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GB/T 15251-2008 English PDF

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GB/T 15251-2008: Rubber -- Determination of free sulfur
Status: Valid

GB/T 15251: Evolution and historical versions

Standard IDContents [version]USDSTEP2[PDF] delivered inStandard Title (Description)StatusPDF
GB/T 15251-2008English349 Add to Cart 3 days [Need to translate] Rubber -- Determination of free sulfur Valid GB/T 15251-2008
GB/T 15251-1994English199 Add to Cart 2 days [Need to translate] Rubber--Determination of free sulpher--Copper spiral method Obsolete GB/T 15251-1994

PDF similar to GB/T 15251-2008


Standard similar to GB/T 15251-2008

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Basic data

Standard ID GB/T 15251-2008 (GB/T15251-2008)
Description (Translated English) Rubber -- Determination of free sulfur
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard G40
Classification of International Standard 83.060
Word Count Estimation 15,124
Date of Issue 2008-05-15
Date of Implementation 2008-11-01
Older Standard (superseded by this standard) GB/T 15251-1994; GB/T 3514-1992
Quoted Standard GB/T 3516; ISO 383-1976
Adopted Standard ISO 7269-1995, MOD
Regulation (derived from) National Standard Approval Announcement 2008 No.8 (Total No.121)
Issuing agency(ies) General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China
Summary This standard specifies the method for the determination of three free sulfur vulcanized rubber. That two kinds of copper sulfite spiral method and one method. This standard applies to all kinds of vulcanized rubber, two copper spiral method is also applicable to Chapter 4 describes the limitations of uncured rubber range. Appendix A provides the effect of various enhancers on the product of the determination of free sulfur, expressed in wt.

GB/T 15251-2008: Rubber -- Determination of free sulfur

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Rubber. Determination of free sulfur ICS 83.060 G40 National Standards of People's Republic of China Replacing GB/T 15251-1994, GB/T 3514-1992 Rubber - Determination of free sulfur (ISO 7269.1995, MOD) Posted 2008-05-15 2008-11-01 implementation Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China Standardization Administration of China released

Foreword

This revised standard adopts ISO 7269.1995 "Determination of free sulfur rubber" (in English), including its amendments ISO 7269.1995 / Cor. 1.2002 (in English). This standard replaces GB/T 3514-1992 "vulcanized rubber Determination of sulfur content of free sulfite method", GB/T 15251-1994 "Determination of free sulfur rubber copper spiral method." This standard is based on ISO 7269.1995 re-drafted. This standard is the international standard ISO 7269.1995 and its main difference causes changes reg structured as follows. --- Increasing the standard iodine titration solution and sodium thiosulfate standard titration solution preparation and calibration method (This standard 5.1.7,5.1.8), In order to enhance the standard of operability. --- In the sulfite process, added porcelain zeolite (this standard 7.1.2) when heated; use ordinary conical flask (7.2.1 of this standard); silicon Diatomaceous earth by the thickness of 5mm to 2mm (ISO 7269.1995 7.3.3; 7.3.3 of this standard); instead of the surface with a small funnel Cover dish conical mouthpiece (ISO 7269.1995 7.3.1; 7.3.1 of this standard). Such provisions enhance the operability of this standard For sex. For ease of use, this standard made the following editorial changes. a) "this International Standard" by "this standard"; b) Delete the international standard preface; c) increase the informative Appendix B. This standard is GB/T 3514-1992 and GB/T 15251-1994 revision of integration, and technical content GB/T 3514-1992 And GB/T 15251-1994 compared to the main changes are as follows. --- Increased introduction; --- Increased warnings; --- Increase the limitations of standard instructions (edition 4); --- Increased rapid extraction method, copper spiral method B (6 edition); --- Increasing the size measurement method used glassware (GB/T 3514-1992 of 4, GB/T 15251-1994 5; Excerpts 5.2,6.2,7.2); --- Increasing the standard iodine titration solution and sodium thiosulfate standard titration solution preparation and calibration methods (Excerpts 5.1.7, 5.1.8); --- Modify the processing method of compound (GB/T 3514-1992 of 5, GB/T 15251-1994 6; Excerpts 5.3,6.3, 7.3); --- In the sulfite method. when heated to prevent foaming, an increase of liquid paraffin (Excerpts 7.1.10,7.3.1); instead of using diatomaceous earth Asbestos as a filter packing (GB/T 3514-1992 3.8 and 5; edition of 7.1.9 and 7.3.3); --- Modified test procedure. The back-titration method instead of direct titration (GB/T 3514-1992 5; edition 7.3.4); --- Increased content requires the test report (edition 8); --- The test replicates tolerance to informative Appendix B (GB/T 3514-1992 7; edition of Appendix B); --- Increase the informative appendix, accelerator on (Excerpts Appendix A) on the test results. The Standard Appendix A and Appendix B are informative. The standard proposed by China Petroleum and Chemical Industry Association. This standard by the National Standards Commission rubber rubber physical and chemical test methods Technical Committee (SAC/TC35/SC2) centralized. The main drafting standard units. Beijing Rubber Industry Research and Design Institute, Hangzhou Zhongce Rubber Co., Ltd. The main drafters of this standard. Jiangyun Ping, Wujiang Tao, Zhang Yan, item cicada, Yang Yu, Lu Yi, Xue show. This standard replaces the standards previously issued as follows. --- GB/T 3514-1992; --- GB/T 15251-1994.

