Testing method for hydrophobic group content of hydrophobically associating polymer

Abstract

The present invention discloses a method for testing the content of hydrophobic groups in a hydrophobically associating polymer. First, a standard curve equation for the change of the maximum relative fluorescence intensity I / I0 of the polymer solution with C H is established, where C H is the molar concentration of methylene and methyl units on the hydrophobic side chain, and C H is obtained through the relationship between C H and the content of hydrophobic groups [H]; then, by combining the obtained standard curve equation and the relationship between C H and the content of hydrophobic groups [H], I / I0 of the polymer solution to be tested is substituted into the standard curve equation to obtain C H of the polymer to be tested, and then [H] of the polymer to be tested is obtained through the relationship between C H and the content of hydrophobic groups [H]. The present invention realizes the accurate determination of the content of hydrophobic groups at a fixed temperature and a certain sample concentration by a simple and effective method, improves the standardized detection of the special performance parameters of this type of polymer, and provides technical support for the quality control of its product performance.

Description

Technical Field

[0001] The present invention belongs to the field of polymer testing, and particularly relates to a method applicable to the testing of the hydrophobic group content of hydrophobically associating polymers. Background Art

[0002] Hydrophobically associating water-soluble polymers (hereinafter referred to as "associating polymers") are novel polymers formed by introducing a very small amount (generally less than 2%, mol / mol) of hydrophobic groups onto the hydrophilic main chain of conventional water-soluble polymers. When the polymer concentration reaches above the critical association concentration (CAC), the molecular side chains aggregate through hydrophobic association, and microscopically form a three-dimensional cross-linked network mainly based on intermolecular association, and macroscopically the solution viscosity increases significantly. Benefiting from the improvement of the solution properties, at present, associating polymers have been put into use in the fields of oil and gas exploitation, coatings, biomedicine, wastewater treatment, etc. In the field of oil and gas exploitation, such polymers have been widely used in operation links such as drilling, well completion, fracturing, tertiary oil recovery, water plugging, and profile control, and obvious effects have been achieved.

[0003] However, since the content of hydrophobic monomers in associating polymers is extremely low, lower than the detection limits of most instruments, it is difficult to detect with traditional instruments. Therefore, in some research and industrial production, the accurate determination of the hydrophobic group content cannot be carried out, and it is only assumed to be consistent with the initial feeding content. However, due to the difference in the reactivity of comonomers, the added hydrophobic monomers often fail to react completely, especially the composition of the associating polymer products prepared by the micellar polymerization method will drift. Therefore, there is an urgent need to establish a standard detection method for product quality control.

[0004] With the development of analytical methods, in the prior art, the hydrophobic group content of hydrophobically associating polymers can be determined by various means. For example, the content of hydrophobic monomers in acrylamide copolymers can be determined by visible light-ultraviolet spectroscopy. Also, for another example, 1 1H NMR spectra are used to test the hydrophobic group content of a series of associating polymers. In this method, if there are obvious absorption peaks at 0.8 and 1.2 ppm for the introduced alkyl side chains, it proves that the hydrophobic groups are successfully introduced; at the same time, based on the integral area of the characteristic peak absorption peaks, the hydrophobic group content of different products can be calculated.

[0005] Although the above methods have been verified for their reliability, there are still many limitations in field applications. For example, visible light-ultraviolet spectroscopy requires that the hydrophobic groups contain chromophores such as benzene or aromatic groups, while most of the hydrophobic groups in existing associating polymers do not contain chromophores, so this method is not universal; 1Although the 1H NMR spectrum can accurately analyze the structure of hydrophobic associating polymers, the equipment is expensive, the operation is cumbersome, and it is not suitable for rapid testing. Therefore, there is an urgent need to establish a method to meet the rapid and standardized detection of the content of hydrophobic groups in associating polymers. Summary of the Invention

[0006] The object of the present invention is to provide a method for testing the content of hydrophobic groups in hydrophobic associating polymers in view of the deficiencies of the prior art, to accurately determine the content of hydrophobic groups at a fixed temperature and a certain sample concentration, to improve the standardized detection of special performance parameters of such polymers, and to provide technical support for the quality control of their product performance.

