Method for modifying oyster shells based on ultrasonic-assisted surfactant and application of method

Abstract

A method for modifying oyster shells based on an ultrasonic-assisted surfactant comprises the following steps that 1, clean and dry oyster shells are smashed and sieved, and oyster shell powder with the average particle size being 10-20 microns is obtained; step 2, dispersing the oyster shell powder in distilled water, performing ultrasonic treatment for 25-35 minutes to break aggregates and increase the specific surface area, then adding a surfactant with the mass fraction of 1.5-2.5%, and continuing ultrasonic treatment for 30 minutes to enable the surfactant to be uniformly adsorbed on the surface of the oyster shell powder; step 3, filtering the oyster shell powder obtained in the step 2, washing to remove the unadsorbed surfactant, and drying to obtain modified oyster shell powder; according to the invention, the surfactant is added to cooperate with ultrasonic treatment, and the cavitation effect of ultrasonic waves is utilized, so that the surfactant is uniformly adsorbed on the surface of the oyster shell powder, and the compatibility of the surfactant and the ethylene propylene diene monomer is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oyster shell modification, and particularly relates to a method for modifying oyster shells by ultrasonic-assisted surfactant and its application. Background Art

[0002] Modified calcium carbonate, also known as active calcium carbonate, is a widely used filler. Its main characteristics are that the particle size is less than 0.1 μm, the particle size is relatively uniform, the specific surface area is large, and its application performance is much better than that of ordinary calcium carbonate. When modified calcium carbonate is used as a rubber supplement and added to rubber products, its mechanical properties are significantly improved. For example, the tear strength can be increased by more than one time, and the flexing times can be increased by 5 - 6 times. Therefore, active calcium carbonate is both a filler and a reinforcing agent for rubber. In China, the rubber industry is the largest user of calcium carbonate, with an annual consumption of more than half of the total amount of calcium carbonate.

[0003] In recent years, the oyster farming area has been expanding year by year in the coastal areas of China. Most oyster shells are collected and landfilled as garbage or abandoned on the beach. The abandoned oyster shells not only occupy a large amount of land area but also easily breed and spread germs, bringing many adverse effects to the environment. Oyster shell is a natural biological layered nanocomposite material, in which the content of calcium carbonate accounts for 80% - 95%, and the rest are organic components such as proteins and chitosan.

[0004] Therefore, making full use of the abandoned oyster shells, turning waste into treasure, and using them as rubber fillers to increase the added value of oyster shells are technical problems that need to be urgently solved by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for modifying oyster shells by ultrasonic-assisted surfactant and its application

[0006] The present invention adopts the following technical scheme:

[0007] A method for modifying oyster shells by ultrasonic-assisted surfactant, comprising the following steps:

[0008] Step 1: Crush the clean and dry oyster shells and sieve them to obtain oyster shell powder with an average particle size of 10 - 20 μm;

[0009] Step 2: Disperse the oyster shell powder in distilled water, and use ultrasonic treatment for 25 - 35 min to break the aggregates and increase the specific surface area. Then add a surfactant with a mass fraction of 1.5 - 2.5%, and continue ultrasonic treatment for 30 min to make the surfactant uniformly adsorbed on the surface of the oyster shell powder;

[0010] Step 3: Filter and wash the oyster shell powder obtained in Step 2 to remove the unadsorbed surfactant, and dry it to obtain modified oyster shell powder;

[0011] Among them, the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate in a mass ratio of 1:0.56 - 0.72.

[0012] Furthermore, in step 2, the frequency of ultrasonic treatment is 20 - 40 kHz, and the power is 450 - 600 W.

[0013] Furthermore, step 1 specifically includes: crushing the clean and dry oyster shells, sieving to obtain oyster shell powder with an average particle size of 10 - 20 μm, then placing the obtained oyster shell powder in a treatment solution at 50 - 60 °C, soaking for 1 - 2 h, and then filtering and drying.

[0014] Furthermore, the treatment solution is composed of acetic acid, ammonium persulfate, propylene glycol alginate, tea polyphenols, and water. Among them, the mass concentration of acetic acid is 25 - 35%, the mass concentration of ammonium persulfate is 6 - 10%, the addition amount of propylene glycol alginate is 20 - 30 g / L, and the addition amount of tea polyphenols is 10 - 15 g / L.

[0015] Furthermore, in step 3, the drying temperature of the washed oyster shell powder is 120 - 150 °C, and the drying time is 25 - 35 min.

