Electrophoretic Mobility Study of Fresh Hevea Latex

1954 ◽  
Vol 27 (2) ◽  
pp. 472-480 ◽  
Author(s):  
William W. Bowler
Keyword(s):  
Electrophoretic Mobility ◽  
Colloidal Particles ◽  
Mechanical Stability ◽  
Natural Rubber Latex ◽  
Direct Methods ◽  
Electrical Mobility ◽  
Rubber Latex ◽  
Mechanical Agitation ◽  
The Stability ◽  
Mobility Study

Abstract To both the producer of natural rubber latex and the manufacturer of latex goods, the stability of Hevea latex is one of its most important properties. Two aspects of this important property are the mechanical stability and the chemical stability. The former is measured by the sensitivity of latex to mechanical agitation, the latter by the sensitivity to addition of ionic material. Although there is no clear relation known to exist between these two stabilities, the electrical charge on the rubber particles is considered to be important in either case. Since electrophoretic mobility determinations furnish one of the most direct methods for studying the charge on colloidal particles such as those in rubber latex, the effect of seasonal and clonal variations, latex aging, ionic strength, pH, and the presence of added materials on the electrical mobility of fresh Hevea latex was studied. At the same time the mechanical stability of many latexes was measured in order to determine what correlation exists between mobility and mechanical stability.

Characterization of Lidocaine Transdermal Patches from Natural Rubber Latex

2013 ◽  
Vol 747 ◽  
pp. 103-106 ◽  
Author(s):  
Prapaporn Boonme ◽  
Hasleena Boontawee ◽  
Wirach Taweepreda ◽  
Wiwat Pichayakorn
Keyword(s):  
Drug Release ◽  
Natural Rubber ◽  
Physicochemical Properties ◽  
Rubber Tree ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Transdermal Patches ◽  
The Stability ◽  
Main Component

The mucous liquid of Hevea brasiliensis or Para rubber tree, called natural rubber latex (NRL), composes of cis-1,4-polyisoprene which can form a patch under suitable formulation. In this study, blank and 5% lidocaine-loaded NRL patches were formulated and then characterized for physicochemical properties as well as evaluated in vitro drug release and stability. The patches were observed for their appearances. Surface morphology of the patches was investigated using a SEM. XRD was employed to study the crystallinity of the drug, the patch, and the drug-loaded patch. The extractions of lidocaine-loaded patches were analyzed for drug contents by HPLC. In vitro drug release study was performed using modified Franz diffusion cells. The patches at initial preparation and after kept at 4, 25, and 45 °C for 3 months were investigated for the stability determination. The results suggested that NRL could be used as a main component in pharmaceutical transdermal patches with acceptable physicochemical properties. Lidocaine-loaded NRL patches provided desirable drug release but high storage temperatures could age the patches resulting in darken color and lower release amount.

scholarly journals INFLUENCE OF THE VOLATILE FATTY ACID CONTENT TO RADIATION VULCANIZED NATURAL RUBBER LATEX (RVNRL)

2012 ◽  
Vol 09 (17) ◽  
pp. 38-41
Author(s):  
Hugo David CHIRINOS ◽  
Sueli CARVALHO DE JESUS
Keyword(s):  
Fatty Acid ◽  
Natural Rubber ◽  
Acid Content ◽  
Volatile Fatty Acid ◽  
Fatty Acid Content ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Protein Layer ◽  
Physical Strength ◽  
The Stability

Natural rubber latex is a dispersion of natural rubber particles in water. These particles are coated with a protein layer which will stabilize the dispersion in water by forming an electric charge in the layer. Any different condition affecting this layer disturbs the stability of dispersion. Microorganism attack disturbs the protein layer and consequently the stability of the dispersion. By adding 1.2% by weight of NH3, the stability of the dispersion can be improved. The fresh latex was irradiated by Co-60 with irradiation dose of 10, 20, 30, 40 and 100 kGy. The results showed a relationship between the volatile fatty acid content (VFA, product from microorganism attack on carbohydrate) and the green strength or the physical properties of vulcanized film. Low VFA number showing a higher physical strength of the film either un-vulcanized or vulcanized. It appeared that the structure was responsible in yielding a good physical property of the film.

