Quantitative analysis method for grafting rate of high-density polyethylene grafted maleic anhydride

Abstract

A quantitative analysis method for the grafting rate of high-density polyethylene grafted maleic anhydride comprises the following steps: a) preparing a high-density polyethylene grafted maleic anhydride sample, and testing the grafting rate of the high-density polyethylene grafted maleic anhydride sample through an acid-base titration method; b) mixing and dissolving the sample with the known grafting rate and ungrafted samples with different proportions in a first organic solvent, pouring the mixed solution into a second organic solvent for precipitation, and performing suction filtration and drying to obtain high-density polyethylene grafted maleic anhydride samples with different grafting rates; c) measuring the peak height of maleic anhydride and the peak height of a polyethylene internal standard peak of the high-density polyethylene grafted maleic anhydride samples with different grafting rates prepared in the step b) by adopting an infrared spectroscopy method, and calculating the ratio of the maleic anhydride peak height to the polyethylene internal standard peak height; and finally, carrying out linear fitting on the known grafting rate and the characteristic peak ratio, drawing a standard curve, and further obtaining a formula. The quantitative analysis method saves a lot of time for related research and production, and is accurate in test result and high in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of using infrared light to test or analyze the physical or chemical properties of materials. More specifically, it relates to a quantitative analysis method for the grafting rate of maleic anhydride grafted onto high-density polyethylene. Background Art

[0002] Grafting maleic anhydride onto high-density polyethylene is to graft maleic anhydride molecules onto the molecular chain of high-density polyethylene through a chemical reaction method, making high-density polyethylene have the re-reactivity and strong polarity of maleic anhydride polar molecules. The anhydride group therein can undergo an esterification reaction with the hydroxyl groups in wood powder, thereby reducing the polarity and hygroscopicity of wood powder and making it have good compatibility with the matrix resin. Therefore, it is mainly used as a wood-plastic compatibilizer.

[0003] The grafting rate of high-density grafted maleic anhydride is an important index for evaluating wood-plastic compatibilizers. At present, the commonly used testing methods for the grafting rate mainly include acid-base titration method and infrared spectroscopy method. The acid-base titration method has cumbersome steps and many artificial judgment factors in the determination process, which interfere with the judgment of the titration results. Although the infrared spectroscopy method is convenient for testing, the grafting rate cannot be directly read from the spectrum. Therefore, combining the acid-base titration method and the infrared spectroscopy method is an effective way to establish an accurate and rapid method for determining the grafting rate. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a quantitative analysis method for the grafting rate of maleic anhydride grafted onto high-density polyethylene. By combining the advantages and disadvantages of the acid-base titration and infrared spectroscopy methods, a quantitative analysis method for accurately and simply determining the grafting rate of maleic anhydride grafted onto high-density polyethylene is established.

[0005] The present invention provides a quantitative analysis method for the grafting rate of maleic anhydride grafted onto high-density polyethylene, including the following steps:

[0006] a) Prepare a sample of maleic anhydride grafted onto high-density polyethylene and test its grafting rate by the acid-base titration method;

[0007] b) Mix and dissolve the above sample with a known grafting rate and un-grafted samples in different proportions in a first organic solvent, then pour the mixed solution into a second organic solvent for precipitation, filter by suction and dry to obtain high-density polyethylene grafted maleic anhydride samples with different grafting rates;

[0008] c) Use infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of the polyethylene internal standard peak of the high-density polyethylene grafted maleic anhydride samples with different grafting rates prepared in step b), and calculate their ratio; finally, perform a linear fitting on the known grafting rate and the characteristic peak ratio, draw a standard curve, and further obtain a formula.

[0009] Preferably, the preparation process of the high-density polyethylene grafted maleic anhydride sample in step a) is specifically as follows:

[0010] Put the dried grafted product into the first organic solvent, heat it for reflux dissolution, and after complete dissolution, pour it into the second organic solvent while it is hot in a fume hood, let it stand and cool, filter the precipitate, and dry the obtained flocculent substance to obtain the purified grafted product.

[0011] Preferably, the mass ratio of the dried grafted product to the first organic solvent is (1-8):100.

