CN1191115C - Preparation method of surface patterned sulfide polymer composite microspheres - Google Patents

Abstract

The present invention relates to a preparation method of sulfide macromolecular composite microspheres with patternized surfaces, which comprises the following steps: (1), mixed surfactant preparation, (2), oil phase preparation, (3), emulsification, (4), water phase preparation, (5), the preparation of copolymerization microgel containing Cd<2+>, or Pb<2+>, or Zn<2+>, or Cu<2+>, and (6), the preparation of P(NIPAM-co-MAA)/CdS, or PbS, or ZnS, or CuS compound microspheres. The preparation method has the advantages of reasonable design, feasible technology, convenient operation, short reaction time, reaction at a normal temperature, etc. Compared with the existing preparation method of inorganic macromolecule composite materials, the preparation method of sulfide macromolecular composite microspheres with patternized surfaces controls the pattern of the composite microsphere surfaces through preliminary design; composite materials prepared by the preparation method of sulfide macromolecular composite microspheres with patternized surfaces have the advantages of rigidity and stability of organic materials, flexibility of organic materials, etc. The composite materials have high specific surfaces and relatively small mass, and can be applied to wave and shock absorption, catalyst supporting, adsorptive separation, etc.

Description

Preparation method of surface patterned sulfide polymer composite microspheres

technical field

The invention belongs to the technical field of using inorganic substances or non-high-molecular organic substances as compound materials, and specifically relates to sulfur-, selenium- or tellurium-containing compounds using inorganic ingredients.

Background technique

There are many methods for preparing micro-nano organic-inorganic composite materials, but there are four main methods, namely sol-gel method, intercalation method, blending method and filling method. Various methods have certain shortcomings, for example, the synthesis process of the sol-gel method is complicated, and the choice of nanomaterials and organic polymer materials is not large. There are not many inorganic materials to choose from for the intercalation method. At present, the main research is montmorillonite. Although the blending method is the simplest and most convenient method for preparing organic-inorganic composite materials, it is difficult to ensure the uniform compounding of organic components and inorganic components at the molecular level (or nanoscale). Similarly, it is also difficult to obtain a uniformly composited organic-inorganic composite material using the filling method.

Microgel is a kind of spherical latex particles with a three-dimensional network structure and a size of micronano scale. The size, internal structure and types of functional groups contained in the microgel can be controlled by changing the monomer, crosslinker type and preparation conditions. Therefore, as a template for the preparation of spherical micro-nanomaterials, microgels have incomparable advantages over natural templates. In fact, there are many research groups engaged in spherical micro-nano organic-inorganic composite materials at home and abroad. For example, Silver's research group prepared a copolymer microgel of N-isopropylacrylamide (NIPAM) and acrylic acid (AA) by soap-free emulsion polymerization, which induced the deposition of inorganic components, and obtained a spherical microgel after high-temperature calcination. Structure of inorganic Y ₂ O ₃ : Eu luminescent material. Antonietti et al. prepared polystyrene microgels by microemulsion polymerization. After sulfonation treatment, the microgels were soaked in the solution of metal salts. By controlling the crosslinking density of microgels and the reduction mode of metal salts , prepared spherical nano-metals with different particle sizes and structures. In recent years, Pan Caiyuan and others have carried out a lot of work on the preparation and application of polymer microgels, and prepared various types of organic/inorganic nanocomposites. Shen Jiacong and others copolymerized metal salts containing polymerizable double bonds (such as lead methacrylate or zinc methacrylate) with monomers such as styrene, methacrylic acid, and methyl methacrylate to form polymer microgels, and then This lead-containing or zinc-containing copolymer microgel is dissolved in an organic solvent, and PbS or ZnS particles stabilized by the polymer network are prepared in situ by reacting with hydrogen sulfide gas. However, the preparation of spherical organic/inorganic composites with specific surface patterns using microgels as templates has not been reported.