[0007] A method for testing the content of hydrophobic groups in a hydrophobic associating polymer provided by the present invention includes the following:

[0008] (1) Preparing a solution: using pure water or a saline solution as a solvent for the polymer to be tested, and adding a fluorescent probe to prepare a fluorescent solution of the polymer; preparing a pure fluorescent probe solution that only does not contain the polymer in the same way.

[0009] (2) Fluorescence spectrum testing: using a fluorescence spectrometer to obtain the fluorescence emission spectrum data of the polymer solution to obtain the maximum emission intensity I of the polymer solution; obtaining the maximum emission intensity I0 of the fluorescent solution under the same test conditions; calculating the maximum relative fluorescence intensity I / I0 of the polymer solution.

[0010] Establish a standard curve equation for the change of the maximum relative fluorescence intensity I / I0 of the polymer solution with C H where C H is the molar concentration of methylene and methyl units on the hydrophobic side chain. Substituting I / I0 of the polymer solution to be tested into the standard curve equation, the C H of the polymer solution to be tested can be obtained;

[0011] (3) According to the obtained C H of the polymer solution to be tested and the known carbon chain length (alkyl chain length) of the hydrophobic side chain of the polymer, calculate the content [H] of the hydrophobic groups in the hydrophobic associating polymer sample according to formula (1):

[0012]

[0013] In the formula: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C pρ is the polymer mass concentration, %(w / w); [H] is the molar percentage content of the hydrophobic group, %(mol / mol); L is the carbon chain length; M1 is the molecular weight of the hydrophilic structural unit in the polymer, g / mol; M2 is the molecular weight of the hydrophobic structural unit in the polymer, g / mol. This formula can be derived based on the relationship between the mass concentration and molar concentration of the polymer in the solution.

[0014] In the above method, further, in step (2), the standard curve equation for the change of the maximum relative fluorescence intensity I / I0 of the polymer with C H is as follows,

[0015]

[0016] In the formula: I is the maximum fluorescence emission intensity of the polymer solution, CPS; I0 is the maximum fluorescence emission intensity of the pure fluorescence solution, CPS; C H is the molar concentration of methylene and methyl units on the hydrophobic side chain, mol / L;

[0017] In the above method, further, the polymer is a hydrophobically associating polymer with a long-chain alkyl hydrophobic chain. The chain length of the hydrophobic chain is required as supplementary information for calculating the polymer group content according to formula (1) and formula (2). Preferably, the polymer is one of a hydrophobically modified polyacrylamide with a long-chain alkyl, a hydrophobically modified polyacrylic acid, and a multi-component copolymer containing acrylamide units and hydrophobic units. When the polymer is a hydrophobically modified polyacrylamide with a long-chain alkyl, the molecular weight of the hydrophilic structural unit of the acrylamide monomer is 71 g / mol, that is

[0018]

[0019] In the formula: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C p is the polymer mass concentration, %(w / w); [H] is the molar percentage content of the hydrophobic group, %(mol / mol); L is the carbon chain length; 71 is the molecular weight of the AM monomer unit, g / mol; M is the molecular weight of the hydrophobic structural unit, g / mol.

[0020] In the above method, further, according to whether the polymer to be tested is charged and the amount of charge carried, it is determined whether pure water or a salt solution is used to prepare the polymer solution in step (1). The role of the inorganic salt in the salt solution is to neutralize the charge carried by the polymer and avoid affecting the accuracy of the probe. Preferably, when the polymer is the above polymer, a salt solution is used as the solvent to prepare the solution, and the salt is sodium chloride and / or calcium chloride.

