Making a green rubber stamp: emerging dynamics of natural rubber eco-certification

The Cyclization of Natural Rubber

The effects of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber (NR) was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl4). Iodometric titration show, with 8% SnCl4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of c...

[Medical rubber stamp: a legal necessity or an informal imposition?].

1 M.D., Professor of the Forensic Medicine, Medical Ethics, and Social and Work Medicine Department of Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil 2 Ph.D. in Odontological Sciences Professor of Universidade Santa Cecília, São Paulo, SP, Brazil 3 Ph.D. in Preventive Odontology– Professor of post-graduation in Forensic Medicine of Universidade de São Paulo – USP, São P...

Natural Rubber Latex Allergy

Natural rubber latex allergy.

Immediate hypersensitivity to natural rubber latex (NRL) has become increasingly common during the last 20 years. It is currently one of the most frequently encountered occupational diseases among the healthcare workers and a problem even in other occupations where protective gloves are used. Several groups at high risk for developing NRL allergy have been defined, including healthcare workers ...

Natural rubber-clay nanocomposites

The mechanical properties of non-vulcanized natural rubber and dialyzed natural rubber-clay nanocomposites have been studied by uniaxial deformations to evaluate the reinforcement efficiency of the clay. We show that while non-rubber molecules contribute to auto-reinforcement, removal of these molecules improves significantly the performance of clay as reinforcement agent. These mechanical prop...