Poly N-isopropylacrylamide (PNIPAM) has both hydrophilic amide groups and hydrophobic isopropyl groups on the molecular chain, so it exhibits the lowest critical solution temperature effect (LCST, 32°C), that is, at low At this characteristic temperature, the poly-N-isopropylacrylamide solution is clear and transparent, and at a temperature higher than this, the solution is turbid and phase-separated. The microgel processed from poly-N-isopropylacrylamide retains this basic property of poly-N-isopropylacrylamide solution, which is manifested as the swelling and shrinking effect of the microgel. The sensitivity of the volume of poly-N-isopropylacrylamide microgels to temperature has made it widely used in the controlled release of drugs, the regulation of catalytic activity of catalysts, the gentle separation of downstream products of biotechnology, and sewage treatment. Polymethacrylic acid (PMAA) is a typical water-soluble polymer whose conformation depends on the solution pH. The cross-linked polymethacrylic acid is in gel state and can swell in water. The swelling behavior of polymethacrylic acid gel is closely related to the pH of the medium. When the pH is low (usually less than 5.5), the carboxyl group (-COOH) on the side chain of the polymethacrylic acid molecule exists in a protonated form, the molecular chain is neutral, and the presence of the side chain methyl group makes the polymethacrylic acid chain in the contracted state. As the pH rises, the carboxyl group is ionized, so that the polymethacrylic acid molecular chain is negatively charged, and the repulsion of the adjacent side chain carboxylate groups makes the polymethacrylic acid molecular chain stretch, accompanied by the swelling of the polymethacrylic acid gel.

Contents of the invention

The technical problem to be solved by the present invention is to provide a surface-patterned sulfide polymer composite microsphere with reasonable design, feasible process, simple operation, short reaction time, reaction at room temperature, and conversion of metal ions into metal sulfide particles. method of preparation.

The technical solution adopted to solve the problems of the technologies described above is that the preparation method comprises the following steps:

(1) Preparation of mixed surfactant

Mix Span-80 and Tween-80 at a weight ratio of 5:1 to prepare a mixed surfactant.

(2) Preparation of oil phase

Add the prepared mixed surfactant into a three-necked flask filled with n-heptane, and mix the mixed surfactant and n-heptane at a weight ratio of 1:115-130 to form an oil phase.

(3) emulsification

Stir the oil phase prepared in (2) with a stirrer at a temperature of 18-30° C. at a stirring speed of 300-350 rpm, feed nitrogen gas, and emulsify for 1 hour to prepare an emulsion.

(4) Preparation of water phase

Dissolve 1.2g of N-isopropylacrylamide and methacrylic acid mixed monomer in 5mL of secondary water, the weight percentage of methacrylic acid in the mixed monomer is 5-30%, and then add 0.015-0.09g NaOH To neutralize methacrylic acid, add 0.04~0.08g N,N'-methylenebisacrylamide, 80mg potassium persulfate and Cd(Ac) ₂ or Pb(Ac) ₂ or Zn at a concentration of 0.3mol/L (Ac) ₂ or Cu(Ac) ₂ solution 1.5mL, stir, mix well, filter, the total volume of the aqueous phase is 8-10mL.

(5) Preparation of microgels containing Cd ²⁺ or Pb ²⁺ or Zn ²⁺ or Cu ²⁺ copolymers

Quickly add the water phase to the emulsion, adjust the stirring speed to 500-600 rpm, add 0.5 mL of 50 mg/mL tetramethylethylenediamine after 5 minutes, and carry out the reaction for 2-4 hours to obtain P(NIPAM-co -MAA)/Cd ²⁺ or P(NIPAM-co-MAA)/Pb ²⁺ or P(NIPAM-co-MAA)/Zn ²⁺ or P(NIPAM-co-MAA)/Cu ²⁺ copolymer microgel .

(6) Preparation of P(NIPAM-co-MAA)/CdS or PbS or ZnS or CuS composite microspheres

To (5) P(NIPAM-co-MAA)/Cd ²⁺ copolymer microgel, P(NIPAM-co-MAA)/Pb ²⁺ copolymer microgel, P(NIPAM-co-MAA)/Zn ^{2 +} copolymerized microgel and P(NIPAM-co-MAA)/Cu ²⁺ copolymerized microgel were slowly fed with H ₂ S gas for 0.5 hours, and then fed with N ₂ to remove excess H ₂ S gas, and passed through secondary water Alternately washed with acetone and dried naturally, yellow P(NIPAM-co-MAA)/CdS composite microspheres, brown-black P(NIPAM-co-AA)/PbS composite microspheres, white P(NIPAM-co-MAA)/PbS composite microspheres, white P(NIPAM-co- MAA)/ZnS composite microspheres, black P(NIPAM-co-MAA)/CuS composite microspheres.

