Novel Zinc-Catalytic Systems for Ring-Opening Polymerization of ε-Caprolactone

Abstract

Polycaprolactone (PCL) is a biodegradable synthetic polymer that is currently widely used in many pharmaceutical and medical applications. In this paper we describe the coordination ring-opening polymerization of ε-caprolactone in the presence of two newly synthesized catalytic systems: diethylzinc/gallic acid and diethylzinc/propyl gallate. The chemical structures of the obtained PCLs were characterized by 1H- or 13C-NMR, FTIR spectroscopy and MALDI TOF mass spectrometry. The average molecular weight of the resulting polyesters was analysed by gel permeation chromatography and a viscosity method. The effects of temperature, reaction time and type of catalytic system on the polymerization process were examined. Linear PCLs with defined average molecular weight were successfully obtained. Importantly, in some cases the presence of macrocyclic products was not observed during the polymerization process. This study provides an effective method for the synthesis of biodegradable polyesters for medical and pharmaceutical applications due to the fact that gallic acid/propyl gallate are commonly used in the pharmaceutical industry.

Efficient Diethylzinc/Gallic Acid and Diethylzinc/Gallic Acid Ester Catalytic Systems for the Ring-Opening Polymerization of rac-Lactide

“…As was shown, the content of cyclic products generally increased with increasing of the temperature and polymerization time. In our previous paper, we reported that when ROP of CL was carried out in the presence of ZnEt 2 /PGAc catalytic system at 40–60 °C within 48 h or at 80 °C within 6 h, macrocyclic products did not formed [40]. As shown in Table 1, Table 2, Table 3 and Table 4, trends of macrocyclization process during ROP of rac -LA in the presence of ZnEt 2 /PGAc were similar.…”

“…The same trend was observed in our previous experiments concerning ROP of CL in the presence of ZnEt 2 /PGAc or ZnEt 2 /GAc catalytic systems. This likely demonstrates that only -OZn- active species are formed in the first case (ZnEt 2 /PGAc) whereas in the second case (ZnEt 2 /GAc), -COOZn- species are also formed [40].…”

“…100% in some cases). Most importantly, when the ROP of CL was carried out in the presence of ZnEt 2 /PGAc catalytic system at 40–60 °C within 48 h or at 80 °C within 6 h, no macrocyclic products were formed [40].…”

Switching from linear to cyclic δ‐Polyvalerolactone synthesized via zeolitic imidazolate framework as a catalyst: A promising approach

“…The NMR spectra of PVL is shown in Figure . Each characteristic peak of the proton is detected and allocated, conform to the structure of PVL described in previous reports . The methylene signal of PVL is observed around 4.17 ppm while the other chemical peaks of PVL were observed around 2.44, and 1.78 ppm respectively confirming the formation of PVL.…”

Treatment of Coral Wounds by Combining an Antiseptic Bilayer Film and an Injectable Antioxidant Biopolymer

“…In recent years, the natural polymer hyaluronic acid (HA) has also played an important role in the pharmaceutical field due to its anti-inflammatory, regenerative and anti-age properties. By the same token, polycaprolactone (PCL) is a biodegradable synthetic polyester 26 that has been broadly applied in biomedical fields for the preparation of controlled drug delivery systems such as implants and scaffolds 27,28 . It has been recently combined or co-polymerized with effective natural antioxidants such as vanillic, ferulic, p-coumaric and syringic acids 29 .…”