2
Flexural Testing of Plastics
LAAN-J-AG-E002
Material Testing & Inspection
Autograph Precision Universal Tester
Standard No. ISO178: 2010 (JIS K 7171: 1994)
Introduction
Measurement Results
Measurements and Jigs
In recent years, a large variety of synthetic resin (plastic) materials has become available for use in a diversity of products. They
are used in applications that take advantage of their respective characteristics. For example, polyethylene (PE) is cheap and easy
to mold, and thus used for containers, packaging film, and other everyday applications. In contrast, polycarbonate (PC) is
transparent, has a high mechanical strength, and is heat-resistant; consequently, it is used for CDs and DVDs in the electrical and
electronics fields, as well as in transportation equipment, optics, and medical fields.
In this Data Sheet, flexural testings are performed on four materials, including polyvinyl chloride (PVC) and polypropylene (PP).
T. Murakami
In plastic flexural testings, the width of the two supports and central loading edge must be larger than the width of the specimen,
and parallelism within ± 0.2 mm is required. The loading edge radius is 5 mm ±0.1 mm, and the supports radius is specified as 2
mm ± 0.2 mm for specimens with a thickness of 3 mm or less, and 5 mm ± 0.2 mm for specimens with a thickness exceeding 3
mm. The span must be adjusted to a value of 16 (± 1) times the specimen thickness. In this test, since a 4 mm-thick specimen is
used, the span is set to 64 mm (specimen thickness of 4 mm × 16 = 64 mm).
Fig. 1: Test Status Fig. 2: Relationship Between Flexural Stress and Flexural Strain
0 10 1 2 3 4 5 6 7 8 9
150
0
140
130
120
110
100
90
80
70
60
50
40
30
20
10
曲げひずみ(%)
曲げ応力(MPa)
PC
PVC
PE
PP
Flexural stress (MPa)
Flexural strain (%)
Table 1: Test Conditions
Item Set Value
Test Speed
Span
2 mm/min
64 mm
Table 2: Test Results
1527 33.0
2378 99.7
3257 97.8
2559 62.6
Sample Flexural Modulus (MPa) Flexural Strength (MPa)
PE (polyethylene)
PC (polycarbonate)
PVC (polyvinyl chloride)
PP (polypropylene)
