HG/T 2626-1994 Determination of viscosity of dilute solutions of castable methyl methacrylate polymers and copolymers HG/T2626-1994 Standard download decompression password: www.bzxz.net

Chemical Industry Standard of the People's Republic of China
HG/T 2626-94
Determination of viscosity of dilute solutions of castable methyl methacrylate polymers
and copolymers
Issued on April 13, 1994
Ministry of Chemical Industry of the People's Republic of China
Implementation on January 1, 1995
Chemical Industry Standard of the People's Republic of China
Determination of viscosity of dilute solutions of castable methyl methacrylate polymers
and copolymers
Main content and scope of application
G/T2626-94
This standard specifies the method for determining the viscosity of dilute solutions of castable methyl methacrylate polymers. This standard is applicable to homopolymers, copolymers and mixtures of methyl methacrylate (MMA) in molded and non-molding extrusion types, containing at least 80% (m/m) of methyl methacrylate in the mixture. May or may not contain additives 2 Reference Standards
GB/T1632 Determination of viscosity and intrinsic viscosity of dilute polymer solutions 3 Principle
Determine the flow time of the solvent and the polymer solution of the solvent with the indicated concentration at 25±0.05°C. Calculate the viscosity and intrinsic viscosity from the measured flow time and solution concentration. The viscosity number VN is expressed in mL/mL,
Where:
is the dynamic viscosity of the test solution, mPa·S;
is the dynamic viscosity of the solvent, mPa·s
is the concentration of the polymer solution: n/mL.
(nn,)
If the density β and phase difference of the solution and the bath agent are very small, then the sum n in formula (1) can be replaced by the kinematic viscosity and of the solution and the solvent. Unit: mm2/s.
4 Reagents
Trichloromethane, analytical grade, stored in a brown bottle, stored in a dark place. 5 Apparatus
See Chapter 4 and Table B1 of GB/T1632
5.1 Capillary viscometer Use the 0C suspension Ubbelohde capillary viscometer specified in GB/T1632. The inner diameter of the capillary is 0.36 mm, and the measuring channel volume is 2 mL
Other viscometers that can obtain the same results can be used, but in case of dispute, this type of viscometer must be used. The calibration of the viscometer used is carried out according to Appendix A. 5.2 Stopwatch, readable to 0.1 s.
5.3 Constant temperature bath, capable of maintaining at 25±0.05℃Approved by the Ministry of Chemical Industry of the People's Republic of China on April 13, 1994 and implemented on January 1, 1995
5.4 Volumetric flask with ground glass stopper, 100㎡L. 5.5 Balance, sensitivity 0.1 mg.
5.6 Fritted glass funnel, No. 2
5.7 Agitator.
6 Sample solution
HG/ T 2626
Weigh an appropriate amount of sample that can reflect the material characteristics (accurate to 0.1 mg) and place it in a volumetric flask (5.4). Add 50 mL of chloroform (4) and stir to dissolve completely, then dilute to the scale with 20±1°C chloroform and shake again. Set aside. Note: The flow time of the test solution should be between the flow time of chloroform and tetrachloroethylene. The weighing range can generally be based on the viscosity ratio of 1.2 to 1.4. For compounds containing thickening additives, the solution preparation process needs to be changed. Such changes must be accepted by all parties concerned. For materials containing excess materials and/or special additives, the sample weight should be increased so that 100 mL of the test solution contains an appropriate amount of methyl methacrylate homopolymer or copolymer.
7 Test steps
Inject chloroform or the test solution directly into the viscometer through a sintered glass funnel (5.6). At 25 ± 0.05 °C, measure the flow time of the solvent and the test solution through the same viscometer 3 to 5 times and take the arithmetic mean. For 0C type Ubbelohde viscometer, if the maximum difference in flow time exceeds 0.2 s, the viscometer needs to be cleaned with solvent, dried, and re-measured with the same test solution. If the viscometer used is different from the provisions of this standard, the above test steps may be appropriately modified. 8 Calculation of test results
The viscosity number VN is expressed in mL/g and is calculated according to formula (2): vNu
Where:
Kinematic viscosity of test solution, mm2/s:
-Kinematic viscosity of solvent, mm2/s;
Arithmetic mean of test solution flow time, s;-Arithmetic mean of solvent flow time, s:..Test solution concentration, g/mL;
1 Kinetic energy correction (see Appendix A);
At. . Kinetic energy correction (see Appendix A). At
Note; Formula (2) is in accordance with Formula (5) in GE/T1632, but introduces kinetic energy correction, which is necessary for obtaining accurate results for a specific specification of viscometer.
