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Migration and surface modification in polypropylene (PP)/polyhedral oligomeric silsequioxane (POSS) nanocomposites
Author(s) -
Tang Yong,
Lewin Menachem
Publication year - 2009
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1229
Subject(s) - materials science , surface energy , sublimation (psychology) , contact angle , polypropylene , annealing (glass) , silsesquioxane , nanocomposite , composite material , polymer chemistry , chemical engineering , polymer , psychology , engineering , psychotherapist
This paper reports on the migration of POSS‐based nanocomposites both by annealing the melt and by heating the solid blend in the microwave oven. The migration proceeds to all surfaces of the sample as verified by ATR‐FTIR spectra of the bottom and top surfaces. Concentrations of POSS on the surface, exceeding 50%, are obtained. Polarity of the matrix increases POSS migration. During annealing at 190°C, a sublimation of POSS from the upper surface occurs. In air, sublimation is decreased by oxidizing the organic side groups of POSS and the PP to non‐volatile moieties. No sublimation occurs below 100°C. The AFM and SEM‐EDAX verified the high POSS concentration on the surface and indicated very pronounced roughness of the surface of the sample. The static contact angle measurements reveal very high hydrophobicity as well as low surface free energy (SFE) of the surface of the sample, which is close to that of Teflon and of pristine POSS. The migration of POSS is due to its lower surface tension, the entropy considerations, its lower cohesive energy with the matrix chains as compared to the cohesion energy between the chains, and the density and temperature fluctuations of the matrix chains which upon relaxation repulse and propel POSS to the surfaces. Copyright © 2008 John Wiley & Sons, Ltd.