Gas permeation properties of highly cross-linked castor oil-based polyurethane membranes synthesized through thiol-yne click polymerization

• Published in: Reactive & functional polymers 2021-01, Vol.158, p.104799, Article 104799
• Main Authors: Mansouri, Mahsa, Ghadimi, Ali, Gharibi, Reza, Norouzbahari, Somayeh
• Format: Article
• Language: English
• Subjects: Azobisisobutyronitrile; Carbon dioxide; Castor oil; Castor oil-based polyurethane membrane; Chemical synthesis; Crosslinking; Diisocyanates; Dilution; Gas permeation; Gas permeation properties; Gas separation; Isocyanates; Mechanical properties; Membranes; Penetration; Polydimethylsiloxane; Polyethylene glycol; Polymers; Polyurethane; Polyurethane resins; Prepolymers; Propargyl alcohol; Selectivity; Thermodynamic properties; Thiol-yne click polymerization
• ISSN: 1381-5148; 1873-166X
• DOI: 10.1016/j.reactfunctpolym.2020.104799

In this paper, a new chemistry approach was developed for synthesis of castor oil (CO)-based polyurethane (PU) membranes to attain improved structural properties for gas separation applications. For this purpose, propyne-terminated CO-based PU prepolymer (PTPU) was synthesized by the reaction of CO and isophorone diisocyanate (IPDI), followed by propargyl alcohol (PrAl) and isocyanate (NCO) terminated prepolymer reaction. The ultimate membranes were prepared through thiol-yne cross-linking reaction of PTPU and pentaerythritol tetrakis (3-mercaptopropionate) (PETMP), in presence of azobisisobutyronitrile (AIBN), as a reaction initiator. It was revealed that mechanical and thermal properties of the prepared membranes were improved owing to the formation of flexible thioether linkages through cross-linking reaction. The gas permeation measurements were carried out in the temperature and pressure ranges of 298–338 K and 200–1200 kPa, respectively. The results exhibited reverse size selective performance, as a typical transport behavior of rubbery membranes. The infinite dilution permeability coefficient of CO2 at 298 K was found identical to 2.78 Barrer, along with the infinite dilution perm-selectivity values for CO2/CH4 and CO2/H2 obtained equal to 25.27 and 7.94, respectively. Furthermore, higher permeation activation energies were found in this work compared to a number of cross-linked rubbery membranes in the literature, such as poly (dimethylsiloxane) (PDMS) and poly(ethylene glycol) diacrylate (PEGDA). [Display omitted] •Castor oil-based polyurethane (COPU) membranes were synthesized via thiol-yne click polymerization.•The COPU membranes exhibited promising thermo-mechanical properties.•Permeability measurements were carried out for CO2, H2, and CH4 gases.•Promising CO2/H2 separation performance was attained.