Organocatalytic Ring-Opening Copolymerization of Trimethylene Carbonate and Dithiolane Trimethylene Carbonate: Impact of Organocatalysts on Copolymerization Kinetics and Copolymer Microstructures

Abstract

The ring opening copolymerization of trimethylene carbonate (TMC) and dithiolane trimethylene carbonate (DTC) using acidic and basic organocatalysts, i.e., diphenyl phosphate (DPP) and triazabicyclo[4.4.0]dec-5-ene (TBD), was systemically investigated. Interestingly, DPP and TBD gave rise to completely different polymerization kinetics and copolymer sequences. The copolymerization of TMC and DTC using methoxy poly(ethylene glycol) (mPEG-OH) as an initiator and DPP as a catalyst proceeded in a first-order manner and to near completion in 72 h for both monomers, yielding well-controlled copolymers with random sequences, predictable molar mass, and low dispersity ( M/ M = 1.09-1.19). By contrast, TBD brought about much faster copolymerization of TMC and DTC under similar conditions (high monomer conversion achieved in 2-4 h), to furnish copolymers with controlled molar mass and moderate dispersity ( M/ M = 1.27-1.80). Moreover, polymerization kinetics revealed that DTC was preferentially polymerized followed by first-order polymerization of TMC, leading to blocky copolymers. These results signify that type of organocatalysts has a critical influence on polymerization kinetics of cyclic carbonates, copolymer sequence, and molar mass control.

A Macromolecule Reversing Antibiotic Resistance Phenotype and Repurposing Drugs as Potent Antibiotics

“…The gene binding ability of pEt_20 was investigated by agarose gel electrophoresis. DNA extracted from A. baumannii BAA-1709 was mixed with pEt_20 at various polymer to DNA mass ratios (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Briefly, 9.5 µL of the pEt_20/gene complex solution containing 300 ng of gene and corresponding polymer at their respective mass ratios was mixed with 0.5 µL of 5× DNA loading dye.…”

“…Polycarbonates are biodegradable polymers that have been studied for biomedical applications such as drug/gene delivery [19][20][21][22][23][24][25][26][27] and antimicrobial materials [28][29][30] due to their good biocompatibility and ease of incorporating various functional groups. Recently, we reported broad-spectrum antimicrobial guanidinium-functionalized polycarbonates with unique mechanism: membrane translocation followed by precipitation of cytosolic materials.…”

Dithiolane-Crosslinked Poly(ε-caprolactone)-Based Micelles: Impact of Monomer Sequence, Nature of Monomer, and Reducing Agent on the Dynamic Crosslinking Properties

“…The copolymerization of CL and DTC using DPP or TBD as catalyst followed a similar procedure with slight modifications: molar ratios of CL/DTC/mPEG-OH/DPP and CL/DTC/mPEG-OH/TBD were adjusted to 9/4/1/10 13 and 9/4/1/0.25, 46 respectively. The applied reaction times are shown in Table 1 , and when TBD was used as catalyst, the reaction was carried out at room temperature (RT) and the termination reagent was replaced by benzoic acid.…”

“… 6 − 8 These different mechanisms might lead to different polymerization behaviors of monomers, thus yielding copolymers with different structural parameters, e.g ., composition, microstructure ( i.e ., the monomer sequence), and polydispersity, which are important factors that determine the properties of polymers, and thus their applications. 9 − 13 For instance, it has been demonstrated that an acidic organocatalyst, diphenyl phosphate (DPP), and a basic organocatalyst, TBD, have different ring-opening copolymerization behaviors of cyclic carbonate-based monomers, leading to copolymers with random and blocky microstructures, respectively. 13 In this regard, understanding the role of the catalyst in the kinetics of polymerization becomes important since it offers an important opportunity to satisfy different applications by preparing polymers with different molecular features (monomer sequence, predictable molar masses, narrow molecular weight distribution, etc.)…”

“… 9 − 13 For instance, it has been demonstrated that an acidic organocatalyst, diphenyl phosphate (DPP), and a basic organocatalyst, TBD, have different ring-opening copolymerization behaviors of cyclic carbonate-based monomers, leading to copolymers with random and blocky microstructures, respectively. 13 In this regard, understanding the role of the catalyst in the kinetics of polymerization becomes important since it offers an important opportunity to satisfy different applications by preparing polymers with different molecular features (monomer sequence, predictable molar masses, narrow molecular weight distribution, etc.) via catalytic tuning.…”