Introduction

Uncured rubber compounds content of free sulfur (such as rubber compound unbound sulfur content) should represent all of the added elemental sulfur. As the sulfur and gradually combine with the rubber vulcanization, the number of free sulfur will be gradually reduced, so the recipe is known and elemental sulfur (package Under appropriate ratio including other components), the number of free sulfur in any given product in both its degree of cure of a certain relationship. A high percentage of free sulfur vulcanized rubber easier blooming, so in some specific product specification need to be shown the largest free sulfur content value. Rubber - Determination of free sulfur Warning --- personnel should use this standard regular laboratory work experience. This standard does not point out all possible security asked question. Users have the responsibility to take appropriate safety and health practices and to ensure compliance with the conditions relevant national regulations.

1 Scope

This standard specifies the vulcanized rubber in the determination of free sulfur three methods, namely, Auger and one of Copper sulfite method. This standard applies to all kinds of vulcanized rubber two copper spiral method also applies to Chapter 4 describes the unvulcanized rubber material within a confined range. Appendix A provides more accelerators Goods influence of free sulfur determination, expressed in mass fraction.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard. GB/T 3516 Determination of rubber solvent extract (GB/T 3516-2006, ISO 1407.1992, MOD) ISO 383. 1976 Laboratory glassware interchangeable cone Interface Principle 3 3.1 Cu Auger 3.1.1 Method A Solvent extraction method according to GB/T 3516 regulations, with acetone extraction of the free sulfur in a sample, and placing the flask in acetone Place a helical copper mesh. The extracted copper and sulfur reaction and produce copper sulfide. Treated with hydrochloric acid does not remain in the flask Dissolved in acetone copper and copper sulfides. With cadmium acetate buffer solution to absorb the generated hydrogen sulfide, the resulting final determination of cadmium by iodometry Sulfides. 3.1.2 Method B Fast copper and copper helix spiral method B A similar method, except that the use of Method B have a vapor jacket Soxhlet extraction to reduce the time between. Soxhlet extractor by reducing the volume (volume 6mL) to increase the extraction temperature. 3.2 Sodium sulfite method Free sulfur in a sample is reacted with sodium sulfite, sodium thiosulfate generated measured by iodometry.

4 Limitations

4.1 Determination of copper spiral method usually only elemental sulfur content, but thiuram disulfide and diamine sulfide sulfur vulcanizing agent will guide carrier Cause high results. In addition, the unvulcanized rubber, elemental sulfur is added if insoluble in acetone, or the so-called insoluble amorphous sulfur, the copper Auger does not apply. In a sample of the total mass of free sulfur should be between 0.2mg ~ 10mg. 4.2 Method of sulfite sulfur vulcanizing agent and antioxidant carrier too sensitive, and does not apply to uncured rubber. 4.3 These methods without sulfur donor curing agent is relatively precise conditions. Note. In fact, in addition to the determination of elemental sulfur, a number of active sulfur compounds, such as the disulfide and polysulfide sulfur, will produce the same experiment effect.

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