[0021] In the above method, further, the fluorescent probe is 8-anilino-1-naphthalenesulfonic acid (ANS), and the probe concentration in the polymer solution and the fluorescent solution is 0.03% - 0.07%, preferably 0.05%.

[0022] In the above method, further, the concentration of the polymer solution prepared in step (1) is in the range of concentrated solution or semi-dilute solution concentration, preferably 0.3% - 0.8% by mass concentration, and more preferably 0.5% by mass concentration.

[0023] In the above method, further, in step (2), a FluoroMax-4 fluorescence spectrometer is used, and the relevant test parameters are set as follows: temperature 25°C, xenon lamp as the light source with 150w, excitation wavelength 415nm, emission wavelength 430 - 630nm, resolution 1nm, and the data processing form is S1c.

[0024] In the above method, further, the standard curve equation in step (2) is obtained by the standard curve method, including the following content:

[0025] ① A series of polymer standards are prepared into polymer standard solutions with the same mass concentration as the polymer solution to be measured according to the same method as in step (1) above, and at the same time, a pure fluorescent solution is prepared; the alkyl chain length of the hydrophobic side chain of the polymer standard solution is known, and the molar content of the hydrophobic group is known. According to formula (4), the total molar concentration C of methyl and methylene units in the alkyl side chain of each polymer standard is calculated. H ,

[0026]

[0027] In the formula: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C p is the polymer mass concentration, %(w / w); [H] is the molar percentage content of the hydrophobic group, %(mol / mol); L is the carbon chain length; M1 is the molecular weight of the hydrophilic structural unit, g / mol; M2 is the molecular weight of the hydrophobic structural unit, g / mol.

[0028] ② Run the fluorescence spectrometer to obtain the fluorescence emission spectrum of the polymer standard solution, and obtain the maximum emission intensity I of the polymer solution; measure the maximum emission intensity I0 of the pure fluorescent solution under the same conditions; calculate the maximum relative fluorescence intensity I / I0 of each polymer standard solution.

[0029] ③ Using C H as the independent variable, plot the curve of the maximum relative fluorescence intensity of polymer standards with different hydrophobic group contents changing with C H to obtain the standard curve equation.

[0030] In the above method, further, the polymer standard sample used for establishing the standard curve is a polymer prepared by introducing hydrophobic groups onto polyacrylamide macromolecules using the chemical modification method. The mass concentration of the polymer standard sample solution is preferably 0.05%.

[0031] In the above method, further, a FluoroMax-4 fluorescence spectrometer is used during the process of drawing the standard curve, and the relevant test parameters are set as follows: temperature 25 °C, xenon lamp as the light source with 150 w, excitation wavelength 415 nm, emission wavelength 430 - 630 nm, resolution 1 nm, and the data processing form is S1c.

[0032] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0033] 1. The present invention has established a new testing method, achieving a breakthrough in the fluorescence spectrometry from the past qualitative analysis of hydrophobically associating polymers to the quantitative calculation of hydrophobic groups, filling the blank in the prior art, and providing technical support for understanding the state of hydrophobic association in solution.

[0034] 2. The present invention preferably uses ANS as a fluorescence probe. Compared with other fluorescence probes, this probe has a simple solution preparation process and high sensitivity to hydrophobic regions, and is suitable for related research on hydrophobically associating polymers.

[0035] 3. The present invention synthesizes a hydrophobically associating water-soluble polymer standard sample using the chemical modification method, directly introducing hydrophobic groups onto polyacrylamide macromolecules, enabling the comparison of the structure before and after, and excluding the interference of other influencing factors on the test results. At the same time, this method avoids the potential problem of group drift that may occur in the past mainstream micelle polymerization method, making the distribution of hydrophobic groups in the sample more uniform, and thus making the test results more accurate.

[0036] 4. The testing method described in the present invention can maintain high accuracy when the content of hydrophobic groups in the polymer is low.

