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Aguiar A, Marcelino LP, Mariquito A, Simões CL, Simoes R, Pinho I, Marques AC. Microcapsules of Poly(butylene adipate- co-terephthalate) (PBAT) Loaded with Aliphatic Isocyanates for Adhesive Applications. ACS APPLIED POLYMER MATERIALS 2024; 6:5618-5629. [PMID: 38807950 PMCID: PMC11129179 DOI: 10.1021/acsapm.4c00033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/23/2024] [Accepted: 04/23/2024] [Indexed: 05/30/2024]
Abstract
This work introduces the encapsulation of hexamethylene diisocyanate derivatives (HDI, TriHDI, and PHDI) with the biodegradable polymer poly(butylene adipate-co-terephthalate) (PBAT) through a solvent evaporation method. These microcapsules (MCs) were then employed in adhesive formulations for footwear. Moreover, MCs containing PHDI were produced in a closed vessel, demonstrating the potential for recovering and reusing organic solvents for the first time. The MCs were achieved with an isocyanate payload reaching up to 68 wt %, displaying a spherical shape, a core-shell structure, and thin walls without holes or cracks. The application of MCs as cross-linking agents for adhesives was evaluated following industry standards. The adhesives' strength surpassed the minimum requirement by a significant margin. Creep tests demonstrated that the formulation with MCs exhibits superior thermostability. Furthermore, the formulation with MCs-PHDI presented the best results reported to date for this type of system, as no displacement was observed in the bonded substrates. Environmental assessment indicates that adhesives with MCs have higher global warming potential (+16.2%) and energy consumption (+10.8%) than the standard commercial adhesives, but under alternative realistic scenarios, the differences can be insignificant. Therefore, adhesive formulations incorporating MCs promise to be on par with traditional adhesive systems regarding environmental impacts while providing benefits such as improved and safe handling of isocyanates and excellent bonding effectiveness.
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Affiliation(s)
- António Aguiar
- CERENA,
DEQ, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Lucas P. Marcelino
- CERENA,
DEQ, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - António Mariquito
- CERENA,
DEQ, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Carla L. Simões
- Polytechnic
Institute of Cavado and Ave (IPCA), 4750-810 Barcelos, Portugal
| | - Ricardo Simoes
- Polytechnic
Institute of Cavado and Ave (IPCA), 4750-810 Barcelos, Portugal
- Institute
for Polymers and Composites (IPC), University
of Minho, 4800-058 Guimarães, Portugal
| | - Isabel Pinho
- CIPADE, Av. Primeiro
de Maio 121, 3700-227 São João
da Madeira, Portugal
| | - Ana C. Marques
- CERENA,
DEQ, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
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Skleničková K, Suchopárová E, Abbrent S, Pokorný V, Kočková O, Nevoralová M, Cajthaml T, Strejček M, Uhlík O, Halecký M, Beneš H. Biodegradation of aliphatic polyurethane foams in soil: Influence of amide linkages and supramolecular structure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169062. [PMID: 38061651 DOI: 10.1016/j.scitotenv.2023.169062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/22/2023] [Accepted: 11/30/2023] [Indexed: 01/18/2024]
Abstract
Polyurethane (PU) foams are classified as physically nonrecyclable thermosets. The current effort of sustainable and eco-friendly production makes it essential to explore methods of better waste management, for instance by modifying the structure of these frequently used polymers to enhance their microbial degradability. The presence of ester links is known to be a crucial prerequisite for the biodegradability of PU foams. However, the impact of other hydrolysable groups (urethane, urea and amide) occurred in PU materials, as well as the supramolecular structure of the PU network and the cellular morphology of PU foams, is still relatively unexplored. In this work, fully aliphatic PU foams with and without hydrolyzable amide linkages were prepared and their aerobic biodegradation was investigated using a six-month soil burial test. Besides the variable chemical composition of the PU foams, the influence of their different supramolecular arrangement and cellular morphologies on the extent of biodegradation was also evaluated. Throughout the soil burial test, the release of carbon dioxide, and enzyme activities of proteases, esterases, and ureases were measured. At the same time, phospho-lipid fatty acids (PLFA) analysis was conducted together with an assessment of microbial community composition achieved by analysing the genetic information from the 16S rRNA gene and ITS2 region sequencing. The results revealed a mineralization rate of 30-50 % for the PU foams, indicating a significant level of degradation as well as indicating that PU foams can be utilized by soil microorganisms as a source of both energy and nutrients. Importantly, microbial biomass remained unaffected, suggesting that there was no toxicity associated with the degradation products of the PU foams. It was further confirmed that ester linkages in PU foam structure were easily enzymatically cleavable, while amide linkages were not prone to degradation by soil microorganisms. In addition, it was shown that the presence of amide linkages in PU foam leads to a change in the supramolecular network arrangement due to increased content of hard segments, which in turn reduces the biodegradability of PU foam. These findings show that it is important to consider both chemical composition and supramolecular/macroscopic structure when designing new PU materials in an effort to develop environmentally friendly alternatives.
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Affiliation(s)
- Kateřina Skleničková
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 06, Czech Republic; Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Eliška Suchopárová
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Sabina Abbrent
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 06, Czech Republic
| | - Václav Pokorný
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 06, Czech Republic
| | - Olga Kočková
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 06, Czech Republic
| | - Martina Nevoralová
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 06, Czech Republic
| | - Tomáš Cajthaml
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, Prague 4 142 20, Czech Republic
| | - Michal Strejček
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Ondřej Uhlík
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Martin Halecký
- Department of Biotechnology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic.
| | - Hynek Beneš
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 06, Czech Republic.
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