In the process step of (2) preparing the oil phase of the present invention, the mixed surfactant and n-heptane are mixed in a preferred weight ratio of 1:120-125 to prepare the oil phase. In (3) emulsification process step, the emulsification temperature is preferably 20-25°C. In (4) preparation of the water phase process step, the preferred weight percentage of methacrylic acid in the mixed monomer is 10-25%, then preferably add 0.02-0.08g NaOH to neutralize methacrylic acid, and then preferably add 0.05-0.06 gN,N'-methylenebisacrylamide.

In the process step of (2) preparing the oil phase of the present invention, the mixed surfactant and n-heptane are mixed in an optimal weight ratio of 1:122 to form the oil phase. In (3) emulsification process step, the optimum emulsification temperature is 25°C. In (4) preparation of aqueous phase process step, the optimum percentage by weight of methacrylic acid is 20% in mixed monomer, then optimally add 0.06g NaOH to neutralize methacrylic acid, optimally add 0.06g N again, N'-methylenebisacrylamide.

The present invention uses the surface functional group -COOH of the copolymerized microgel to effectively coordinate or electrostatically interact with metal ions, so that the metal ions are evenly distributed around the polymer chain, and the metal ions are converted into metal ions through in-situ conversion reactions. Sulfur particles. The copolymerized microgel network structure can limit the size of inorganic substances, prevent the aggregation of particles, and improve the stability of inorganic particles. The three-dimensional network structure and spherical shape of the microgel impose confinement and guidance on the inorganic crystallization or deposition reaction in it, control the nucleation, growth, arrangement, etc. of inorganic substances, and form composite microspheres with surface patterning . The present invention has the advantages of reasonable design, feasible process, easy operation, short reaction time, and reaction at room temperature. Designed to control the morphology of the material surface, the composite material prepared by the invention has the advantages of rigidity and stability of inorganic materials and flexibility of organic materials. This kind of composite material has a high specific surface and relatively small mass, and can be applied in wave absorption and shock absorption, catalyst loading, adsorption and separation, etc.

Description of drawings

Figure 1 is a scanning electron microscope observation picture of P(NIPAM-co-MAA)/CdS composite microspheres with a methacrylic acid content of 15%.

FIG. 2 is a partially enlarged schematic view of the surface of FIG. 1 .

Fig. 3 is a scanning electron microscope observation picture of P(NIPAM-co-MAA)/CdS composite microspheres with a methacrylic acid content of 20%.

FIG. 4 is a partially enlarged schematic view of the surface of FIG. 3 .

Fig. 5 is a scanning electron microscope observation picture of P(NIPAM-co-MAA)/PbS composite microspheres with a methacrylic acid content of 20%.

FIG. 6 is a partially enlarged schematic view of the surface of FIG. 5 .

Fig. 7 is a scanning electron microscope observation picture of P(NIPAM-co-MAA)/ZnS composite microspheres with methacrylic acid content of 20%.

FIG. 8 is a partially enlarged schematic view of the surface of FIG. 7 .

Fig. 9 is a scanning electron microscope observation picture of P(NIPAM-co-MAA)/CuS composite microspheres with methacrylic acid content of 20%.

FIG. 10 is a partially enlarged schematic view of the surface of FIG. 9 .

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

Example 1

This embodiment provides the preparation method of surface patterned P(NIPAM-co-MAA)-CdS composite microspheres, and its process steps are as follows:

(1) Preparation of mixed surfactant

Mix Span-80 and Tween-80 at a weight ratio of 5:1 to prepare a mixed surfactant.

(2) Preparation of oil phase

Add the prepared mixed surfactant into a three-necked flask filled with n-heptane, and mix the mixed surfactant and n-heptane at a weight ratio of 1:122 to form an oil phase.

(3) emulsification

Stir the oil phase prepared in (2) with a stirrer at a temperature of 25° C. at a stirring speed of 300 to 350 rpm, feed nitrogen gas, and emulsify for 1 hour to prepare an emulsion.

(4) Preparation of water phase

Dissolve 1.2g of N-isopropylacrylamide and methacrylic acid mixed monomer in 5mL of secondary water, and the weight percentage of methacrylic acid in the mixed monomer is 15%, and then add 0.06g of NaOH to neutralize the formaldehyde base acrylic acid, then add 0.06g N,N'-methylenebisacrylamide, 80mg potassium persulfate and 1.5mL of Cd(Ac) ₂ solution with a concentration of 0.3mol/L, stir, mix well, filter, and the water phase The volume is 8-10mL.