[0037] 5. The testing method described in the present invention is simple to operate, and the cost of instruments and reagents is low, and it can be used for on-site testing of various hydrophobically associating polymer products. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic flow chart of an embodiment of the method for determining the content of hydrophobic groups described in the present invention.

[0039] Figure 2 It is the 400M nuclear magnetic resonance hydrogen spectrum and the product structural formula of the hydrophobically associating polymer standard sample used for establishing the standard curve.

[0040] Figure 3 It is a schematic diagram of the synthesis of the polymer standard sample in Example 1.

[0041] Figure 4 Fluorescence emission spectrum of the hydrophobically associating polymer standard sample used for establishing the standard curve.

[0042] Figure 5 Relationship curve established using the maximum relative fluorescence intensity of the hydrophobically associating polymer standard sample described in the present invention.

[0043] Figure 6 Fluorescence emission spectrum of the hydrophobically associating polymer A in Example 2.

[0044] Figure 7 Fluorescence emission spectrum of the hydrophobically associating polymer B in Example 3.

[0045] Figure 8 Fluorescence emission spectrum of the hydrophobically associating polymer C in Example 4.

[0046] Figure 9 1H NMR spectrum of polymer A in the verification of the test results in Example 2.

[0047] Figure 10 1H NMR spectrum of polymer B in the verification of the test results in Example 3. Detailed implementation manners

[0048] The present invention will be further described below through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the protection scope of the present invention. Those skilled in the art make some non-essential improvements and adjustments to the present invention according to the above-mentioned invention content and conduct specific implementation, which still fall within the protection scope of the invention.

[0049] The instruments and reagents used for testing the hydrophobic group content of the hydrophobically associating water-soluble polymer in the following examples include a fluorescence spectrometer, a magnetic stir bar, an intermediate container for containing the polymer solution to be tested, a cuvette, a funnel, and 8-anilino-1-naphthalenesulfonic acid (ANS).

[0050] Example 1

[0051] This example is a method for establishing a standard curve.

[0052] Step 1: Preparation of brine Add sodium chloride and calcium chloride to a volumetric flask and make up to the mark with pure water to prepare the required brine solution;

[0053] Specifically, weigh 9900 mg of NaCl and 100 mg of CaCl2 into a 1 L volumetric flask, make up to the mark with pure water, and shake well to prepare a brine solution with a salinity of 10000 mg / L as the test solvent.

[0054] Step 2: Add 8-anilino-1-naphthalenesulfonic acid to the prepared brine solution to prepare the fluorescent solution to be used. Filter the prepared solution to remove insoluble substances, and wrap it with tin foil and store it in a dark place;

[0055] Specifically, weigh (199.90 ± 0.01) g of standard brine into a 500 mL beaker, and then accurately weigh (0.1 ± 0.0001) g of 8-anilino-1-naphthalenesulfonic acid and add it to the brine to prepare a 0.05% fluorescent solution. Filter the prepared solution to remove insoluble substances, and wrap it with tin foil and store it in a dark place.

[0056] Step 3: Using an appropriate amount of the fluorescent solution as a solvent, weigh a series of hydrophobically associating polymer standards and slowly add them to the fluorescent solution under stirring. After the solution is completely dissolved, store it in a dark place and let it stand;

[0057] Select the H8-0.3, H8-0.5, H8-0.7, H8-0.9, H8-1.0, H8-1.5, H10-0.5, H12-0.5 series of polymers as polymer standards. Weigh 49.75 g of the fluorescent solution, take 0.25 g of the hydrophobically associating polymer standard powder in a beaker, and continuously stir at 150 r / min for 24 h to prepare a polymer solution with a mass concentration of 0.5%. For the naming of the polymer standards, taking H8-1.0 as an example, H represents hydrophobically associating polymer, 8 represents the alkyl chain length of the hydrophobic side chain, and 1.0 represents the molar content of the hydrophobic group. Figure 2 The characterization results for the above series of polymer standards were obtained by a Bruker AV ii-400MHz nuclear magnetic resonance spectrometer.

