Influence of shape and surface modification of nanoparticle on the rheological and dynamic‐mechanical properties of polyamide 6 nanocomposites

Abstract

Nanocomposites of polyamide 6 (PA6) with different concentrations of silane‐treated, organic‐treated, and nontreated nanoparticles of halloysite (HNT) and montmorillonite (MMT) had their microstructure and melt and solid state rheological behavior analyzed. The microstructure analysis was done using transmission electron microscopy (TEM) and wide angle X‐ray diffraction (WAXD); the effectiveness of the silanization was studied by thermogravimetric analysis (TGA) and Fourier transform infrared. It was found that exfoliation occurred in the organic‐treated MMT, but not in the silane‐treated MMT and that silanization was small in the HNT nanoparticles (due to its low amount of surface hydroxyls groups). Steady state shear, small amplitude oscillatory, and transient tests also indicated that: (i) only the nanocomposites with organic‐treated MMT, at concentrations above the theoretical percolation threshold developed a percolated network; (ii) the silane treatment increased the shear elastic modulus (G) of the PA6/HNT nanocomposites in the solid state, but not of the PA6/MMT; (iii) the organic‐treated MMT formed composites with the highest G, as expected. Thus, it was concluded that the HNT nanoparticles had a high potential as nanofiller for PA6, but further research on more efficient compatibilizers for HNT is still needed. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.

Organoclay-reinforced dynamically vulcanized thermoplastic elastomers of polyamide-6/polyepichlorohydrin-co-ethylene oxide

“…Moreover, increasing OC loading promotes the steady torque. This increase in the mixing torque can be attributed to the increase in the number of active sites of OC surface available for the reaction with PA‐6 and ECO chains. This reaction grafts the polymer chains to the OC surface which increases the viscosity of the medium.…”

Preparation of biodegradable poly(butylene succinate)/halloysite nanotube nanocomposite foams using supercritical CO2 as blowing agent

“…It is generally believed that the addition of HNT to a polymer matrix will improve the melt rheological properties [33,42]. The storage modulus (G′), loss modulus (G″), and complex viscosity (η*) of PBS and PBS/HNT nanocomposites as a function of frequency for a typical response at 150°C are shown in Fig.…”

Optical Properties of Blown Films of PA6/MMT Nanocomposites

“…On the other hand, for the PA6/oMMT nanocomposite, the diffraction peak related to the NP was not observed, showing that an extensive exfoliation process occurred during the mixture. These results are standard to nanocomposites based on PA6 matrix 9,14,18,19 ; the exfoliation occurs when high levels of stress (shear and elongational) are applied during the processing of nanocomposites with increased affinity between the matrix and the reinforcing filler (due to the organic modification of the MMT). The NP content used (5 wt%) was above the theoretical percolation threshold (estimated as 2 wt% 14 ).…”

“…The incorporation of small contents (usually less than 5%) of these fillers can lead to improvements in the mechanical, thermal and barrier properties in magnitude comparable to the use of high levels of conventional micro-sized fillers. This optimized state is reached when the NPs are well dispersed and distributed through the matrix and when there are good polymer-NP interactions (forming an efficient interface); in this case, NPs with high aspect ratio and high surface area can lead to even more significant improvements in final properties 14 …”