Rubber mixing, TPE courses held.

Courses titled "Compounding and mixing of rubber" and "Thermoplastic elastomers" will be held April 3-5 and April 9-10, respectively, by the University of Wisconsin - Milwaukee. The rubber mixing course will take place at the Manchester East Hotel & Suites, Milwaukee, WI, and the TPEs course will be held at the Center for Continuing Engineering Education, Milwaukee, WI.

"Compounding and mixing of rubber" will serve as an update on developments in compounding and mixing technology, procedures and equipment for people already in the field, and as a primer for anyone in the rubber industry who wishes to understand the current state-of-the-art.

Speakers will include Dr. Peter S. Johnson, a processing consultant from Samia, Ontario, Canada, and Dr. Richard F. Grossman, technical director of Halstab Stabilizers.

The course outline will include a discussion of compounding and compounding ingredients, including an overview of the science of compounding; review of the properties and applications of natural and synthetic rubbers; major classes of additives (i.e., fillers, oils, plasticizers, processing aids, antidegradants and curative systems); and examples of how compounds are designed to meet the requirements of various end applications.

The mixing process will be highlighted, including an account of the mixing process from raw material acceptance to packaging of the mixed compound. Topics will include raw material specification and testing; weighing and feeding of ingredients; the mixing process (incorporation, distribution and dispersion); flow behavior in mixers; modeling the mixing process; process variables (e.g., temperature control, basic mixing procedures, natural rubber mastication and dump criteria); operating variables (e.g., rotor speed, ram pressure and chamber loading); control of the mixing process; discharge; and shaping and cooling.

Mixing cycles and procedures will be examined, including cost of internal mixing; unit operations in mixing; single-pass versus multiple-pass mixing; types of mix cycle; and mill mixing.

Rubber mixing equipment, including basic mixer design and review of developments in rotor design, will be discussed.

Compounding and mixing for specific applications will be discussed, including mixing procedures for specific compounds; illustrating the variations that follow from the nature of the ingredients; application and the equipment available; and the relationship between compounding and successful mixing.

The effect of various compounding ingredients on processing behavior of the rubber compound will be examined, including the effect of various elastomers, fillers, plasticizers and process aids.

Vulcanization will also be emphasized, including equipment, compounding, and desired flow properties and cure rates for the batch processes of molding and autoclave vulcanization, and for continuous vulcanization of hose, profiles, wire coverings and calendered products.

Compounding and mixing of tire compounds will be examined, and will include an outline of the various tire components, required properties in the finished tire, and resultant compositions and mixing procedures.

Continuous mixing of rubber will be highlighted, and will include an outline of developments in extruder mixing.

Physical testing of rubber will be discussed, including tensile, hardness, thermal, dynamic mechanical, electrical testing of vulcanizates, tests for dispersion and contamination, and tests to identify surface exudation.

Processability testing of rubber compounds will be examined, including a review of the tests and testing equipment used to assess the processability of mixed compounds (i.e., the Mooney test, capillary rheometers, torque rheometers, oscillating disc curemeters, rotorless curemeters, dynamic mechanical rheological testers and stress relaxation instruments); correlation (or its lack) between ODR and MDR cure times; comparative evaluation of processability tests; and which is the best processability tester.

Participants in the "Thermoplastic elastomers" course will learn about the development, polymerization, properties and structure of TPEs. This course is designed to provide a comprehensive understanding of TPEs so that participants can compare them with conventional rubbers. In addition, it will examine special applications of TPEs, such as adhesives, sealants and coatings.

Polymer and rubber chemists will find this course very useful, according to the sponsor. The course will also be of interest to designers and engineers involved with polymeric materials, managers and molders.

The course speaker is Geoffrey Holden, retired from Shell Development, and author of the book Understanding Thermoplastic Elastomers.

An introduction and historical survey will include an overview of thermoplastic elastomers. Discussion of classification and structure will include phase structure, phase properties, polymer structure and nomenclature.

Styrenic block copolymers will be examined, including such common features as domain theory, filler effects, polystyrene/elastomer ratio, clarity, thermodynamics of phase separation, miscibility with other polymers and solubility. Styrenic block copolymers produced by anionic polymerization and by carbocationic polymerization will also be examined.

Multi block copolymers, thermoplastic elastomers based on polyurethanes, polyethers and polyamides, will be highlighted, including polymerization; monomers and their effects on polymer properties (polyurethane TPEs, polyester TPEs and polyamide TPEs); common features; thermoplastic elastomers based on polyolefins (segmental structures and polymerization); and miscellaneous block copolymars.

Hard polymer/elastomer combinations, including simple blends and dynamic vulcanizates, will be discussed.

Graft copolymers, ionomers and core-shell morphologies will be examined, including importance; graft copolymers (structure, chain statistics, molecular parameters, production and properties); ionomers; and core-shell morphologies.

Commercial applications of thermoplastic elastomers will be highlighted, including styrenic block copolymers; replacements for vulcanized rubber; adhesives, sealants and coatings; blends with thermoplastics or other polymeric materials (thermoplastics, thermosets, asphalt blends and wax blends); multi-block copolymers; and hard polymer/elastomer combinations.

Economic aspects, tradenames and future developments will also be examined, including price and commercial sales.

The registration fee for "Compounding and mixing of rubber" is $1,090. Participants completing the course will receive 1.8 Continuing Education Units. The registration fee for "Thermoplastic elastomers" is $915. Participants completing this course will receive 1.2 CEUs. Fees include notebooks, program materials, refreshments and networking lunches.

Further information on both of these courses is available from Murali Vedula [phone].