Thermo-mechanical properties of poly ε-caprolactone/poly l -lactic acid blends: Addition of nalidixic acid and polyethylene glycol additives

Abstract

Abstract:The search for ideal biomaterials is still on-going for tissue regeneration. In this study, blends of Poly ε-caprolactone (PCL) with Poly l-lactic acid (PLLA), Nalidixic Acid (NA) and Polyethylene glycol (PEG) were prepared. Mechanical and thermal properties of the blends were investigated by tensile and flexural analysis, DSC, TGA, WXRD, MFI, BET, SEM and hot stage optical microscopy. Results showed that the loading of PLLA caused a significant decrease in tensile strength and almost total eradication of the elongation at break of PCL matrix, especially after PEG and NA addition. Increased stiffness was also noted with additional NA, PEG and PLLA, resulting in an increase in the flexural modulus of the blends.Isothermal degradation indicated that bulk PCL, PLLA and the blends were thermally stable at 200°C for the duration of 2h making extrusion of the blends at this temperature viable.Morphological study showed that increasing the PLLA content and addition of the very low viscosity PEG and powder NA decreased the Melt Flow Indexer and increased the viscosity.At the higher temperature the PLLA begins to soften and eventually melts allowing for increased flow and, coupling this with, the natural increase in MFI caused by temperature is enhanced further. The PEG and NA addition increased dramatically the pore volume which is important for cell growth and flow transport of nutrients and metabolic waste.

Effect of poly ethylene glycol on the mechanical and thermal properties of bioactive poly(ε-caprolactone) melt extrudates for pharmaceutical applications

“…We have already reported our investigation of the effect of PLLA addition on the thermomechanical properties of PCL/NA blends [11]; here we report on the effect of PEG on the mechanical and thermal properties of PCL/NA blends as prepared by hot melt extrusion. PEG is approved by FDA for use in medical devices, it is commonly used for PEGylation and it can transfer its properties to other molecules by covalent bonding, which can result in toxic molecules becoming non-toxic and hydrophobic molecules becoming soluble at certain ratios [13,14].…”

“…Full details regarding the polymers physical properties and reason of selection can be found in [10,11]. NA's chemical formula is C12H12N2O3 and is chemically known as 1,4-dihydro-1-ethyl-7-methyl-4-oxo-1,8-naphthridine-3-carboxylic acid.…”

“…The method used for tensile and flexural analysis, dynamic mechanical thermal analysis, DSC, TGA and wide angle XRD is identical to that described in [10,11].…”

“…PCL blends/compounds are used in sutures, ultra-thin films for dressing cutaneous wounds [6], contraceptive and fixation devices [7,8], dentistry as root fillings [9] and pharmaceutical applications for manufacturing polymeric devices for controlled drug delivery [10]. Dosage formulations for drug delivery have received excessive attention as they can transfer drugs, genes and proteins via various administration routes, including intravenous, ocular, nasal and oral [11]. A previous study has focused on controlling the release profile of a model active pharmaceutical ingredient (API), the antibacterial nalidixic acid (NA), from PCL by blending with PEG [10].…”

Mechanical characterization and modelling of the temperature-dependent impact behaviour of a biocompatible poly(L-lactide)/poly(ε-caprolactone) polymer blend

“…(Douglas et al, 2015;Hwang and Todo, 2012;Muliana and Rajagopal, 2012). There are few studies regarding the basic mechanical properties of these polymer blends at high strain rates and body temperature.…”