Characterization and thermal degradation kinetics of poly(l -lactide) nanocomposites with carbon nanotubes

Abstract

The purpose of this research was to study the thermal degradation kinetics of nanocomposites of poly(l‐lactide) (PLLA) with carbon nanotubes (CNT) in order to provide further insight into their thermal stability. Nanocomposites were prepared by solvent casting with 1, 3, and 5% by weight of pristine CNT (P‐CNT) or functionalized CNT (F‐CNT), and were characterized using infrared spectroscopy, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic‐mechanical‐thermal analysis. The kinetic parameters of thermal decomposition were determined employing Coats‐Redfern method to calculate the reaction order and E2 function model to calculate the activation energy (Ea). We found no major changes in PLLA glass transition temperatures due to CNT presence, but melt‐crystallization temperature increased slightly in some composites. In general, composites consisting of 3% or 5% of F‐CNT had superior thermal stability than did pure polymer or P‐CNT composites. This improved thermal stability was revealed by slightly higher degradation and onset temperatures, and Ea obtained from kinetic analysis. In addition, 3% or 5% of F‐CNT in PLLA composites slightly enhanced the storage modulus above the glass transition. Therefore, functionalization promoted, in some extent, better morphology and dispersion of CNT into the matrix, which was responsible for improved thermal stability and thermomechanical performance of composites at higher temperatures relative to pure polymer. POLYM. ENG. SCI., 55:710–718, 2015. © 2014 Society of Plastics Engineers

Sustainable and Antioxidant Lignin–Polyester Copolymers and Nanofibers for Potential Healthcare Applications

“…The presence of the CNT wall did not promote enough interactions at the interface that could induce a change in the behavior during thermal transitions. 50 With respect to the crystallization behavior of PLLA/lignin−PCLLA nanofibers, the DSC results do not reveal a consistent trend. However, since the materials do not display a sharp T cc transition point, subtle changes in the PLLA and lignin−PCLLA interactions may remain undetected.…”

“…The insignificant alteration of the T g and T m values of PLLA/lignin–PCLLA nanofibers is consistent with the previous report on the PLLA/carbon nanotube (CNT) composite system. The presence of the CNT wall did not promote enough interactions at the interface that could induce a change in the behavior during thermal transitions . With respect to the crystallization behavior of PLLA/lignin–PCLLA nanofibers, the DSC results do not reveal a consistent trend.…”

Performance of poly(lactic acid)/ cellulose nanocrystal composite blown films processed by two different compounding approaches

“…5. Table 3 lists the band assignments for the wavenumbers of peaks found in these spectra to their corresponding functional groups [6,36,[50][51][52][53][54][55].…”

Characterization of maghemite (γ-Fe2O3)-loaded poly-l-lactic acid/thermoplastic polyurethane electrospun mats for soft tissue engineering

“…In order to improve 3D scaffold characteristics, two main factors of fabrication technique and proper biomaterial selection are debatable. Such scaffolds can be fabricated using synthetic, natural materials, or a combination of both via traditional and modern techniques [20][21][22].…”