[0016] An application of modified oyster shell powder in the preparation of ethylene propylene diene monomer (EPDM) rubber, wherein the modified oyster shell powder is prepared by the method described in any one of the above.

[0017] Furthermore, the modified oyster shell powder is used as a filler, and its added mass ratio with ethylene propylene diene monomer (EPDM) rubber is 100:20 - 40.

[0018] As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are as follows: This application specifically defines the modification method of oyster shells. First, ultrasonic treatment is performed on the oyster shell powder to break the aggregates and increase the specific surface area of the oyster shell powder. Then, a surfactant is added in combination with ultrasonic treatment. Utilizing the cavitation effect of ultrasonic waves, the surfactant is evenly adsorbed on the surface of the oyster shell powder, increasing its compatibility with ethylene propylene diene monomer (EPDM) rubber. Moreover, it is further defined that the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate, and under the premise of meeting environmental protection requirements, it is evenly adsorbed on the surface of the oyster shell powder;

[0019] Before ultrasonic treatment, oyster shell powder is first soaked in a treatment solution for a period of time. Ammonium persulfate and acetic acid are introduced into the treatment solution to remove surface impurities of the oyster shell powder. Tea polyphenols and propylene glycol alginate are introduced to improve the hydrophobicity of the oyster shell powder surface. In combination with subsequent surfactant treatment, the wettability and binding force between materials are improved, the surface adhesion of the prepared oyster powder is significantly increased, and then the binding force with rubber is improved, thereby improving the performance of the prepared modified oyster shell powder, increasing its filling amount in ethylene propylene diene monomer (EPDM) rubber, and enabling the filling amount to be increased to 40%. Detailed implementation mode

[0020] The present invention will be further described below through specific implementation modes.

[0021] A method for modifying oyster shells assisted by ultrasonic waves and surfactants includes the following steps:

[0022] Step 1: Crush clean and dry oyster shells and sieve them to obtain oyster shell powder with an average particle size of 10 - 20 μm. Then place the obtained oyster shell powder in a treatment solution at 50 - 60 °C, soak it for 1 - 2 h, and then filter and dry it.

[0023] Step 2: Disperse the oyster shell powder in distilled water and use ultrasonic waves to treat it for 25 - 35 min to break up aggregates and increase the specific surface area. Then add a surfactant with a mass fraction of 1.5 - 2.5% and continue ultrasonic treatment for 30 min to make the surfactant evenly adsorbed on the surface of the oyster shell powder. Among them, the frequency of ultrasonic treatment is 20 - 40 kHz and the power is 450 - 600 W.

[0024] Step 3: Filter and wash the oyster shell powder obtained in Step 2 to remove the unadsorbed surfactant, and then dry it to obtain modified oyster shell powder.

[0025] Among them, in Step 1, the treatment solution is composed of acetic acid, ammonium persulfate, propylene glycol alginate, tea polyphenols, and water. Among them, the mass concentration of acetic acid is 25 - 35%, the mass concentration of ammonium persulfate is 6 - 10%, the addition amount of propylene glycol alginate is 20 - 30 g / L, and the addition amount of tea polyphenols is 10 - 15 g / L.

[0026] In Step 2, the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate in a mass ratio of 1:0.56 - 0.72.

[0027] In Step 3, the drying temperature of the washed oyster shell powder is 120 - 150 °C and the drying time is 25 - 35 min.

[0028] Application of modified oyster shell powder in preparation of ethylene propylene diene monomer rubber. The modified oyster shell powder is prepared by the above method and used as a filling material in the preparation of ethylene propylene diene monomer rubber. The added mass ratio of the modified oyster shell powder to ethylene propylene diene monomer rubber is 100:20 - 40.

[0029] When preparing vulcanized ethylene propylene diene monomer rubber based on the modified oyster shell powder, first mix ethylene propylene diene monomer rubber and oyster shell powder on an open mill. The mixing temperature is 50 °C and the mixing time is 10 min. Then add a vulcanizing agent accounting for 2% of the rubber mass, mix evenly and send it into a mold for vulcanization. The vulcanization temperature is 160 °C and the vulcanization time is 15 min.

[0030] Example 1

[0031] A method for modifying oyster shells assisted by ultrasonic waves with surfactants, comprising the following steps:

[0032] Step 1: Crush clean and dry oyster shells and sieve to obtain oyster shell powder with an average particle size of 10 - 20 μm. Then place the obtained oyster shell powder in a treatment solution at 50 °C, soak for 2 h, filter and dry.

