Thermal stability, crystallization behavior, and phase morphology of poly(ϵ‐caprolactone)diol‐grafted‐multiwalled carbon nanotubes

Abstract

Poly(e-caprolactone)diol (PCL) with five different molecular weights (e.g., 400, 2000, 3000, 4000, and 8000 g/mol) was grafted onto the surface of functionalized-multiwalled carbon nanotubes (f-MWNTs) by grafting to approach to form PCL-grafted-MWNTs (PCL-gMWNTs). The grafting was confirmed by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). Thermal stability of PCL-g-MWNTs improved with the addition of f-MWNTs in PCL, and the maximum was observed at 6 wt % of f-MWNTs. Differential scanning calorimetric (DSC) studies showed that crystallization temperature, melting temperature, heat of crystallization, and heat of fusion decreased with the weight proportion of f-MWNTs in the composites, but they showed an increasing trend with increasing molecular weight of PCL in the composites. DSC results were of good agreement with the X-ray diffraction data, as crystallinity decreased with the incorporation of f-MWNTs in PCL. The crystallite size (P hkl ) of PCL in (110) direction increased, but in (200) direction it decreased. The size anisotropy (P 110 /P 200 ) of the crystals in (110) and (200) directions increased regularly, indicating that the crystal growth was nonuniform in the two directions. The morphological observation by scanning electron microscopy and TEM showed that the PCL-g-MWNTs had higher diameter than raw multi-walled carbon nanotubes. Polarized optical microscopy showed that PCL-g-MWNTs had core/ shell structure with the nanotubes as the 'hard' core and the hairy polymer layer as the 'soft' shell.

Correlation between Grafting Density and Confined Crystallization Behavior of Poly(ethylene glycol) Grafted to Silica

“…However, in these previous studies, the grafting density varied when the molecular weight of the grafted chains increased and the effect of the two structural factors had not been explored independently so far. Less attention has been paid to the confined crystallization behavior imposed by grafting density and molecular weight of the grafted polymers on SiO2 surface, whereas these effects have been extensively reported for polymers confined in other systems, such as carbon nanotubes 24 and block copolymers with grafted brushes. [27][28] Poly(ethylene oxide) is an attractive semicrystalline polymer for fundamental research [29][30] and its silica nanocomposites can increase ion conductivity for applications in solid-state lithium batteries materials [31][32] .…”

Isothermal Crystallization Behavior of Poly(ε-Caprolactone) Diol/Functionalized-Multiwalled Carbon Nanotube Composites

“…The degree of crystallinity (X c ) for the composite is 35.5%, whereas for neat PCL (MW ¼ 4000) it is about 36.3%. [33] Activation Energy for Crystallization Process Activation energy for the crystallization process can be measured from the kinetic rate constant (k) using the following Arrhenius type equation:…”

“…We have used different weight proportions of f-MWNTs with different MW of PCL to prepare PCL=f-MWNT composites and to find the effect of MW and weight proportion of f-MWNTs on isothermal crystallization behavior of the composites at three different temperatures (30 , 35 , 40 C produced carboxylic acid groups at the surface of the MWNTs, [33][34][35] then treated them with thionyl chloride to give acylchloride functionalized MWNTs (f-MWNTs), and finally different weight proportions of f-MWNTs were melt-mixed with PCL. The isothermal crystallization kinetics of the composites was studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction.…”

Properties and degradation behavior of surface functionalized MWCNT/poly(L‐lactide‐co‐ε‐caprolactone) biodegradable nanocomposites

“…Jana and Cho grafted PCL-diol onto the surface of acylchloride-functionalized MWCNTs (MWCNT-COCl) by grafting to approach to form PCL-graft-MWCNTs. 22, 23 Kim et al 24 grafted PLLA onto the surface of hydroxylated MWCNTs and prepared the composite of PLLA with PLLA-grafted MWCNTs by melt compounding. Saeed et al 25,26 at first functionalized MWCNTs by Friedele-Crafts acylation, which introduced the aromatic amine groups on the sidewall of prepared MWCNT composite by in situ polymerization using functionalized MWCNTs.…”