Study on abnormal behavior of extremely dilute poly(benzobisoxazole) s(PBZs) solution

The viscosity of PBO/MSA and PBOT/MSA solution was measured by using Ubbelohde viscometer.The relationship of the solution concentration with the viscosity was analyzed by dilution extrapolation method.The experimental results show that the solution viscosity will abnormally rise when the solution concentration fell down to extremely dilute range.Through experiment,the effects of viscometer and critical contact concentration on the abnormal behavior of poly(benzobisozazole)s(PBZs) solution were excluded.Meanwhile,semistiff polyelectrolyte model was proven to be the best explanation for the abnormal behavior of extremely dilute PBZs solution by adding different concentration salt.In order to avoid the abnormal behavior of the extremely dilute PBZs solution and assure the measurement accuracy of viscosity,the value of ηr should be within 1.2～2.0.