Efficient One‐Pot Preparation of Thermoresponsive Polyurethanes with Lower Critical Solution Temperatures. Issue 12 (1st December 2021)

• Record Type: Journal Article
• Authors: Maiti, Binoy; Nandi, Mridula; Bonardd, Sebastián; Franco, Lourdes; Puiggalí, Jordi; Enshaei, Hamidreza; Alemán, Carlos; Díaz Díaz, David
• Is Part Of: ChemPlusChem. Volume 86:Issue 12(2021)
• Page Start: 1570
• Page End: 1576
• Publication Date: 2021-12-01
• Subjects: copolymerization -- critical solution temperatures -- polyurethanes -- tensile strength -- thermoresponsive materials; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.202100451
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: This work reports a simple and scalable strategy to prepare a series of thermoresponsive polyurethanes synthesized via copolymerization of dicyclohexyl diisocyanate with glycerol ethoxylate in a single one‐pot system. These polyurethanes exhibit lower critical solution temperatures (LCST) at 57 °C. The LCST of synthesized polyurethane was determined from Dynamic Scanning Calorimetry and UV‐vis measurements. Both the LCST and T g of synthesized polyurethane was tuned by varying the ratio between hard segment (dicyclohexyl diisocyanate) and soft segment (glycerol ethoxylate). Thus, T g values could be tuned from −54.6 °C to −19.9 °C for samples with different flexibility. The swelling and deswelling studies were done at room temperature and above the LCST respectively. The results showed that the swelling ratio increases with the increase of soft segment (glycerol ethoxylate) in synthesized polyurethanes. Furthermore, the mechanical properties of the membrane were studied by universal tensile testing measurements. Specifically, stress at break values varied from 0.35±0.07 MPa to 0.91±0.15 MPa for the tested membranes, whereas elongation at break data ranged from 101.9±20.9 % to 192.4±24.4 %, and Young's modulus varied from 0.35±0.03 MPa to 1.85±0.19 MPa. Tensile strength of the films increased with the increase of the hard segment and elongation at break decreased. Abstract : Thermoresponsive polyurethanes exhibiting lower critical solution temperatures (LCST) can be easily synthesized via copolymerization of dicyclohexyl diisocyanate with glycerol ethoxylate in a single one‐pot system. Both the lower critical solution temperatures and the glass transition temperatures of synthesized polyurethane can be tuned by varying the ratio between the hard segment (i. e. dicyclohexyl diisocyanate) and the soft segment (i. e. glycerol ethoxylate) of the polymers.