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PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique

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 pri...

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Autores principales: Sabatini, Valentina, Taroni, Tommaso, Rampazzo, Riccardo, Bompieri, Marco, Maggioni, Daniela, Meroni, Daniela, Ortenzi, Marco Aldo, Ardizzone, Silvia
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7023541/
https://www.ncbi.nlm.nih.gov/pubmed/31952200
http://dx.doi.org/10.3390/polym12010211
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author Sabatini, Valentina
Taroni, Tommaso
Rampazzo, Riccardo
Bompieri, Marco
Maggioni, Daniela
Meroni, Daniela
Ortenzi, Marco Aldo
Ardizzone, Silvia
author_facet Sabatini, Valentina
Taroni, Tommaso
Rampazzo, Riccardo
Bompieri, Marco
Maggioni, Daniela
Meroni, Daniela
Ortenzi, Marco Aldo
Ardizzone, Silvia
author_sort Sabatini, Valentina
collection PubMed
description 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.
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spelling pubmed-70235412020-03-12 PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique Sabatini, Valentina Taroni, Tommaso Rampazzo, Riccardo Bompieri, Marco Maggioni, Daniela Meroni, Daniela Ortenzi, Marco Aldo Ardizzone, Silvia Polymers (Basel) Article 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. MDPI 2020-01-15 /pmc/articles/PMC7023541/ /pubmed/31952200 http://dx.doi.org/10.3390/polym12010211 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Sabatini, Valentina
Taroni, Tommaso
Rampazzo, Riccardo
Bompieri, Marco
Maggioni, Daniela
Meroni, Daniela
Ortenzi, Marco Aldo
Ardizzone, Silvia
PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique
title PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique
title_full PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique
title_fullStr PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique
title_full_unstemmed PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique
title_short PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique
title_sort pa6 and halloysite nanotubes composites with improved hydrothermal ageing resistance: role of filler physicochemical properties, functionalization and dispersion technique
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7023541/
https://www.ncbi.nlm.nih.gov/pubmed/31952200
http://dx.doi.org/10.3390/polym12010211
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