[0058] The standards adopt the chemical modification method, introducing hydrophobic groups onto the polyacrylamide macromolecule to maintain the comparability of the structure before and after. See the reaction mechanism diagram in Figure 3 Taking H8-1.0 as an example for the synthesis method: Introduce 2.0 g of polyacrylamide (PAM) and 418 g of anhydrous DMSO into a 1 L four-necked round-bottom flask equipped with a condenser, a nitrogen inlet / outlet, and a mechanical stirrer. After continuously stirring at 80 °C for 20 hours under a nitrogen atmosphere, when the dissolution of PAM in DMSO is completely finished, cool the solution to room temperature. Then, dropwise add 11 g of an anhydrous DMSO solution containing 0.158 g of potassium tert-butoxide with active stirring, and continuously stir the mixture for 1 h. Then, dissolve 0.054 g of n-octyl bromide in 10 g of DMSO, inject it into the constant-pressure funnel through a syringe, and add it dropwise. The alkylation reaction is stirred at 65 °C for 24 hours, maintaining a nitrogen atmosphere during the process and keeping the reaction mixture homogeneous. After adding 400 ml of cold water to terminate the reaction, dialyze the final emulsion reaction mixture for one week and freeze-dry to obtain a white solid product for standby. The same process is used to prepare other polymers in this series.

[0059] Step 4: Turn on the FluoroMax-4 fluorescence spectrometer, set the relevant parameters, and run the fluorescence spectrometer to obtain the fluorescence emission spectrum of the polymer solution;

[0060] In the embodiments of the present application, the FluoroMax-4 fluorescence spectrometer is used to quantitatively test the hydrophobic associating polymer standards with different hydrophobic group contents, which has both qualitative and quantitative effects on the analysis of hydrophobic interactions in solution. Specifically, the following analysis conditions are used to analyze the hydrophobic group content of the polymer to be tested, as shown in Table 1. Table 1 is the sample analysis conditions of the embodiments of the present application.

[0061] Table 1.

[0062] Temperature 25℃ Light source Xenon lamp 150w Excitation wavelength 415nm Emission wavelength 430~630nm Resolution 1nm Data processing S1c

[0063] Then, mark the maximum emission peak in the fluorescence emission spectrum (as Figure 4 shown), record the peak intensity I of the emission peak; test the maximum emission fluorescence intensity I0 of the solvent under the same conditions, and calculate the maximum relative fluorescence intensity I / I0 of the polymer solution.

[0064] Step 5: Calculate the total molar concentration C of methyl and methylene units in the alkyl side chain of the polymer through formula (3) H , and the corresponding relationship between the hydrophobic group content and chain length of the hydrophobic associating polymer standard and C H is shown in Table 2:

[0065] Table 2.

[0066]

[0067] Step 6: Taking C H as the independent variable, based on formula (2), draw the curve of the maximum relative fluorescence intensity of polymers with different hydrophobic group contents varying with C H at 0.5% ( Figure 5 ).

[0068]

[0069] In the formula: I is the fluorescence intensity of the polymer solution, CPS; I0 is the fluorescence intensity of the pure solvent, CPS; C H is the molar concentration of methylene and methyl units on the hydrophobic side chain, mol / L.

[0070] The hydrophobic group content of the hydrophobic associating polymer with different carbon chain lengths can be calculated through formula (1) and formula (2). It should be noted that formula (1) is applicable to the hydrophobic associating polymer with a long-chain alkyl hydrophobic chain. To calculate the polymer group content according to this formula and formula (2), the hydrophobic chain length is required as supplementary information.

[0071] Example 2

[0072] The sample in this example is a hydrophobically associating polymer A with an unknown content of hydrophobic groups.

