GB/T 7139-2023 English PDF (GB/T7139-2023)

GB/T 7139-2023: Plastics - Vinyl chloride homopolymers and copolymers - Determination of chlorine content
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GB/T 7139-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.080.20
CCS G 31
Replacing GB/T 7139-2002
Plastics - Vinyl chloride homopolymers and copolymers -
Determination of chlorine content
(ISO 1158:1998, MOD)
ISSUED ON: AUGUST 06, 2023
IMPLEMENTED ON: MARCH 01, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Method A - Incendiary bomb method ... 6
5 Method B - Molotov cocktail method ... 10
6 Test report ... 13
Annex A (informative) Comparison of structural number changes between this
document and ISO 1158:1998 ... 15
Annex B (informative) Technical differences between this document and
ISO1158:1998 and their reasons ... 18
Annex C (informative) Filling method of sodium peroxide, starch or sucrose, specimens
... 20
Foreword
This document was drafted in accordance with the rules given in GB/T 1.1-2020
"Directives for standardization - Part 1: Rules for the structure and drafting of
standardizing documents".
This document replaces GB/T 7139-2002 "Plastics -- Vinyl chloride homopolymers and
copolymers -- Determination of chlorine content". Compared with GB/T 7139-2002, in
addition to structural adjustments and editorial changes, the main technical changes are
as follows:
a) Changed the scope of the document (see Chapter 1 of this Edition; Chapter 1 of
Edition 2002);
b) Changed the principles (see 4.1, 5.1 of this Edition; Chapter 3 of Edition 2002);
c) Changed the unit of nitric acid solution concentration. Added the preparation
method (see 4.2.3, 5.2.4 of this Edition; 4.1 of Edition 2002);
d) Added the determination method of titration endpoint of potentiometric titration
(see 4.4.8, 5.4.8 of this Edition);
e) Added the preparation method of potassium hydroxide solution (see 5.2.3 of this
Edition);
f) Changed the regulations on incendiary bottles (see 5.3.4 of this Edition; 5.8 of
Edition 2002);
g) Changed the filter paper requirements (see 5.3.5 of this Edition; 5.9 of Edition
2002);
h) Changed the test steps and the amount of liquid collected in the combustion bottle
method for collecting the liquid after combustion (see 5.4.6 of this Edition; 7.2.5
of Edition 2002);
i) Changed the tolerance of the incendiary bottle method (see 5.6 of this Edition; 8.2
of Edition 2002);
j) Deleted the Volhard method for determining chlorine content (see Annex B and
Annex C of Edition 2002).
The modification of this document adopts ISO 1158:1998 "Plastics -- Vinyl chloride
homopolymers and copolymers -- Determination of chlorine content".
Compared with ISO 1158:1998, this document has more structural adjustments. The
comparison table of structural number changes between the two documents is shown in
Annex A.
Plastics - Vinyl chloride homopolymers and copolymers -
Determination of chlorine content
WARNING -- The personnel who use this document need to have practical
experience in formal laboratory work. This document does not point out all
possible safety issues. The user is responsible for taking appropriate safety and
health measures and ensuring that the conditions stipulated by relevant national
laws and regulations are met.
1 Scope
This document describes methods for the determination of the chlorine content of
homopolymers and copolymers of vinyl chloride.
This document is applicable to the determination of chlorine content in vinyl chloride
homopolymers and copolymers without plasticizers and additives. It can be used as a
reference for the determination of chlorine content in other chlorine-containing
polymers without plasticizers and additives.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 601, Chemical reagent -- Preparations of reference titration solutions
GB/T 603, Chemical reagent -- Preparations of reagent solutions for use in test
methods
GB/T 6682, Water for analytical laboratory use -- Specification and test methods
GB/T 9725-2007, Chemical reagent -- General rule for potentiometric titration
3 Terms and definitions
There are no terms or definitions that require definition in this document.
of the bomb body. Then remove the empty incendiary bomb. Put in the specimen
incendiary bomb. Heat the specimen incendiary bomb to 300℃~400℃ for about 10
min. Combustion usually starts at 50℃~60℃, with a crackling sound, and the bottom
of the bomb body begins to emit a glowing light.
