Probing the confining effect of clay particles on an amorphous intercalated dendritic polyester

Abstract

The fourth generation of a hydroxylated dendritic hyperbranched polyester (HBP) was combined with sodium montmorillonite clay (Na + MMT) using water to generate a broad range of polymer clay nanocomposites from 0 to 100% wt/wt Na + MMT. Analysis with differential scanning calorimetry (DSC) showed a deviation in heat capacity, ∆C p , with clay content at the T g from a two-phase trend which was attributed to the formation of an immobilized rigid amorphous fraction (RAF) in the interlayer spacing of the intercalated system. This deviation occurred in a step-like fashion which we attributed to 0.5 nm incremental changes in the interlayer spacing, previously observed through X-ray diffraction analysis. A simple series model was utilized to quantify these interlayer spacings based on the ∆C p values and showed good correspondence with the X-ray results. The RAF was quantified from changes in heat capacity with clay content and was verified by an alternative novel positron annihilation lifetime spectroscopy (PALS) approach. The PALS quantification of the RAF was possible through an analysis of changes in the hole size thermal expansivity of the nanocomposites as a function of clay composition. Results indicated that as much as 32% by weight of the system is made up of the RAF at its maximum.

Biodegradable PLA/PBSA Multinanolayer Nanocomposites: Effect of Nanoclays Incorporation in Multinanolayered Structure on Mechanical and Water Barrier Properties

“…The presence of the C30B fillers in PBSA led to increase the percent of RAF by a factor two ( Table 1 ). Such an increase in RAF by incorporation of fillers has already been observed in PBSA [ 38 ], in PU [ 39 ] or in an hyperbranched polyester [ 40 ] for example. This significant decrease of Δ C p values, evidencing an increase in local rigidity, can be due to the reduction in free volumes in polymer by addition of fillers and the resulting mobility restrictions of macromolecular chains coming from the presence of fillers.…”

Dendrimers and hyper-branched polymers interacting with clays: fruitful associations for functional materials

“…47 The confinement of the HBPE in the nanocomposite has been studied, using XRD, dielectric relaxation, 48 and differential scanning calorimetry (DSC). 49 The association HBPE/MMT has been used as additive in polylactic acid and polyamide-blockether. An improvement of toughness was shown, potentially suitable for packaging applications.…”

Enhancement of the physical and mechanical properties of wood using a novel organo-montmorillonite/hyperbranched polyacrylate emulsion

“…Waterborne hyperbranched polymers are a new kind of macromolecule with a unique tree-like structure. It is hard to crystallize and can be easily dissolved in water with a slight increase in the viscosity (Amin et al 2010;Faris et al 2016;Meyers et al 2017). Besides, it possesses a smaller particle size when compared with the linear polymers of the same molecular weight (Lai et al 2016), which makes it possible to enter into the cell wall of the wood.…”