[0073] After using the fluorescent solution of the brine prepared in Reference Example 1 as the solvent, the sample to be measured was added, and a polymer fluorescent solution with a mass concentration of 0.5% was prepared. Its fluorescence spectrum was measured by a FluoroMax-4 fluorescence spectrometer. The test conditions were 25 °C, an excitation wavelength of 415 nm, an emission wavelength of 430 - 630 nm, a resolution of 1 nm, and the data processing form was S1c.

[0074] The obtained fluorescence spectrum is as Figure 6 shown. According to the fluorescence spectrum results, the maximum emission peak in the emission spectrum was marked, and the peak intensity I was recorded. The fluorescence intensity I0 of the staining solvent was measured in the same process. According to the maximum relative fluorescence intensity I / I0 (4.63797) and Equation (2) in Example 1, the molar concentration C of the methyl and methylene units in the hydrophobic side chain of the sample was calculated H :

[0075]

[0076] After calculation, C H was 6.43×10 -3 mol / L. The chain length of the side chain of the hydrophobically associating polymer a was 8. Then, the content of hydrophobic groups could be calculated according to Equation (3):

[0077]

[0078] In the formula: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C p is the polymer concentration, %; [H] is the content of hydrophobic groups, %; L is the carbon chain length; 71 is the molecular weight of the AM monomer unit, g / mol; M is the molecular weight of the hydrophobic structural unit (183 when the chain length is 8), g / mol.

[0079] After calculation, its content of hydrophobic groups was 1.16 mol%.

[0080] Example 3

[0081] The sample in this example is a hydrophobically associating polymer B with an unknown content of hydrophobic groups. After using the fluorescent solution of the brine prepared in Reference Example 1 as the solvent, the sample to be measured was added, and a polymer fluorescent solution with a mass concentration of 0.5% was prepared. Its fluorescence spectrum was measured by a FluoroMax-4 fluorescence spectrometer. The test conditions were 25 °C, an excitation wavelength of 415 nm, an emission wavelength of 430 - 630 nm, a resolution of 1 nm, and the data processing form was S1c.

[0082] The obtained fluorescence spectrum is as Figure 7 shown. According to the fluorescence spectrum results, mark the maximum emission peak in the emission spectrum and record the peak intensity I. Measure the fluorescence intensity I0 of the staining solvent in the same process. Calculate the molar concentration C of the methyl and methylene units of the hydrophobic side chain of the sample according to the maximum relative fluorescence intensity I / I0 (8.35408) and Equation (2) in Example 1 H .

[0083] After calculation, C H is 7.95×10 -3 mol / L. Assuming that the side chain length of the hydrophobic associating polymer a is 8, the hydrophobic group content can be calculated according to Equation (1). After calculation, its hydrophobic group content is 1.45 mol%.

[0084] Example 4

[0085] The sample described in this example is a hydrophobic associating polymer C with an unknown hydrophobic group content. After preparing a fluorescent solution of brine as a solvent with reference to Example 1, add the sample to be measured and prepare a polymer fluorescent solution with a mass concentration of 0.5%. Test its fluorescence spectrum with a FluoroMax-4 fluorescence spectrometer. The test conditions are 25 °C, an excitation wavelength of 415 nm, an emission wavelength of 430 - 630 nm, a resolution of 1 nm, and the data processing form is S1c. The obtained fluorescence spectrum is as Figure 8 shown. According to the fluorescence spectrum results, mark the maximum emission peak in the emission spectrum and record the peak intensity I. Measure the fluorescence intensity I0 of the staining solvent in the same process. Calculate the molar concentration C of the methyl and methylene units of the hydrophobic side chain of the sample according to the maximum relative fluorescence intensity I / I0 (14.34538) and Equation (2) in Example 1 H .

[0086] After calculation, C H is 9.49×10 -3 mol / L. Assuming that the side chain length of the hydrophobic associating polymer a is 12, the hydrophobic group content can be calculated according to Equation (1). After calculation, its hydrophobic group content is 1.15 mol%.

