Latex - February 2010

This month we're looking at latex and latices, both natural and synthetic.

To the average man in the street, the term Latex means the natural milky substance harvested from trees and the thin, stretchy gloves that are made from it. However, those in the industry are aware that there are also many synthetic forms too which have a host of applications, including in paints, coating and adhesives. For both natural and synthetic latices, there are many areas for development, from how the latex is compounded and the manufacturing processes used, through to changing industry standards and potential new materials.

Abstracts

Please see below a selection of abstracts highlighted in the February Newsletter. These are records which relate to latex or latices that have been recently added to the Polymer Library.

Click on the 7-digit accession numbers to find out about ordering a copyright-cleared full text copy of the items shown.

1056278 - DANDELIONS COULD PROVE TO BE SOURCE OF HYPOALLERGENIC LATEX (short article)
Scientists at the Fraunhofer Institute for Molecular Biology & Applied Ecology are reported to have genetically modified the Russian dandelion to prevent rapid polymerisation upon harvesting of the plant. Latex from the plant has been shown not to cause allergic reactions in preliminary testing on humans and is considered a potential source of latex for medical applications. This is a short article.
APRI Journal, Dec.2009, p.5-6

1055758 - MALAYSIA'S LATEST NR GRADE FOR MEDICAL SECTOR IS PURER (short article)
It is briefly reported that the boycott of Malaysia's natural latex rubber gloves by the global medical sector, due to the protein allergy concerns, may come to an end soon. The Malaysian Rubber Board has introduced a new grade of deproteinised NR. Pureprena is produced by treating fresh natural latex with an industry enzyme that hydrolyses all naturally occurring proteins in the latex into water soluble forms. The difference in the new grade is that it contains 96% rubber hydrocarbons, compared to the 93% for commercial SMR grades. Removal of these non-rubber components makes the new grade suitable for specialised applications, other than rubber gloves, like the automotive sector. MRB is currently conducting trials and is looking at working with manufacturers in the pharmaceutical, food and medical products sectors as well. Features of rubber compounds based on Pureprena are the low creep and stress relaxation, making it suitable for use as joint rings, shock absorbers and suspension bushes. Its low water absorption property also makes it suitable for underwater applications, while the dynamic and ageing properties means that it is ideal for anti-vibration mountings.
Rubber Journal Asia, Dec.2009, p.1. This issue is published within Plastics and Rubber Asia, 24, No.170, Dec.2009

1055529 - ELABORATION OF STIMULI RESPONSIVE CORE-SHELL MAGNETIC LATEXES FROM OIL IN WATER FERROFLUID EMULSION
The development of temperature-sensitive highly magnetic latex particles was investigated. The particle core was a crosslinked polymer matrix containing iron oxide nanoparticles. The shell was a combination of highly crosslinked hydrophobic polymer and crosslinked stimuli-responsive hydrophilic polymer. The polymerisation was performed in two steps, i.e. the elaboration of seed magnetic latex particles for oil-in-water magnetic emulsion and the functionalisation of the obtained magnetic latices via seed polymerisation in the presence of water-soluble reactants. The obtained final core-shell latices exhibited an iron oxide content of above 50 wt. %, a size distribution governed by the size distribution of the used oil-in-water magnetic emulsion. The thermal sensitivity of the shell was due to the presence of poly(N-isopropylacrylamide). The cationic character of the outer layer shell was due to the use of cationic initiator and amino-containing monomer. 31 refs.
E-Polymers, No.139, 2009, pp.15, ISSN: 1618-7229
Pibre G; Hakenholz L; Braconnot S; Mouaziz H; Elaissari A

1055207 - HYDROGENATION OF NBR LATEX BY DIIMIDE REDUCTION USING SELENIUM CATALYSTS
Effective hydrogenation of a nitrile-butadiene rubber latex was carried out using a diimide in the presence of selenium catalysts, and the reaction was optimised with high numbers of carbon-carbon double bonds being reduced per atom of selenium. Gel formation was inhibited by the use of antioxidants, and the resulting hydrogenised NBR was characterised using nuclear magnetic resonance spectroscopy, infrared spectroscopy and optical emission spectroscopy. 20 refs.
Journal of Applied Polymer Science, 115, No.3, 5th Feb.2010 p.1390-1394, ISSN: 0021-8995, DOI: 10.1002/app.30818
Schulz G A S; Comin E; De Souza R F

1054971 - VYSTAR CORPORATION SET TO REVOLUTIONISE THE LATEX INDUSTRY WITH VYTEX NRL
Vystar has launched the superior Vytex Natural Rubber Latex (Vytex NRL) with protein levels minimised to undetectable levels with a revolutionary patented technology. This is highly encouraging news for the NR latex products makers the world over, healthcare professionals and workers in particular, who have been confronted with the vexed issue of latex protein allergy. The patented protein removal process involves adding aluminium hydroxide, a well-known protein binding chemical, to latex while it is still in liquid form. The company claims the key benefit is that it is achieving low protein levels in the raw material prior to production. Additionally, manufacturers' efforts to reduce protein through the leaching process contribute to achieving the distinctively low levels. Vystar and Alatech Healthcare are introducing the first consumer product made with Vytex NRL: the Envy condom. Vystar and Alatech have received 510(k) clearance from the US FDA to market and sell the first exam glove made from Vytex NRL. In addition, Vystar has more than 55 manufacturing trials worldwide for numerous products including catheters, foam mattresses, elastic threads, adhesives and surgical dressings.
Rubber Asia, 23, No.6, Nov.-Dec.2009, p.34/44
Kalamani T N

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