If a viscometer with a smaller capillary inner diameter is used, the kinetic energy correction is less than 0.2% of the flow time, then the result calculated by the following formula (3) provided in GB/T1632 has similar precision to the above formula (2). N. bZxz.net
Test report
The test report includes the following items
. Indicate reference to this standard. If there is a separate standard for the polymer being tested. Also indicate: b. Complete identification of the sample to be tested, including model, batch number, and manufacturer's code; 2
HG/T2626
Concentration of the solution, description of the solvent and details of the solution preparation: Detailed description of the viscometer used;
Test temperature:
Test results;
Test schedule and operator.
HG/T2626—94
Appendix A
Calibration of viscometer
(Supplement)
A1 Experience has shown that the high precision required for determining the viscosity of methyl methacrylate homopolymer or copolymer solutions is often not obtained from commercially available Ubbelohde viscometers due to slight irregularities in the inner diameter of the capillary. Therefore, it is recommended to verify the accuracy of the viscometer with the help of a calibration liquid with known kinematic viscosity.
A2 Viscometer constant K
Use analytically pure n-undecane and pass it through a viscometer 3 to 5 times at 25°C. For the determination of the average flow time t, see Article 7.2 of GB/T1632. Calculate the viscometer constant K according to formula (A1): K=
Wherein: i
The kinematic viscosity of n-undecane is 1.4675mm2/s at 25°C. Note: 25c The density of n-undecane is p-0.7365g/mLA3 Kinetic energy correction 4t, and At
If the kinetic energy correction is less than 0.2% of the flow time, it can be ignored: The flow time of the OC type Ubbelohde viscometer is greater than 270s, which can meet the requirements.
If the flow time is less than the above regulations, the following low viscosity liquid should be used as the standard to make kinetic energy correction for the viscometer; a. Dichloromethane (analytical grade), Vzsr = 0.3142 mm / s, Past = 1.3163 g / mL;
h trinitroethylene (analytical grade), Vzst = 0.3693 mm2 / sP2sc = 1. 455 5 g / mL;
c, tetrachloroethylene (analytical grade), V2sr = 0.5257 mm2 / s, Pzsc = 1. 614 4 g / mL.
Measure the flow time of each calibration liquid 3 to 5 times, and calculate the kinetic energy correction ALat of each calibration liquid according to formula (A2): ALat=n
where: -- flow time of the ith calibration liquid, s; ​​K
- kinematic viscosity of the ith calibration liquid, mm/s; K-
viscometer constant, mm/s
According to the following formula (A3), linear interpolation is made between the flow times t., and t., of the two calibration liquids i=1 and i2 (see Figure A1), and the kinetic energy correction Ato of the flow time L. of the solvent chloroform is obtained: A
HG / 2626 — 94
In the same way, linear interpolation is made between t., and t., according to formula (A5), and the kinetic energy correction At of the flow time 1 of the test liquid is obtained:At=A1
Inverse of flow time
Figure A1 Relationship between kinetic energy correction and inverse of flow time Additional notes:
This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China and is under the jurisdiction of the Chemical Method Branch of the National Technical Committee for Plastics Standardization. This standard was drafted by Shanghai Fudan University. The main drafters of this standard are Ma Ruishen, Zhang Nianhong, (AS)
People's Republic of China
Chemical Industry Standard
Determination of Viscosity of Dilute Solutions of Cast Methyl Methacrylate Polymers
and Copolymers
HG/ T2625-94
Chemical Industry Standard Editorial Department
(Institute of Standardization, Ministry of Chemical Industry)
Postal Code: 100011
Printing Institute of Standardization, Ministry of Chemical Industry
Copyright reserved. No reproduction allowed
Format 880×1230 1/16
Number of Words 10000
Edition - November 1994
First Printing November 1994
Print 1 — 500
Cost 3.00 yuan
1929/0
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