This document discusses environmental stress cracking resistance (ESCR) testing of thermoplastic polymers. ESCR is one of the most common causes of unexpected brittle failure in plastics. The rate of ESCR depends on factors like a polymer's chemical makeup, molecular weight, and residual stress as well as the liquid's chemistry, temperature, and strain rate. The document describes an ESCR testing machine and procedure where samples are clamped and submerged in a detergent solution at elevated temperature for 30 minutes before being examined for surface cracks. The test determines a material's resistance to environmental stresses.

1. Environmental stress
cracking resistance
Prepared by
Sivaprakash. S
Department of Polymer Technology
Kamaraj college of Engineering and Technology
+91 99407 33520

2. Introduction
 Environmental Stress Cracking Resistance is
one of the most common cause of
unexpected brittle failure of thermoplastic
(especially amorphous) polymers known at
present.
 ESC may account for around 15 - 30% of all
plastic component failures in service.
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3. Predicting Environmental Stress
Cracking Resistance
 The rate of esc is dependent on many factors
including the polymer`s chemical makeup,
bonding, crystalinity, surface roughness,
molecular weight, residual stress.
 It also depends on the liquid reagent`s
chemical nature and concentration, the
temperature of the system and the strain
rate.
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4. Environmental Stress Cracking
Resistance Testing Machine
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5. Top View of ESCR5

6. ESCR sample holder and test
tube
Sample
After clamping
Sample
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7. Procedure
 The sample of 1.5 X 4 cm is taken.
 The sample is clamped in the sample holder. (ten samples
per holder)
 Then it is placed into the boiling tube.
 The tube is filled with detergent solution.
 Then it is closed with cork.
 Then it is placed in the instrument.
 The temperature is turned on.
 The test is carried out for half an hour.
 Then the samples are taken out.
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8. What to do after the test?
 The samples are carefully taken out.
 The samples are examined for cracks on the
surface.
 The results are given by defects per 10
samples.
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9. Significance
 The test is carried out to know about the
withstanding of the material to the contact
of the environment.
 This test tells about the character of the
sample to the environment.
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