ASTM D7605 Rheological & Dynamic Property Testing for Thermoplastic Elastomers
ASTM D7605 test method determines the flow properties and dynamic properties of polymer melts and thermoplastic elastomers, respectively, by employing a rotorless oscillating shear rheometer. These properties are essential for product processing and performance evaluation. The final results of this test method are expressed in SI units.
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- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
Overview
ASTM D7605 describes a standard test method for measuring the rheological and dynamic mechanical properties of thermoplastic elastomers (TPEs) using a dynamic mechanical analyzer (DMA) or similar rheometric instrumentation. These properties define how TPEs behave under oscillatory deformation and are critical for processing and end-use performance prediction.
This test method supports TPE formulation development, quality control, and material selection for applications in automotive, medical, consumer goods, and industrial sectors where the balance between thermoplastic processability and elastomeric performance is essential.
Scope, Applications, and Benefits
Scope
ASTM D7605 covers the measurement of:
- Storage modulus (E’ or G’) of thermoplastic elastomers
- Loss modulus (E” or G”) under dynamic loading
- Loss tangent (tan δ) vs. temperature or frequency
- Viscoelastic behavior in the solid and melt states
Applications
- Thermoplastic elastomer formulation development
- Automotive seals, grips, and flexible components
- Medical device TPE material qualification
- Consumer product material selection
- Processing parameter optimization for TPE extrusion and injection molding
Benefits
- Provides comprehensive viscoelastic property data
- Enables direct comparison of different TPE grades
- Supports performance prediction under dynamic service conditions
- Identifies thermal transitions (Tg, softening) relevant to processing
- Applicable across a wide temperature and frequency range
Test Process
Specimen Preparation
Prepare molded or cut specimens to required dimensions (rectangular bar or disc geometry depending on the test mode).
1DMA Setup & Conditioning
Mount the specimen in the DMA fixture; equilibrate to the starting temperature under controlled conditions.
2Dynamic Sweep
Apply sinusoidal deformation over the set sweep and record stress–strain continuously.
3Data Analysis
Calculate storage and loss moduli and tan δ from phase angle, and identify thermal transitions.
4Technical Specifications
| Parameter | Details |
|---|---|
| Standard | ASTM D7605 |
| Test Principle | Dynamic Mechanical Analysis (DMA) or rheometry |
| Applicable Materials | Thermoplastic elastomers (TPEs) |
| Measured Outputs | E' (or G'), E'' (or G''), tan δ |
| Test Modes | Tension, flexure, shear, compression |
| Temperature Range | Typically -100°C to 200°C |
Instrumentation Used for Testing
- Rotational rheometer
- Dynamic mechanical analyzer (DMA)
- Temperature control system
- Parallel plate or cone-and-plate fixtures
- Frequency control unit
- Data acquisition software
- Sample preparation tools
Results and Deliverables
- Storage modulus (E’/G’) and loss modulus (E”/G”) vs. temperature/frequency
- Tan δ (loss tangent) spectra and peak identification
- Glass transition temperature (Tg) and other thermal transition data
- Comparative viscoelastic profiles between TPE formulations
- Processing behavior predictions based on melt-state rheology
- Material characterization reports for TPE qualification
Why Choose Infinita Lab for ASTM D7605?
Infinita Lab is a trusted USA-based testing laboratory offering ASTM D7605 testing services across an extensive network of accredited facilities across the USA.
Infinita Lab is built to serve the full spectrum of modern testing needs—across industries, materials, and methodologies. Our advanced equipment and expert professionals deliver highly accurate and prompt test results, helping businesses achieve quality compliance and product reliability.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote
Frequently Asked Questions
TPEs exhibit both thermoplastic (melt-processable) and elastomeric (flexible, recoverable) properties. Unlike vulcanized rubbers, they soften and flow at elevated temperatures, requiring dynamic testing across both the solid and melt states for full characterization.
Tan δ is the ratio of energy dissipated to energy stored per cycle. High tan δ indicates damping-dominated behavior, which is desirable in vibration isolation applications. The temperature at the tan δ peak is often used to identify Tg.
Yes, melt-state dynamic rheology measurements (G' and G'' in the melt) provide information on melt viscosity, elasticity, and processability that can be correlated to extruder pressure requirements and die flow behavior.
In strain-controlled tests, the instrument applies a defined oscillatory strain and measures the resulting stress. In stress-controlled tests, the applied stress is defined and strain is measured. The choice affects instrument accuracy depending on material stiffness.
Higher test frequencies generally shift modulus transitions to higher temperatures due to the time-temperature superposition principle. This means results measured at 1 Hz correspond to different effective temperatures than those at 10 Hz, and frequency should always be reported with results.
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