Polyamide 6 (PA6) suffers from fast degradation in humid conditions due to hydrolysis of amide bonds, which limits its durability. The addition of nanotubular fillers represents a viable strategy for overcoming this issue, although the additive/polymer interface at high filler content can become privileged site for moisture accumulation. As a cost-effective and versatile material, halloysite nanotubes (HNT) were investigated to prepare PA6 nanocomposites with very low loadings (1-45% w/w). The roles of the physicochemical properties of two differently sourced HNT, of filler functionalization with (3-aminopropyl)triethoxysilane and of dispersion techniques (in situ polymerization vs. melt blending) were investigated. The aspect ratio (5 vs. 15) and surface charge (-31 vs.-59 mV) of the two HNT proved crucial in determining their distribution within the polymer matrix. In situ polymerization of functionalized HNT leads to enclosed and well-penetrated filler within the polymer matrix. PA6 nanocomposites crystal growth and nucleation type were studied according to Avrami theory, as well as the formation of different crystalline structures (α and γ forms). After 1680 h of ageing, functionalized HNT reduced the diffusion of water into polymer, lowering water uptake after 600 h up to 90%, increasing the materials durability also regarding molecular weights and rheological behavior.

PA6 and halloysite nanotubes composites with improved hydrothermal ageing resistance : role of filler physicochemical properties, functionalization and dispersion technique / V. Sabatini, T. Taroni, R. Rampazzo, M. Bompieri, D. Maggioni, D. Meroni, M.A. Ortenzi, S. Ardizzone. - In: POLYMERS. - ISSN 2073-4360. - 12:1(2020 Jan), pp. 211.1-211.19. [10.3390/polym12010211]

PA6 and halloysite nanotubes composites with improved hydrothermal ageing resistance : role of filler physicochemical properties, functionalization and dispersion technique

V. Sabatini
Primo
;
T. Taroni
Secondo
;
R. Rampazzo;D. Maggioni;D. Meroni;M.A. Ortenzi
Penultimo
;
S. Ardizzone
Ultimo
2020-01

Abstract

Polyamide 6 (PA6) suffers from fast degradation in humid conditions due to hydrolysis of amide bonds, which limits its durability. The addition of nanotubular fillers represents a viable strategy for overcoming this issue, although the additive/polymer interface at high filler content can become privileged site for moisture accumulation. As a cost-effective and versatile material, halloysite nanotubes (HNT) were investigated to prepare PA6 nanocomposites with very low loadings (1-45% w/w). The roles of the physicochemical properties of two differently sourced HNT, of filler functionalization with (3-aminopropyl)triethoxysilane and of dispersion techniques (in situ polymerization vs. melt blending) were investigated. The aspect ratio (5 vs. 15) and surface charge (-31 vs.-59 mV) of the two HNT proved crucial in determining their distribution within the polymer matrix. In situ polymerization of functionalized HNT leads to enclosed and well-penetrated filler within the polymer matrix. PA6 nanocomposites crystal growth and nucleation type were studied according to Avrami theory, as well as the formation of different crystalline structures (α and γ forms). After 1680 h of ageing, functionalized HNT reduced the diffusion of water into polymer, lowering water uptake after 600 h up to 90%, increasing the materials durability also regarding molecular weights and rheological behavior.
Functionalizing agent; Halloysite nanotube; Hydrothermal ageing; In situ polymerization; Melt blending; Nanocomposite; Polyamide 6; Polymorphism
Settore CHIM/04 - Chimica Industriale
Settore CHIM/02 - Chimica Fisica
Settore CHIM/03 - Chimica Generale e Inorganica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/709643
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