[0012] Preferably, the heating temperature is 100°C - 135°C.

[0013] Preferably, the process of testing by acid-base titration in step a) is specifically as follows:

[0014] In a single-neck flask, add mg of the purified sample, the first organic solvent and a magnetic stirrer, and dissolve it in an oil bath under stirring conditions; then add 2 - 4 drops of phenolphthalein solution to the solution, and titrate it with a 0.01 mol / L sodium hydroxide-ethanol standard solution until it turns red and does not fade, record the volume V1 of the sodium hydroxide-ethanol standard solution used, and then heat and reflux in the oil bath for 0.5 h - 1.5 h; afterwards, back-titrate the red solution with a 0.01 mol / L HCl-isopropanol standard solution, and stop titration when the solution completely changes from red to colorless, and record the volume V2 of the HCl-isopropanol standard solution used.

[0015] Preferably, the grafting rate X is calculated according to formula (1):

[0016]

[0017] In formula (1), V1 is the volume of the potassium hydroxide-ethanol standard solution / mL; V2 is the volume of the HCl-isopropanol standard solution / mL; m is the mass of the purified sample / g; C is the concentration of the potassium hydroxide and hydrochloric acid standard solutions; M is the relative molecular mass of maleic anhydride.

[0018] Preferably, the first organic solvent in step b) is selected from one or more of toluene, xylene, absolute ethanol, amyl acetate, trichloroethylene, dichloroethane, tetralin;

[0019] The second organic solvent is selected from one or more of acetone, absolute ethanol, cyclohexane, ethyl acetate, ether, chloroform.

[0020] Preferably, the infrared spectroscopy in step c) adopts the transmission mode; the infrared spectroscopy is the tablet pressing method, and specifically includes the following steps:

[0021] Set the temperature of the infrared tablet press to 90°C - 110°C. Take the grafted sample, clamp it in the specimen fixture, and place it in the infrared tablet press. Press the sample for 1 min - 5 min, then take out the specimen fixture and let it cool naturally. Take out the successfully pressed grafted sample film.

[0022] Preferably, the peak positions of maleic anhydride in the infrared spectrum in step c) are at 1785 cm -1 and 1712 cm -1 .

[0023] Preferably, the peak positions of polyethylene in the infrared spectrum in step c) are 1470 cm -1 , 1368 cm -1 and 720 cm -1 or one or more of them.

[0024] The present invention provides a quantitative analysis method for the grafting ratio of high-density polyethylene grafted with maleic anhydride, comprising the following steps: a) Prepare a high-density polyethylene grafted with maleic anhydride sample, and test its grafting ratio by acid-base titration; b) Mix and dissolve the above-mentioned sample with known grafting ratio and ungrafted samples in different proportions in a first organic solvent, then pour the mixed solution into a second organic solvent for precipitation, filter and dry to obtain high-density polyethylene grafted with maleic anhydride samples with different grafting ratios; c) Use infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of the polyethylene internal standard peak of the high-density polyethylene grafted with maleic anhydride samples with different grafting ratios prepared in step b), and calculate their ratio; finally, perform linear fitting on the known grafting ratio and the characteristic peak ratio, draw a standard curve, and further obtain a formula. Compared with the prior art, the quantitative analysis method for the grafting ratio of high-density polyethylene grafted with maleic anhydride provided by the present invention uses acid-base titration to test the grafting ratio values of a series of grafted samples, and uses infrared spectroscopy to test the ratio of the peak height of maleic anhydride to the peak height of the high-density polyethylene internal standard peak of these samples, and then performs linear fitting on these two sets of data to obtain a standard curve; use infrared spectroscopy to measure the characteristic peak ratio of the unknown grafted sample, and the formula obtained from the standard curve can quickly and accurately obtain the grafting ratio of the sample by infrared method, saving a lot of time for relevant research and production, and the test results are accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the standard curve of high-density polyethylene grafted with maleic anhydride. DETAILED DESCRIPTION OF THE INVENTION

[0026] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0027] The present invention provides a quantitative analysis method for the grafting rate of maleic anhydride grafted onto high-density polyethylene, comprising the following steps:

