GB/T 25254-2022 PDF English (GB/T 25254-2010: Older version)
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Poly-(tetra methylene ether glycol)(PTMEG) for industrial use
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GB/T 25254-2022: PDF in English (GBT 25254-2022) GB/T 25254-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.040.01
CCS G 32
Replacing GB/T 25254-2010
Poly-(Tetra Methylene Ether Glycol) (PTMEG) for
Industrial Use
ISSUED ON: APRIL 15, 2022
IMPLEMENTED ON: NOVEMBER 1, 2022
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 ... 6
4 Classification and Naming ... 6
5 Technical Requirements ... 6
6 Test Methods ... 7
7 Inspection Rules ... 12
8 Marking and Accompanying Documents ... 13
9 Packaging, Transportation and Storage ... 13
Appendix A (Normative) Determination of Average Molar Mass and Hydroxyl Value
... 15
Appendix B (Normative) Determination of Carbonyl Ratio ... 19
Poly-(Tetra Methylene Ether Glycol) (PTMEG) for
Industrial Use
1 Scope
This Document specifies the classification and naming, technical requirements, test methods,
inspection rules, marking and accompanying documents, packaging, transportation and storage
of poly-(tetra methylene ether glycol) (PTMEG) for industrial use.
This Document applies to industrial PTMEG produced by polymerization of tetrahydrofuran
monomer.
2 Normative References
The provisions in following documents become the essential provisions of this Document
through reference in this Document. For the dated documents, only the versions with the dates
indicated are applicable to this Document; for the undated documents, only the latest version
(including all the amendments) is applicable to this Document.
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 3143 Color Determination Method of Liquid Chemicals (Hezen Unit – Platinum –
Cobalt Scale)
GB/T 4472-2011 Determination of density and relative density for chemical products
GB/T 6283 Chemical products – Determination of water Karl Fischer method (general
method)
GB/T 6678 General Principles for Sampling Chemical Products
GB/T 6680 General rules for sampling liquid chemical products
GB/T 6682 Water for analytical laboratory use – Specification and test methods
GB/T 8170 Rules of rounding off for numerical values & expression and judgement of
limiting values
6.7.2.3 Analytical balance, with graduation value of 0.01g.
6.7.3 Reagents
6.7.3.1 pH standard buffer solution: pH=4.00.
6.7.3.2 pH standard buffer solution: pH=6.86.
6.7.3.3 Lithium chloride, guaranteed reagent.
6.7.3.4 Electrode replenishment solution: Prepare a saturated solution of lithium chloride in
ethanol; and dilute the saturated solution with water in a ratio of 2+1 (volume ratio).
6.7.3.5 Electrode soaking solution: Prepare a saturated solution of lithium chloride in ethanol;
and dilute the saturated solution with water in a ratio of 1+1 (volume ratio).
6.7.3.6 Standard hydrochloric acid titration solution, c(HCl) is approximately 0.005mol/L:
dilute by standard hydrochloric acid titration solution with c(HCl) approximately 0.1mol/L
before use.
6.7.3.7 Standard sodium hydroxide solution: c(NaOH) is about 0.1mol/L.
6.7.3.8 Methanol solvent: Take 60mL of distilled water into a 2000mL volumetric flask. Add
0.8mL standard sodium hydroxide solution; dilute to the mark with methanol; transfer to a glass
bottle; and stir for 4h~6h.
6.7.4 Determination procedures
6.7.4.1 Instrument settings
Set the control parameters according to the operating instructions of the automatic
potentiometric titrator; and set the end point determination method to pH=5.3.
6.7.4.2 Determination
Take 10g of the specimen (accurate to 0.01g) into a 100mL glass beaker; add 50.00mL of
methanol solvent; stir until completely dissolved; perform potentiometric titration with
standard hydrochloric acid titration solution; record the standard titration solution volume (V1)
required when the titration reaches pH=5.3. At the same time, measure the blank solution
volume (V10).
6.7.5 Calculation of the result
The acid value (by consumption of KOH) of PTMEG (AN) is calculated according to Formula
(1):
3.06460 - the negative logarithm of the value K of PTMEG in the Mark-Houwink
equation.
Calculation results of the molar mass ratio are rounded to two digits after the decimal
point.
