This standard specifies the test method for determining the insoluble content (also known as degree of curing) of fiber reinforced plastic resin by extraction method. This standard is applicable to fiber reinforced plastics with glass fiber, carbon fiber and aramid as reinforcement materials and epoxy, polyester and phenolic resin as matrix. GB/T 2576-1989 Test method for insoluble content of fiber reinforced plastic resin GB/T2576-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
GB/T2576-1989
Test method for insoluble content of fiber reinforced plastic resin
State Administration of Building Materials Industry
1996—08—01
Page 1
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Test method for insoluble content of fiber reinforced plastic resin" Data number:
2576-1989
1 Subject content and scope of application
2 Reference standards
3 Instruments and reagents
4 Sample
5 Test steps
6 Result calculation
7 Test report
Additional notes:
Page 2
"Test method for insoluble content of fiber reinforced plastic resin"
Material number:
2576-1989
1 Subject content and scope of application
This standard specifies the test method for determining the insoluble content (also known as degree of curing) of fiber reinforced plastic resin by extraction methodinoaec.com
This standard is applicable to fiber reinforced plastics with glass fiber, carbon fiber and aramid as reinforcement materials and epoxy, polyester and phenolic resin as matrix.

《Fiber
Fiber reinforced plastics
Test method
Plastic tree factory
Fat insoluble box
2576-1989
Page 3
Referenced standards
GB1446 General principles for test methods for properties of fiber reinforced plasticsinoaec.com
GB2577 Test method for resin content of glass fiber reinforced plastics GB3855 Test method for resin content of carbon fiber reinforced plastics《Fiber
Fiber reinforced plastics
Test method
Fat insoluble
2576-1989
Page 4
3 Apparatus and reagents
3.1 Soxhlet extractor (see Figure 1) (Figure omitted): Specification 250mL, or other suitable instruments with the same function. .sinoaec.com
3.2 Electric constant temperature water bath: temperature range 37~100℃, temperature control accuracy ±2℃. 3.3 Blast drying oven: should have an appropriate controllable temperature range, with a deviation range of ±2℃. 3.4 Analytical balance: sensitivity 0.1mg.
3.5 File or other suitable crushing tools: such as crusher, etc. 3.6 Quantitative filter paper: Φ15cm or other suitable size. 3.7 Standard sieve: 0.4mmc
3.8 Weighing bottle of appropriate size
3.9 Acetone reagent: chemically pure or industrial grade
Fiber reinforced
Plastic tree factory
Fat insoluble
Testing method
2576-1989
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4.1 Sample preparation
4 Sample
4.1.1 Sample selection and appearance inspection According to the provisions of GB1446, the sample should be taken close to the part where the resin content is measured. 4.1.2 The sample is wiped clean with a soft cloth with a solvent (non-corrosive to the sample). 4.1.3 Use a file or other suitable tool to process the sample into powder, and be careful not to cause overheating of the resin. 4.1.4 Sieve the crushed sample with a 0.4mm standard sieve, and crush the residue on the sieve again until it is all sieved and stirred for use.
For samples with too low curing degree, sticky when crushed or lint-like fibers after crushing, it is not necessary to sieve. 4.2 Sample pretreatment
The sample can be pretreated in one of the following ways or according to product requirements. 4.2.1 Glass fiber reinforced plastics
a. Place in a dryer for at least 24 hours;
b. Dry in an oven at 80±2℃ for 2 hours, put in a dryer, and cool to room temperature. 4.2.2 Carbon fiber and aramid reinforced plastics
a. Place in a dryer for at least 48 hours;
b. Dry in an oven at 80±2℃ for 3 hours, put in a dryer, and cool to room temperature. 4.2.3 For products cured at room temperature, sample pretreatment cannot use the above method b. 4.3 Take 3 samples as a group, each sample is 1±0.2g. Page 6 bzxZ.net
Fiber reinforced plastic resin insoluble content test method
2576-1989
5 Test steps
5.1 Use a dry weighing bottle to weigh the filter paper tube (including absorbent cotton) or filter paper on the analytical balance, accurate to 0.1 mg. 5.2 Place the powder sample in the filter paper tube (cover the sample with a thin layer of absorbent cotton) or filter paper bag in the weighing bottle, and weigh it, accurate to 0.1 mg.
