Effect of vulcanizing and antioxidant systems on aged tensile properties of MicrOptic gloves

Abstract

MicrOptic glove is a powder free surgical glove which is made out from the natural rubber latex. Thin nature of MicrOptic glove facilitate exceptional dexterity and tactile sensitivity and at the same time outstanding strength and barrier protection (Ansell Medical GBU, 2014).Aged tensile properties of the glove cannot be maintained in a stable level due to the thin nature of the glove. Natural rubber vulcanizates can be given adequate heat-aging resistance by a suitable choice of vulcanization and by using ammine or phenolic antioxidants (Morton, 2010). The study was conducted to disclose the effect of vulcanizing system, antioxidant system and their combined effect on aged tensile properties of MicrOptic glove.

Materials and Methodology

The study was carried out centralizing to Ansell Lanka (Pvt) Ltd, EPZ - Biyagama. Aged tensile test was done at Quality Control (QA) laboratory at Ansell Lanka (Pvt) Ltd. Nine trials with different treatments were conducted during this study. 0.5 pphr elementary sulphur(V1), 0.25 pphr elementary sulphur with 0.5 pphr sulphur donor compound (V2) and 0.25 pphr elementary sulphur with 1.0 pphr sulphur donor compound (V3) were utilized as three different vulcanizing systems in MicrOptic formula. 1.5 pphr primary antioxidant (A1), 1.0 pphr primary antioxidant with 0.25 pphr secondary antioxidant (A2) and 1.0 pphr primary antioxidant with 0.5 pphr secondary antioxidant (A3) were utilized as three different antioxidant systems in MicrOptic formula.

All the dispersions of vulcanizing agents and antioxidants were made by using laboratory scale ball mill. Nine glove compounds with three replicates were produced according to MicrOptic glove formula except the vulcanizing agent and antioxidant system. Vulcanizing agents and antioxidant were added according to the treatment combinations.The compounded latex was kept for 36 hours to obtain optimum degree of crosslinks. 65 - 75 % toluene swelling index (TSI) was used as optimum degree of crosslinks.Sample gloves are made under laboratory conditions.Clean former was heated up to 65 ºC by using an oven and then former was dipped in a MicrOptic glove coagulant solution at 65 ºC with constant time of 22 seconds. Coagulant solution was dried by using an oven and heated up to 55 ºC. Then former was dipped in latex solution with constant time of 23 seconds and bead of the glove made by manually. After that gloves were leached in hot water (70 ºC) for 2 minute. Finally, formers with gloves were cured at 120 ºC for 35 minutes.

Aged tensile properties (ATP) such as force at break (FB), elongation at break (EB) and 500 % modulus (MOD) were measured according to the BS EN 455-2:2000 standards. Factor factorial in complete randomized design was conducted and data obtained from aged tensile properties were subjected to analysis of variance (ANOVA) using the general linear model procedure of MINITAB 16. Significant means of treatments were separated using the least significant difference (LSD) (P< 0.05) test.

Results and Discussion

The study revealed that the effect of vulcanizing system on force at break, elongatio n at break and 500 % modulus were significant (p < 0.05). Also combine effect of vulcanizing system and antioxidant system on force at break, elongation at break and 500 % modulus were significant(p < 0.05).Further, this study disclosed, the effect of antioxidant system on elongation at break was significant (p < 0.05). However, effect of antioxidant system on force at break and 500 % modulus were not significant at 5% significant level.