Morphological, mechanical, and thermal characterization of biopolymer composites based on polylactide and nanographite platelets

Abstract

This work focuses on development and optimization of polylactide (PLA) and nanographite platelets (NGP) based composites to display possible superior mechanical and improved thermal stability. Melt blending and dry mixing methods of fabrication were employed at temperature of 180°C. Different Loading fractions of NGP were incorporated into polymer matrix. Morphological evaluation techniques such as XRD and TEM were applied to determine the degree of dispersion of NGPs into PLA matrix. Mechanical properties were evaluated and correlated to structural morphologies of PLA/NGP composites. Thermal properties of composites were studied to examine possible changes in Tg, Tc, Tm, and percentage crystallinity of these composites. The effect of mixing was also explored through double extrusion of some samples. It was concluded that composites containing 3 wt% NGP showed optimum mechanical performance without any significant changes in the thermal characteristics. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Extensional Rheological Investigation of Biodegradable Polylactide-Nanographite Platelet Composites via Constitutive Equation Modeling

“…A steady transformation from linear to nonlinear behavior occurred at strain ≈10; hence, in order to calculate the damping functions of the samples, the nonlinear stress relaxation measurements were conducted at strain magnitudes above 10. The formation of the percolation network of the NGPs within PLA matrix at 180 °C was methodically studied by the authors in earlier publications . Briefly, the percolation threshold of the samples (i.e.…”

“…The authors have already reported the morphological, thermal, mechanical and shear rheological characterizations of the samples . Figure illustrates the transmission electron microscopy (TEM) of PLA/NGP composites of this study, which were comprehensively investigated and reported elsewhere .…”

“…The first and foremost source of error during the processing and characterization steps is likely to be the thermal degradation of PLA based samples at elevated temperatures which suggests that efficient drying (<250 ppm) is an indispensable stage prior to the processing and characterization of the samples . Detailed drying procedure of these samples are explained elsewhere …”

“…Mechanical, rheological and barrier properties of PLA could be enhanced through the addition of a variety of nanofiller reinforcements such as carbon nanotubes (CNTs), silicate clay and nanographite platelets (NGP) layered double hydroxide . NGPs possess a combination of layered structure of silicate clay, as well as the extraordinary thermal and mechanical properties of CNTs .…”

“…TEM micrographs of PLA/NGP composites at 0.2 μm magnification microtomed from compression moulded specimens: PLA01 (a and b), PLA02 (c and d), and PLA03 (e and f) …”