Similarities between homopolymers and triblock copolymers derived from poly(ε-caprolactone) (PCL) macrodiols (HOPCL–E–PCLOH and HOPCL–PEG–PCLOH) and their poly(ester-ether-urethanes): synthesis and characterization

Monodisperse oligo(ε-caprolactones) with terpenes and alkyl end-groups: synthesis, isolation, characterization, and antibacterial activity

Linear aliphatic oligoesters derived from ε-caprolactone (CL) were synthesized by ring-opening polymerization (ROP) using terpene alcohols that have antibacterial activity as initiators (nerol, geraniol, β-citronellol and farnesol). Ammonium decamolybdate (NH4)8[Mo10O34] was used as a catalyst. From previous oligoesters, monodisperse species of monomers, dimers, and trimers were isolated by flash column chromatography (FCC). Poly(ε-caprolactone) (PCL) oligoesters [oligo(CLs)] and monodisperse oligomeric species were characterized by different analytical techniques, such as nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization quadrupole time-of-flight mass spectrometry (ESI/MS-QTOF), and Fourier-transform infrared (FTIR) spectroscopy to determine the chemical nature of the samples. The thermal properties were analyzed by differential scanning calorimetry (DSC), which showed significant differences between the olefin and alkyl terminal groups. The end-groups affected crystalline domains according to the crystallization temperatures (T c), melting temperatures (T m), and glass transition temperature (T g) of the oligo(CLs) and monodisperse oligomeric species. In addition, the results of thermogravimetric analysis (TGA) suggest that the thermal degradation in the case of the monomer and dimer species with olefin terminal groups is similar compared to that with the alkyl terminal group. Due to the antimicrobial properties of olefinic initiators, microbiological tests were carried out on the monodisperse oligomeric species through studies of the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiograms. This is the first time in the literature that monodisperse oligomers derived from PCL functionalized with terpenes and alkyl end-groups were tested in terms of their antibacterial properties. The results indicated that these monodisperse species could lead to new antibiotic compounds with potential applications.

Biodegradable and Biocompatible Thermoplastic Poly(Ester-Urethane)s Based on Poly(ε-Caprolactone) and Novel 1,3-Propanediol Bis(4-Isocyanatobenzoate) Diisocyanate: Synthesis and Characterization

A series of non-toxic biodegradable and biocompatible polyurethanes bearing p-aminobenzoate moieties are presented. The introduction of this attractive motif was carried out by the synthesis of a novel isocyanate. These biodegradable polymers were chemically and physically characterized by several techniques and methods including bioassay and water uptake measurements. The molecular weight of the soft segment (poly-ε-caprolactone, PCL) and hard segment crystallinity dictated the mechanical behavior and water uptake. The behavior of short PCL-based polyurethanes was elastomeric, whilst increasing the molecular weight of the soft segment led to plastic polyurethanes. Water uptake was hindered for long PCL due to the crystallization of the soft segment within the polyurethane matrix. Furthermore, two different types of chain extender, hydrolyzable and non-hydrolyzable, were also evaluated: polyurethanes based on hydrolyzable chain extenders reached higher molecular weights, thus leading to a better performance than their unhydrolyzable counterparts. The good cell adhesion and cytotoxicity results demonstrated the cell viability of human osteoblasts on the surfaces of these non-toxic biodegradable polyurethanes.