Synthesis and Properties of Functionalized Poly(ε-caprolactone); Chain Polymerization Followed by Polycondensation in One Pot with Initiator and Catalyst in One Molecule. Synthesis and Molecular Structures

Abstract

Poly(ε-caprolactone) and polylactide are biocompatible and biodegradable polymers. Both are hydrophobic, and their backbones do not contain reactive groups. The existing methods of functionalization are mostly based on copolymerization with functional comonomers that require additional syntheses. In the method of functionalization described in this work, special end groups are introduced that allow, after chain polymerization of ε-caprolactone (CL), the following step, in one pot, namely polycondensation. Chain polymerization was initiated/catalyzed by hydroxymethylphosphonic acid. Since one of the end groups contains two acidic groups, one is used in polycondensation with the hydroxyl group from the other end group and the other one, becoming less reactive, is introduced to the polymer chains. Thus, polymer chains contain phosphoacidic groups along the chain. When, for example, CL was the first chain polymerized to an oligomer of the molar mass ∼3 × 10 3 g•mol −1 , its further polycondensation resulted in polymers with a molar mass approaching ∼10 5 g•mol −1 , with ∼30 acidic groups along the statistical chain.

Polycaprolactone and its derivatives for drug delivery

“…92 In the literature functionalization of PCL with polylactide using hydromethyl phosphonic acid as the catalyst, which added end groups required for polycondensation, this lead to the formation of macromolecules with acidic groups. 93 PCL-PEG-PCL triblock copolymers are also synthesized by ROP using DPP as catalyst. 94 Amokrane et al used UV radiation to graft poly (sodium styrene sulfonate) (polyNaSS) on PCL this involved oxidation of PCL surface followed by submersion in NaSS.…”

“…Some of the possible methods of functionalization are modifying the polymer back bone, polymerization of functionalized monomers, or copolymerization with other monomers 92 . In the literature functionalization of PCL with polylactide using hydromethyl phosphonic acid as the catalyst, which added end groups required for polycondensation, this lead to the formation of macromolecules with acidic groups 93 . PCL‐PEG‐PCL triblock copolymers are also synthesized by ROP using DPP as catalyst 94 .…”

Design, Synthesis and Actual Applications of the Polymers Containing Acidic P–OH Fragments: Part 1. Polyphosphodiesters

“…have shown that hydroxymethyl phosphonic acid can act as a catalyst and initiator of the ROP of ε-caprolactone (εCL) with the formation of εCL oligomers containing reactive groups on both ends of the macromolecule. Very recently they demonstrated that these oligomers can be subjected to polycondensation at 100–110 °C with a formation of PCPAs ( M n up to 25 kDa) ( Scheme 8 ) with mostly linear microstructure ( 31 P NMR data) [ 60 ].…”

Replacing all petroleum-based chemical products with natural biomass-based chemical products: a tutorial review

“…PCL: polycaprolactone: (C 6 H 10 O 2 ) n PCL is a caprolactone polymer with a molecular weight of more than 25 000 and is a biodegradable thermoplastic resin with a relatively low melting temperature (60 °C), which can be obtained by polymerizing 3-polycaprolactone. 25,26 Owing to the high heat stability and low melting temperature of PCL, thermal decomposition and hydrolysis are not serious problems in the extruder, making PCL suitable for the production of lms, sheet molding, injection molding, and yarning. Attempts have been made to utilize PCL for the production of agricultural lms and compost bags, as well as glue, because of its high adhesion property due to its high crystallinity.…”