GB/T 43316.1-2023Plastics - Determination of resistance to environmental stress cracking (ESC) - Part 1: General guidance (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting:

This document is Part 1 of GB/T 43316 "Determination of Environmental Stress Crack Resistance (ESC) of Plastics": GB/T 43316 has been released the following sections are included:

---Part 1: General principles;

---Part 2: Constant tensile load method;

---Part 3: Bending method;

---Part 4: Ball pressure or acupressure method;

---Part 5: Constant tensile deformation method;

---Part 6: Slow strain rate method:

This document has been modified to adopt ISO 22088-1:2006 "Determination of environmental stress cracking (ESC) resistance of plastics - Part 1: General principles":

Compared with ISO 22088-1:2006, this document has made the following structural adjustments:

---The eighth to eleventh paragraphs of the introduction correspond to Chapter 5 of ISO 22088-1:2006;

---Chapter 1 corresponds to 1:1 and 1:7 in ISO 22088-1:2006;

---Chapter 3 corresponds to 3:4 in ISO 22088-1:2006;

---Chapter 4 corresponds to Chapter 6 in ISO 22088-1:2006;

---Chapter 5 corresponds to Chapter 7 in ISO 22088-1:2006;

---Chapter 4 in ISO 22088-1:2006 has been deleted:

The technical differences between this document and ISO 22088-1:2006 and their reasons are as follows:

---Deleted 1:2~1:6 in ISO 22088-1:2006 to make the text more applicable;

---Deleted 3:1~3:3, 3:4:1, and 3:4:2 in ISO 22088-1:2006 to make the text more applicable;

---Chapter 4 in ISO 22088-1:2006 has been deleted to make the text more applicable;

---Replaced ISO 293 and GB/T 17037.1 with normatively quoted GB/T 9352, replaced ISO 294-1 and GB/T 39812 ISO 2818 (see Chapter 4) has been replaced to adapt to my country's technical conditions and increase operability:

The following editorial changes have been made to this document:

---Change the note in 7:3 of ISO 22088-1:2006 to a declarative clause:

Please note that some content in this document may be subject to patents: The publisher of this document assumes no responsibility for identifying patents:

Introduction

The stress that exists externally or internally, or both, when plastics are subjected to stresses or strains below their yield point in air:

The combined action of plastics can cause cracking: This type of cracking is often accelerated by the chemical environment in which the plastic is located: This phenomenon is called environmental stress:

Cracking (ESC): ESC damage can occur in many materials, including plastics, which can significantly reduce the ability of the material to survive long-term use:

force or strain:

The ESC process is as follows:

1) After applying stress, microscopic holes are formed in the sample due to stress concentration;

2) The action of the chemical environment causes the rupture of intermolecular bonds, causing the formation and expansion of larger pores, thereby forming interconnected pores:

Silver streaks composed of holes and microfiber structures;

3) Under the combined action of stress and chemical environment, the microfiber structure breaks and silver streaks grow;

4) Cracks appear at the tip of the craze and continue to develop, eventually leading to brittle failure:

Cracks may continue to develop along the thickness of the material until the material breaks into two or more fragments; cracks may also develop when low stress is reached:

forces, different materials, and/or different morphological regions:

The ESC test is relatively complex and is affected by the following parameters:

---Sample size;

---Sample state (orientation, microstructure, internal stress);

---Sample preparation method;

---Thermal history of the specimen;

---Stress and strain;

---Test temperature;

---Test duration;

---Chemical environment;

---Methods for applying stress and strain;

---Failure criterion:

By using one parameter as a variable and keeping other parameters unchanged, the impact of variable parameters on ESC can be evaluated: The main purpose of the ESC test the purpose is to determine the relative effects of chemical media on the plastics (specimens and articles) to which they are exposed:

When the failure modes are consistent with those obtained in actual use, these test results can be used to evaluate molding conditions for molding:

impact on product quality:

Since the influencing factors of ESC performance of products in actual applications are more complex, it is necessary to establish the relationship between the sample ESC test results and the actual product performance:

Direct correlation is very difficult:

Environmental stress cracking testing is used as a quality control tool and in research and development to evaluate stress cracking resistance:

The test method is chosen based on the types of stresses or strains the material will be subjected to in service: When using constant strain testing methods such as the bending bar method or when using the needle intrusion method, be aware that the stress applied to the material will decay over time as the stress relaxes:

