Test standards Alpine supports: ASTM D5289, ASTM D6204, ASTM D6601, ASTM D7750, ASTM D8059
Rubber Process Analyzers (RPA) are advanced rheometers used to characterize uncured and cured elastomers by measuring viscoelastic properties under controlled strain, frequency, and temperature, mimicking the shear and thermal conditions experienced during the manufacturing process. It evaluates engineering properties such as storage modulus (G’), loss modulus (G”), tan delta, polymer viscosity (n*), and cure profiles to determine scorch time, cure rate, and torque development, helping predict processing characteristics, filler dispersion, and in-application material behavior. Our RPA system is equipped with Encapsulated Shear Rheometer (ESR) capabilities, allowing testing in sealed, pressurized environments. The ESR addition allows for deeper testing of rubbers and provides capabilities for testing high-temperature plastics (PEEKs), films, fibers, and rubber and plastic blend composites.
Alpine Polytech provides precise RPA and ESR testing services to support compound development, troubleshooting, and process optimization while aligning material performance testing with real-world service environments.
Testing Details
ASTM D6204: Measures processability of unvulcanized rubber using rotorless shear rheometers
ASTM D6601: Evaluates dynamic properties during and after cure using rotorless rheometers
ASTM D8059: Measures strain softening in filled rubber using rotorless rheometers and gives information on polymer filler interactions
ASTM D7750: Characterizes cure behavior of thermosetting composites by dynamic mechanical rheometry
ASTM D5289: Measures cure properties (cure time, torque, etc.) of rubber with rotorless cure meters
During RPA testing, a small thermoplastic or thermoset sample is placed between dies within the sealed test chamber. The system applies oscillation at controlled strain and frequency while precisely heating the sample to defined temperatures. Torque is measured as the material is sheared, and these torque readings can be converted to Mooney viscosity values if needed. The RPA runs programmed test profiles to record data such as storage modulus, loss modulus, tan delta, and cure characteristics over time. When using ESR capabilities, the chamber is sealed and can be pressurized with inert gas to contain volatiles and simulate in-application environments. After the test, the sample can be collected for additional analysis using FTIR, TGA, DSC, or DMA to provide a comprehensive understanding of the compound’s material properties and cure state