If you use an electric ignition incendiary bomb, operate according to the equipment
instruction manual.
4.4.4 Cool the bomb. If the bomb is cooled in water, be careful not to allow water to
come into contact with the joint between the plug and the bomb. When there is doubt
whether a reaction has occurred, the bomb material shall not be dissolved in water as
this may reason an explosion. It is advisable to spread the bomb contents flat on dry
sand and spray with water from a safe distance and then rinse with plenty of water.
After the bomb has cooled, if a gas-ignited bomb is used, open the bomb. Remove the
nickel crucible and carefully place it in a beaker containing 100 mL of distilled water.
Immediately cover the beaker with a watch glass. When the reaction stops, rinse the
inside of the bomb and the stopper. Place the wash in the beaker.
After the bomb body cools down, if an electric ignition bomb is used, remove it after
cooling. Open the head and pour the material into a beaker filled with 100 mL of
distilled water. Place the melting cup and the head horizontally in the same beaker and
immediately cover with a watch glass.
4.4.5 Heat the beaker until the contents are boiling. Cool. Remove the nickel crucible
and lid or the crucible and head. Rinse with water and collect the washings in the beaker.
4.4.6 Slowly add 15 mL of concentrated nitric acid (4.2.2). Then, add nitric acid solution
(4.2.3) dropwise while stirring until the mixture is neutral. Then, add 2 mL of nitric acid
solution (4.2.3) in excess. Dilute the contents of the beaker with water to about 200 mL.
NOTE: Methyl orange is a suitable indicator for neutralization.
4.4.7 Without adding the specimen, a blank combustion test is carried out using exactly
the same test steps, reagents and amounts as those for the specimen.
4.4.8 The chlorine content is determined by potentiometric titration. The titration
endpoint is automatically given by the instrument or determined according to the
graphical method in 6.2 of GB/T 9725-2007 or the second-order derivative method.
4.5 Test data processing
The chlorine (Cl) content in the sample is expressed as mass fraction w1 and is
calculated according to formula (1):
Where,
c1 - The exact value of the concentration of the standard silver nitrate titration solution,
in moles per liter (mol/L);
M - The molar mass of chlorine, in grams per mole (g/mol) (M = 35.453);
V1 - The volume of the standard silver nitrate titration solution used to measure the
specimen, in milliliters (mL);
V2 - The volume of the standard silver nitrate titration solution used to measure the
blank combustion test, in milliliters (mL);
m1 - The mass of the specimen, in grams (g).
The calculation result is rounded to one decimal place.
4.6 Allowable difference
The absolute value of the difference between two measured values shall not exceed
0.2%. The arithmetic mean of the two parallel measurement results shall be reported as
the result.
5 Method B - Molotov cocktail method
5.1 Principle
The specimen is oxidized with oxygen. The resulting chloride is then titrated
potentiometrically.
5.2 Reagents or materials
Unless otherwise specified, analytically pure reagents and grade 3 water in GB/T 6682
or water of equivalent purity shall be used in the analysis. The required standard titration
solutions, preparations and products shall be prepared in accordance with the provisions
of GB/T 601 and GB/T 603.
5.2.1 Sodium nitrate.
5.2.2 Hydrogen peroxide solution: 300 g/L.
5.2.3 Potassium hydroxide solution: 100 g/L. Weigh 100 g potassium hydroxide and
add it to a beaker containing 300 mL of water in 3~5 times. Cool to room temperature
under cold water while stirring. Transfer to a 1000 mL volumetric flask. Dilute to the
mark.
