Biobased Copolymers via Cationic Ring-Opening Copolymerization of Levoglucosan Derivatives and ε-Caprolactone

Abstract

Simultaneous ring-opening copolymerization is a powerful strategy for the synthesis of highly functional copolymers from different types of cyclic monomers. Although copolymers are essential to the plastics industry, environmental concerns associated with current fossil-fuel-based synthetic polymers have led to an increasing interest in the use of renewable feedstock for polymer synthesis. Herein, we report a scalable synthetic platform to afford unique polysaccharides with different pendant functional groups from biomass-derived levoglucosan and ε-caprolactone via cationic ring-opening copolymerization (cROCOP). Biocompatible and recyclable bismuth triflate was identified as the optimal catalyst for cROCOP of levoglucosan. Copolymers from tribenzyl levoglucosan and ε-caprolactone, as well as from tribenzyl and triallyl levoglucosan, were successfully synthesized. The tribenzyl levoglucosan monomer composition ranged from 16% to 64% in the copolymers with ε-caprolactone and 22% to 79% in the copolymers with triallyl levoglucosan. The allylic levoglucosan copolymer can be utilized as a renewably derived scaffold to modify copolymer properties and create other polymer architectures via postpolymerization modification. Monomer reactivity ratios were determined to investigate the copolymer microstructure, indicating that levoglucosan-based copolymers have a gradient architecture. Additionally, we demonstrated that the copolymer glass transition temperature (T g, ranging from −44.3 to 33.8 °C), thermal stability, and crystallization behavior could be tuned based on the copolymer composition. Overall, this work underscores the utility of levoglucosan as a bioderived feedstock for the development of functional sugar-based copolymers with applications ranging from sustainable materials to biomaterials.

Levoglucosan and levoglucosenone as bio-based platforms for polymer synthesis

“…1 The cationic ring opening polymerisation of a levoglucosan tri-monomer was first reported more than 50 years ago. 26,27 Significant progress on cROP has been made by Reineke and coworkers 1,28 as initial reports involve very low polymerisation temperatures (−60 °C), with the highly toxic and corrosive initiator phosphorus pentafluoride (PF 5 ).…”

Modular Approach to Bio-Based Poly(enol ether)s with Tunable Thermal Properties and Degradability

“…The recent applications of controlled polymerization techniques in biomass resources have unlocked the access to a library of well-defined biomass-derived polymers with novel structures, predetermined molecular weights, and desired properties. , In this emerging direction, biomass-derived small molecules are incorporated with a polymerizable functionality that allows them to polymerize via a specific controlled polymerization mechanism such as reversible-deactivation radical polymerization, − cationic ring-opening polymerization, − and ring-opening metathesis polymerization (ROMP). − Among those polymerization techniques, ROMP has received an increasing interest in producing biobased polymers due to its excellent functional group compatibility and high tolerance to air and water . To date, a variety of biomass-derived feedstocks, including apopinene, δ-pinene, , terpenoid, rosin, lignin, fatty acid, levoglucosenone, , sinapic acids, itaconic anhydride, vanillin, and d -glucose, have been transformed into synthetic polymers by the ROMP method.…”

Fine-Tuning Gradient Copolymers with Diverse and Controlled Microstructure and Mechanical Properties via Monomer Sequence Distribution: An In Silico Study

“…The properties of copolymers are highly influenced by their composition and sequence distribution, which determine the microstructural morphology. − Gradient copolymers represent a novel class of copolymers that feature a gradual change in composition along the chain backbone. The composition profile of the chains gradually changes from one type of monomer to another, leading to unique properties compared to block and random copolymers. ,, For example, gradient copolymers exhibit lower interfacial tension, − a wider glass transition temperature, ,− higher transmittance in the visible light range, and high ionic conductivity. , As a result, they can be used in various applications such as compatibilizer, − damping materials, ,, shape-memory polymer materials, thermoplastic elastomers, − and drug delivery carriers. − In addition, they hold promise for use in the fields of optoelectronic materials and biomedical applications.…”

“…There are several techniques for synthesizing gradient copolymers, including anionic , and cationic , polymerization, ring-opening polymerization, ,− and controlled radical polymerization (CRP). ,,− The advantage of the CRP method is that the chain structure can be precisely controlled by the simultaneous or sequential reaction of different monomers, resulting in the synthesis of various types of copolymers. There are two primary strategies for achieving compositional gradient changes in copolymers.…”