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Surface properties of hydrosilylated polyolefins annealed in supercritical carbon dioxide
Author(s) -
Zhu S.H.,
Tzoganakis C.
Publication year - 2008
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.984
Subject(s) - materials science , annealing (glass) , contact angle , polyethylene , polypropylene , polyolefin , supercritical fluid , supercritical carbon dioxide , composite material , analytical chemistry (journal) , chemical engineering , chromatography , organic chemistry , chemistry , layer (electronics) , engineering
Two hydrosilylated polyolefin compounds are obtained by reacting polypropylene (PP) and polyethylene (PE) with di‐ and multi‐functional hydride‐terminated poly(dimethylsiloxane) (dH‐PDMS and mH‐PDMS), respectively. The PDMS‐rich surface layers on these two samples show different Si concentrations but similar thicknesses. Samples of these materials are annealed in supercritical carbon dioxide (scCO 2 ) at various temperatures and pressures for different periods of time. On the PP/dH‐PDMS sample, an increase in the annealing temperature does not affect the Si concentration up to 120°C. However, the Si concentration is sharply reduced at T = 150°C at which point the surface appears to be covered by SiO 2 particles. Annealing the PP/dH‐PDMS sample for short times leads to submicron scale SiO 2 particle formation on the surface. The particles form aggregated clusters that spread all over the surface uniformly when the annealing time is extended. However, Si concentration on the PE/mH‐PDMS sample surface is enhanced as the annealing temperature increases, reaching a maximum at an annealing temperature of 100°C. No particle formation is observed on the PE/mH‐PDMS sample surface. The contact angle of both samples is found to increase with annealing temperature. Increasing the scCO 2 pressure leads to a higher Si concentration on the surfaces of both samples. On the other hand, increasing the CO 2 pressure leads to opposite trends in contact angle with the PP/dH‐PDMS sample exhibiting an increasing contact angle and the PE/mH‐PDMS sample exhibiting a decreasing one. Copyright © 2007 John Wiley & Sons, Ltd.