Preparation of PLA-TPU-Nanoclay composites and characterization of their morphological, mechanical, and shape memory properties

Abstract

In this study, a combination of polylactic acid polymer and thermoplastic polyurethane with the addition of nano-clay particles was used. The reason for using clay nanoparticles and their strength is the low price and availability of this material. Adding nano-clay particles to the polymer composition improves the mechanical properties of the composite as they will interact with functional groups of the polymer. The results of the FTIR spectroscopy confirmed the presence of three components in the compound indicating that no chemical reactions occurred among the three components during the compounding process. The FE-SEM images taken from the compounds showed that TPU and nano-clay particles were evenly distributed in the PLA matrix. The DMTA results were utilized to determine the transfer temperature of the compounds as well as the storage and loss modulus and the shape memory properties. The XRD spectroscopy was used to determine the crystallinity and exfoliation of the nanoparticles. The mechanical properties of the fabricated polymer compounds were determined. It was found that the sample with 3% by weight of clay nanoparticles had the highest strength, and the sample with 5 wt% of clay nanoparticles had the highest toughness among nanocomposites. According to the hardness measurement, the sample with 5% by weight of clay nanoparticles has the highest hardness amongst all prepared composites. The memory properties of the prepared nanocomposites showed a significant improvement with increasing the amount of nanoparticles. This study showed the suitability and efficiency of PLA, TPU, and clay nanoparticle melt mixing methods in achieving a relatively tough shape memory composite. At the same time, this method is also inexpensive and scalable.

Keywords: Mechanical properties; Nano-clay; Polylactic acid; Shape memory; Thermoplastic polyurethane.