(5) Preparation of microgels containing Cd ²⁺ or Pb ²⁺ or Zn ²⁺ or Cu ²⁺ copolymers

Quickly add the water phase to the emulsion, adjust the stirring speed to 500-600 rpm, add 0.5 mL of 50 mg/mL tetramethylethylenediamine after 5 minutes, and carry out the reaction for 2-4 hours to obtain P(NIPAM-co -MAA)/Cd ²⁺ copolymer microgels.

(6) Preparation of P(NIPAM-co-MAA)/CdS or PbS or ZnS or CuS composite microspheres

Slowly feed H ₂ S gas into the P(NIPAM-co-MAA)/Cd ²⁺ copolymer microgel in (5) for 0.5 hours, then feed N ₂ to remove excess H ₂ S gas, and pass through secondary water and acetone Alternately washing and drying naturally, the yellow P(NIPAM-co-MAA)/CdS composite microspheres can be obtained.

Example 2

In this embodiment, in (4) the process step of preparing the water phase, the weight percentage of methacrylic acid in the mixed monomer of N-isopropylacrylamide and methacrylic acid is 20%. Other processing steps are identical with embodiment 1.

Example 3

In this embodiment, in (2) the process step of preparing the oil phase, the mixed surfactant and n-heptane are mixed at a weight ratio of 1:115 to prepare the oil phase. In (3) emulsification process step, the emulsification temperature is 18°C. In (4) preparation of aqueous phase process step, the percentage by weight of methacrylic acid in N-isopropylacrylamide and methacrylic acid mixed monomer is 5%, then add 0.015g NaOH to neutralize methacrylic acid, then Add 0.04g of N,N'-methylenebisacrylamide, 80mg of potassium persulfate and 1.5mL of Cd(Ac) ₂ solution with a concentration of 0.3mol/L, stir, mix well, and filter. The total volume of the aqueous phase is 8～ 10mL. Other processing steps are identical with embodiment 1.

Example 4

In this embodiment, in (2) the process step of preparing the oil phase, the mixed surfactant and n-heptane are mixed at a weight ratio of 1:130 to prepare the oil phase. In (3) emulsification process step, the emulsification temperature is 30°C. In (4) preparation of aqueous phase process step, the percentage by weight of methacrylic acid in N-isopropylacrylamide and methacrylic acid mixed monomer is 30%, then add 0.09g NaOH to neutralize methacrylic acid, then Add 0.08g of N,N'-methylenebisacrylamide, 80mg of potassium persulfate and 1.5mL of Cd(Ac) ₂ solution with a concentration of 0.3mol/L, stir, mix well, and filter. The total volume of the aqueous phase is 8～ 10mL. Other processing steps are identical with embodiment 1.

Example 5

This embodiment provides the preparation method of surface patterned P(NIPAM-co-MAA)-PbS composite microspheres, and its process steps are as follows:

In the above Examples 1-4, in (4) preparation of the aqueous phase process step, the N-isopropylacrylamide and methacrylic acid mixed monomers were dissolved in 5 mL of secondary water, and then NaOH was added to neutralize the formaldehyde base acrylic acid, then add N,N'-methylenebisacrylamide, 80mg potassium persulfate and 1.5mL of Pb(Ac) ₂ solution with a concentration of 0.3mol/L, stir, mix evenly, and filter, the total volume of the aqueous phase is 8 ~ 10mL. In the process step of (5) preparing the copolymerized microgel containing Cd ²⁺ or Pb ²⁺ or Zn ²⁺ or Cu ²⁺ , P(NIPAM-co-MAA)/Pb ²⁺ copolymerized microgel is obtained. In (6) the process step of preparing P(NIPAM-co-MAA)/CdS or PbS or ZnS or CuS composite microspheres, brown-black P(NIPAM-co-MAA)/PbS composite microspheres are obtained. The consumption and proportioning thereof of other components are identical with corresponding embodiment. Other process steps are the same as the corresponding embodiment.