[0028] a) Prepare a high-density polyethylene grafted maleic anhydride sample and measure its grafting rate by acid-base titration;

[0029] b) Mix and dissolve the above sample with known grafting rate and ungrafted samples in different proportions in a first organic solvent, then pour the mixed solution into a second organic solvent for precipitation, filter and dry to obtain high-density polyethylene grafted maleic anhydride samples with different grafting rates;

[0030] c) Use infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of the polyethylene internal standard peak of the high-density polyethylene grafted maleic anhydride samples with different grafting rates prepared in step b), and calculate their ratio; finally, perform linear fitting on the known grafting rate and the characteristic peak ratio, draw a standard curve, and further obtain a formula.

[0031] The present invention first prepares a high-density polyethylene grafted maleic anhydride sample and measures its grafting rate by acid-base titration.

[0032] In the present invention, the preparation process of the high-density polyethylene grafted maleic anhydride sample is preferably specifically:

[0033] Put the dried grafted product into a first organic solvent, heat for reflux dissolution, and after complete dissolution, pour it into a second organic solvent while it is hot in a fume hood, let it stand and cool, filter the precipitate, and dry the obtained flocculent material to obtain a purified grafted product; thereby realizing the purification of the sample. In the present invention, the purification of the sample can eliminate the residual maleic anhydride in the sample, make it closer to the grafting rate of industrial products, and improve the accuracy.

[0034] In the present invention, the mass ratio of the dried grafted product to the first organic solvent is preferably (1 - 8):100.

[0035] In the present invention, the heating temperature is preferably 100°C - 135°C.

[0036] In the present invention, the process of measuring the grafting rate by acid-base titration is preferably specifically:

[0037] In a single-necked flask, add mg of the purified sample, a first organic solvent, and a magnetic stirrer. Under stirring conditions (the present invention has no special restrictions on the stirring speed, and a suitable speed can be adopted), place it in an oil bath to dissolve; then add 2 - 4 drops of phenolphthalein solution to the solution, and titrate it with a 0.01 mol / L sodium hydroxide-ethanol standard solution until it turns red and does not fade. Record the volume V1 of the sodium hydroxide-ethanol standard solution used. Then, heat and reflux in the oil bath for 0.5 h - 1.5 h to allow maleic anhydride to fully react with the base; afterwards, back-titrate the reddened solution with a 0.01 mol / L HCl-isopropanol standard solution (titration needs to be carried out slowly). Stop titration when the solution completely changes from red to colorless, and record the volume V2 of the HCl-isopropanol standard solution used.

[0038] On this basis, the grafting rate X is preferably calculated according to formula (1):

[0039]

[0040] In formula (1), V1 is the volume of the potassium hydroxide-ethanol standard solution / mL; V2 is the volume of the HCl-isopropanol standard solution / mL; m is the mass of the purified sample / g; C is the concentration of the potassium hydroxide and hydrochloric acid standard solutions; M is the relative molecular mass of maleic anhydride.

[0041] Afterwards, the present invention mixes and dissolves the above-mentioned purified sample with a known grafting rate and ungrafted samples in different ratios in a first organic solvent, and then pours the mixed solution into a second organic solvent for precipitation. Filter by suction and dry to obtain high-density polyethylene grafted maleic anhydride samples with different grafting rates.

[0042] In the present invention, the first organic solvent is preferably selected from one or more of toluene, xylene, absolute ethanol, amyl acetate, trichloroethylene, dichloroethane, tetrahydronaphthalene, and more preferably toluene, xylene, absolute ethanol, amyl acetate, trichloroethylene, dichloroethane or tetrahydronaphthalene; the second organic solvent is preferably selected from one or more of acetone, absolute ethanol, cyclohexane, ethyl acetate, ether, chloroform, and more preferably acetone, absolute ethanol, cyclohexane, ethyl acetate, ether or chloroform. The present invention has no special restrictions on the sources of the first organic solvent and the second organic solvent, and commercially available products well-known to those skilled in the art can be used.

