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Photooxidative weathering of biodegradable nanocomposite films containing halloysite
Author(s) -
Scarfato Paola,
Acierno Domenico,
Russo Pietro
Publication year - 2015
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.23478
Subject(s) - nanocomposite , materials science , halloysite , oxygen permeability , fourier transform infrared spectroscopy , attenuated total reflection , polymer , photodegradation , amorphous solid , composite material , ultimate tensile strength , chemical engineering , oxygen , photocatalysis , organic chemistry , chemistry , catalysis , engineering
This study reports the results of photodegradation experiments performed on biodegradable nanocomposite blown films based on a commercial grade of poly(3‐hydroxybutyrate‐ co −3‐hydroxyvalerate)/poly(butylene adipate‐ co ‐terephthalate) blend added with different amounts (3, 5, and 10 wt%) of tubular halloysite nanoclays, natural and organomodified. The films, subjected to photooxidative weathering in a climatic chamber under UV exposure, were systematically analyzed to check the chemical and physical changes induced by the aging protocol, taking the as‐produced films as the reference materials. In particular, the samples were characterized using several techniques [colorimetry, water contact angle tests, UV–vis, attenuated total reflectance (ATR)‐Fourier transform infrared (FTIR) spectrophotometry, X‐ray diffraction, oxygen permeability, and mechanical tests]. The experiments demonstrated that all nanocomposite films, when compared with the unfilled one, show higher changes in the total color difference Δ E * and higher reduction in the average transparency due to the changes in the molecular structure of the polymer (hydrolysis of the ester linkage, multiple chain scissions, and crosslinking), as observed from ATR‐FTIR analysis. The phenomenon, which basically involves the amorphous phase, tends to increase with the nanofiller percentage in the films and is more relevant in the presence of the organomodified halloysite. As a consequence of the photodegradation of the amorphous polymer chains that increase their molecular mobility, the oxygen permeability worsens, even in the presence of nanofillers. Instead, in terms of mechanical response, the addition of pure and organomodified halloysite to polymer matrix had positive effects on tensile properties both before and after photooxidation. POLYM. COMPOS., 36:1169–1175, 2015. © 2015 Society of Plastics Engineers