Modelling the transport of toluene liquid in protective polymer gloves using a fluorescent dye-tracing technique

Visualizing Penetration of Fluorescent Dye through Polymer Coatings

Understanding how small molecules penetrate and contaminate polymer films is of vital importance for developing protective coatings for a wide range of applications. To this end, rhodamine B fluorescent dye is visualized diffusing through polystyrene-polydimethylsiloxane block copolymer (BCP) coatings using confocal microscopy. The intensity of dye inside the coatings grows and decays non-monotonically, which is likely due to a combination of dye molecule transport occurring concurrently in different directions. An empirical fitting equation allows for comparing the contamination rates between copolymers, demonstrating that dye penetration is related to the chemical makeup and configuration of the BCPs. This work shows that confocal microscopy can be a useful tool to visualize the transport of a fluorophore in space and time through a coating.

An alternative method to assess permeation through disposable gloves

Previously, we have demonstrated the capability of activated charcoal cloth (ACC) to assess dermal exposure to VOCs. Here we investigated whether ACC patches can be used as an under-glove indicator to evaluate the ingress of toluene through disposable gloves in a controlled environment, and compared these results to the amount of toluene ingress determined from the standardized test methods for determining chemical permeation through PPE. In a test chamber, with plugs for air sampling, five to six ACC patches were placed on a mannequin hand underneath disposable gloves (latex, nitrile, neoprene, polymer laminate). Three work-exposure scenarios were simulated to assess toluene ingress through the different gloves: vapor exposure; spray exposure, and immersion. The standard permeation test, using a diffusion cell, was carried with glove material of the palm, with continuous contact conditions. In all of ACC test, the order of toluene ingress was latex > neoprene > nitrile > Barrier, but for the standardized testing, the order of the neoprene and nitrile was reversed, and nitrile had higher levels of toluene ingress. These results show the need to think beyond standard testing techniques for occupational exposure to hazardous substances, and the added value of "application style" testing.