[0043] Finally, the present invention uses infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of the polyethylene internal standard peak of the high-density polyethylene grafted maleic anhydride samples with different grafting rates prepared in step b), and calculates their ratio; finally, linearly fit the known grafting rate and the characteristic peak ratio, draw a standard curve, and further obtain a formula.

[0044] In the present invention, the infrared spectroscopy preferably adopts a transmission mode; the infrared spectroscopy is preferably a tablet method, which specifically includes the following steps:

[0045] Set the temperature of the infrared press to 90°C - 110°C. Take the grafted sample, clamp it in the specimen fixture, and place it in the infrared press. Press the sample for 1 min - 5 min, then take out the specimen fixture and let it stand to cool. Take out the successfully pressed grafted sample film.

[0046] In the present invention, the peak position of maleic anhydride in the infrared spectrum is preferably at 1785 cm -1 and 1712 cm -1 ; the peak position of polyethylene in the infrared spectrum is preferably one or more of 1470 cm -1 、1368 cm -1 and 720 cm -1 。

[0047] The present invention provides a quantitative analysis method for the grafting rate of maleic anhydride grafted onto high - density polyethylene, including the following steps: a) Prepare a sample of maleic anhydride grafted onto high - density polyethylene, and test its grafting rate by acid - base titration; b) Mix and dissolve the above - mentioned sample with a known grafting rate and ungrafted samples in different proportions in a first organic solvent, then pour the mixed solution into a second organic solvent for precipitation, filter by suction and dry to obtain high - density polyethylene grafted maleic anhydride samples with different grafting rates; c) Use infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of the polyethylene internal standard peak of the high - density polyethylene grafted maleic anhydride samples with different grafting rates prepared in step b), and calculate their ratio; finally, perform linear fitting on the known grafting rate and the ratio of characteristic peaks to draw a standard curve, and further obtain a formula. Compared with the prior art, the quantitative analysis method for the grafting rate of maleic anhydride grafted onto high - density polyethylene provided by the present invention uses acid - base titration to test the grafting rate values of a series of grafted samples, and uses infrared spectroscopy to test the ratio of the peak height of maleic anhydride to the peak height of the high - density polyethylene internal standard peak of these samples, then performs linear fitting on these two sets of data to obtain a standard curve; uses infrared spectroscopy to measure the ratio of characteristic peaks of unknown grafted samples, and the formula obtained through the standard curve can quickly and accurately obtain the grafting rate of the sample by infrared method, saving a large amount of time for related research and production, and the test results are accurate and reliable.

[0048] To further illustrate the present invention, the following examples are used to detail a quantitative analysis method for the grafting rate of maleic anhydride grafted onto high - density polyethylene provided by the present invention.

[0049] Example 1

[0050] Test the grafting rate of the maleic anhydride grafted onto high - density polyethylene specimen by acid - base titration.

[0051] The grafted products of maleic anhydride grafted onto high - density polyethylene with different grafting rates were prepared by Huanghe Delta Jingbo Chemical Industry Research Institute Co., Ltd.

[0052] Perform sample purification: Take 5 g of the dried grafted product, put it into 200 mL of xylene, heat and reflux it at 135 °C for dissolution. After complete dissolution, pour it into a large amount of ethyl acetate while it is hot in a fume hood, let it stand and cool, filter the precipitate, and dry the obtained flocculent substance in a vacuum drying oven to obtain the purified grafted product.

[0053] Test the grafting rate of the grafted product by acid-base titration method: In a single-neck flask, add 0.5 g of the purified sample (record the accurately weighed value), xylene and a magnetic stir bar, set an appropriate rotation speed, and place it in an oil bath to completely dissolve. After adding 2 - 4 drops of phenolphthalein solution to the solution, titrate it with a 0.01 mol / L sodium hydroxide-ethanol standard solution until it turns red and does not fade (record the volume V1 of the sodium hydroxide-ethanol standard solution used), heat and reflux it in the oil bath for 1 h to allow maleic anhydride to fully react with the base. Back-titrate the red solution with a 0.01 mol / L HCl-isopropanol standard solution (titrate slowly), and stop titrating when the solution completely changes from red to colorless (record the volume V2 of the HCl-isopropanol standard solution used).

