RHEOOPTICAL INVESTIGATIONS OF SHEAR-INDUCED AGGREGATION OF POLYMERS IN DILUTE-SOLUTIONS

The phenomenon of shear-induced aggregation has been investigated in d ilute solutions of high molar mass polystyrene standards in phthalic a cid esters by light scattering and simultaneous rheometrical measureme nts. An optical-rheological correlation is found which can easily be u nderstood by simple molecular kinetic models. Systematic examination o f the polymer solutions, varying temperature, concentration, and molar mass, shows a dependence of the aggregation on these parameters which fits thermodynamic models.