Synthesis of Exfoliated Monomer Casting Polyamide 6/Na⁺‐Montmorillonite Nanocomposites by Anionic Ring Opening Polymerization

Abstract

Summary: In this work, a novel method using water as a pre‐dispersant of pristine sodium montmorillonite (Na+‐MMT) and ε‐caprolactam (CL) monomer was developed for the preparation of exfoliated monomer casting polyamide 6 (MCPA6)/MMT nanocomposites via in situ anionic ring opening polymerization. The dispersion effect of MMT in the MCPA6 matrix was investigated by means of X‐ray diffraction (XRD), as well as transmission electronic microscopy (TEM). The results indicated that nanoscale dispersed MMT was successfully achieved in the MCPA6 matrix. Furthermore, the addition of a small amount of MMT dramatically improved the thermal stability of MCAP6. Analysis using differential scanning calorimetry (DSC) and XRD indicated that nanoscale dispersed MMT sheets acted as heterogeneous nucleation agents, which favored the formation of the γ‐crystalline form of the MCPA6 matrix.

Efficient one-step melt-compounding of copolyetheramide/pristine clay nanocomposites using water-injection as intercalating/exfoliating aid

“…However, polyamide shows better thermodynamical interactions with pristine clay than with modified clay as calculated by molecular simulation [6,7] and illustrated by reported successful (i.e. dispersed and exfoliated) PA6/pristine clay nanocomposites elaboration by in situ polymerization [8]. An interaction mechanism has been proposed by Shelley et al [2] who mention the complexation of the polyamide chains (precisely by the carbonyl oxygen atoms) with the negatively charged layers.…”

Comparison of Polyamide‐6 Nanocomposites Based on Pristine and Organic Montmorillonite Obtained via Anionic Ring‐Opening Polymerization

“…Then acetone and traces of water were removed under vacuum and AROP was carried out according to the previous method. [24] MCPA6/ OMMT with 2 wt.-% OMMT content was obtained, which was denoted PAO.…”

“…[ 24] MCPA6 and MCPA6/MMT with 1.5 wt.-% Na þ -MMT content were obtained, which were denoted PA and PAM, respectively.…”

“…The differences between them were discussed in our previous work. [24] Characterization A Waters-991 gel permeation chromatography (GPC) instrument was used to evaluate the weight-average molecular weight (M w ) of MCPA6 nanocomposites and their polydispersities (M w =M n ), where M n is the number-average molecular weight by calibration with a PA6 standard. The measurements were performed at 35 8C on polymeric solutions in m-cresol…”

“…[21][22][23] A novel method has been developed by us recently using water as pre-dispersant of pristine Na þ -MMT and ecaprolactam (CL) monomer for preparation of exfoliated monomer casting polyamide 6/MMT nanocomposites (MCPA6/MMT) via in situ anionic ring opening polymerization (AROP). [24] In this paper, MCPA6 nanocomposites based on pristine and organic montmorillonite via AROP were compared in detail. The objective was to study the effects of exfoliated pristine MMT and intercalated OMMT on the mechanical properties, viscosity, thermal stability, crystalline and hydrogen bonding of Polyamide-6.…”