5.3 Place the filter paper tube or filter paper bag containing the sample and absorbent cotton into the extractor, and the filter paper tube should be slightly higher than the extractor siphon. Install the condenser, extractor, and flask. Inject 150 mL of acetone [1] into the flask. Continue to extract for 3 hours in a constant temperature water bath at 80 ± 2℃. The extract is refluxed 610 times per hour in the siphon. If necessary, several samples can be extracted in one extractor at the same time, but the extraction time can be appropriately extended (extraction of 2 samples for 4 hours; extraction of 3 samples for 6 hours). Note: 1) Ethanol can be used for fiber-reinforced plastics based on phenolic resin. 5.4 Take out the extracted filter paper tube or filter paper bag, drain it for a while and put it into an oven with a constant temperature of 105±2℃. At the same time, put it into an empty weighing bottle of appropriate size that can accommodate the filter paper tube and dry it to constant weight. a. Glass fiber reinforced plastics are generally dried at 105±2℃ for 2 hours. b. Carbon fiber and aramid reinforced plastics are generally dried at 105±2℃ for 3 hours. 5.5 Quickly put the filter paper tube that has been dried to constant weight into the weighing bottle, cover it, take it out of the oven and put it into the desiccator, cool it to room temperature, and weigh it to an accuracy of 0.1mg.
5.6 Take out the filter paper tube in the bottle and weigh the weight of the weighing bottle again. The difference between the weight and the weighing result in 5.5 is the total weight of the filter paper and residue after extraction.
5.7 Carry out a blank test under the same conditions as above, and use it to calibrate the sample filter paper cylinder when calculating. 5.8 Determination of fiber reinforced plastic resin content
5.8.1 Determination of glass fiber reinforced plastic resin content shall be in accordance with GB2577. 5.8.2 Determination of carbon fiber reinforced plastic resin content shall be in accordance with GB3855. 5.8.3 Determination of aramid reinforced plastic resin content shall refer to GB3855. The digestion process is as follows: the sample is heated to 130 ± 5°C in 50mL of dimethyl sulfoxide, kept at constant temperature for 1h, and cooled to room temperature. Concentrated nitric acid is added so that the nitric acid accounts for 10% (volume) in the mixed solution, and the mixed solution is heated to 130 ± 5°C and kept at constant temperature for 30min. Page 7
Test method for insoluble content of fiber reinforced plastic resin
2576-1989
6 Result calculation
6.1 The mass loss rate of blank filter paper is calculated according to formula (1): C0=m4-m5/m4×100.
Wherein: CO is the mass loss rate of blank filter paper, %; m4 is the mass of blank filter paper before extraction (including absorbent cotton), g; m5 is the mass of blank filter paper after extraction (including absorbent cotton), g. 6.2 The mass of the sample after extraction is calculated according to formula (2): m2=m3-m（1-Co）.
Wherein: m2 is the mass of the sample after extraction, g; m3 is the total mass of the filter paper cartridge and the residue after extraction, g; m is the mass of the filter paper cartridge loaded with the sample before extraction (including absorbent cotton), g; CO is the same as formula (1).
6.3 The insoluble content of fiber reinforced plastic resin is calculated according to formula (3): Cr=(1-ml-m2/ml.Wr)×100..
Wr=fiber reinforced plastic resin content, %; ml-sample mass before extraction, g;
Wr=fiber reinforced plastic resin content, %; m2 is the same as formula (2).
6.4 Calculate the arithmetic mean of each group of samples and take three significant figures. ·(2
·（3）
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Fiber reinforced plastics
(Test method for insoluble content of plastic resin)
2576-1989
7 Test report
The test report shall include the following contents
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d. Sample pretreatment conditions and sample crushing method; indicate that the test is carried out in accordance with this standard;
b. Test conditions, items and names;
Type and source of test materials;
e: Abnormal phenomena during the test;
f.Test results, indicate the single value of the sample; test personnel, date and other
《Fiber-reinforced plastics test method
Resin is not allowed
2576-1989
Page 9
Additional instructions:
This standard is proposed and managed by the National Fiber Reinforced Plastics Standardization Technical Committee. inoaec.com
This standard is drafted by the Harbin Glass Fiber Reinforced Plastics Research Institute of the State Building Materials Industry Bureau. The main drafters of this standard are Wang Rongqiu and Wang Hui. 《Fiber-reinforced plastics test method
Resin is not allowed
2576-1989
Page 10
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