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Cross‐Linking of Polyolefins: A Study by Thermoporosimetry with Benzene Derivatives as Swelling Solvents
Author(s) -
Billamboz Nicolas,
Nedelec JeanMarie,
Grivet Manuel,
Baba Mohamed
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200400472
Subject(s) - swelling , differential scanning calorimetry , solvent , naphthalene , chemistry , polyethylene , freezing point depression , polypropylene , analytical chemistry (journal) , xylene , benzene , materials science , polymer chemistry , thermodynamics , organic chemistry , composite material , freezing point , physics
Abstract The solvents o ‐, m ‐, p ‐xylene, p ‐dichlorobenzene, 1,2,4‐trichlorobenzene, and naphthalene were calibrated as condensates used in the thermoporosimetry technique. Exponential relationships were found connecting the pore radii R p (in nm) and the freezing‐point depression of the swelling solvent Δ T (in °C) on the one hand and the apparent energy of crystallization W a (in J cm −3 ) and Δ T on the other hand: ${{\rm R}{_{p}}={\rm t}\,exp[- 1/({\rm c}{\Delta}{\rm T})]}$ ; ${{\rm W}{_{a}}={\rm W}{_{0}}\,exp({\Delta}{\rm T}/{\rm f})}$ . Pore‐ or mesh‐size distributions can be derived from differential scanning calorimetry results by using the following equation: ${d{\rm V}{_{p}}/d{\rm R}{_{p}}={\rm k}\{[{\rm cY}({\rm T}){\Delta}{\rm T}{^{2}}]/[{\rm W}{_{a}}{\rm R}{_{p}}]\}}$ . All the numerical parameters were determined. Polyethylene and polypropylene samples, cross‐linked with high‐energy electrons or γ‐rays, were submitted to thermoporosimetry study. Relative mesh‐size distributions, which depend on the polymer/solvent pair, were calculated for these polyolefins with o ‐, m ‐, and p ‐xylene as solvent and were found to be in the same sequence as those of their degrees of swelling and the irradiation doses received.