Reinforcement of Natural Rubber Latex Film by Starch Nanocrystal

2014 ◽  
Vol 543-547 ◽  
pp. 3886-3891 ◽  
Author(s):  
Yang Jian Shu Gao ◽  
Sen Zhao ◽  
Shuang Quan Liao ◽  
Lin Fang ◽  
Zhi Fen Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Acid Hydrolysis ◽  
Mechanical Stability ◽  
Natural Rubber Latex ◽  
Crosslinking Density ◽  
Latex Film ◽  
Latex Films ◽  
Rubber Latex ◽  
Starch Nanocrystals

Starch nanocrystals obtained from acid hydrolysis, and the starch/natural rubber latex film was prepared by blending the starch nanocrystals with natural rubber latex. The latex properties such as viscosity and mechanical stability, water and toluene uptake, crosslinking density and mechanical properties of the latex films were investigated. The results showed that the mechanical stability of natural rubber latex reinforced by starch nanocrystals increased, but the change of viscosity was not obvious. By adding starch nanocrystals in natural rubber latex, the swelling by toluene decreases and the swelling by water increased. The mechanical properties and crosslinking density of films were enhanced with the increase of starch loading.

Influence of hydrophobically modified inulin (INUTEC NRA) on the stability of vulcanized natural rubber latex

2014 ◽  
Vol 451 ◽  
pp. 90-100 ◽  
Author(s):  
Manroshan Singh ◽  
Jordi Esquena ◽  
Conxita Solans ◽  
Karl Booten ◽  
Tharwat F. Tadros
Keyword(s):  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Hydrophobically Modified ◽  
The Stability

A novel computer vision approach to classify the mechanical stability of natural rubber latex concentrate

2018 ◽  
Vol 12 (3) ◽  
pp. 323-334
Author(s):  
Ming Chieng Tan ◽  
Chee Seng Chan ◽  
Weng Kin Lai ◽  
Khoon Hee Chew ◽  
Ping Yong Chua
Keyword(s):  
Computer Vision ◽  
Natural Rubber ◽  
Mechanical Stability ◽  
Natural Rubber Latex ◽  
Rubber Latex

The Natural Higher Fatty Acid Soaps in Natural Rubber Latex and Their Effect on the Mechanical Stability of the Latex

1984 ◽  
Vol 57 (2) ◽  
pp. 243-253 ◽  
Author(s):  
Seong-Fong Chen ◽  
Chiew-Sum Ng
Keyword(s):  
Fatty Acid ◽  
Extraction Method ◽  
Surface Charge Density ◽  
Mechanical Stability ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Latex Particles ◽  
Rate Of Increase ◽  
Hydrolysis Of ◽  
Better Than

Abstract The natural HFA soaps present in ammoniated NR latex concentrates are derived from the hydrolysis of the saponifiable lipids on the surfaces of the latex particles. A method based on cold extraction of the soaps has been developed for determining the natural HFA soaps in freshly concentrated latices. This method is better than the hot extraction method, which has been shown to cause some hydrolysis of the lipids. The natural HFA soaps in NR latex increase with time and reach a constant value in 3 to 6 weeks. The rate of increase of the soaps is divided into two linear regions and is more rapid in the first 1 to 2 weeks. More than 92% of the natural HFA soaps are adsorbed on the surfaces of the latex particles. This results in an increase in the negative electrical surface charge density of the particles and causes an increase in the mechanical stability of the latex. In fact, the increase in log MST is linearly proportional to the increase in natural HFA soaps in the latex. After the natural HFA soaps become constant, further increase in MST value is likely to be caused partly by the oxygen from the air.

On the stability of natural rubber latex acidified by acetic acid and subsequent epoxidation by peracetic acid

1991 ◽  
Vol 27 (6) ◽  
pp. 557-563 ◽  
Author(s):  
Nguyen Viet Bac ◽  
Marin Mihailov ◽  
Levon Terlemezyan
Keyword(s):  
Acetic Acid ◽  
Natural Rubber ◽  
Peracetic Acid ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
The Stability
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