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Surface tension of polyethylene used in thermal coating
Author(s) -
Demarquette Nicole Raymonde,
Da Silva Fabio Teodoro,
Brandi Sergio Duarte,
Gouvêa Douglas
Publication year - 2000
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.11298
Subject(s) - stearic acid , materials science , polyethylene , surface tension , low density polyethylene , polymer , drop (telecommunication) , coating , composite material , chemical engineering , polymer chemistry , thermodynamics , telecommunications , physics , computer science , engineering
In this work the surface tension of a polyethylene used in thermal coating, identified as a mixture of low density polyethylene (LDPE) and stearic acid, was measured as a function of temperature for temperatures ranging from 120°C to 150°C using a pendant drop apparatus. The values were compared to the surface tension of the pure components (low density polyethylene and stearic acid). It was shown that the surface tension of the mixture is higher than the surface tension of the pure components (more than 25%). Surface analysis by Electron Spectroscopy for Chemical Analysis (E.S.C.A.) of the polyethylene used in thermal coating before and after surface tension measurement was conducted; the experimental results showed that the oxygen and the carbon present at the surface of both the powder and the drop were involved in COH and COOH bonds (for oxygen) and in CC and CO bonds (for carbon). It was shown that there is an increase of COOH and a decrease of COH bonds at the surface when the polymer is heated. It was also shown that there is an increase of C bounded to O at the surface of the drop and consequently a decrease of CC bonds. The decrease of COH was attributed to the drying of the polymer during heating and the decrease of CC was attributed to the coalescence of the polymer particles during pendant drop fomation.