Overview
ISO 1183-2:2026 - Plastics - Methods for determining the density of non-cellular plastics - Part 2: Density gradient column method is an internationally recognized standard developed by ISO. This document specifies the density gradient column method for accurate determination of the density of non-cellular, void-free, moulded or extruded plastics, as well as plastic pellets. The method is widely utilized in material testing laboratories and across plastics manufacturing industries to assess the consistency and quality of plastic materials.
Density is a key indicator of a polymer's physical structure and composition. Monitoring density is vital for ensuring the uniformity and performance characteristics of finished plastic products. The ISO 1183-2:2026 standard enables repeatable and precise measurement, supporting both quality control and product development.
Key Topics
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Test Methodology:
The document details a procedure using a density gradient column filled with a mixture of two miscible liquids of different densities. Plastic specimens are introduced to the column, and their equilibrium positions are used to determine density.
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Equipment and Materials:
- Density gradient column (minimum 40 mm diameter, with cover and graduated scale)
- Thermostatically controlled liquid bath for temperature regulation
- Calibrated glass floats for column calibration
- Analytical balance with 0.1 mg accuracy
- Siphon or capillary tube for precise filling of the column
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Specimen Preparation:
Samples should be cut to a manageable size with smooth surfaces to minimize air entrapment. Careful preparation is essential to avoid altering the physical characteristics of the material.
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Calibration and Measurement:
The calibration of glass floats is critical, either via purchase or in-lab preparations, and should cover the relevant density range. The position of the sample in the column after equilibrium corresponds to its density.
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Test Reporting:
The standard identifies required information for test reports, including specimen identification, preparation method, immersion liquids, measured values, test temperature, any corrections, deviations, and unusual observations.
Applications
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Quality Control in Production:
Ensures consistency in the density of manufactured non-cellular plastic parts and pellets, supporting product reliability and compliance with specifications.
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Material Research and Development:
Used by researchers and polymer scientists to investigate structural variations, effect of additives, or process optimization in plastic materials.
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Material Specification Compliance:
The method helps producers and consumers of plastics verify that materials meet agreed technical requirements, especially for void-free, extruded, or moulded plastics.
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Uniformity Assessment:
Regular use allows manufacturers to detect changes in production batches or identify sources of inconsistency, crucial for applications where density impacts performance or safety.
Related Standards
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ISO 1183-1:
Plastics - Methods for determining the density of non-cellular plastics - Part 1: Immersion method, liquid pycnometer method and titration method
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ISO 291:
Plastics - Standard atmospheres for conditioning and testing
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ISO 80000-4:
Quantities and units - Part 4: Mechanics
These related standards provide complementary procedures for density determination and guidance for the conditioning of specimens and reporting of physical quantities.
By implementing ISO 1183-2:2026, organizations can ensure precise, reproducible, and internationally accepted measurement of plastic density, supporting product quality, compliance, and innovation in the plastics industry.