ABSTRACT
I. INTRODUCTION A great variety of instruments have been used to measure the rheological properties of polymer solutions and polymer melts when these are subjected to shear dcl'ormation [ 1-3]. These instruments range in sophistication from simple melt indexers employed for quality control purposes to very complicated. researchgrade rheometers capable of measuring. as a function of temperature and rate of deformation. both steady-state and transient values of the various material functions defined in the previous chapter. As might be expected. these instruments span a wide price range [2.3]. depending on the capability of the viscometer. and they are manufactured and marketed by a large number of manufacturers all over the world. Ln this chapter. we consider general-purpose. shear instruments that one might expect to find in any laboratory devoted to rheological work: these include capillary viscomcters as well as rotational viscometers. vVe describe the essential features of each type of instrument. present the basic equations used for data analysis. and discuss equipment limitations and sources of error. A consideration of actual data, their possible molecular interpretation. and representation using constitutive equations is deferred to later chapters. Extensional viscometers are examined in Chapter 7. while specialized instruments are introduced throughout this book as appropriate.
