Effect of low nanoclay content on the physico-mechanical properties of poly(lactic acid) nanocomposites

Abstract

In this work, three different nanoclays (1.44P, 1.34MN, and Cloisite 15A) were used to reinforce an injection grade poly(lactic acid) (PLA). The nanocomposites (NCs) were prepared using three different nanoclay concentration levels (1, 3, and 5 wt%) in a twin-screw extruder. To evaluate their mechanical performance (static and dynamic tests) and thermal properties, the respective samples were obtained by injection molding. Results showed that the three nanoclays significantly increased the tensile and flexural modulus of the injection grade PLA. The 1.34MN NCs also showed improvement in the tensile strength. An increment in flexural strength was obtained with 1.34MN and 1.44P nanoclays, while with nanoclay 15A, the flexural strength decreased. Additionally, the use of 5 wt% of 1.44P nanoclay allowed an increase in impact strength while using 1.34MN and 15A nanoclays, the impact strength was similar to the one observed for pure PLA. In general, mechanodynamic analysis results showed that storage modulus increased with nanoclay content; while thermogravimetric analysis indicated that none of the nanoclays has a significant effect over the degradation temperature of pure PLA. Differential scanning calorimetry results showed that the crystallinity of PLA is enhanced with nanoclay inclusion. For 1.34MN NCs, X-ray diffraction observations exposed that the mineral clay relative intensity peaks disappeared indicating nanoclay exfoliation, which contributes to the increase in tensile and flexural strength in the NCs. Nevertheless for 1.44P and 15A nanoclays, an increase in the interlayer distance (intercalation) was detected.

Glycidyl Methacrylate as Compatibilizer of Poly(lactic Acid)/Nanoclay/Agave Fiber Hybrid Biocomposites: Effect on the Physical and Mechanical Properties

“…6. The inclusion of nanoclay in the PLA did not show any significant effect in the impact strength, as it was reported before by Robledo-Ortíz et al (2019) probably due to the low amount of nanoclay content which is not significant in comparison to the high values of absorbed energy supported by the neat PLA. Jandas et al (2013) reported that impact strength decreased with the addition of modified montmorillonite to PLA.…”

Effect of Halloysite Nanotube on Mechanical Properties, Thermal Stability and Morphology of Polypropylene and Polypropylene/Short Kenaf Fibers Hybrid Biocomposites

“…Their ductility is also not reduced as they all break at around ~30% of strain. This gain can be attributed to reduced creep by the presence of HNT nanoclay or increased crystallinity owing to the nucleating effect of HNTs [ 28 , 29 , 30 ]. However, further addition of HNTs diminished the gain and for 10 vol.% content of HNTs, the tensile strength is even reduced by 7%, while the strain to break is reduced to 2.8%.…”

Impact of hybrid nanosilica and nanoclay on the properties of palm rachis-reinforced recycled linear low-density polyethylene composites

“…In addition, another reason for decrease in impact strength may be the stiffening of polymer chains which result in less ability to absorb impact energy. 34,35…”

“…In addition, another reason for decrease in impact strength may be the stiffening of polymer chains which result in less ability to absorb impact energy. 34,35 Figure 9 shows the hardness of composites containing different contents of NS, NC, and NSNC. Incorporation of NS at (2, 4, and 6 phc) slightly increased the hardness by 1.45%, 3%, and 5.1%, respectively.…”