Example 6

This embodiment provides the preparation method of surface patterned P(NIPAM-co-MAA)-ZnS composite microspheres, and its process steps are as follows:

In the above Examples 1-4, in (4) preparation of the aqueous phase process step, the N-isopropylacrylamide and methacrylic acid mixed monomers were dissolved in 5 mL of secondary water, and then NaOH was added to neutralize the formaldehyde base acrylic acid, then add N, N'-methylenebisacrylamide, 80 mg potassium persulfate and 1.5 mL of Zn(Ac) ₂ solution with a concentration of 0.3 mol/L, stir, mix evenly, and filter, the total volume of the aqueous phase is 8 ~ 10mL. In the process step of (5) preparing the copolymerized microgel containing Cd ²⁺ or Pb ²⁺ or Zn ²⁺ or Cu ²⁺ , P(NIPAM-co-MAA)/Zn ²⁺ copolymerized microgel is obtained. In (6) the process step of preparing P(NIPAM-co-MAA)/CdS or PbS or ZnS or CuS composite microspheres, white P(NIPAM-co-MAA)/ZnS composite microspheres are obtained. The consumption and proportioning thereof of other components are identical with corresponding embodiment. Other process steps are the same as the corresponding embodiment.

Example 7

This embodiment provides the preparation method of surface patterned P(NIPAM-co-MAA)-CuS composite microspheres, and its process steps are as follows:

In the above Examples 1-4, in (4) preparation of the aqueous phase process step, the N-isopropylacrylamide and methacrylic acid mixed monomers were dissolved in 5 mL of secondary water, and then NaOH was added to neutralize the formaldehyde base acrylic acid, then add N,N'-methylenebisacrylamide, 80mg potassium persulfate and 1.5mL of Cu(Ac) ₂ solution with a concentration of 0.3mol/L, stir, mix evenly, filter, and the total volume of the aqueous phase is 8 ~ 10mL. In the process step of (5) preparing the copolymerized microgel containing Cd ²⁺ or Pb ²⁺ or Zn ²⁺ or Cu ²⁺ , P(NIPAM-co-MAA)/Cu ²⁺ copolymerized microgel is obtained. In (6) the process step of preparing P(NIPAM-co-MAA)/CdS or PbS or ZnS or CuS composite microspheres, black P(NIPAM-co-MAA)/CuS composite microspheres are obtained. The consumption and proportioning thereof of other components are identical with corresponding embodiment. Other process steps are the same as the corresponding embodiment.

In order to verify the beneficial effects of the present invention, the inventors compounded the P(NIPAM-co-MAA)/CdS composite microspheres prepared in Example 1 of the present invention and the P(NIPAM-co-MAA)/CdS prepared in Example 2. Microspheres, the P(NIPAM-co-MAA)/PbS composite microspheres prepared in Example 5, the P(NIPAM-co-MAA)/ZnS composite microspheres prepared in Example 6, the PbS composite microspheres prepared in Example 7 (NIPAM-co-MAA)/CuS composite microspheres were observed in the laboratory using a scanning electron microscope, and the observations are as follows:

1. Observation instrument

Hitachi S-570 scanning electron microscope.

2. Observe objects

P(NIPAM-co-MAA)/CdS composite microspheres, P(NIPAM-co-MAA)/PbS composite microspheres, P(NIPAM-co-MAA)/ZnS composite microspheres, P(NIPAM-co-MAA) /CuS composite microspheres.

3. Observation results

The observation results are shown in Figures 1-10.

4. Observation conclusion

(1) The chemical properties of the copolymerized microgel, especially the content of methacrylic acid, have a significant impact on the surface pattern of the composite microspheres, for example, the P obtained when the content of methacrylic acid in the copolymerized microgel template is 20%. The surface of (NIPAM-co-MAA)/CdS composite microspheres is denser than the surface of the composite microspheres obtained by the template with methacrylic acid content of 15%, see Figure 2 and Figure 4, but the pattern on the surface of the composite microspheres Basically similar.

(2) The surface patterns of the composite microspheres are not only related to the chemical properties of the copolymerized microgel templates, but also have a great relationship with the properties of the inorganic deposits. It can be seen that the patterns and surface microstructures of composite microspheres obtained from the same copolymerized microgel template are different when CdS, PbS, ZnS or CuS are used as deposits. Apparently, the difference in the deposition behavior among the inorganic sulfides CdS, PbS, ZnS, or CuS results in a large difference in the surface patterns of the microspheres.

