Ludwig Vinches

Development of a test method for protective gloves against nanoparticles in conditions simulating occupational use

Nanoparticle manufacture and use are in full expansion. The associated risks of occupational exposure raise large concerns due to their potential toxicity. Even if they stand as a last resort in the traditional occupational Health & Safety (H&S) risk management strategy, personal protective equipment (PPE) against nanoparticles are an absolute need in the context of precautionary principle advocated by H&S organizations worldwide. However no standard test method is currently available for evaluating the efficiency of PPE against nanoparticles, in particular in the case of gloves. A project is thus underway to develop a test method for measuring nanoparticle penetration through protective gloves in conditions simulating glove-nanoparticle occupational interaction. The test setup includes an exposure and a sampling chamber separated by a circular glove sample. A system of cylinders is used to deform the sample while it is exposed to nanoparticles. The whole system is enclosed in a glove box to ensure the operator safety during assembly, dismounting and clean-up operations as well as during the tests. Appropriate nanoparticle detection techniques were also identified. Results are reported here for commercial 15nm TiO2 nanoparticles - powder and colloidal solutions in 1,2-propanediol, ethylene glycol and water - and four types of protective gloves: disposable nitrile and latex as well as unsupported neoprene and butyl rubber gloves. They show that mechanical deformations and contact with colloidal solution liquid carriers may affect glove materials. Preliminary results obtained with TiO2 powder indicate a possible penetration of nanoparticles through gloves following mechanical deformations.

Experimental evaluation of the resistance of nitrile rubber protective gloves against TiO2 nanoparticles in water under conditions simulating occupational use

Manufactured nanoparticles (NPs), including titanium dioxide nanoparticles (nTiO2), now enter in the formulation of several commercial products. Some studies have been carried out to assess the resistance of protective gloves against NPs, they have generally not considered the conditions prevailing in occupational settings. This study was designed to evaluate the behavior of protective gloves materials against NPs in solution under conditions simulating occupational use. Mechanical deformations, simulating those produced by flexing the hand, were applied to nitrile rubber glove samples in contact with nTiO2 in water. The first analysis showed that nTiO2 solution penetrates some of the materials after prolonged dynamic deformations. These results were partly attributed to modifications in the physical and mechanical properties of protective gloves materials that were induced by repetitive mechanical deformations and/or the presence of the colloidal solution.

Swelling of elastomers in solutions of TiO2 nanoparticles

Elastomers used in protective gloves can be sensitive to the action of solvents used to disperse commercial solutions of nanoparticles. These effects may include the swelling of the polymer, leading to a modification of its mechanical and chemical properties. Modifications to the properties of the polymer will impact the protection provided by the protective gloves. The goal of this work was therefore to study the swelling of several elastomers when exposed to commercial solutions of nanoparticles. The study involved four elastomers and three commercial solutions of colloidal titanium dioxide (). Swelling was assessed by measurements of mass gain and length change. Tests were also performed with technical and ultrapure solvents corresponding to the liquid carriers. The solutions had a significant effect on the swelling of nitrile rubber, latex, and neoprene. A large mass gain was recorded for short immersion times, indicating a possible penetration of the nanoparticle liquid carrier into these elastomers. Length change measurements revealed a swelling anisotropy effect with nitrile rubber and latex in the solutions of colloidal . No effect was measured with butyl rubber. The results show that great care must be taken when selecting protective gloves for the handling of nanoparticle dispersions.

Effects of Sweat and 3D-deformation on the Mechanical Behaviour of Nitrile Rubber Gloves

Research has proven that mechanical deformations (MD) caused by hand flexing affect the structure of disposable protective gloves. However, these studies do not consider the presence of a physiological solution such as sweat. The combination of mechanical constraints and sweat might modify the mechanical and physical properties of the protective gloves and therefor their effectiveness. The main objective of this work is to evaluate the combined effects of human sweat and MDs on certain physical and mechanical phenomena that could affect the structure of nitrile rubber protective gloves. The strain energy, crystallinity, swelling and glove surface profile were investigated. Combined with MDs, the physiological solution significantly affects the structure of the gloves. Contact of the glove sample with the physiological solution modified the strain energy and induced a swelling that modified mechanical properties. Also, the deformation frequency greatly affected the strain energy and the number of deformations changed the degree of crystallinity. A qualitative analysis by SEM showed the deterioration of the surface of the gloves in contact with skin. Based on these results, further investigation is needed on the overall effect of sweat on the effectiveness of protective gloves against mechanical and chemical hazards.

An improved experimental methodology to evaluate the effectiveness of protective gloves against nanoparticles in suspension

ABSTRACT Recent studies underline the potential health risks associated to the “nano” revolution, particularly for the workers who handle engineered nanoparticles (ENPs) that can be found in the formulation of several commercial products. Although many Health & Safety agencies recommend the use of protective gloves against chemicals, few studies have investigated the effectiveness of these gloves towards nanoparticle suspensions. Moreover, the data that are available are often contradictory. This study was designed to evaluate the effectiveness of protective gloves against nanoparticles in suspension. For this purpose, a new methodology was developed in order to take into account parameters encountered in the workplace such as mechanical deformations (MD) that simulate hand flexion and sweat. The effects of the precise experimental protocol on the concentrations of nanoparticles that were detected in the sampling suspension were assessed. Several samples of nitrile rubber gloves (73 µm thick), taken from different boxes, were brought into contact with gold nanoparticles (5 nm) in water. During their exposure to ENPs, the glove samples submitted systematic mechanical deformations and were placed in contact with a physiological solution simulating human sweat. Under these conditions, results obtained by inductively coupled plasma mass spectrometry (ICPMS) showed that the 5 nm gold nanoparticles passed through the protective gloves. This result was acquired, in spite of the observation of significant losses during the sampling phase that will be important for future experiments evaluating the effectiveness of these materials.

Resistance of Type 5 chemical protective clothing against nanometric airborne particles: behaviour of seams and zipper

ABSTRACT In the field of dermal protection, the use of chemical protective clothing (CPC) (including coveralls) are considered as the last barrier against airborne engineered nanomaterials (ENM). In the majority of cases, Type 5 CPC, used against solid particles (ISO 13982-1), perform well against ENM. But in a recent study, a penetration level (PL) of up to 8.5% of polydisperse sodium chloride airborne nanoparticles has been measured. Moreover, in all the previous studies, tests were performed on a sample of protective clothing material without seams or zippers. Thus, the potential for permeation through a zipper or seams has not yet been determined, even though these areas would be privileged entry points for airborne ENM. This work was designed to evaluate the PL of airborne ENM through coveralls and specifically the PL through the seams on different parts of the CPC and the zipper. Eight current models of CPC (Type 5) were selected. The samples were taken from places with and without seams and with a zipper. In some cases, a cover strip can be added to the zipper to enhance its sealing. Polydisperse nanoparticles were generated by nebulization of a sodium chloride solution. A penetration cell was developed to expose the sample to airborne nanometric particles. The NaCl particle concentration in number was measured with an ultrafine particle counter and the PL was defined as the downstream concentration divided by the upstream concentration. The results obtained show that the PL increased significantly in the presence of seams and could reach up to 90% depending on the seams design. Moreover, this study classifies the different types of seams by their resistance against airborne ENM. As for the penetration of airborne NaCl particles through the zipper, the PL was greatly attenuated by the presence of a cover strip, but only for certain models of coveralls. Finally, the values of the pressure drop were directly linked to the type of seam. All of these conclusions provide recommendations to both manufacturers and users.