[0054] Calculate according to Equation (1):

[0055]

[0056] In Equation (1): V1 - volume of potassium hydroxide-ethanol standard solution / mL; V2 - volume of HCl-isopropanol standard solution / mL; m - sample mass / g; C - concentration of potassium hydroxide and hydrochloric acid standard solutions; M - relative molecular mass of maleic anhydride.

[0057] The test results are shown in Table 1.

[0058] Table 1 Grafting rate test results of Example 1

[0059] Number Sample mass / g <![CDATA[V1 / mL]]> <![CDATA[V2 / mL]]> Grafting rate / % 1# 0.4986 4 2.2 0.18 2# 0.5023 4.4 0.7 0.36 3# 0.5051 6.4 0.7 0.55 4# 0.4988 7.6 1.1 0.64 5# 0.5032 8.3 0.5 0.76

[0060] Example 2

[0061] Formulate the grafting rate formula by infrared spectroscopy analysis method.

[0062] Use infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of polyethylene internal standard peak of the purified grafted product, and calculate their ratio. Perform linear fitting on the known grafting rate and the characteristic peak ratio, draw a standard curve, and further obtain the formula.

[0063] Specifically, the peak position of maleic anhydride in the infrared spectrum is at 1790 cm -1 and 1712 cm -1 ; the peak position of polyethylene in the infrared spectrum is at 720 cm -1 .

[0064] The test results are shown in Table 2.

[0065] Table 2 Infrared internal standard peak height test results of Example 2

[0066]

[0067]

[0068] The known grafting rate and the ratio of characteristic peaks were linearly fitted to plot a standard curve, see Appendix Figure 1 , and the grafting rate equation was obtained: MAH group content (wt%) = 2.4108 × H 1785+1712 / H 720 + 0.018 (2);

[0069] In formula (2): H 1785+1712 - The intensity of the stretching vibration absorption peak of the carboxyl group in the MAH group; H 720 - The intensity of the bending vibration absorption peak of CH3 in PE.

[0070] Application Example 1

[0071] The standard curve was used to measure the grafting rate of industrial high-density polyethylene grafted with maleic anhydride.

[0072] Industrial high-density polyethylene grafted with maleic anhydride was prepared by Jingbo Chemical Research Institute of the Yellow River Delta.

[0073] To verify the accuracy of the established standard curve, the grafting rate of industrial high-density polyethylene grafted with maleic anhydride was measured by the standard curve method and the titration method (without purification) according to this protocol. The test results are shown in Tables 3 and 4. It can be seen from the data in the table that the error between the grafting rate measured by the standard curve and the grafting rate measured by the titration method is small, and this standard curve can calculate the grafting rate more accurately.

[0074] The test results are shown in Tables 3 and 4.

[0075] Table 3 Grafting rate test by the standard curve method in Application Example 1

[0076] Number <![CDATA[H 1785 > <![CDATA[H 1712 > <![CDATA[H 720 > <![CDATA[H (1785+1712) / H 720 > Grafting rate (%) standard curve method S1 0.442 0.087 1.566 0.34 0.83 S2 0.692 0.192 2.191 0.40 0.99 S3 0.16 0.695 2.161 0.40 0.97 S4 0.18 0.361 1.368 0.40 0.97 S5 0.443 0.174 1.762 0.35 0.86

[0077] Table 4 Grafting rate error in Application Example 1

[0078] Number Grafting rate (%) standard curve method Titration grafting rate / % Error value / % S1 0.83 0.84 0.01 S2 0.99 0.99 0.00 S3 0.97 0.96 -0.01 S4 0.97 0.97 0.00 S5 0.86 0.88 0.02

[0079] The experimental results show that by combining the advantages and disadvantages of acid-base titration and infrared spectroscopy, the present invention has established a relatively accurate and simple quantitative analysis method for determining the grafting ratio of maleic anhydride grafted onto high-density polyethylene. This method is characterized by high accuracy, high efficiency, and convenient operation, and has guiding significance for the determination of the grafting ratio in industrial continuous production, which helps to control product quality and improve production efficiency.