Claims (3)

1. A method for preparing surface patterned sulfide polymer composite microspheres, characterized in that the preparation method comprises the following steps: (1) Preparation of mixed surfactant Mix Span-80 and Tween-80 in a 5:1 weight ratio to prepare a mixed surfactant; (2) Preparation of oil phase Add the prepared mixed surfactant into a three-necked flask filled with n-heptane, and mix the mixed surfactant and n-heptane at a weight ratio of 1:115 to 130 to form an oil phase; (3) emulsification Stir the oil phase prepared in (2) with a mixer at a temperature of 18-30°C at a stirring speed of 300-350 rpm, inject nitrogen gas, and emulsify for 1 hour to make an emulsion; (4) Preparation of water phase Dissolve 1.2g of N-isopropylacrylamide, namely NIPAM, and methacrylic acid, namely MAA, in 5mL of secondary water. The weight percentage of methacrylic acid in the mixed monomer is 5-30 %, then add 0.015~0.09g NaOH to neutralize methacrylic acid, then add 0.04~0.08g N,N'-methylenebisacrylamide, 80mg potassium persulfate and Cd(Ac) with a concentration of 0.3mol/L ₂ or Pb(Ac) ₂ or Zn(Ac) ₂ or Cu(Ac) ₂ solution 1.5mL, stir, mix well, filter, the total volume of the aqueous phase is 8-10mL; (5) Preparation of microgels containing Cd ²⁺ or Pb ²⁺ or Zn ²⁺ or Cu ²⁺ copolymers Quickly add the water phase to the emulsion, adjust the stirring speed to 500-600 rpm, add 0.5 mL of 50 mg/mL tetramethylethylenediamine after 5 minutes, and carry out the reaction for 2-4 hours to obtain P(NIPAM-co -MAA)/Cd ²⁺ or P(NIPAM-co-MAA)/Pb ²⁺ or P(NIPAM-co-MAA)/Zn ²⁺ or P(NIPAM-co-MAA)/Cu ²⁺ copolymer microgel ; (6) Preparation of P(NIPAM-co-MAA)/CdS or PbS or ZnS or CuS composite microspheres To (5) P(NIPAM-co-MAA)/Cd ²⁺ copolymer microgel, P(NIPAM-co-MAA)/Pb ²⁺ copolymer microgel, P(NIPAM-co-MAA)/Zn ^{2 +} copolymerized microgel and P(NIPAM-co-MAA)/Cu ²⁺ copolymerized microgel were slowly fed with H ₂ S gas for 0.5 hours, and then fed with N ₂ to remove excess H ₂ S gas, and passed through secondary water Alternately washed with acetone and dried naturally, yellow P(NIPAM-co-MAA)/CdS composite microspheres, brown-black P(NIPAM-co-MAA)/PbS composite microspheres, white P(NIPAM-co-MAA)/PbS composite microspheres, and white P(NIPAM-co-MAA)/CdS composite microspheres could be obtained. MAA)/ZnS composite microspheres, black P(NIPAM-co-MAA)/CuS composite microspheres. 2. According to the preparation method of surface patterned sulfide polymer composite microspheres according to claim 1, it is characterized in that: in (2) in the process step of preparing the oil phase, wherein the mixture of surfactant and n-heptane by 1: 120-125 weight ratio mixed to form an oil phase; in (3) the emulsification process step, wherein the emulsification temperature is 20-25 °C; in (4) the preparation of the water phase process step, wherein the methacrylic acid in the mixed monomer The weight percentage is 10-25%, wherein 0.02-0.08g NaOH is then added to neutralize methacrylic acid, and 0.05-0.06g N,N'-methylenebisacrylamide is added. 3. According to the preparation method of surface patterned sulfide polymer composite microspheres according to claim 1, it is characterized in that: in (2) in the process step of preparing the oil phase, wherein the mixture of surfactant and n-heptane by 1: A weight ratio of 122 is mixed to form an oil phase; in (3) the emulsification process step, wherein the emulsification temperature is 25°C; in (4) the preparation of the water phase process step, wherein the weight percent of methacrylic acid in the mixed monomer is 20%, in which 0.06g NaOH was then added to neutralize methacrylic acid, in which 0.06g N,N'-methylenebisacrylamide was added.

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