5.2.4 Nitric acid solution: 125 g/L. Take 135 mL of concentrated nitric acid and dilute
GB/T 7139-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.080.20
CCS G 31
Replacing GB/T 7139-2002
Plastics - Vinyl chloride homopolymers and copolymers -
Determination of chlorine content
(ISO 1158:1998, MOD)
ISSUED ON: AUGUST 06, 2023
IMPLEMENTED ON: MARCH 01, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Method A - Incendiary bomb method ... 6
5 Method B - Molotov cocktail method ... 10
6 Test report ... 13
Annex A (informative) Comparison of structural number changes between this
document and ISO 1158:1998 ... 15
Annex B (informative) Technical differences between this document and
ISO1158:1998 and their reasons ... 18
Annex C (informative) Filling method of sodium peroxide, starch or sucrose, specimens
... 20
Foreword
This document was drafted in accordance with the rules given in GB/T 1.1-2020
"Directives for standardization - Part 1: Rules for the structure and drafting of
standardizing documents".
This document replaces GB/T 7139-2002 "Plastics -- Vinyl chloride homopolymers and
copolymers -- Determination of chlorine content". Compared with GB/T 7139-2002, in
addition to structural adjustments and editorial changes, the main technical changes are
as follows:
a) Changed the scope of the document (see Chapter 1 of this Edition; Chapter 1 of
Edition 2002);
b) Changed the principles (see 4.1, 5.1 of this Edition; Chapter 3 of Edition 2002);
c) Changed the unit of nitric acid solution concentration. Added the preparation
method (see 4.2.3, 5.2.4 of this Edition; 4.1 of Edition 2002);
d) Added the determination method of titration endpoint of potentiometric titration
(see 4.4.8, 5.4.8 of this Edition);
e) Added the preparation method of potassium hydroxide solution (see 5.2.3 of this
Edition);
f) Changed the regulations on incendiary bottles (see 5.3.4 of this Edition; 5.8 of
Edition 2002);
g) Changed the filter paper requirements (see 5.3.5 of this Edition; 5.9 of Edition
2002);
h) Changed the test steps and the amount of liquid collected in the combustion bottle
method for collecting the liquid after combustion (see 5.4.6 of this Edition; 7.2.5
of Edition 2002);
i) Changed the tolerance of the incendiary bottle method (see 5.6 of this Edition; 8.2
of Edition 2002);
j) Deleted the Volhard method for determining chlorine content (see Annex B and
Annex C of Edition 2002).
The modification of this document adopts ISO 1158:1998 "Plastics -- Vinyl chloride
homopolymers and copolymers -- Determination of chlorine content".
Compared with ISO 1158:1998, this document has more structural adjustments. The
comparison table of structural number changes between the two documents is shown in
Annex A.
Plastics - Vinyl chloride homopolymers and copolymers -
Determination of chlorine content
WARNING -- The personnel who use this document need to have practical
experience in formal laboratory work. This document does not point out all
possible safety issues. The user is responsible for taking appropriate safety and
health measures and ensuring that the conditions stipulated by relevant national
laws and regulations are met.
1 Scope
This document describes methods for the determination of the chlorine content of
homopolymers and copolymers of vinyl chloride.
This document is applicable to the determination of chlorine content in vinyl chloride
homopolymers and copolymers without plasticizers and additives. It can be used as a
reference for the determination of chlorine content in other chlorine-containing
polymers without plasticizers and additives.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 601, Chemical reagent -- Preparations of reference titration solutions
GB/T 603, Chemical reagent -- Preparations of reagent solutions for use in test
methods
GB/T 6682, Water for analytical laboratory use -- Specification and test methods
GB/T 9725-2007, Chemical reagent -- General rule for potentiometric titration
3 Terms and definitions
There are no terms or definitions that require definition in this document.
of the bomb body. Then remove the empty incendiary bomb. Put in the specimen
incendiary bomb. Heat the specimen incendiary bomb to 300℃~400℃ for about 10
min. Combustion usually starts at 50℃~60℃, with a crackling sound, and the bottom
of the bomb body begins to emit a glowing light.
If you use an electric ignition incendiary bomb, operate according to the equipment
instruction manual.
4.4.4 Cool the bomb. If the bomb is cooled in water, be careful not to allow water to
come into contact with the joint between the plug and the bomb. When there is doubt
whether a reaction has occurred, the bomb material shall not be dissolved in water as
this may reason an explosion. It is advisable to spread the bomb contents flat on dry
sand and spray with water from a safe distance and then rinse with plenty of water.
After the bomb has cool...