[0033] Step 2: Disperse the oyster shell powder in distilled water, treat with ultrasonic waves for 25 min to break up aggregates and increase the specific surface area. Then add a surfactant with a mass fraction of 1.5%, and continue ultrasonic treatment for 30 min to make the surfactant evenly adsorbed on the surface of the oyster shell powder. The frequency of ultrasonic treatment is 20 kHz and the power is 600 W.

[0034] Step 3: Filter and wash the oyster shell powder obtained in Step 2 to remove the unadsorbed surfactant, and dry to obtain the modified oyster shell powder.

[0035] Among them, in Step 1, the treatment solution is composed of acetic acid, ammonium persulfate, propylene glycol alginate, tea polyphenols and water. The mass concentration of acetic acid is 25%, the mass concentration of ammonium persulfate is 10%, the addition amount of propylene glycol alginate is 20 g / L, and the addition amount of tea polyphenols is 15 g / L.

[0036] In Step 2, the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate in a mass ratio of 1:0.56.

[0037] In Step 3, the drying temperature of the washed oyster shell powder is 120 °C and the drying time is 35 min.

[0038] Application of modified oyster shell powder in preparation of ethylene propylene diene monomer rubber. The modified oyster shell powder is prepared by the above method and used as a filling material in the preparation of ethylene propylene diene monomer rubber. The added mass ratio of the modified oyster shell powder to ethylene propylene diene monomer rubber is 100:20.

[0039] When preparing sulfurized ethylene propylene diene monomer (EPDM) rubber based on modified oyster shell powder, first mix the EPDM rubber and oyster shell powder on an open mill. The mixing temperature is 50 °C and the mixing time is 10 min. Then add a vulcanizing agent accounting for 2% of the rubber mass, mix well and send it into a mold for vulcanization. The vulcanization temperature is 160 °C and the vulcanization time is 15 min.

[0040] Example 2

[0041] A method for modifying oyster shells assisted by ultrasonic waves with surfactants, comprising the following steps:

[0042] Step 1: Crush the clean and dry oyster shells and sieve them to obtain oyster shell powder with an average particle size of 10 - 20 μm. Then place the obtained oyster shell powder in a treatment solution at 60 °C, soak it for 1 h, filter and dry it.

[0043] Step 2: Disperse the oyster shell powder in distilled water and treat it with ultrasonic waves for 35 min to break up the aggregates and increase the specific surface area. Then add a surfactant with a mass fraction of 2.5% and continue to treat it with ultrasonic waves for 30 min to make the surfactant evenly adsorbed on the surface of the oyster shell powder. Among them, the frequency of the ultrasonic treatment is 40 kHz and the power is 450 W.

[0044] Step 3: Filter and wash the oyster shell powder obtained in Step 2 to remove the unadsorbed surfactant, and dry it to obtain the modified oyster shell powder.

[0045] Among them, in Step 1, the treatment solution is composed of acetic acid, ammonium persulfate, propylene glycol alginate, tea polyphenols and water. Among them, the mass concentration of acetic acid is 35%, the mass concentration of ammonium persulfate is 6%, the addition amount of propylene glycol alginate is 30 g / L, and the addition amount of tea polyphenols is 10 g / L.

[0046] In Step 2, the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate in a mass ratio of 1:0.72.

[0047] In Step 3, the drying temperature of the washed oyster shell powder is 150 °C and the drying time is 25 min.

[0048] An application of modified oyster shell powder in the preparation of ethylene propylene diene monomer (EPDM) rubber, wherein the modified oyster shell powder is prepared by the above method and is used as a filler in the preparation of EPDM rubber, and the added mass ratio of it to EPDM rubber is 100:30.

[0049] When preparing vulcanized ethylene propylene diene monomer (EPDM) rubber based on modified oyster shell powder, first mix the EPDM rubber and oyster shell powder on an open mill at a mixing temperature of 50 °C for 10 min; then add a vulcanizing agent accounting for 2% of the rubber mass, mix well and send it into a mold for vulcanization at a vulcanization temperature of 160 °C for 15 min.

[0050] Example 3

[0051] A method for modifying oyster shells assisted by ultrasonic waves with surfactants includes the following steps:

[0052] Step 1: Crush the clean and dry oyster shells and sieve them to obtain oyster shell powder with an average particle size of 10 - 20 μm. Then place the obtained oyster shell powder in a treatment solution at 55 °C, soak it for 1.5 h, filter and dry it.

