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Supercritical carbon dioxide (scCO 2 ) dispersion of poly(ethylene terephthalate)/clay nanocomposites: Structural, mechanical, thermal, and barrier properties
Author(s) -
Yang Fengyuan,
Mubarak Christopher,
Keiegel Robert,
Kannan Rangaramanujam M.
Publication year - 2017
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.44779
Subject(s) - materials science , nanocomposite , differential scanning calorimetry , supercritical carbon dioxide , crystallinity , montmorillonite , composite material , dynamic mechanical analysis , glass transition , ultimate tensile strength , chemical engineering , supercritical fluid , polymer , chemistry , organic chemistry , physics , thermodynamics , engineering
Dispersed poly(ethylene terephthalate) (PET)/clay nanocomposites can lead to materials with superior barrier and mechanical properties. PET/clay nanocomposites were prepared by melting extrusion of PET with as‐received or supercritical carbon dioxide (scCO 2 ) predispersed Cloisite ® 30B (30B). The predispersion of 30B was assessed by WAXD, SEM, and TGA, and results indicated that scCO 2 processing could predisperse 30B and the surface modification of the clay was preserved after processing. The structure of PET/30B nanocomposites was investigated by WAXD and TEM confirming that PET has penetrated into the clays inter‐galleries and the predispersed clays lead to improved interfacial interaction and homogenous clay dispersion. Both tensile strength and Young's modulus were improved by 12.1% and 24.9% respectively, as incorporating of 3 wt % of scCO 2 processed clay. Differential scanning calorimetry (DSC) results indicated that clay particles served as nucleation agent could increase the crystallinity whereas had no impact on melting process. In addition, with the addition of 1 wt % of predispersed clay, a significant reduction of oxygen permeation (∼33%) was achieved at 23 °C and the maximum reduction (44%) was achieved by adding 3 wt % processed clay. Moreover, we confirmed the effect of temperature on the permeation of PET/30B nanocomposites depended both on the Arrhenius behavior of the organic phases and tortuous path effects, where improved clay dispersion resulted in a higher effective activation energy. Moreover, the transparency of PET matrix was preserved for all nanocomposites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44779.