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GB/T 12811-2025: Test method for average cell size of rigid cellular plastics
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GB/T 12811-1991	English	119	Add to Cart	2 days [Need to translate]	Test method for average cell size of rigid cellular plastics

GB/T 12811-2025: Test method for average cell size of rigid cellular plastics

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ICS 83.100 CCSG32 National Standards of the People's Republic of China Replaces GB/T 12811-1991 Test method for average cell size of rigid foam plastics Published on 2025-10-31 Implemented on May 1, 2026 State Administration for Market Regulation The State Administration for Standardization issued a statement.

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 supersedes GB/T 12811-1991 "Test Method for Average Cell Size of Rigid Foamed Plastics" and is consistent with GB/T 12811-1991. Compared to previous versions, aside from structural adjustments and editorial changes, the main technical changes are as follows. ---The scope has been changed (see Chapter 1, Chapter 1 of the.1991 edition); ---The principle of Method A (projector method) has been modified (see 4.1, Chapter 3 of the.1991 edition); ---The principles of Method B (optical microscopy) and Method C (scanning electron microscopy) have been added (see 4.2 and 4.3); ---The instruments required for Method A (projector method) have been changed (see 5.1, Chapter 4 of the.1991 edition); ---Added the instruments required for Method B (optical microscopy) and Method C (scanning electron microscopy) (see 5.2, 5.3); ---The sample size and preparation methods for Method B (optical microscopy) and Method C (scanning electron microscopy) have been expanded (see 6.1); ---The number of trials has been changed (see 6.2, 5.2 in the.1991 edition); ---The conditions for state adjustment have been changed (see Chapter 7, Chapter 6 in the.1991 edition); ---The experimental procedures for Method A (projector method) have been modified (see 8.1, Chapter 7 of the.1991 edition); ---Experimental procedures for Method B (optical microscopy) and Method C (scanning electron microscopy) have been added (see 8.2 and 8.3); ---The formula for the experimental results has been changed (see Chapter 9, Chapter 8 in the.1991 edition); ---The test report content has been revised (see Chapter 10, Chapter 9 of the.1991 edition). Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents. This document was proposed by the China National Light Industry Council. This document is under the jurisdiction of the National Technical Committee on Standardization of Plastic Products (SAC/TC48). This document was drafted by. Beijing Technology and Business University, Jiangsu Jianghua Polyurethane Product Quality Testing Co., Ltd., and the Light Industry Plastics Processing and Application Research Institute. Research Institute, Wanhua Chemical (Ningbo) Rongwei Polyurethane Co., Ltd. The main drafters of this document are. Li Tianhua, Luo Chen, Wang Lei, Ye Jun, and Han Xuerong. The release history of this document and the document it replaces is as follows. ---First published in.1991 as GB/T 12811-1991; ---This is the first revision. Test method for average cell size of rigid foam plastics

1 Scope

This document describes a method for determining the average cell size of rigid foam by calculating the number of cell wall intersections within a desired length. The experimental methods are. Method A (projector method), Method B (optical microscope method), and Method C (scanning electron microscope method). This document applies to the determination of the average cell size of rigid foam plastics. For the determination of the average cell size of other types of foam plastics, refer to [the relevant documentation]. implement.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included. For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document. GB/T 2918 Standard Environment for Conditioning and Testing of Plastic Specimens GB/T 6342 Determination of linear dimensions of foamed plastics and rubber

3 Terms and Definitions

This document does not contain any terms or definitions that need to be defined. 4.Principles 4.1 Method A (Projector Method) Foam plastic is cut into thin sheets using a slicer, with a thickness not exceeding 1 mm. The image of the thin sheets is then projected onto a screen using a projector, within the specified time frame. Within the length, calculate the number of bubbles in the cross section, calculate the average chord length from this number, and then convert the average chord length into the average bubble size. 4.2 Method B (Optical Microscopy) Cut the foam plastic to make its surface smooth. Observe it with an optical microscope and count the number of bubbles on the surface within a suitable length. Calculate the average chord length, then convert it to the average cell size. When the cell walls are thick, the wall thickness needs to be considered when calculating the average chord length. The impact. 4.3 Method C (Scanning Electron Microscopy) The sample was prepared by breaking it into pieces using liquid nitrogen quenching, and a conductive thin layer was sputtered onto the quenched surface of the foam sample. This was then analyzed using scanning electron microscopy. Observe and calculate the number of bubbles in the cross-section within a suitable length. Calculate the average chord length from this number, and then convert the average chord length into the average bubble size. When the cell walls are thick, the effect of the wall thickness needs to be considered when calculating the average chord length.

5 Instruments

5.1 Instruments required for Method A 5.1.1 Foam plastic slicer. capable of cutting thin slices. ...