Occupational Exposure during the Production and the Spray Deposition of Graphene Nanoplatelets-Based Polymeric Coatings
Abstract
:1. Introduction
2. Materials and Methods
2.1. Production Process of the GNP-Filled Polyurethane Composite
- Phase 1: tip-sonication of the worm-like expanded graphite (WEG)/acetone suspension and solvent evaporation in hoven to obtain a GNP dried powder;
- Phase 2: mixing and sonication steps of dried GNPs with PU paint, DI water, and curing agent; spray casting deposition with airbrush of the final coating.
2.2. Morphological and Chemical Characterizations of the Nanocomposite Coating
2.3. Workplace Description
2.4. Measurements and Sampling Method
- Condensation Particle Counter (CPC mod. 3007, TSI Inc., Shoreview, MN, USA). It is an optical counter that can measure the Particle Number Concentration (PNC [part/cm3]) with a time resolution of 1 s and an accuracy of ±20%. CPC can detect nano-objects with an average size in the range between 10 and 1000 nm. CPC has a concentration range from 0 to 100,000 part/cm3 as declared by the manufacturer. The working fluid is Isopropanol;
- Mini Diffusion Size Classifier (DiSCmini, mod. TESTO, TESTO SE & Co. KGaA, Titisee-Neustadt, Germany). It is a diffusion charging (DC) instrument that measures three parameters—PNC (part/cm3), modal average diameter (Davg [nm]), and Lung Deposited Surface Area (LDSA [µm2/cm3])—in the environment and in correspondence with the worker’s personal breathing zone (PBZ) with a time resolution of 1 s and an accuracy of ±30%. This instrument is able to detect airborne particles characterized by a diameter ranging from 10 nm to 700 nm for PNC measurements and from 10 nm to 300 nm for Davg measurements. Sampling TygonTM tubes 1.5 m length have been used for DiSCmini (DM) measurements;
- Nanoparticle Surface Area Monitor (NSAM mod. 3550, TSI Inc., Shoreview, MN, USA). This instrument measures the average and cumulative LDSA (µm2/cm3) of particles from 10 nm to 1000 nm with 1 s time resolution, corresponding to the tracheobronchial (TB) or alveolar (A) pulmonary fractions, and based on the model published by the International Commission on Radiological Protection [43];
- Personal impactor (mod. Sioutas, SKC Inc., Eighty Four, PA, USA) equipped with 5 different filter stages. It separates and collects ultrafine, fine, and >2.5 µm airborne particles characterized by different aerodynamic diameters ranges: <0.25 µm, 0.25–0.50 µm, 0.50–1.0 µm, 1.0–2.5 µm, >2.5 µm (up to 10 µm). Particles above each cut point are collected on a 25 mm aluminum filter in each appropriate stage when the Sioutas is used with a 9 L/min sample pump. Particles of less than 0.25 µm cut point of the last stage are collected on a 37 mm PTFE after-filter.
- Inside the production laboratory, before starting the manufacturing process, for Near-Field (NF) background characterization. The NF background measurements sessions lasted 15 min and they were conducted with the furnace off and the fume hood turned on, representing the standard conditions in the lab before starting the production process;
- In the other room not influenced by the process, where NMs are not produced/handled and no other sources of nanoparticles are present, simultaneously with the manufacturing process, for Far-Field (FF) background characterization.
2.5. Experimental Campaign Setting Up
3. Results and Discussion
3.1. Characterization of the Background Environment When No Production Occurred
3.2. Real-Time Measurements
3.3. SEM and EDS Analysis on Sampled Materials
4. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Material | Acetone [mL] | GNPs [g] | Pu Paint and Hardener [g] | DI Water [mL] |
---|---|---|---|---|
Paint type A | 150 | 1.75 | 62.5 | 10 |
Paint type B | 150 | 4 | 62.5 | 40 |
Day | Time | Measurements |
---|---|---|
DAY 1 Instruments setup | 12:15 p.m.–01:35 p.m. | Instruments comparison |
DAY 2 Production: phase 1 and phase 2A (paint type A) | 10:50 a.m.–05:25 p.m. | Background FF |
10:50 a.m.–11:05 a.m. | Background NF | |
11:10 a.m.–02:20 p.m. | Production: phase 1 | |
02:25 p.m.–05:25 p.m. | Production: phases 2A | |
DAY 3 Production: phase 2B (paint type B) Instruments setup | 10:20 a.m.–01:20 p.m. | Background FF |
10:20 a.m.–10:35 a.m. | Background NF | |
10:40 a.m.–01:20 p.m. | Production: phases 2B | |
02:05 p.m.–02:45 p.m. | Instruments comparison |
DAY 2 | DAY 3 | ||||||
---|---|---|---|---|---|---|---|
NF | PBZ * | FF * | NF | PBZ * | FF * | ||
PNC (part/cm3) | CPC | DM | DM | CPC | DM | DM | |
Mean | 8000 | 7800 | 5900 | 5700 | 5500 | 3900 | |
σ | 600 | 700 | 600 | 300 | 400 | 500 | |
Significant Value | 9800 | 9900 | 7700 | 6600 | 6700 | 5400 | |
Davg (nm) | DM | DM | DM | DM | |||
Mean | - | 53 | 70 | - | 56 | 68 | |
σ | - | 2 | 6 | - | 2 | 6 | |
LDSA (μm2/cm3) | NSAM | DM | DM | NSAM | DM | DM | |
Mean | 29 | 28 | 29 | 20 | 20 | 16 | |
σ | 3 | 3 | 1 | 2 | 1 | 1 |
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Bellagamba, I.; Boccuni, F.; Ferrante, R.; Tombolini, F.; Natale, C.; Marra, F.; Sarto, M.S.; Iavicoli, S. Occupational Exposure during the Production and the Spray Deposition of Graphene Nanoplatelets-Based Polymeric Coatings. Nanomaterials 2023, 13, 1378. https://doi.org/10.3390/nano13081378
Bellagamba I, Boccuni F, Ferrante R, Tombolini F, Natale C, Marra F, Sarto MS, Iavicoli S. Occupational Exposure during the Production and the Spray Deposition of Graphene Nanoplatelets-Based Polymeric Coatings. Nanomaterials. 2023; 13(8):1378. https://doi.org/10.3390/nano13081378
Chicago/Turabian StyleBellagamba, Irene, Fabio Boccuni, Riccardo Ferrante, Francesca Tombolini, Claudio Natale, Fabrizio Marra, Maria Sabrina Sarto, and Sergio Iavicoli. 2023. "Occupational Exposure during the Production and the Spray Deposition of Graphene Nanoplatelets-Based Polymeric Coatings" Nanomaterials 13, no. 8: 1378. https://doi.org/10.3390/nano13081378