Poly(ε-caprolactone)/Clay Nanocomposites by in-Situ Intercalative Polymerization Catalyzed by Dibutyltin Dimethoxide

Abstract

Poly(ε-caprolactone)/clay nanocomposites were prepared by in-situ ring-opening polymerization of ε-caprolactone by using dibutyltin dimethoxide as an initiator/catalyst. A nonmodified Na+−montmorillonite and two montmorillonites surface-modified by dimethyl 2-ethylhexyl (hydrogenated tallow alkyl) and methyl bis(2-hydroxyethyl) (hydrogenated tallow alkyl) ammonium cations, respectively, were used. The evolution of molecular weights was followed in relation to silicate surface modification and clay concentration. The alcohol-bearing organo-modified clay was a co-initiator for the polymerization reaction and thus controlled the molecular weight of the PCL chains. Furthermore, the number-average molecular weight of the growing PCL chains linearly increased with the monomer conversion. Nanocomposites were analyzed by small-angle X-ray diffraction, transmission electron microscopy, and thermogravimetry. The clay dispersion depended on the structure of the alkylammonium used to make the clay more hydrophobic. Exfoliated nanocomposites were formed when hydroxyl-containing alkylammonium was used; otherwise, intercalated structures were reported. Thermogravimetric analyses showed a higher degradation temperature for the exfoliated structures than for the intercalated ones, both of them exceeding the degradation temperature of unfilled poly(ε-caprolactone).

Fire and Gas Barrier Properties of Poly(styrene-co-acrylonitrile) Nanocomposites Using Polycaprolactone/Clay Nanohybrid Based-Masterbatch

“…And finally, the resulting polyester-grafted organoclay nanohybrids are used as masterbatches and are dispersed in commercial polymeric matrices by melt blending. This technique has already successfully led to a large improvement of clay dispersion within the PCL matrix [17] and a chlorinated polyethylene matrix [15,16]. In each case, typical properties of nanocomposites are studied both as a function of the clay dispersion and of the matrix/clay interactions.…”

Polymer/layered silicate nanocomposites by combined intercalative polymerization and melt intercalation: a masterbatch process

“…Nanocomposites based on poly( -caprolactone) (PCL) have already been prepared by in situ polymerization of -caprolactone in the presence of montmorillonite modified by alkylammonium cations bearing a carboxylic acid [12], and a hydroxyl end-group [13][14], respectively. This type of nanocomposites has been used to prepare segmented PCL-based polyurethane/clay nanocomposites by step-growth polymerization of diphenylmethane diisocyanate, butanediol and preformed polycaprolactone diol [15].…”

Rheology of Polymers with Nanofillers

“…The low-frequency slope, g ′ ≡ d ln G ′ /d ln ω, decreased with silicate loading and their p from g ′ (matrix) ≈ 1.2 to 0.3, 0.62, and 0.82, respectively. It is noteworthy that exfoliation is not the only mechanism leading to slope reduction (e.g., formation of clay aggregates, phase separation, or presence of compatibilizer micelles leads to similar effects) [Lepoittevin et al, 2002]. Similarly, melt blending PP: PP-MA = 0: 1 or 1: 1 with C6A resulted in intercalated CPNC with d 001 = 3.3 nm [Galgali et al, 2001].…”