Plasticorder® rheometer

Brabender plasticorder flow See test, Brabender plasticorder rheometer melt-flow, brackish water See water, brackish, braiding See fiber braided reinforced-plastic pul-trusion, braided. 

Treatment of PVC, suspended in chlorobenzene, with Et2AlCl followed by the addition of methanol greatly improved the thermal stability (6). This will be the subject of a separate publication. However, the nature of the improvement was different—i.e., film pressed in air at 200°C was yellow not colorless, but processing stability as determined by the torque rheometer test in the Brabender Plasticorder at 195°C was far superior and was measured in hours rather than minutes. The removal of labile chlorine atoms by Et2AlCl undoubtedly contributed to heat resistance. However, in the absence of a further reaction, such dehalo-genation probably became dehydrohalogenation, contributing to color development. 

Materials. Two types of standard tire cord obtained from Gen Corporation were used in this investigation polyester, 1300/3, and nylon 66, 1260/3. The rubber composition to which the adhesively dipped cords were bonded had the following composition in parts by weight styrene-butadiene rubber (SBR) 1502, 100 N330 carbon black, 50 zinc oxide, 5 stearic acid, 0.5 sulfur, 1.7 2-morpholinothio-benzothiazole, 2. Master batches were mixed 7 min in a 350-ml Brabender Plasticorder, and curatives were added on a cool two-roll mill. Cure characteristics at 155 °C were determined with an oscillating disc rheometer (ASTM D 2084). The time to reach 90% of the final cure state was 23 min, and the Shore A hardness of the final vulcanizate was approximately 60. 

The Plasticorder, described as a "torque rheometer" by the supplier, is one version of a practical tool well known and used in the plastics and rubber industries. We believe that our use of the Plasticorder as a polymerization reactor may be unique, and that the instrument is probably not well known in polymer science laboratories, so we felt it appropriate to picture it. Additional detail of the mixing chamber/measuring head and the removable sigma blade rotors is also pictured (see Photographs A, B, and C). 

Commercial instruments are available the Brabender Plastograph, and Plasticorder, this latter allowing use of an extruder head the RAPRA variable torque rheometer [5]. The advantages of these instruments are based on the similarity of their action to full-scale extrusion equipment and on the fact that they can be operated at shear rates appropriate for factory equipment. But because of the difficulty of matching exactly the range of shear rates which exist in full-scale plant, successful scaling-up is difficult. Elongation flow measurements have been reported by several workers, in which a sample is stretched in uniaxial tension at a constant strain rate [6]. 

Swelltest die heads also allow contactless estimation of die-swell to be obtained. A Planetarimixing head also allows the study of powdery materials (again useful in PVC processing). Temperatures up to 300°C can be studied. Current equipment of this type is produced by Brabender ( Plasticorder ), Haake ( Rheocord ) and Hampden Instruments (variable torque rheometer). 

Allen, E. O. and WiUium, R. F, Prediction of Polymer Processing Characteristics Using C. W. Brabender Plasticorder Torque Rheometer, SPE ANTEC (1971), p. 587. 

These capillary rheometers are principally the same as those described in Sections 3.2.1 and 3.2.2 except for the melt transport system which is of the screw extrusion type rather than the plunger type discussed earlier. A schematic diagram of an extrusion capillary rheometer is shown in Fig. 3.5. Commercially available extrusion capillary rheometers are the Haake Rheocord (Haake Buchler Instruments, Inc., Saddle Brook, NJ) and the Brabender Plasticorder (Brabender, Duisburg, Germany). The rheological property measurements can be done using a circular or slit orifice, as these are separate attachments for the miniaturized single screw extruder. 

The most common approach to characterize the PVC fusion process employs the Brabender Plasticorder or Haake Rheometer, which consists of a mixing head with two rolls. Figure 14-1 shows the PVC fusion process as reflected in the curve of fusion torque vs. time. The melt temperature in each stage can also be recorded. Point A is referred as the compaction peak and corresponds to compression and densification of the powder. Point B refers to the beginning of melting, followed by the appearance of the fusion peak. Point C occurs as PVC fuses into melt. The difference in time between A and C is called fusion time . The torque observed at... 

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