Tensile drawing of high and low molecular weight polyethylene terephthalate

The tensile drawing of polyethylene terephthalate fibers spun from polymer of high and low molecular weight over a range of windup speeds has been studied. An analysis of the mechanical properties, orientation, and shrinkage behavior for different draw ratios leads to two conclusions. First, the network structure is the same for both polymers and the same as that described for a medium molecular weight polymer in an earlier paper. Secondly, an increase in molecular weight has an effect similar to an increase in the windup speed on the spun fiber molecular structure, which affects the ultimate mechanical properties obtainable by the chosen processing routes.