6.10 Stabilizer (BHT) content
6.10.1 Method summary
Prepare a standard solution based on the features with characteristic absorption of BHT at
278nm; and establish a standard curve between concentration and absorbance.
6.10.2 Instruments
6.10.2.1 Volumetric analytical instruments and vessels for general laboratory use.
6.10.2.2 UV-visible spectrophotometer with scanning function.
6.10.2.3 Analytical balance with graduation value of 0.1mg, 0.01g.
6.10.3 Reagents
6.10.3.1 Methanol.
6.10.3.2 standard BHT solution, 1mg/mL: Weigh 0.1g of BHT (accurate to 0.0002g) in a 100mL
volumetric flask; fully dissolve it with methanol; and dilute to the mark.
6.10.4 Drawing of working curve
6.10.4.1 Add 1.0mL, 2.0mL, 3.0mL, 4.0mL and 5.0mL of standard BHT solution to the 100mL
volumetric flask respectively, and dilute to the mark by methanol.
6.10.4.2 Use methanol as a blank and measure at the wavelength of 278nm using a 10mm
cuvette.
6.10.4.3 Draw the standard curve with BHT (mg/100mL) in 100mL standard solution as the
abscissa and the corresponding absorbance as the ordinate.
6.10.5 Determination of sample
Weigh 10g of the sample (accurate to 0.01g), add it to a 100mL volumetric flask; dilute to the
mark with methanol; and shake well. Use methanol as a blank, use a 10mm cuvette to perform
spectral scanning; perform data processing on the spectrum; and calculate the corrected
absorbance at 278nm.
6.10.6 Calculation of result
Except for the molar mass ratio, all other items are exit-factory inspection items, and the exit-
factory inspection items shall be inspected batch by batch.
7.2 Batching rules
Products are inspected in batches, and the mixing volume in the same storage tank is considered
a batch, and the batch size does not exceed 3000t.
7.3 Sampling
Carry out nitrogen replacement and protection sampling according to the provisions in GB/T
6678 and GB/T 6680. The sample size shall be no less than 0.5kg. The sample shall be mixed
and divided into two clean, dry, and sealed glass bottles or plastic bottles. Attach a label to
indicate the product name, manufacturer, batch number, batch size, sampling date, sampling
location, and sampler. One bottle is used for testing, and the other bottle is kept for future
reference.
7.4 Judgment rules
The inspection results are judged according to the rounding value comparison method specified
in GB/T 8170 to determine whether they meet the requirements in Clause 5. If an index does
not meet the technical requirements in Clause 5, double the amounts of samples shall be taken
from the storage tank or packaging unit for reinspection. Even if one index does not meet the
technical requirements in Clause 5, the whole batch of products shall be judged to be
unqualified.
8 Marking and Accompanying Documents
8.1 Marking
PTMEG products shall be accompanied by product marks, including: product name, product
standard number, manufacturer name and address, net content, production batch number,
certificate of conformity, etc.
8.2 Accompanying files
Each batch of products shall be accompanied by safety technical instructions and quality
inspection reports, including: name of the manufacturer, product name, technical requirements,
net content, batch number, or production date, etc., and shall be stamped with a special quality
inspection seal and the signature (seal) of the inspector.
9 Packaging, Transportation and Storage
9.1 Packaging
Appendix A
(Normative)
Determination of Average Molar Mass and Hydroxyl Value
A.1 Method overview
The hydroxyl group at the end of PTMEG reacts with excessive p-toluenesulfonyl isocyanate
(TSI) to generate acidic carbamate. Excessive TSI reacts with water to form sulfamide; and the
acidic carbamate is directly titrated potentiometrically with tetrabutylammonium hydroxide
(TBAH) in a low-water medium.
A.2 Instruments
A.2.1 Volumetric analytical instruments and vessels for general laboratory use.
A.2.2 Automatic potentiometric titrator: equipped with a 20mL burette and a pH aqueous phase
composite electrode. The volume resolution of the burette is less than or equal to 1/20000.
A.2.3 Analytical balance with graduation value of 0.1mg.
A.3 Reagents
A.3.1 Acetonitrile: moisture shall not exceed 300mg/kg.
A.3.2 Absolute ethanol.
A.3.3 Isopropyl alcohol.
A.3.4 Standard pH buffer solution: pH=4.00.
