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Different effects of process conditions on PA6/nanoclay composites at nanoclay contents above and below percolation threshold: Rheological, thermo‐dynamical, and thermal properties
Author(s) -
Moghri Mehdi,
Garmabi Hamid,
Kiany Parvin,
Seyed Shahabadi Seyed Ismail
Publication year - 2016
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.21431
Subject(s) - materials science , rheology , percolation threshold , percolation (cognitive psychology) , composite material , dispersion (optics) , diffusion , thermal diffusivity , shear (geology) , plastics extrusion , thermal , thermodynamics , engineering , electrical engineering , biology , electrical resistivity and conductivity , physics , optics , neuroscience
The effects of several factors (i.e., nanoclay content (NC), melt temperature, screw speed, and feeding rate), on morphology, rheology, thermodynamics, and thermal stability of PA6/NC samples produced in a co‐rotating twin‐screw extruder were studied. We discuss how changes in the level of these factors can vary diffusion or imposed shear, how these variations in diffusion and/or shear can affect NC dispersion, and how the changes in the state of NC dispersion can influence several properties of the samples. Samples with low NC content, below percolation threshold, showed exfoliated/intercalated structure with negligible sensitivity to changes in the level of the factors; whereas, samples with high NC content, above percolation threshold, showed intercalated with sporadic flocculated structures and noticeable sensitivity to the changes in the level of the factors. Moreover, NC dispersion was found to be mostly diffusion‐controlled: changes that resulted in higher diffusion or residence time (i.e., high melt temperature or low screw speed) also eventuated in better NC dispersion. What is more, percolation threshold was seen to move to lower NC contents as diffusion rate was increased. Moreover, as NC content increased, opposite thermal stability behaviors were observed at above and below the percolation threshold. J. VINYL ADDIT. TECHNOL., 22:259–266, 2016. © 2014 Society of Plastics Engineers