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

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.

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Effect of Storage Conditions on the Properties of Latex. I.

Rubber Chemistry and Technology ◽

10.5254/1.3542652 ◽

1956 ◽

Vol 29 (4) ◽

pp. 1502-1508 ◽

Cited By ~ 1

Author(s):

H. M. Collier

Keyword(s):

Natural Rubber ◽

Acid Content ◽

Ammonium Acetate ◽

Mechanical Stability ◽

Natural Rubber Latex ◽

Storage Conditions ◽

Rubber Latex ◽

Air Space ◽

Stability Time

Abstract Working with ammonia-preserved natural-rubber latex, concentrated by centrifuging, the author shows that the slight fall in mechanical stability associated with the shipment of bulk supplies of latex can be explained by the fact that, during shipment, latex does not have access to the oxygen of the air. The mechanical stability of samples taken at the time of shipment increased in value when there was an appreciable air-space in the storage bottle, but fell when the bottle was full and air was excluded. These differences were accentuated when air was replaced by oxygen and was then possible to find marked differences not only in mechanical stability time but also in the volatile fat acid content of the latexes. The increase of volatile fat acid content of the samples stored in the absence of air was much greater than in the sample stored in the presence of oxygen. The fall of mechanical stability in the absence of air is ascribed to the formation of increasing quantities of salts, such as ammonium acetate. In the presence of oxygen, the rate of formation of salts of this type is very much less, and at the same time other changes take place which lead to a marked increase of mechanical stability.

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Natural rubber latex concentrate. Determination of mechanical stability

10.3403/02998846 ◽

2004 ◽

Keyword(s):

Natural Rubber ◽

Mechanical Stability ◽

Natural Rubber Latex ◽

Rubber Latex

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Alternative Methods for Accelerating Mechanical Stability of Concentrated Natural Rubber Latex

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.382.26 ◽

2018 ◽

Vol 382 ◽

pp. 26-30 ◽

Cited By ~ 1

Author(s):

Dechnarong Pimalai ◽

Yodsathorn Wongngam ◽

Cattaleeya Pattamaprom

Keyword(s):

Natural Rubber ◽

Colloidal Stability ◽

Mechanical Stability ◽

Natural Rubber Latex ◽

Negative Ions ◽

Alternative Methods ◽

Rubber Latex ◽

Forming Process ◽

Slow Increase ◽

Phospholipid Hydrolysis

The mechanical stability time (MST) of latex is an important parameter indicating the colloidal stability of concentrated natural rubber latex (CNRL). This stability is crucial for the transport and storage of CNRL before the product forming processes. A popular method to increase the MST of CNRL in Thailand is by adding laureth soap or other surfactants. Nevertheless, the laureth soap provides a steady but slow increase in the MST without reaching a stable value after 30 days. At the same time, the phospholipids on the surfaces of natural rubber latex particles will naturally undergo hydrolysis reaction leading to even higher MST. For long storage, too high MST leads to coagulation problem in the product-forming step. Therefore, alternative methods were studied in this research to expedite phospholipid hydrolysis, which results in the increase in MST for CNRL without causing problems from excessive negative ions in the product-forming process. The alternative methods including heating in the presence of metal chips and the use of enzyme lipase were compared to the popular laurate soap addition method. It was found that lipase addition was the most effective method to expedite the hydrolysis of phospholipids to reach the standard MST value within 3 days, and reach a plateau within 10 days.

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Zinc Oxide Testing of Latex

Rubber Chemistry and Technology ◽

10.5254/1.3542875 ◽

1955 ◽

Vol 28 (4) ◽

pp. 1211-1220 ◽

Cited By ~ 1

Author(s):

E. W. Madge ◽

H. M. Collier ◽

J. L. M. Newnham

Keyword(s):

Zinc Oxide ◽

Natural Rubber ◽

Mechanical Stability ◽

Natural Rubber Latex ◽

Rubber Latex ◽

Experimental Conditions ◽

Ammonia Content ◽

Similar Investigation ◽

Naturally Occurring ◽

Viscosity Changes

Abstract Viscosity changes in concentrated natural rubber latex under different experimental conditions were investigated with the object of determining the mechanism of zinc oxide thickening and to find reasons for inconsistencies in correlating results of the zinc oxide thickening or ZOT test with other latex tests. It has been found that small variations of the amount of naturally occurring soap are of great importance in the thickening of latex containing zinc oxide, especially at the low ammonia content used for the ZOT test. The effect of added soap on the ZOT test was found to vary from latex to latex and to be different for different soaps. Less than about 0.3 per cent of various soaps added to latex prior to the zinc oxide reduced the degree and rate of thickening. With more than this amount of soap, the thickening depended on the soap used. A similar investigation in which the mechanical stability of latexes containing varying amounts of added soap and a standard amount of zinc oxide was measured, showed that the latexes varied anomalously with the amount and the type of soap added. The results of the work presented in this paper show that new tests for the zinc sensitivity of latexes must take into account a number of hitherto unsuspected factors, particularly when such tests are required to have a bearing on processing behavior.

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