Triblock Copolymers from CO₂, Propylene Oxide, and p-Tosyl Isocyanate of Higher Toughness than Polyethylenes

Abstract

In this report, a series of ABA triblock copolymers composed of a poly(propylene carbonate-co-propylene oxide)s (PPPC) middle block flanked by two poly(N-tosyl propylene urethane) (PTPU) outer blocks were synthesized in one-pot, using a difunctional initiator in the presence of triethyl borane (TEB). In the first step, the central PPPC block was obtained through the copolymerization of propylene oxide (PO) with CO2. Varying the polymerization pressure of CO2, the carbonate content in the PPPC central block could be adjusted, giving access to PPPC blocks with different glass transition temperatures. In the second step, p-tosyl isocyanate (TSI) was subsequently added and copolymerized with the remaining PO, affording the growth of two outer PTPU blocks without any incorporation of polyether or polycarbonate and the formation of well-defined ABA triblock copolymers as confirmed by 1H NMR and size exclusion chromatography (SEC). Their thermal and mechanical properties were measured using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and universal testing machine (UTM). PTPU-b-PPPC-b-PTPU (U-PC-U) triblock copolymers with PTPU (hard blocks) weight fraction of 28% and 80–85 wt % of carbonate content in the middle PPPC block show higher toughness than commercial polyolefins.

Heat-Resistant CO2-Based Polycarbonate Thermoplastics

“…Subsequently, the mechanical properties of this linear triblock copolymer (PC-CHP) 2 (81, 0.24) were assessed using a Shimadzu tensile tester first at room temperature. The two-armed linear triblock polymer (PC-CHP) 2 (81, 0.24) displayed a typical ductile behavior with a Young modulus ( E ) equal to 38 ± 4 MPa, excellent tensile strength (σ m = 25.7 ± 2.4 MPa), and elongation at break (ε b = 835 ± 73%), resulting in a strong toughness (123.6 ± 15 MJ m –3 ) (entry 1, Table and Figure A), values that are comparable to our previously prepared triblock copolymer U-PC-U (80, 28) with two external polyurethane hard blocks . Notably, it demonstrated superior extensile strength, longer elongation at break, and stronger toughness compared to those of HDPE, low-density polyethylene (LDPE), PBAT, styrene-ethylene-butylene-styrene (SEBS), and OBC (entries 7–11, Table and Figure B).…”

“…The thermal and mechanical properties of the (PC-CHP) 2 (81, 0.24) copolymer were then comprehensively examined through TGA, DSC, and uniaxial tensile test. This copolymer exhibited enhanced degradation temperatures [ T d(5%) = 240 °C], indicating a notable enhancement of thermal stability compared to that of pure polycarbonate; its degradation temperature was slightly lower than that of external PLA or polyurethane hard blocks , (Figure C and Table ). Additionally, (PC-CHP) 2 (81, 0.24) displayed two distinct glass transition temperatures at 19 and 140 °C, indicative of phase separation between PPPC and PCHPE blocks (Figure D and Table ).…”

“…Upon associating such soft blocks with either PLAs or polyurethanes as hard blocks, ABA triblock copolymers could be generated in one pot; such triblock copolymers exhibited significantly higher toughness, higher tensile strength, and higher elongation at break than commercial polyolefins at room temperature. 22,23 On the other hand, fossil-based polyolefins such as highdensity polyethylene (HDPE) not only exhibit outstanding mechanical properties at room temperature�besides other remarkable mechanical properties�but they are also engineered to withstand high temperatures. In contrast, the mechanical performances of CO 2 -based materials at higher temperatures were seldom discussed or even mentioned in the literature: most results reported in previous works were indeed limited to tests run at room temperature.…”

Preparation of Well-Defined Double-Metal Cyanide Catalysts for Propylene Oxide Polymerization and CO2 Copolymerization

“…This CO 2 incorporation has raised interest in its potential for commercialization as an exemplar of carbon capture and utilization technology. PO/CO 2 copolymerization remains a vibrant and highly researched topic, necessitating the development of novel and efficient catalytic systems. − …”

Creating Remarkably Moisture‐ and Air‐Stable Macromolecular Lewis Acid by Integrating Borane within the Polymer Chain: A Highly Active Catalyst for Homo(co)polymerization of Epoxides

“…[7] This pioneering work spurred further research into borane-based catalysts including binary ststems and one-component multifunctional catalysts, for a variety of ROP and ring-opening copolymerization (ROCOP) reactions. [8][9][10][11][12][13][14] It is noteworthy that the activity and selectivity of ROP and ROCOP are often influenced significantly by adjusting the borane-to-Lewis base ratio. Activation of epoxides through interaction with Lewis acidic boron species, among other reasons, [15] plays a critical role in catalytic performance.…”