A.3.5 Standard pH buffer solution: pH=6.86.
A.3.6 Lithium chloride, guaranteed reagent.
A.3.7 Electrode replenishment solution: Prepare a saturated solution of lithium chloride in
ethanol; and dilute the saturated solution with water at a ratio of 2+1 (volume ratio).
A.3.8 Electrode soaking solution: Prepare a saturated solution of lithium chloride in ethanol;
and dilute the saturated solution with water at a ratio of 1+1 (volume ratio).
A.3.9 Standard KHP titration solution, c(C8H5KO4) = 0.1000mol/L, prepared according to
GB/T 601.
A.3.10 Stabilizer (BHT).
A.3.11 1,4-butanediol (BDO).
A.3.12 Tetrahydrofuran (THF) solvent, moisture not exceeding 300mg/kg:
Weigh 0.2g (accurate to 0.01g) of BDO and BHT each; add to 5000mL of THF; mix well and
set aside.
A.3.13 Standard TBAH titration solution, c(C16H37NO) is about 0.1mol/L:
a) Preparation: Take 128mL of distilled water and 49mL of TBAH (55%) into a 1000mL
volumetric flask. After cooling, dilute to the mark with isopropyl alcohol and shake well;
b) Calibration: Pipette 10.00mL of standard KHP titration solution into a 100mL tall beaker;
add water to about 60mL; titrate the standard KHP titration solution with TBAH solution;
determine the end point by potentiometric titration. Repeat the titration four times; and
take the arithmetic average as the concentration of the standard TBAH titration solution;
c) Calculation: standard TBAH titration solution is calculated according to Formula (A.1),
accurate to four digits after the decimal point.
Where:
c2 - concentration of standard TBAH titration solution, in mol/L;
c3 - concentration of standard KHP titration solution, in mol/L;
V3 - the volume of pipetted standard KHP titration solution, in mL;
V2 - the volume of the consumed TBAH solution, in mL.
A.3.14 TSI solution, 6.2%: Weigh 25g (accurate to 0.01g) of TSI (96%); dissolve it in
acetonitrile; transfer it to a 500mL volumetric flask; dilute it to the mark with acetonitrile; and
shake well.
A.4 Test procedures
A.4.1 Instrument settings: Set the control parameters according to the automatic potentiometric
titrator operating instructions.
A.4.2 Measure the sample: Weigh 0.5g~1.0g (accurate to 0.0002g, adjust the weighing
according to the product type) of specimen into a 100mL tall glass beaker; add 50mL of THF
solvent, 10mL of TSI solution; and stir for 10 min. Add 2 mL of distilled water and stir for 5
min. Use standard TBAH titration solution to titrate to the end point, and the instrument will
record two end points V4 and V5.
Appendix B
(Normative)
Determination of Carbonyl Ratio
B.1 Method overview
Determine the sum of the absorption of the carbonyl band in the infrared region and the
absorption of the composite band of the ether compound; and calculate the carbonyl ratio (C/R).
B.2 Instruments
B.2.1 Volumetric analytical instruments and vessels for general laboratory use.
B.2.2 Fourier transform infrared spectrometer: The sensitivity and stability of the whole
machine shall comply with the relevant regulations in GB/T 21186.
B.2.3 Stopwatch with resolution of 0.1s.
B.2.4 Analytical balance with graduation value of 0.1mg and 0.1g.
B.3 Reagents
B.3.1 Adipic acid, standard substance.
B.3.2 Nitrogen with volume fraction of 99.999%.
B.3.3 PTMEG1000, the carbonyl ratio is less than 0.1.
B.3.4 Standard adipic acid stock solution:
Weigh 1.5g (accurate to 0.0002g) of adipic acid in a 2000mL glass bottle; weigh 1498.5g
(accurate to 0.1g) of PTMEG1000 in the above bottle; pass nitrogen into the above glass bottle
at a lower flow rate; and put in an oven at 50℃±5℃ and keep constant temperature for 16h.
B.3.5 Potassium bromide, spectrally pure.
B.4 Test procedures
B.4.1 Preparation of infrared spectrum samples
Use the liquid film method to prepare infrared spectrum samples. The preparation shall be
carried out according to the instrument operating instructions to avoid the generation of bubbles.
The finished potassium bromide salt tablets can also be purchased.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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