Preparation and characterization of nylon 6/organoclay nanocomposite filament fibers

A series of nylon 6 (NY6)/organoclay nanocomposites were prepared via in situ polymerization of ε‐caprolactam in the presence of 1,2‐aminododecanoic acid‐intercalated montmorillonite (ADA‐MMT) organoclay (1–5 wt%) using 6‐aminocaproic acid as polymerization catalyst. The extent of organoclay dispersion in NY6 matrix was analyzed using WAXD and SEM measurements. DSC studies revealed marginal shift in melting and melt‐crystallization peaks toward lower temperature with increasing clay content. Melt viscosity studies for NY6/ADA‐MMT exhibited higher shear‐thinning behavior than neat NY6 probably due to the slip between NY6 matrix and exfoliated organoclay platelets during shear flow. The prepared nanocomposites were melt‐spun and studied for their property improvements against varying clay content, draw ratios, and annealing conditions. Birefringence and sonic velocity values increased initially at lower draw ratios (≤2.5) due to increased orientation of molecular chains along the drawing direction but saturated at higher draw ratio (3.0) for all the samples. At the same draw ratio; compared to neat NY6, NY6/organoclay fibers showed increased chain orientation along the drawing direction which can be attributed to the “tethering effect” of organoclay on NY6 matrix. The initial modulus and stress at break were sensitive to factors such as draw ratio, clay content, and annealing conditions. POLYM. COMPOS., 2009.