[0087] Verification of the test results in Example 2

[0088] At room temperature, take an appropriate amount of the unknown hydrophobic associating polymer product A and add it to heavy water. After preparing a polymer solution, characterize the structure of polymer A with a Bruker AV ii-400MHz nuclear magnetic resonance spectrometer. The specific results are shown in Figure 9 .

[0089] Figure 9It shows that the chemical shift assignment of the protons of the hydrophobic groups in the hydrophobic associating polymer product A is consistent with the theoretical values. Among them, peak a and peak b correspond to the polyacrylamide main chain, the peak c at 1.2 ppm corresponds to the protons of the methylene unit on the hydrophobic chain, and the peak d at 0.8 ppm corresponds to the protons of the terminal methyl unit on the hydrophobic chain. By Figure 9 integrating the relevant characteristic peaks and the main peak in it, it is calculated that the hydrophobic side chain length of this hydrophobic associating polymer product is 8, and the content of hydrophobic groups is 1.16%, which is consistent with the theoretical calculation results.

[0090] Verification of the test results of Example 3

[0091] At room temperature, an appropriate amount of the unknown hydrophobic associating polymer product B was added to heavy water. After preparing a polymer solution, the polymer structure was characterized by a Bruker AV ii-400MHz nuclear magnetic resonance spectrometer. The specific results are shown in Figure 10 .

[0092] Figure 10 It shows that the chemical shift assignment of the protons of the hydrophobic groups in the hydrophobic associating polymer product B is consistent with the theoretical values. Among them, peak a and peak b correspond to the polyacrylamide main chain, the chemical peak c at 1.2 ppm corresponds to the protons of the methylene unit on the hydrophobic chain, and the peak d at 0.8 ppm corresponds to the protons of the terminal methyl unit on the hydrophobic chain. By Figure 10 integrating the relevant characteristic peaks and the main peak in it, it is calculated that the hydrophobic side chain length of this hydrophobic associating polymer product is 8, and the content of hydrophobic groups is 1.48%, which only differs from the theoretical calculation results by 0.03%.

Claims

1. A method for testing the content of hydrophobic groups in a hydrophobic associating polymer, comprising the following steps: (1)Prepare a solution: Use pure water or a saline solution as the solvent for the polymer to be measured, and add a fluorescent probe to prepare a fluorescent solution of the polymer; Prepare a pure fluorescent probe solution that only does not contain the polymer according to the same method; (2)Fluorescence spectroscopy test: Use a fluorescence spectrometer to obtain the fluorescence emission spectrum data of the polymer solution and obtain the maximum emission intensity of the polymer solution I ; Obtain the maximum emission intensity of the fluorescent solution under the same test conditions I 0; Calculate the maximum relative fluorescence intensity of the polymer solution I / I 0; Establish the standard curve equation for the change of the maximum relative fluorescence intensity of the polymer solution I / I 0 with C H wherein C H is the molar concentration of methylene and methyl units on the hydrophobic side chain, and substitute the I / I 0 of the polymer solution to be measured into the standard curve equation to obtain the C H of the polymer solution to be measured; (3)According to the C H of the polymer to be measured obtained, and knowing the carbon chain length of the hydrophobic side chain of the polymer, calculate the hydrophobic group content of the hydrophobic associating polymer sample according to formula (2) H : ， Wherein: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C p is the polymer mass concentration, % (w / w); H is the molar percentage content of the hydrophobic group, % (mol / mol); L is the carbon chain length; M 1 is the molecular weight of the hydrophilic structural unit, g / mol; M 2 is the molecular weight of the hydrophobic structural unit, g / mol; The maximum relative fluorescence intensity of the polymer in step (2) I / I 0with C H The standard curve equation for the change is as follows, ， In the formula: I is the maximum fluorescence emission intensity of the polymer solution, CPS; I 0 is the maximum fluorescence emission intensity of the pure fluorescence solution, CPS; C H is the molar concentration of methylene and methyl units on the hydrophobic side chain, mol / L; The polymer is selected from one of hydrophobic modified polyacrylamide with long-chain alkyl groups, hydrophobic modified polyacrylic acid, and a multi-component copolymer containing acrylamide units and hydrophobic units; when the polymer is hydrophobic modified polyacrylamide with long-chain alkyl groups, the molecular weight of the hydrophilic structural unit acrylamide monomer unit is 71 g / mol, and formula (2) is ， In the formula: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C p is the polymer mass concentration, % (w / w); H is the molar percentage content of the hydrophobic group, % (mol / mol); mol% L is the carbon chain length; 71 is the molecular weight of the AM monomer unit, g / mol; M is the molecular weight of the hydrophobic structural unit, g / mol.

