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Crosslinking of polycaprolactone in the pre‐gelation region
Author(s) -
Gandhi K.,
Kriz D.,
Salovey R.,
Narkis M.,
Wallerstein R.
Publication year - 1988
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.760282209
Subject(s) - polycaprolactone , materials science , irradiation , moduli , ionizing radiation , hydrogen peroxide , carbon monoxide , shear (geology) , yield (engineering) , composite material , carbon dioxide , polymer chemistry , chemical engineering , polymer , organic chemistry , chemistry , catalysis , physics , quantum mechanics , nuclear physics , engineering
Polycaprolactone (PCL) crosslinked below the gel point either with peroxide or by exposure to ionizing radiation was compared by Theological studies. As a result of peroxide crosslinking, PCL increases in viscosity and shear rate dependence and exhibits increased dynamic moduli that converge at higher frequencies. The analysis of gases evolved from γ‐irradiated PCL shows that the yield of hydrogen (G = 0.39) approximates the sum of the yields of carbon monoxide (G = 0.19) and carbon dioxide (G = 0.21). It is inferred that equal amounts of crosslinking and scission result from ionizing irradiation. As a result, PCL is converted by irradiation to a densely branched system. Steady shear viscosities do not depend strongly on dose and overlap at higher shear rates. Similarly, dynamic moduli, especially G″, become less sensitive to dose.