Volume 2, Issue 4 (April 2005)
A Study on the Puncture Resistance of Rubber Materials Used in Protective Clothing
The aim of this work is to investigate the intrinsic parameters that control the puncture resistance of materials used in protective clothing. The effect of various probe geometries and sample holder sizes on puncture tests results were investigated. Medical needles of different diameters and tip angles were also used as puncture probes. Various available commercial rubbers used in protective gloves were characterized. The findings of this study will be useful for recommendations for standard test method protocols to characterize the puncture resistance of protective clothing materials. When cylindrical probes with flat and rounded tip geometries are used, material puncture occurs when the strain reaches one material failure value independent of tip geometry. The failure strain is also independent of sample thickness, probe tip diameter, and the sample holder size. The results demonstrated that the tip angle of conical probes has a dramatic effect on puncture test results. The material puncture resistance obtained with conical probes with different tip angles having a tip diameter d1 and a rod diameter d2 can be interpolated from the corresponding values obtained with cylindrical probes having the same d1 and d2 diameters. On the other hand, cylindrical probes provide a more straightforward characterization of puncture and also eliminate the complex effect of conical probe-tip geometry. Test results with medical needles showed that the puncturing mechanism is different from that of conical and cylindrical probes. Puncture by medical needles involves cutting and fracture energy, whereas puncture by conical and cylindrical probes relates to failure strain.