rubber division, acs - effect of oxygen on natural rubber latex

The University of British Columbia Log In | Register Please note: If you are a current RD member, you DO NOT need to sign in or create an account. Your access is granted as part of your dividsion membership. Please go to http://www.rubber.org/ to log in. Quick Search Go < Previous Next > Current Issue Available Issues ISSN: 0035-9475 Frequency: Quarterly Not Yet Registered? Benefits of Registration Include: A Unique User Profile that will allow you to manage your current subscriptions (including online access) The ability to create favorites lists down to the article level The ability to customize email alerts to receive specific notifications about the topics you care most about and special offers Register Now! (What is this?) Articles Citing this Article Google Scholar Search for Other Articles By Author E. M. Bevilacqua Previous Article Volume 38, Issue 5 (November 1965) Next Article Add to Favorites Share Article Export Citations Track Citations Permissions PDF Article Citation: E. M. Bevilacqua (1965) Effect of Oxygen on Natural Rubber Latex. Rubber Chemistry and Technology: November 1965, Vol. 38, No. 5, pp. 1214-1227. doi: http://dx.doi.org/10.5254/1.3547110 Effect of Oxygen on Natural Rubber Latex E. M. Bevilacqua 1 1 United States Rubber Company Research Center, Wayne, N. J. Abstract Natural rubber is exposed to oxygen from the time that trees are tapped through its vulcanization and final use. Reaction with oxygen at each stage in its history affects its properties. Extensive studies have been made of the effects in later stages, on raw and vulcanized rubber; much less work has been done on the oxidation of latex. Fresh latex is a dilute aqueous emulsion in which the non-volatile content is approximately 90 per cent rubber hydrocarbon. The rest is a complex mixture of compounds, most of which are normal constituents of plant sera. Rubber exists as high polymer in latex at tapping; in mature trees tapped for the first time, it is of high molecular weight and is extensively crosslinked. In normal commercial practice, when latex is withdrawn as fast as rubber is sythesized by the tree, rubber is essentially all linear high polymer of average molecular weight 10 5 to 10 6 . As soon as a tree is tapped the latex begins to change. In the short period between tapping and coagulation the changes are small and not usually significant when latex is used for the production of dry rubber. Changes in preserved latex continue over a long time and are significant in its use. Latex of commerce is preserved with ammonia, which serves the dual function of being toxic and controlling pH in a range where latex stability is high. It is sometimes supplemented with another biocide because of the desire to keep ammonia level as low as possible for the convenience of the final user. All Publications > Rubber Chemistry and Technology > November 1965 > Effect of Oxygen on Natural Rubber Latex Advanced Search Home Author Submissions Rubber Division Home Help Volume 38, Issue 5 (November 1965) Journal Information Register for a Profile Related Articles Journal Tools Rubber Division, ACS - Effect of Oxygen on Natural Rubber Latex http://rubberchemtechnol.org/doi/abs/10.5254/1.3547110 1 of 2 30/01/2013 9:16 AM

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Page 1: Rubber Division, ACS - Effect of Oxygen on Natural Rubber Latex

The University of British Columbia Log In | Register

Please note: If you are a current RD member, you DO NOT need to sign in or create anaccount. Your access is granted as part of your dividsion membership. Please go tohttp://www.rubber.org/ to log in.

Quick Search Go

< Previous Next >

Current IssueAvailable Issues

ISSN: 0035-9475Frequency: Quarterly

Not Yet Registered?

Benefits of Registration Include:

A Unique User Profile that willallow you to manage yourcurrent subscriptions (includingonline access)

The ability to create favoriteslists down to the article level

The ability to customize emailalerts to receive specificnotifications about the topics youcare most about and specialoffers

(What is this?)

Articles Citing this ArticleGoogle Scholar

Search for Other Articles By Author

E. M. Bevilacqua

Previous Article Volume 38, Issue 5 (November 1965) Next Article

Add to Favorites Share Article Export Citations Track Citations Permissions

PDF

Article Citation:E. M. Bevilacqua (1965) Effect of Oxygen on Natural Rubber Latex. Rubber Chemistry and Technology: November 1965, Vol. 38, No. 5,pp. 1214-1227.

doi: http://dx.doi.org/10.5254/1.3547110

Effect of Oxygen on Natural Rubber Latex

E. M. Bevilacqua 1

1United States Rubber Company Research Center, Wayne, N. J.

Abstract

Natural rubber is exposed to oxygen from the time that trees are tapped through its vulcanization and final use. Reaction withoxygen at each stage in its history affects its properties. Extensive studies have been made of the effects in later stages, onraw and vulcanized rubber; much less work has been done on the oxidation of latex. Fresh latex is a dilute aqueous emulsionin which the non-volatile content is approximately 90 per cent rubber hydrocarbon. The rest is a complex mixture ofcompounds, most of which are normal constituents of plant sera. Rubber exists as high polymer in latex at tapping; in maturetrees tapped for the first time, it is of high molecular weight and is extensively crosslinked. In normal commercial practice,when latex is withdrawn as fast as rubber is sythesized by the tree, rubber is essentially all linear high polymer of averagemolecular weight 105 to 106. As soon as a tree is tapped the latex begins to change. In the short period between tapping andcoagulation the changes are small and not usually significant when latex is used for the production of dry rubber. Changes inpreserved latex continue over a long time and are significant in its use. Latex of commerce is preserved with ammonia, whichserves the dual function of being toxic and controlling pH in a range where latex stability is high. It is sometimes supplementedwith another biocide because of the desire to keep ammonia level as low as possible for the convenience of the final user.

All Publications > Rubber Chemistry and Technology > November 1965 > Effect of Oxygen on Natural Rubber Latex Advanced Search

Home Author Submissions Rubber Division Home Help

Volume 38, Issue 5(November 1965)

Journal Information

Journal Tools

Rubber Division, ACS - Effect of Oxygen on Natural Rubber Latex http://rubberchemtechnol.org/doi/abs/10.5254/1.3547110

1 of 2 30/01/2013 9:16 AM