[0080] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A quantitative analysis method for the grafting rate of maleic anhydride grafted on high-density polyethylene, characterized in that, It includes the following steps: a) Prepare a high-density polyethylene grafted maleic anhydride sample and test its grafting rate by acid-base titration; b) Mix and dissolve the above sample with a known grafting rate and ungrafted samples in different proportions in a first organic solvent, then pour the mixed solution into a second organic solvent for precipitation, filter by suction and dry to obtain high-density polyethylene grafted maleic anhydride samples with different grafting rates; c) Use infrared spectroscopy to measure the peak height of maleic anhydride and the peak height of the polyethylene internal standard peak of the high-density polyethylene grafted maleic anhydride samples with different grafting rates prepared in step b), and calculate their ratio; finally, perform linear fitting on the known grafting rate and the characteristic peak ratio, draw a standard curve, and further obtain a formula.

2. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 1, characterized in that, The preparation process of the high-density polyethylene grafted maleic anhydride sample described in step a) is specifically as follows: Put the dried grafted product into a first organic solvent, heat it for reflux dissolution, and after complete dissolution, pour it into a second organic solvent while it is hot in a fume hood, let it stand and cool, filter the precipitate, and dry the obtained flocculent substance to obtain a purified grafted product.

3. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 2, characterized in that, The mass ratio of the dried grafted product to the first organic solvent is (1-8):

100.

4. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 2, characterized in that, The heating temperature is 100°C to 135°C.

5. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 1, wherein The process of testing by acid-base titration described in step a) is specifically as follows: In a single-necked flask, add mg of purified sample, a first organic solvent and a magnetic stirrer, and dissolve it in an oil bath under stirring conditions; then add 2-4 drops of phenolphthalein solution to the solution, and titrate it with a 0.01 mol / L sodium hydroxide-ethanol standard solution until it turns red and does not fade, record the volume V1 of the sodium hydroxide-ethanol standard solution used, and then heat and reflux in the oil bath for 0.5 h to 1.5 h; afterwards, back-titrate the red solution with a 0.01 mol / L HCl-isopropanol standard solution, and stop titration when the solution completely changes from red to colorless, and record the volume V2 of the HCl-isopropanol standard solution used.

6. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 5, wherein, The grafting rate X is calculated according to formula (1): In formula (1), V1 is the volume of potassium hydroxide-ethanol standard solution / mL; V2 is the volume of HCl-isopropanol standard solution / mL; m is the mass of the purified sample / g; C is the concentration of the potassium hydroxide and hydrochloric acid standard solutions; M is the relative molecular mass of maleic anhydride.

7. The quantitative analysis method for the grafting ratio of maleic anhydride grafted on high-density polyethylene according to claim 1, characterized in that, The first organic solvent described in step b) is selected from one or more of toluene, xylene, absolute ethanol, amyl acetate, trichloroethylene, dichloroethane, tetrahydronaphthalene; The second organic solvent is selected from one or more of acetone, absolute ethanol, cyclohexane, ethyl acetate, ether, chloroform.

8. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 1, characterized in that, The infrared spectroscopy described in step c) adopts a transmission mode; the infrared spectroscopy is a tablet pressing method, which specifically includes the following steps: Set the temperature of the infrared tablet press to 90°C to 110°C, clamp the grafted sample into the specimen clamp and put it into the infrared tablet press, press the sample for 1 min to 5 min, then take out the specimen clamp and let it stand and cool, and take out the successfully pressed grafted sample film.

9. The quantitative analysis method for the grafting ratio of maleic anhydride grafted on high-density polyethylene according to claim 1, wherein The peak positions of maleic anhydride described in step c) in the infrared spectrogram are at 1785 cm -1 and 1712 cm -1 .

10. The quantitative analysis method for the grafting ratio of maleic anhydride grafted onto high-density polyethylene according to claim 1, characterized in that, The peak positions of the polyethylene described in step c) in the infrared spectrogram are 1470 cm -1 , 1368 cm -1 and 720 cm -1 or one or more of them.

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