Intrinsic Viscosity Analysis are performed by the Polymer Char’s IVA Instrument; a reliable and automated instrument for intrinsic viscosity analysis of polymeric materials at high temperature. It integrates a dual-capillary relative viscometer combined with a high temperature autosampler. As an option, the infrared detector IR4 can also be added, offering then information about Short Chain Branching in the same process.
The principle of a relative viscometer is simple: the pressure drop across a stainless steel capillary tubing caused by the flow of polymer solution is compared to the one produced by the solvent, which is measured simultaneously by a twin reference capillary. The relative viscosity of polymer solution is derived from the ratio of pressure, and intrinsic viscosity is calculated taking into account the injected mass.
Unlike the glass capillaries used in Ubbelohde viscometers, the IVA stainless steel capillaries and tubing do not require additional washing or rinsing, and provide robust and precise viscosity values over time. The careful design of the heated compartment and transfer lines ensure that no cold spots are found and even the most challenging polymers can be analyzed.