[0053] Step 2: Disperse the oyster shell powder in distilled water, use ultrasonic waves to treat it for 30 min to break up the aggregates and increase the specific surface area. Then add a surfactant with a mass fraction of 2%, and continue ultrasonic treatment for 30 min to make the surfactant evenly adsorbed on the surface of the oyster shell powder. Among them, the frequency of ultrasonic treatment is 30 kHz and the power is 550 W.

[0054] Step 3: Filter and wash the oyster shell powder obtained in Step 2 to remove the unadsorbed surfactant, and dry it to obtain modified oyster shell powder.

[0055] Among them, in Step 1, the treatment solution consists of acetic acid, ammonium persulfate, propylene glycol alginate, tea polyphenols and water. Among them, the mass concentration of acetic acid is 30%, the mass concentration of ammonium persulfate is 8%, the addition amount of propylene glycol alginate is 25 g / L, and the addition amount of tea polyphenols is 12 g / L.

[0056] In Step 2, the surfactant consists of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate in a mass ratio of 1:0.65.

[0057] In Step 3, the drying temperature of the washed oyster shell powder is 135 °C and the drying time is 30 min.

[0058] An application of modified oyster shell powder in the preparation of EPDM rubber, wherein the modified oyster shell powder is prepared by the above method and is used as a filler in the preparation of EPDM rubber, and the added mass ratio of it to EPDM rubber is 100:40.

[0059] When preparing vulcanized EPDM rubber based on modified oyster shell powder, first mix the EPDM rubber and oyster shell powder on an open mill at a mixing temperature of 50 °C for 10 min; then add a vulcanizing agent accounting for 2% of the rubber mass, mix well and send it into a mold for vulcanization at a vulcanization temperature of 160 °C for 15 min.

[0060] Comparative Example 1

[0061] No modified oyster shell powder was added, and ethylene propylene diene monomer (EPDM) rubber was vulcanized with a vulcanizing agent to prepare vulcanized EPDM rubber.

[0062] Comparative Example 2

[0063] Its preparation method was basically the same as that of Example 3, and the differences were as follows: Step 1 included: crushing the clean and dry oyster shells and sieving to obtain oyster shell powder with an average particle size of 10 - 20 μm; the oyster shell powder was not soaked with the treatment liquid.

[0064] Comparative Example 3

[0065] Its preparation method was basically the same as that of Example 3, and the differences were as follows: Steps 2 and 3 were not included, and the oyster shell powder after being soaked with the treatment liquid was filtered and dried for use as modified oyster shell powder.

[0066] Comparative Example 4

[0067] Its preparation method was basically the same as that of Example 3, and the difference was that the surfactant was titanate coupling agent.

[0068] Comparative Example 5

[0069] The oyster shell powder was not modified and was directly added to the EPDM rubber for use after being crushed and sieved.

[0070] Comparative Example 6

[0071] Its preparation method was basically the same as that of Example 3, and the difference was that the surfactant was fatty acid methyl ester ethoxylate.

[0072] Comparative Example 7

[0073] Its preparation method was basically the same as that of Example 3, and the difference was that the surfactant was fatty acid methyl ester sulfonate.

[0074] The vulcanized EPDM rubbers prepared in Examples 1 - 3 and Comparative Examples 1 - 6 were subjected to performance tests, and the following data were obtained. For details, see Table 1. Among them, the tensile strength and elongation at break were tested according to the standard of GB / T 528 - 2009; the tear strength was tested according to the standard of GB / T 529 - 2008; the hardness was tested according to the standard of GB / T 531.1 - 2008; the EPDM rubber added in the examples and comparative examples included, by mass percentage: 65% ethylene, 33% propylene, and 2% dicyclopentadiene.

[0075] Table 1 Performance Detection Data Table

[0076]

[0077]

[0078] As can be seen from the above table, through the comparison of Examples 1 to 3, it can be seen that with the optimization of the surfactant dosage and treatment conditions, the performance of the modified oyster shell powder filled with ethylene propylene diene monomer (EPDM) rubber is gradually improved. Among them, Example 3 shows the best performance in terms of tensile strength, tear strength and hardness, indicating that this combination of conditions (including a surfactant mass fraction of 2%, a mass ratio of 1:0.65, an ultrasonic treatment power of 550 W, a frequency of 30 kHz, and a time of 30 min) is the preferred modification condition of the present invention. The present invention recommends using the treatment parameters described in Example 3 as the best implementation method for modifying oyster shell powder. The vulcanized EPDM rubber prepared with the modified oyster shell powder prepared by this application has good tensile strength and tear strength, and the elongation at break decreases slightly, but still maintains good elasticity.

