IN-LINE CHARACTERIZATION OF POLYMER DEFORMATION IN MELT AND SOLID-PHASE PROCESSING

Constitutive relationships obtained from in-process measurements on po lymers that have been subjected to typical solid or melt phase process ing strain-temperature-time histories can be used for enhanced modelli ng of deformation and flow (e.g. finite element analysis/computer aide d design), or to provide new information on shear and extensional flow s. In some circumstances in-line measurement may be the only practical route to reliable constitutive data. In the case of melts, such measu rements may also be used for real time assessment of polymer state and for process control. The in-process measurements discussed in this pa per are specifically concerned with 'in-line' rheometry, where pressur e, temperature, stress, strain and strain rate measurements are made u pon polymers in actual process geometries, under actual process condit ions. Examples of accurate in-line measurements of polymer rheometry i n an injection moulding nozzle and in a model solid phase forming proc ess-uniaxial drawing of polymers-are discussed.