinated and chlorosulfonated ethylene polymers and copolymers have been examined. The effect of such variables as polymer chain structure, molecular weight, degree of chlorination, and chlorination conditions was studied. A variation in physical properties of different polyolefins chlorinated to the same degree is attributed to differences in residual crystallinity in the chlorinated product. Chlorinated linear polyethylenes are more crystalline than chlorinated branched polyethylene and are semicrystalline, flexible plastics in the 15–35 wt. % range. The chlorinated branched polyethylenes of this chlorine content are soft and rubbery. Chlorination conditions can influence the degree of residual crystallinity in the chlorinated product, and hence have a pronounced effect on the properties of the products Molecular weight of the polymer and degree of chlorination influence the properties of the chlorinated product. Chlorosulfonated linear ethylene polymers and copolymers were tested as elastomers. Stress‐strain properties were better for the chlorosulfonated linear copolymers as compared to chlorosulfonated linear polyethylene or branched polyethylene. Poor residual elongation was characteristic of the chlorosulfonated linear polymers. An increase in the number of side groups in the basic polymer chain did not affect residual elongat

ISSN:0021-8995    

DOI:10.1002/app.1962.070061903

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

年代:1962

数据来源: WILEY

摘要:

AbstractAlthough the necessary conditions are known for formation of tough films from polyurethane intermediates, the chemistry is too complex to allow certain predictions of how variances in the polymerization process effect molecular structure and polymer properties. This research examined the hope that a correlated study of solubility and mechanical behaviors might show the effect of different catalysts and environments on crosslinking or other structural features which can modify film quality. Films (0.01 in. thick) were cast on mercury of intermediates derived from reaction in solvent of 2 moles of diisocyanate per mole of hydroxyl terminated polyesters, catalysts likeN‐methylmorpholine, methyldiethanolamine, and cobalt and/or lead ions being used to promote film‐forming reactions. The films, when dry, were aged at different levels of temperature and humidity. The solubility behavior was rated by measuring swelling ratios, rates of extraction, and intrinsic viscosity of extracts. Mechanical properties were rated by measuring tensile and stress relaxation behavior. The stress‐induced microstructure and fracture process were observed microscopically in a few typical specimens. The data support the theory that hydrogen bonding provides a strong crosslinking mechanism which dominates even the effects of moderate covalent crosslinking. Polymers derived from the same intermediates show very similar mechanical properties, even though significant differences in solubility properties suggest variances in other details of molecular stru

ISSN:0021-8995    

DOI:10.1002/app.1962.070061904

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

年代:1962

数据来源: WILEY

摘要:

AbstractThe thermal stability of a variety of derivatives ofs‐triazine, benzene, and borazine was determined with an isoteniscope. For thes‐triazines the order of stability was found to be aryl triazines>aryl melamines and benzoguanamines>methyl melamines>higher alkyl melamines>aryl cyanurates and thiocyanurates (with the exception of fluoroalkyl cyanurates). The borazines were poorer than the melamines but better than the cyanurates. Several diand trifunctional linking groups were used to connect biphenyl groups which were known to be stable (from previous studies ofp‐quaterphenyl and polyphenyl ethers). The order of stability was found to be phosphate ≅ phosphine oxide ≅ ether>ester>amide>

ISSN:0021-8995    

DOI:10.1002/app.1962.070061905

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

年代:1962

数据来源: WILEY

摘要:

AbstractThe dynamic properties of a natural vulcanized rubber containing carbon black were studied for dynamic tensions of amplitude varying greatly. It was shown that both the elastic responses and viscosity change with amplitude of oscillation and with concentration and type of carbon black. The effects of thermal treatment on the dynamic modulus were also studied. Beginning with conditions of equilibrium between the hard and soft regions of the vulcanizate for very weak stresses, the values for the formation of hard regions from soft regions were determined by means of the Van't hoff isochore.

ISSN:0021-8995    

DOI:10.1002/app.1962.070061906

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

年代:1962

数据来源: WILEY