[0079] In summary, this application specifically defines the modification method of oyster shells. First, ultrasonic treatment is carried out on oyster shell powder to break up the aggregates and increase the specific surface area of oyster shell powder. Then, a surfactant is added and combined with ultrasonic treatment. Utilizing the cavitation effect of ultrasonic waves, the surfactant is evenly adsorbed on the surface of oyster shell powder, increasing its compatibility with EPDM rubber. Furthermore, it is specifically defined that the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate, and is evenly adsorbed on the surface of oyster shell powder on the premise of meeting environmental protection requirements.

[0080] Before ultrasonic treatment, oyster shell powder is first soaked in a treatment solution for a period of time. Ammonium persulfate and acetic acid are introduced into the treatment solution to remove surface impurities of oyster shell powder. Tea polyphenols and propylene glycol alginate are introduced to improve the hydrophobicity of the surface of oyster shell powder. Combined with subsequent surfactant treatment, the wettability and binding force between materials are improved, the surface adhesion of the prepared oyster powder is significantly increased, and then the binding force with rubber is improved, thereby improving the performance of the prepared modified oyster shell powder, increasing its filling amount in EPDM rubber, and enabling the filling amount to be increased to 40%.

[0081] The above is only a preferred embodiment of the present invention, and thus cannot be used to limit the scope of implementation of the present invention. That is, equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the specification should still fall within the scope covered by the patent of the present invention.

Claims

1. A method for modifying oyster shells based on ultrasonic-assisted surfactant, characterized in that: It includes the following steps: Step 1: Crush the clean and dry oyster shells, and sieve them to obtain oyster shell powder with an average particle size of 10 - 20 μm; Step 2: Disperse the oyster shell powder in distilled water, and treat it with ultrasonic waves for 25 - 35 min to break the aggregates and increase the specific surface area. Then add a surfactant with a mass fraction of 1.5 - 2.5%, and continue ultrasonic treatment for 30 min to make the surfactant evenly adsorbed on the surface of the oyster shell powder; Step 3: Filter and wash the oyster shell powder obtained in Step 2 to remove the unadsorbed surfactant, and dry it to obtain modified oyster shell powder; Among them, the surfactant is composed of fatty acid methyl ester ethoxylate and fatty acid methyl ester sulfonate in a mass ratio of 1:0.56 - 0.

72.

2. The method for modifying oyster shells based on ultrasonic-assisted surfactant according to claim 1, wherein: In Step 2, the frequency of ultrasonic treatment is 20 - 40 kHz, and the power is 450 - 600 W.

3. A method for modifying oyster shells based on ultrasonic-assisted surfactant according to claim 1, characterized in that: Step 1 specifically includes: Crush the clean and dry oyster shells, and sieve them to obtain oyster shell powder with an average particle size of 10 - 20 μm. Then place the obtained oyster shell powder in a treatment solution at 50 - 60 °C, soak it for 1 - 2 h, and then filter and dry it.

4. A method for modifying oyster shells based on ultrasonic-assisted surfactant according to claim 3, characterized in that: The treatment solution is composed of acetic acid, ammonium persulfate, propylene glycol alginate, tea polyphenols, and water. Among them, the mass concentration of acetic acid is 25 - 35%, the mass concentration of ammonium persulfate is 6 - 10%, the addition amount of propylene glycol alginate is 20 - 30 g / L, and the addition amount of tea polyphenols is 10 - 15 g / L.

5. A method for modifying oyster shells based on ultrasonic-assisted surfactant according to claim 1, characterized in that: In Step 3, the drying temperature of the washed oyster shell powder is 120 - 150 °C, and the drying time is 25 - 35 min.

6. Application of modified oyster shell powder in the preparation of ethylene propylene diene monomer rubber, characterized in that: The said modified oyster shell powder is prepared by the method described in Claim 1.

7. Use of a modified oyster shell powder in the preparation of ethylene-propylene-diene monomer rubber according to claim 6, characterized in that: The said modified oyster shell powder is used as a filling material, and its added mass ratio with ethylene propylene diene monomer rubber is 100:20 - 40.

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