SynopsisA study of a melt-spun threadline has been carried out to determine the effect of molecular weight on the elongational viscosity of the polymer being spun. Polymer chosen for this study was poly(ethy1ene terephthalate) having different molecular weights. Conventional nonisothermal spinning of the polymers was carried out with cooling by free convection. Threadline surface temperatures were measured by a nullbalance technique. Threadline tension at the take-up device was measured, and eamples of the threadline were taken to obtain linear density profiles. Nonlinear least-squares fits were applied to the linear density data t o obtain equations for velocity and elongation rate. These measurements were then used to determine the threadline elongational viscosity. Least-squares fits were made to a polynomial relating absolute temperature and elongation rate to the elcngational viscosity. These results were then used to determine an activation energy of elongational flow which was found to decrease with elongation rate. Elongational viscosity was found to increase with molecular weight.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.