ASTM D6049 Test Method for Rubber Property Measurement of the Viscous and Elastic Behavior of Unvulcanized Raw Rubbers and Rubber Compounds by Compression Between Parallel Plates

In ASTM D6049, the rheological behavior (viscosity and elasticity) of unvulgarized raw rubbers and rubber compounds, and the macrostructure of rubber polymers, can be measured and characterized using this test method. The values expressed in SI units should be considered the standard.

Talk to an Expert

ASTM D6049 Test Method for Rubber Property Measurement of the Viscous and Elastic Behavior of Unvulcanized Raw Rubbers and Rubber Compounds by Compression Between Parallel Plates

TRUSTED BY

Precision-driven testing for dimensional accuracy and compliance

Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

ASTM D6049 describes the standard test method for determining the viscosity and elasticity of unvulcanised rubbers and rubber compounds. These viscoelastic properties are relevant to several processing operations, including mixing, calendaring, extrusion, and molding.

The test technique assesses the response of rubber materials to the complex deformations experienced in manufacturing. Measuring the storage modulus (G’), loss modulus (G”), and phase angle (δ) in accordance with the ASTM D6049 method enables the prediction of processing behaviour and protection of consistent material performance and quality.

Scope, Applications, and Benefits

Scope

ASTM D6049 provides a sensitive method for measuring rheological properties under low-shear conditions.
It evaluates:

Viscosity-related parameters
Elasticity-related parameters
Storage modulus (G’)
Loss modulus (G”)
Phase angle (δ)
Minute rheological changes
Processability prediction

The method is suitable for compliance testing, quality control, research, and development.

Applications

Rubber compounding
Tire manufacturing
Industrial rubber products
Extrusion and molding operations
Material formulation development
Quality assurance testing
Research laboratories

Benefits

Predicts rubber processing behavior
Detects small rheological changes
Ensures batch-to-batch consistency
Optimizes compound formulations
Supports process control
Improves product quality
Reduces manufacturing defects

Test Process

Specimen Preparation & Temperature Setting

Samples are prepared, and the test temperature is set to 105 ±1°C.

Plate Positioning & Compression

The sample is centered between plates and compressed to 7.0 mm under constant force.

Recovery & Oscillatory Loading

Recovery height is measured, and oscillatory strain/stress is applied.

Data Collection & Analysis

Viscoelastic properties are recorded, and results are plotted.

Technical Specifications

Parameter	Details
Applicable Materials	Unvulcanised rubbers and compounds
Compression Diameter	30.0 ±0.1 mm
Minimum Thickness	≥ 2 mm
Test Temperature	105 ±1°C
Temperature Stability	±0.1°C
Plate Material	Polished steel or aluminium

Instrumentation Used for Testing

Parallel plate rheometer
Temperature control system
Compression device
Precision displacement sensors
Load cell
Data acquisition software
Environmental chamber (if required)

Results and Deliverables

Storage modulus (G’) values
Loss modulus (G”) values
Phase angle (δ)
Rheological curves
Processability assessment
Comparative batch reports
Quality control documentation

Frequently Asked Questions

ASTM D6049 is designed explicitly for unvulcanized raw rubbers and rubber compounds. Different test methods evaluate the properties of vulcanized rubbers.

Temperature significantly affects rubbers' viscoelasticity. Tests can be conducted at different temperatures, mimicking operating and processing conditions prevailing during utilization.

The method is generic and suitable for all kinds of unvulcanized rubbers as long as the requirements of sample preparation and testing mentioned in the standard are met.