november

ArticlesFeaturedLatex and Natural Rubber

Electrically conductive elastomers based on NR and polyaniline

Natural rubber is an electrically insulating material, but introduction of conductive fillers like carbon based materials (carbon black, graphite, carbon nanofibers or nanotubes) or metal fillers can increase the conductivity of the resulting composite. These materials are frequently used for electromagnetic/radiofrequency interference (EMI/RFI) shielding, and laboratory and military uses.

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Preparation of polypropylene and skim natural rubber/thermoplastic natural rubber blends: Determining processing conditions

Centrifuged latex production in Sri Lanka contributes over 25% of the country’s annual total rubber production. This share is an increasing trend, when the production figures for the last decade are considered. During the centrifugation process, concentrated or creamed latex with dry rubber content of 60% is separated as centrifuged latex, and 5% to 10% of rubber available in the field latex is removed as the diluted fraction. It has 3% to 5% dry rubber content and a high amount of non-rubbers. This diluted fraction is known as skim latex, and the rubber extracted from acid coagulation of skim latex is referred to as skim natural rubber (SNR).

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Post International Elastomer Conference Show Daily

This follow-up to the 2021 International Elastomer Conference and Expo, held last month in Pittsburgh, Pennsylvania, and
published for the Rubber Division, ACS by Lippincott & Peto, Inc., includes photographs and summaries of IEC events, including the 2022 Science & Technology Award winners, Rubber Division, ACS
service award recipients, 2021 scholarship and Rubber Technology Training Award recipients, the Experience Elastomers
Student Outreach Program, the Rubber Division’s 2021-2023 Strategic Plan, the inaugural Rubber Chemistry & Technology Excellence Award and Expo exhibitors.

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ArticlesFeaturedLatex and Natural Rubber

Mechanism of oxidation in natural rubber compounds at lower (ambient) temperatures

The oxidation mechanism of natural rubber was studied using several techniques. In a prior article, it was found that the crosslink distribution (sulfur types including polysulfidic, disulfidic and monosulfidic) in a belt coat (conventional cured natural rubber compound) had a different crosslink distribution, depending on the aging temperature (ref. 1). The belt coat compound extracted from an oven aged (65°C) tire was compared to the belt coat compound extracted from a normal service tire (23°C, the average annual temperature in Phoenix, AZ)

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ArticlesFeaturedLatex and Natural Rubber

Homegrown bioelastomers: A sustainable opportunity

It has been estimated that there are 2,500 plants that can produce a natural latex: a bioelastomer. Of course, not all of them can produce a polymeric latex with a high molecular weight, readily processable and commercially viable. To date, three species account for the majority of interest associated and centered
around the discussion of natural latex: Hevea rubber trees (Hevea brasiliensis), guayule (“why-yule-ee,” Parthenium argentatum) and rubber dandelion (Taraxacum kok-saghyz). The rubber tree, typically found in tropical Southeast Asia, produces nearly 90% of the world’s natural latex. Guayule (a desert shrub) and rubber dandelion are plants found in more temperate regions in the U.S., and figure to be potential domestic sources of natural rubber and latex.

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