PREPARATION AND CHARACTERIZATION OF POLYLACTIC ACID/SILICA AND POLYLACTIC ACID/CLAYS BIONANOCOMPOSITE ELECTROSPUN SYSTEMS

Abstract

Introduction Electrospinning is a versatile process technology for the production of fibers ranging from nano- to micro-scale. In order to develop high performance electrospun systems, the use of nanofillers is achieving more and more interest. In this context, silica (Si) and clays (Cl) are often used as fillers due to the possibility to combine the advantages of polymeric materials, such as light weight and flexibility, and inorganic materials, such as high mechanical strength, heat stability, and chemical stability. In this work, the morphology of PLA/Si and PLA/Cl were evaluated on two different weight ratios: 99/1 and 95/5 wt/wt. Material and Methods The nanoparticles were added to a solution of TCM/Ac (2:1 volume). PLA (10 wt% with respect to the solvent phase) was then added to the mixture and completely dissolved by continuous magnetic stirring. Nanofibrous mats were produced with a filler mass ratio equal to 1% and 5%. The nanofibers were collected on a grounded rotary drum rotating at 10 rpm. The morphology of the materials was studied by using a Scanning Electron Microscope (SEM). Results SEM images revealed that PLA showed the typical morphology of an electrospun material with smooth and homogenous fibers in the nearly-nanoscale and randomly oriented. Fillers added at 1 wt% are well dispersed in the polymer matrix. Si caused a slight increase and Cl a slight reduction of the fiber diameter. PLA/Si 5 wt% fibers are characterized by a worst particles’ distribution and higher fiber diameters if compared with PLA/Cl 5 wt%. Discussion The different dispersion degree observed at high filler concentration can be likely ascribed to the different affinity of the nanoparticles with both the polymer matrix and the solvent systems. The different fiber diameter can be ascribed to the viscosity of the polymeric solution. Silica induced an increment of the viscosity and a consequent increase of the fiber diameter. The lower fiber diameter observed for PLA/Cl nanocomposites can be ascribed to the reduction of the viscosity probably due to a degradation of PLA, as already observed in other works.