Cyclic poly(ε -caprolactone) synthesized by combination of ring-opening polymerization with ring-closing metathesis, ring closing enyne metathesis, or “click” reaction

Synthesis, Properties, and Applications of Bio-Based Cyclic Aliphatic Polyesters

Cyclic polymers have long been reported in the literature, but their development has often been stunted by synthetic difficulties such as the presence of linear contaminants. Research into the synthesis of these polymers has made great progress in the past decade, and this review covers the synthesis, properties, and applications of cyclic polymers, with an emphasis on bio-based aliphatic polyesters. Synthetic routes to cyclic polymers synthesized from bioderived monomers, alongside mechanistic descriptions for both ring closure and ring expansion polymerization approaches, are reviewed. The review also highlights some of the unique physical properties of cyclic polymers together with potential applications. The findings illustrate the substantial recent developments made in the syntheses of cyclic polymers, as well as the progress which can be made in the commercialization of bio-based polymers through the versatility this topology provides.

Cyclic topology effects on the morphology of biocompatible and environment-friendly poly(ε-caprolactone) under nanoscale film confinement

Quantitative grazing incidence X-ray scattering analysis combined with X-ray reflectivity using synchrotron radiation sources was explored for the first time cyclic topology effects on the nanoscale film morphology of poly(ε-caprolactone).

Blocking-cyclization technique for precise synthesis of cyclic polymers with regulated topology

Ring-closure and ring-expansion techniques are the two routes for extensive synthesis of cyclic polymers. Here, we report an alternative blocking-cyclization technique referred to as the third route to prepare cyclic polymers with regulated ring size and ring number by ring-opening metathesis polymerization of di- and monofunctional monomers in a one-pot process, where the polymer intermediates bearing two single-stranded blocks are efficiently cyclized by the cyclizing unit of propagated ladderphane to generate corresponding mono-, bis-, and tricyclic polymers, and the well-defined ladderphane structure plays a crucial role in forming the cyclic topology. Monocyclic polymer is further modified via Alder-ene reaction and the cyclic molecular topology is clearly demonstrated. The diversity features of cyclic polymers are comprehensively revealed. This strategy has broken through the limitations of previous two cyclizing routes, and indeed opens a facile and popular way to various cyclic polymers by commercial Grubbs catalyst and conventional metathesis polymerization.

Precise Synthesis, Properties, and Structures of Cyclic Poly(ε-caprolactone)s

Cyclic PCL (c-PCL) has drawn great attention from academia and industry because of its unique, unusual structure and property characteristics due to the absence of end groups in addition to the biocompatibility and biodegradability of its linear analogue. As a result of much research effort, several synthetic methods have been developed to produce c-PCLs so far. Their chain, morphology and property characteristics were investigated even though carried out on a very limited basis. This feature article reviews the research progress made in the synthesis, morphology, and properties of c-PCL; all results and their pros and cons are discussed in terms of purity and molecular weight distribution in addition to the cyclic topology effect. In addition, we attempted to synthesize a series of c-PCL products of high purity by using intramolecular azido-alkynyl click cyclization chemistry and subsequent precise and controlled separation and purification; and their thermal degradation and phase transitions were investigated in terms of the cyclic topology effect.

Efficient synthesis of well-defined cyclic polystyrenes using anionic polymerization, silicon chloride linking chemistry and metathesis ring closure

An efficient method for the synthesis of well-defined cyclic polystyrenes using anionic polymerization, silicon chloride linking chemistry, and metathesis ring closure has been developed.

2,4-Dinitrobenzenesulfonic acid in an efficient Brønsted acid-catalyzed controlled/living ring-opening polymerization of ε-caprolactone

2,4-Dinitrobenzenesulfonic acid as an efficient Brønsted acidic catalyst has been evaluated for the controlled/living ring-opening polymerization of ε-caprolactone end-functionalized, α,ω-dihydroxy telechelic poly(ε-caprolactone), and diblock copolymers were also synthesised successfully.