ASTM D1601 Dilute Solution Viscosity of Ethylene Polymers

Dilute solution viscosity of Ethylene Polymers is determined by standard test method ASTM D1601. The relative viscosity, inherent viscosity, and intrinsic viscosity are all determined in the same way. The values expressed in SI units should be considered as standard.

Talk to an Expert

ASTM D1601 Dilute Solution Viscosity of Ethylene Polymers

TRUSTED BY

Precision-driven testing for dimensional accuracy and compliance

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

Overview

ASTM D1601 describes the standard method of determining the viscosity of dilute solutions of ethylene polymers at an elevated temperature of 135 °C. The viscosity of dilute solutions is one of the most essential properties related to the molecular weight and structure of the polymer, and it affects the mechanical, thermal, and processing properties of polyethylene.

The procedure provides consistent, reproducible, and comparable viscosity data for polymer characterization, quality control, and material development. D1601 is widely used to test ethylene polymers for packaging, construction, medical devices, and other key applications.

Scope, Applications, and Benefits

Scope

ASTM D1601 outlines procedures for measuring the viscosity of dilute ethylene polymer solutions in a specified solvent at 135 °C.
It evaluates:

Relative viscosity (viscosity ratio)
Inherent viscosity (logarithmic viscosity number)
Intrinsic viscosity (limiting viscosity number)
Molecular weight–related polymer characteristics

The method applies to ethylene polymers with densities typically ranging from 0.910 to 0.970 g/cm³ and considers the influence of additives such as colorants, fillers, carbon black, and low-molecular-weight components.

Applications

Quality control of polyethylene resins
Molecular weight characterization of ethylene polymers
Processability and performance assessment
Research and development of polymer formulations
Comparative analysis of polymer grades
Verification of production consistency

Benefits

Provides indirect determination of polymer molecular weight
Enables consistent comparison between polymer batches
Supports control of mechanical and thermal performance
Helps assess the influence of additives and processing history
Enhances confidence in material selection and product reliability

Test Process

Solvent Preparation

Decahydronaphthalene solvent is prepared in accordance with ASTM D1601 requirements to ensure purity and consistency.

Viscometer Cleaning & Setup

Capillary viscometers are thoroughly cleaned and conditioned to eliminate contamination and ensure accurate flow measurements.

Sample Preparation & Conditioning

A known mass of ethylene polymer is dissolved in the solvent at elevated temperature to form a dilute, homogeneous solution.

Viscosity Measurement

Flow times of the solvent and the polymer solution are measured at 135 °C using a capillary viscometer to calculate the viscosities.

Technical Specifications

Parameter	Details
Applicable Materials	Ethylene polymers
Density Range	0.910 to 0.970 g/cm³
Test Temperature	135 °C
Polymer Weight	Typically 0.1 to 0.5 g
Solvent Volume	Approximately 50 to 100 mL
Measured Outputs	Relative, inherent, and intrinsic viscosity

Instrumentation Used for Testing

Capillary viscometers (Ubbelohde or Cannon–Fenske)
Constant-temperature oil bath (135 °C)
Precision timing devices
Analytical balance
Sample dissolution and conditioning apparatus
Data calculation tools for viscosity analysis

Results and Deliverables

Relative viscosity values of ethylene polymer solutions
Inherent and intrinsic viscosity calculations
Data correlating viscosity with molecular weight
Polymer consistency and quality assessment
Comparative viscosity data for material evaluation
Documentation supporting quality control and R&D activities

Frequently Asked Questions

It must be remembered that the customary physical law states that viscosity decreases with increasing temperature and dilution.

In the semi-empirical Mark-Houwink equation, [ η ] = K M v α, where K and α are constants for a particular polymer, solvent, and temperature, the limiting or intrinsic viscosity [η] amount is associated with the molecular weight of the polymer.

Liquid viscosity generally decreases as temperature increases. Pressure: High pressure can increase viscosity, while low pressure can reduce it. Shear rate: Increasing the shear rate or measuring how fast a liquid is deformed tends to decrease viscosity.