Investigation on the role of nanoclay and nano calcium carbonate on morphology, rheology, crystallinity and mechanical properties of binary and ternary nanocomposites based on PLA
Zahra Asadi, Azizeh Javadi, Fatemeh Mohammadzadeh, Kosar Alavi
Abstract
In this work, binary poly (lactic acid) (PLA)/nanoclay (NC), PLA/nano calcium carbonate (NCC) nanocomposites and ternary PLA/NC/NCC samples were prepared via melt mixing. The morphology, rheology, crystallinity and mechanical properties of neat PLA and prepared nanocomposites were studied. The results of the X-ray diffraction (XRD) showed an increase in distance between NC platelets in both binary and hybrid samples, indicating the intercalation of NC particles. It was found that in the hybrid samples, the increase in the distance between platelets was greater than the binary one. The rheological studies showed an increase in the storage modulus of samples at low frequencies in comparison to neat polymer. The tensile test showed an enhancement of modulus and tensile strength of all nanocomposite samples. The highest tensile strength was found in the hybrid sample containing 3 wt.% of NC and 7 wt.% of NCC which was 37% higher than neat PLA. Moreover, the results of differential scanning calorimetry (DSC) showed that the crystalline temperature of hybrid sample containing 3 wt.% of NC and 7 wt.% of NCC was about 8 °C higher than that of the neat PLA, which could be due to the increase in the rate of crystallinity.