Permeability and material characteristics of vulcanized latex film during and following cyclic fatigue in a saline environment

Abstract

ABSTRACT:The importance of stress or fatigue as a source of latex glove failure has been mentioned in several recent studies, but little work has been done to examine the underlying mechanism of these failures. The present work was undertaken to develop techniques for very early detection of structural changes in glove barriers. This was accomplished by monitoring the ion permeability and electrical properties of vulcanized latex glove material during cyclic fatigue in saline. Alteration in the conductance and capacitance of the membrane during the fatigue cycle showed that catastrophic failure of the material was preceded by deviation in the conductance of the membrane 8-10 min before rupture of the material. Disruption of the material coincided with capacitive ''discharge'' of and ion transport across the membrane. Follow-up examination by optical (1001) and scanning electron microscopy (SEM) revealed failure of the original fibril network structure surrounding the latex particles. Failure corresponded to processes consistent with repeated stress and rupture of the fibrils responsible for maintaining membrane integrity. Cyclic creep-strain measurements were carried out on the latex glove material. The estimated strain during cyclic fatigue was consistent with use during normal flexing of the glove finger. The fatigue life-time of the glove material was found to be about 2 h. Based on these studies, we conclude that failure of the glove material due to hole formation is preceded by gradual thinning (and weakening) of the membrane in localized regions. This suggests that latex inhomogeneities (defects) are the ultimate cause of failure. These findings confirm the importance of stress in explaining the source of some glove material failures, especially those failures not obviously accompanied by sharp instrument or needle penetrations. The results of the fatigue study emphasize the importance of changing gloves during prolonged use.

Surgical Gloves – Do they Really Protect Us?

“…Dillon and Schroeder confirmed the abovementioned hypothesis visualizing (optic and electron microscope) numerous micro-defects on the surface of the gloves after their two-hour use (25).…”

Estimation of shelf life of natural rubber latex exam‐gloves based on creep behavior

“…Significant changes in electrical properties were observed by Dillon and Schroeder after ∼117–124 min of fatigue testing; catastrophic rupture appeared about 9 min thereafter. The authors claimed the fatigue lifetime of the latex glove material under the test conditions to be about 2 h 19. These results suggested that a 2‐h creep test would be sufficient.…”

“…This load created a 4–6% initial strain that was modest compared to Aggarwal's results for open and closed hands 9. Dillon and Schroeder found that initial strain had an impact on both the fatigue life of the natural rubber and its creep 19. A small initial strain minimizes its impact on subsequent creep.…”

Abrasion resistance of medical glove materials

“…Physical properties such as puncture resistance, tensile strength, stiffness, and ease of donning for various glove materials have been studied 2, 7, 9, 14, 15. Mechanical durability studies that explore repeated flexing, such as that experienced near the joints and knuckles of a gloved hand while manipulating a sphygmomanometer, as a potential mode of failure for both latex16–19 and nonlatex18, 20 materials have also been performed. The durability studies have shown that repetitive motions, such as flexing, can be detrimental to the barrier properties of medical glove materials.…”