Appendix A gives environmental stress cracking test methods applicable to typical plastics:

Select test conditions based on material variety and usage conditions: Compare the ESC properties of materials under the same test conditions:

GB/T 43316 "Determination of Environmental Stress Crack Resistance (ESC) of Plastics" aims to specify the environmental stress cracking resistance of thermoplastic plastics:

The general principles and description of its determination methods are intended to be composed of six parts:

---Part 1: General principles: The purpose is to establish general principles for determining the resistance of plastics to environmental stress cracking:

---Part 2: Constant tensile load method: The purpose is to establish the resistance of thermoplastics to a constant tensile load in a test medium:

An operational, traceable, and verifiable determination procedure for environmental stress cracking:

---Part 3: Bending method: The purpose is to establish thermoplastics capable of withstanding fixed bending strains in the presence of test agents:

An operational, traceable, and verifiable determination procedure for environmental stress cracking resistance:

---Part 4: Ball pressure or acupressure: The purpose is to establish a thermoplastic ring that can withstand constant strain when a ball or needle is pressed into it:

Operable, traceable, and verifiable measurement procedures for environmental stress cracking:

---Part 5: Constant tensile deformation method: The purpose is to establish a test medium for thermoplastics when subjected to constant tensile deformation:

Operable, traceable, and verifiable measurement procedures for environmental stress cracking resistance:

---Part 6: Slow strain rate method: The purpose is to establish for thermoplastics slowly increasing tension at a constant rate in the test medium:

An operable, traceable and verifiable measurement procedure for environmental stress cracking resistance under tensile specimen strain conditions:

The contents of Part 1 and Part 2 to Part 5 support each other and together constitute the standard for determining the environmental stress cracking resistance of plastics:

system:

The above tests for environmental stress cracking (ESC) resistance are essentially rating tests and are not intended to provide information for design or performance prediction:

data:

Determination of environmental stress cracking (ESC) resistance of plastics Part 1: General principles

1 Scope

This document specifies the general principles for specimen preparation, conditioning and test conditions when determining environmental stress cracking (ESC) resistance:

This document applies to thermoplastics:

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text: Among them, the dated quotations for undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document:

GB/T 9352 Compression molding of plastic thermoplastic material samples (GB/T 9352-2008, ISO 293:2004, IDT) GB/T 17037.1 Preparation of injection molded specimens of plastic thermoplastic materials - Part 1: General principles and multi-purpose specimens and lengths Preparation of strip specimens (GB/T 17037.1-2019, ISO 294-1:2017, MOD) GB/T 39812 Machining preparation of plastic specimens (GB/T 39812-2021, ISO 2818:2018, IDT)

3 Terms and definitions

The following terms and definitions apply to this document:

ESCindexESCindex

The failure-indicating performance value determined in the test medium, measured after the same test time and at the same test temperature, is the same as that of the reference medium (usually is the ratio of performance values determined in air):

4 Sample preparation

The environmental stress cracking resistance of the specimen is not only affected by the type of material, but also by the preparation method: Only if similar specimens are used the test results are comparable only when the preparation method and the specimens are in the same state:

Samples should be prepared in accordance with the appropriate standards: For molding materials, they should be processed in accordance with the provisions of GB/T 9352 or GB/T 17037.1:

Perform sample preparation: For sheets or other products, if there are no corresponding provisions in product standards or specifications, the provisions of GB/T 39812 shall be followed:

Sample preparation:

To obtain comparable results, the specimens used should be of the same size, condition and storage time, and should be prepared in the same way:

The sheet or product should be cut or machined in the corresponding direction and at the corresponding position: The machined surfaces and edges of the specimens shall be free from visible imperfections:

dings, scratches and other defects:

When holding the specimen, only the two ends of the specimen should be touched: If the sample is not clean, use a liquid that has no effect on the sample to clean it before installing it:

clean: Cleaning may affect the test results and the cleaning method used should be recorded in the test report:

Injection molded specimens usually have a greater degree of orientation: If the load is applied parallel to the injection direction, the failure time of the specimen may be significantly shorter than that of the vertical injection direction:

shooting direction: For anisotropic specimens, more useful data can be obtained by applying loads in different directions: