Influence of carbon nanotube functionalization on the physical properties of PCL diol/chitosan blends

Abstract

BACKGROUND Chitosan‐poly(ε)caprolactone diol (PCL) blends were studied for food packaging film applications. The mechanical and thermal properties of blend films can be regulated with different amounts of PCL and the addition of a nanofiller could reinforce specific domains in the blend to generate nanocomposites with desirable properties for food packaging. This is evidence of the selective insertion of functionalized carbon nanotubes in either PCL or chitosan domains, depending on the nature of chemical groups and the structure over the surface nanofiller. RESULTS Multiwalled carbon nanotubes (MWNTs) were functionalized with four different dendritic molecules and were tested as nanofillers to reinforce biodegradable films made from 70 to 30, 80 to 20, and 90 to 10 Chitosan‐PCL blends in an effort to explore their effects on the barrier and mechanical properties of the yielded nanocomposites. PCL was obtained by biocatalysis from ɛ‐caprolactone and diethylene glycol and then blended with commercial chitosan. Blends were prepared from a solution of chitosan in acetic acid (2% wt/wt), adding PCL diol in chloroform dropwise under stirring. The MWNTs were modified with several functional groups (tannic acid via no‐covalent functionalization, poly(citric acid), poly(urea‐urethane), and poly(amino‐amido) dendrimer). Nanocomposites were obtained by adding in situ 0.5 wt/wt functionalized MWNTs during the preparation of blends. The structural interactions, morphological, and mechanical features of MWNTs/Blend nanocomposites were studied by Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscope (SEM), field emission scanning electron microscopy (FE‐SEM), and strain–stress testing. CONCLUSIONS Preferential interactions between nanofiller and matrix strongly depend on the nature of the nanofiller and the amount of hydrogen bonding species. It was possible to reinforce a particular domain in the blend to generate nanocomposites with desirable/tunable properties by using complementary chemical groups onto MWNTs surface. © 2023 Society of Chemical Industry (SCI).