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BS ISO 16790:2021

$142.49

Plastics. Determination of drawing characteristics of thermoplastics in the molten state

Published By Publication Date Number of Pages
BSI 2021 24
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This document specifies a method for determining the drawing and break characteristics of molten plastics. The method involves the measurement of the force generated in deforming a molten filament under defined extrusion temperature and drawing conditions.

Data is generated under non-isothermal and non-homogeneous deformation conditions. However, it is useful for the interpretation of polymer behaviour in extensional flow.

The method is suitable for thermoplastics moulding and extrusion materials that can be extruded using a capillary extrusion rheometer, or an extruder with capillary rod die or other extrusion devices and have sufficient melt strength to be handled without difficulty.

The method is applicable to chemically stable materials that produce a uniform extrudate free from heterogeneities, bubbles, unmelted impurities, etc.

This method can provide information on

  • processability for all extrusion techniques,

  • the effect of mechanical and thermal history, and

  • the effect of chemical structure, such as branching, entanglements and molecular mass.

This technique is one of a number of techniques that can be used to measure the extensional flow behaviour of a material. This method of measurement does not necessarily reproduce the drawing conditions to which thermoplastics are subjected to during their processing.

PDF Catalog

PDF Pages PDF Title
2 National foreword
6 Foreword
7 1 Scope
2 Normative references
3 Terms and definitions
9 4 Principle
5 Apparatus
5.1 Apparatus for heating the polymer and forming the extrudate
5.1.1 General
5.1.2 Capillary extrusion rheometer
10 5.1.3 Extruder
11 5.2 Apparatus for drawing the polymer extrudate
5.2.1 Drawing unit
5.2.2 Drawing unit design
13 5.3 Data-acquisition system
6 Calibration
6.1 General
6.2 Test temperature
6.3 Capillary or rod die
6.4 Drawing-force transducer
6.5 Drawing velocity and drawing acceleration
6.6 Drawing length
14 7 Sampling
8 Procedure
8.1 Cleaning the apparatus
8.2 Rheometer or extruder preparation
15 8.3 Loading the capillary rheometer barrel
8.4 Preheating
16 8.5 Running the extruder
8.6 Preliminary checks of the extrudates
8.6.1 Absence of defects
8.6.2 Check on drawing down under gravity
18 8.7 Determination of the extrudate behaviour
8.7.1 Determination of the mean velocity
8.7.2 Determination of the drawing force as a function of the drawing velocity
19 8.7.3 Measurement of melt strength
20 9 Calculation and expression of results
9.1 Initial cross-sectional area of the extrudate
9.2 Initial velocity
9.3 Drawing velocities
21 9.4 Drawing forces
9.5 Draw ratio
10 Precision
11 Test report
11.2 General:
11.3 Material and test conditions:
22 11.4 Test results:
23 Bibliography
BS ISO 16790:2021
$142.49