Preparation and Characterization of Novel Poly(thiourethane)-Poly(isocyanurate) Covalent Adaptable Networks: Effect of the Catalysts

Author, as appears in the article.: Guerrero, Federico; De la Flor, Silvia; Serra, Angels

Department: Enginyeria Mecànica

URV's Author/s: De la Flor Lopez, Silvia / Guerrero Ruiz, Federico / Serra Albet, Maria Angels

Keywords: 1,6-hexamethylene diisocyanate; Catalysis; Covalent adaptable networks; Isocyanates; Lanthanum; Molecular structure; Poly(isocyanurates); Poly(thiourethanes); Polyurethanes; Recyclability; Self-healin; Self-healing; Self‐healing; Thermosets; Triazines; Trimerizatio

Abstract: Poly(thiourethane)-based covalent adaptable networks are synthesized by reacting a trimer of hexamethylene diisocyanate (Desmodur N3300) containing isocyanurate groups in its structure with 1,6-hexanedithiol. The catalysts evaluated for this process include dibutyltin dilaurate (DBTDL), lanthanum triflate (La(OTf)3), and a thermal precursor of 1,8-diazabicyclo[5.4.0]undec-7-ene (BGDBU). The use of DBTDL results in the initiation of curing upon mixing, while the other two catalysts exhibit a latency period in the reactive mixture, with curing starting at about 90 degrees C. Notably, the use of the lanthanum salt produces an additional minor exothermic reaction at 80 degrees C. This phenomenon corresponds to the trimerization of isocyanates rending isocyanurates, leaving a portion of unreacted thiols. Materials prepared with BGDBU or La(OTf)3 present shorter relaxation times than those prepared with DBTDL. Nevertheless, the materials containing the lanthanum salt do not reach complete relaxation, likely due to the reinforcement of the permanent network through increased isocyanurate content. The formation of isocyanurates produces a stoichiometric imbalance, leaving unreacted thiols. This transforms the exchange process into a dual mechanism involving a dissociative process of thiourethanes to isocyanate and thiol, along with an interchange through thiol attacking the thiourethane group. The materials exhibit good recyclability and self-healing characteristics. Poly(thiourethane)-poly(isocyanurate) covalent adaptable networks are prepared for the first time using an industrially available triisocyanate. The study examines the impact of various catalysts (1,8-diazabicyclo[5.4.0]undec-7-ene, dibutyltin dilaurate, and lanthanum triflate) and their concentrations on the material's properties. Results reveal the recyclability of the cross-linked network and its self-healing capabilities. image

Thematic Areas: Engenharias ii; Materiais; Materials chemistry; Organic chemistry; Polymer science; Polymers and plastics; Química

licence for use: https://creativecommons.org/licenses/by/3.0/es/

Author's mail: silvia.delaflor@urv.cat; federico.guerrero@estudiants.urv.cat; federico.guerrero@estudiants.urv.cat; angels.serra@urv.cat

Record's date: 2024-11-02

Paper version: info:eu-repo/semantics/publishedVersion

Link to the original source: https://onlinelibrary.wiley.com/doi/10.1002/marc.202400330

Paper original source: Macromolecular Rapid Communications. 45 (19): e2400330-

APA: Guerrero, Federico; De la Flor, Silvia; Serra, Angels (2024). Preparation and Characterization of Novel Poly(thiourethane)-Poly(isocyanurate) Covalent Adaptable Networks: Effect of the Catalysts. Macromolecular Rapid Communications, 45(19), e2400330-. DOI: 10.1002/marc.202400330

Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/

Article's DOI: 10.1002/marc.202400330

Entity: Universitat Rovira i Virgili

Journal publication year: 2024

Publication Type: Journal Publications