Preparation and characterization of NaOH treated micro-fibrous polyethylene terephthalate nonwovens for biomedical application

Recently, micro-fibrous polyethylene terephthalate nonwovens have been investigated and applied in many biotechnological and biomedical applications. NaOH treatment has been used as a simple and cost effective method to alter surface properties, in order to overcome their surface inertness. However, the effects of this treatment on the matrices mechanical and physical properties; particularly, those composed of fibers with small diameter (<20 μm); have been poorly investigated. This study investigates the variations, imposed by the NaOH treatment, in the physical and tensile properties of micro-fibrous polyethylene terephthalate mats. Polyethylene terephthalate webs with two different average fiber diameters of 6±2.5 and 10±4 μm were produced by melt blowing process. A number of these webs were consolidated to prepare fibrous matrices using a thermal treatment. The matrices were treated using NaOH 1 N at 65 °C for various durations (ranging from 20 min to 24 h). In addition to their physical properties such as weight loss, thickness, porosity, shrinkage and surface density; their morphology and tensile properties were also evaluated using scanning electron microscopy and micromechanical tester, respectively. In general, by increasing treatment duration, weight loss, porosity, and shrinkage increased, while thickness and density decreased. As a result of treatment duration, pores appeared on the surface of individual fibers, and tensile stress and Young’s modulus decreased while tensile strain increased. Mats with different fiber diameters showed different physical and mechanical properties. These findings suggested that the structure of the matrices and the properties required for its end use, for biomedical applications including scaffolding materials for tissue engineering, should be considered in selecting NaOH treatment condition.

Research highlights
► Surface degradation of PET matrices via NaOH treatment created micro and macro-morphological changes on the structures and altered the physical and mechanical properties of the mats which depended on the treatment duration and also fiber diameter.
► Investigating all the micro- and macro-morphological, physical and tensile properties in one study thoroughly explains the impact of this approach on the substrate.
► Identifying the above mentioned parameters on the melt blown nonwoven PET matrices, as a potential biomaterial; adds valuable knowledge to the biomaterial science.
► It is suggested that in NaOH treatment of PET matrices, the selected treatment condition should be compatible with the matrices structure and also the properties required for their end use, in order to control variations imposed in the matrices properties.