2. The method according to claim 1, wherein According to whether the polymer to be tested is charged and the amount of charge carried, determine whether pure water or a salt solution is used in step (1) to prepare the polymer solution; when the polymer is charged, a salt solution is used as the solvent to prepare the solution, and the salt is sodium chloride and / or calcium chloride.

3. The method according to claim 1, characterized in that, The fluorescent probe is 8-anilino-1-naphthalenesulfonic acid, and the probe concentration in the polymer solution and the fluorescent solution is 0.03% - 0.07%.

4. The method according to claim 1, wherein The mass concentration of the polymer solution prepared in step (1) is 0.3% - 0.8%.

5. The method according to claim 1, wherein In step (2), a FluoroMax-4 fluorescence spectrometer is used, and the relevant test parameters are set as follows: temperature 25 °C, xenon lamp 150 w as the light source, excitation wavelength 415 nm, emission wavelength 430 - 630 nm, resolution 1 nm, and the data processing form is S1c.

6. The method according to claim 1, wherein In step (2), the standard curve equation is obtained by the standard curve method, including the following content: ① Prepare a series of polymer standard solutions with the same mass concentration as the polymer solution to be measured according to the same method as in the above step (1), and at the same time prepare a pure fluorescence solution; the alkyl chain length of the hydrophobic side chain of the polymer standard solution is known, and the molar content of the hydrophobic group is known. Calculate the total molar concentration of methyl and methylene units in the alkyl side chain of each polymer standard according to formula (2). C H : ， Wherein: C H is the total molar concentration of methyl and methylene units in the alkyl side chain, mol / L; C p is the polymer mass concentration, % (w / w); H is the molar percentage content of the hydrophobic group, % (mol / mol); L is the carbon chain length; M 1 is the molecular weight of the hydrophilic structural unit in the polymer, g / mol; M 2 is the molecular weight of the hydrophobic structural unit in the polymer, g / mol; ②Operate the fluorescence spectrometer to obtain the fluorescence emission spectra of the polymer standard solutions, and obtain the maximum emission intensity of each polymer standard solution under the same test conditions I ; Test the maximum emission intensity of the pure fluorescent solution under the same conditions I 0; Calculate the maximum relative fluorescence intensity of each polymer standard solution I / I 0; ③Using C H as the independent variable, plot the curve of the maximum relative fluorescence intensity of polymer standards with different hydrophobic group contents versus C H to obtain the standard curve equation.

7. The method according to claim 6, wherein The polymer standard sample selected for establishing the standard curve is a polymer prepared by introducing hydrophobic groups onto the polyacrylamide macromolecule by chemical modification; the mass concentration of the polymer standard sample solution is 0.5%; during the process of drawing the standard curve, a FluoroMax-4 fluorescence spectrometer is used, and the relevant test parameters are set as follows: temperature 25 °C, xenon lamp 150 w as the light source, excitation wavelength 415 nm, emission wavelength 430 - 630 nm, resolution 1 nm, and the data processing form is S1c.

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