A one‐point intrinsic viscosity method for polyethylene and polypropylene

摘要

AbstractA statistical analysis of dilute solution viscosity data for a wide range of polyethylene and polypropylene samples in Decalin at 135°C has shown that the Martin equationdocumentclass{article}pagestyle{empty}begin{document}$ {{eta _{sp} } mathord{left/ {vphantom {{eta _{sp} } c}} right. kern-nulldelimiterspace} c} = eta + k'eta ^2 c $end{document}fits the experimental data better than the Huggins equationdocumentclass{article}pagestyle{empty}begin{document}$ log left( {{{eta _{sp} } mathord{left/ {vphantom {{eta _{sp} } c}} right. kern-nulldelimiterspace} c}} right) = log eta + keta c $end{document}at higher values of ηc. A grand averagekof 0.139 is applicable to both polymers. Based upon this, tables have been calculated permitting the ready determination of η from a single relative viscosity measurement at a known concentration. The Martin equation has been put into a universal form, permitting ηto be calculated from a measured ηspifkandcare known. Graphs relating ηspto η are included for use of the Martin equation over wide ranges of bothkandc. It was found that the Solomon and Ciuta equationdocumentclass{article}pagestyle{empty}begin{document}$ eta c = left( {2eta _{sp} - 2ln eta _{rel} } right)^{{1 mathord{left/ {vphantom {1 2}} right. kern-nulldelimiterspace} 2}} $end{document}fits the experimental polyethylene and polypropylene data, and the reasons for this are dis