Addition of Transition Metals to Improve Physico-Mechanical Properties of Radiation-Vulcanized Natural Rubber Latex Films

Abstract

The effect of transition metals as a promoter of physico-mechanical properties of radiation-vulcanized natural rubber latex (RVNRL) films was investigated. RVNRL films were prepared by the addition of transition metals (Fe, Mn, etc.) of different concentrations (0-30 ppm) in natural rubber (NR) latex and irradiated with various radiation doses (0-20 kGy). The concentrations of metal ions and radiation doses were optimized and found to be 20 ppm and 12 kGy, respectively. Tensile strength, tear strength, and cross-linking density of the irradiated rubber films were increased with increasing concentration of metal ions as well as radiation doses. The mechanical properties of the films were enhanced by approximately 20% at the optimum conditions. In contrast, elongation at break, permanent set, and swelling ratio of the films were decreased under the same conditions. The comparative effect of metal ions can be explained by Fajan's rules, reported in this article.

Effect of Manganese on Radiation Vulcanization of Natural Rubber

“…The rubber phase mainly consists of rubber hydrocarbon chains, which are surrounded a by rubbery membrane and negatively charged protein phospholipid layer. [12] On further increase in concentration of Mn (>20 ppm) as well as radiation doses (>12 kGy) the tensile properties do not increase but rather show a small downward trend. It is evident that only those additives that are predominantly distributed in the rubber phase increase cross-linking density.…”

“…[1] Further improvement has been achieved by lowering required radiation doses through the invention of sensitizers. [12,13] Lately, the effect of TiO 2 and creaming agents on vulcanization has been reported. [5,6] Not many reports can be found in the literature on how to enhance the degree of vulcanization of NR by using additives other than sensitizers.…”

Blending of Natural Rubber/Recycled Ethylene-Propylene-diene Rubber: Promoting the Interfacial Adhesion Between Phases by Natural Rubber Latex

“…[10,11] NRL is used to make a variety of products such as gloves, catheters, and condoms. Besides consuming less energy when produced, NRL is also known to possess adhesive properties, low viscosity, and low surface tension, which would render some improvements to the interaction between R-EPDM and NR.…”

Gamma-Irradiated Gelatin-Based Films Modified by HEMA for Medical Application

“…[27,28] The permanent set of gelatin films obtained with HEMA of various concentrations as well as with different radiation doses is shown in Figure 3. Therefore, 1 kGy radiation dose and 20 ppm HEMA might be considered the optimum values for GHEMA films.…”