Detailed Description
The following is a clear and complete description of the conception and technical effects produced thereby to fully illustrate the objects, aspects, and effects of the present invention.
In a first aspect, the present invention provides a method for preparing a recyclable polyacrylate emulsion coating, the method comprising the steps of:
(a) Preparation of polyacrylate emulsion
Mixing the monomer A, the monomer B, an emulsifying agent and water to obtain a pre-emulsion;
mixing an initiator, sodium bicarbonate solution and the pre-emulsion, reacting at 75-85 ℃, then adding an amine cross-linking agent, and filtering to obtain polyacrylate emulsion;
(b) Preparation of polyacrylate emulsion coating
Volatilizing volatile substances in the polyacrylate emulsion at 80-120 ℃ to obtain a recyclable polyacrylate emulsion coating;
Wherein the monomer A contains at least one acrylic ester compound or acrylamide compound, and the monomer B is a compound shown in the following structural formula:
,
Wherein R 1 is selected from H, C C1-C4 alkyl groups, R 2 is selected from C1-C8 alkyl groups, and R 3 is selected from H, C C1-C3 alkyl groups.
The film forming reaction mechanism is as follows:
Introducing enamine-ketone dynamic bond into polyacrylate by polymerization of monomer B, and performing dynamic exchange reaction between amine cross-linking agent in emulsion and enamine-ketone dynamic bond on polyacrylate side chain at 80-120deg.C, volatilizing displaced molecular amine together with water, and finally forming cross-linked polyacrylate emulsion coating. The coating can be recycled under hot pressing at 100-180 ℃, and the cross-linked network structure and dynamic chemical bond of the coating enable the coating to have excellent shape memory function.
In some preferred embodiments, the monomer B may be obtained by reacting hydroxyethyl alkyl acrylate with propiolic acid to obtain 2- (propiolate) ethyl alkyl acrylate, and then reacting 2- (propiolate) ethyl alkyl acrylate with an amine compound; the amine compound is small molecular amine with the structure of。
In some preferred embodiments, the R 1 is selected from H, -CH 3、-CH2CH3、-C(CH3)3; said R 2 is selected from -CH2CH3、-C(CH3)3、-CH2CH2CH2CH3、-CH2(CH2)4CH3; and said R 3 is selected from H, -CH 3、-CH2CH3、-CH2CH2CH3.
In some preferred embodiments, the monomer a is at least one of methyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, ethyl acrylate, butyl acrylate, methylolacrylamide. More preferably, the monomer a is present in a molar ratio of 1 to 2:1-2 methyl methacrylate and butyl acrylate.
In some preferred embodiments, the emulsifier is at least one of OP-10, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, ammonium dodecyl polyoxyethylene ether sulfate, polyoxyethylene ether, fatty alcohol polyoxyethylene ether. More preferably, the emulsifier is OP-10 and sodium dodecyl sulfate.
In some preferred embodiments, the initiator is at least one of sodium persulfate, potassium persulfate, ammonium sulfate, ammonium persulfate, sodium bisulfite, azobisisobutyronitrile, benzoyl peroxide.
In some preferred embodiments, the sodium bicarbonate solution is a 5% solids sodium bicarbonate solution.
In some preferred embodiments, the polyacrylate emulsion comprises the following components in weight percent: 10% -60% of monomer A, 3% -10% of monomer B, 4% -11% of amine cross-linking agent, 1% -4% of emulsifying agent, 0.5% -1% of initiator, 1% -5% of sodium bicarbonate solution and the balance of water.
In some preferred embodiments, the amine crosslinker is m-xylylenediamine, 4-diaminodicyclohexylmethane, or a compound represented by one of the following structural formulas:
,
Wherein n is greater than or equal to 1, R 4 is selected from H and-CH 3、-CH2CH3、-C(CH3)3,R5 is selected from H and-CH 3、-CH2CH3、-C(CH3)3.
In some more preferred embodiments, the amine cross-linking agent is m-xylylenediamine.
In some preferred embodiments, the polyacrylate emulsion is poured into a polytetrafluoroethylene mold or sprayed to form a coating, and the coating is placed in an oven at 80-120 ℃ to volatilize volatile components such as moisture and molecular amine.
In a second aspect, the present invention provides a recyclable polyacrylate emulsion coating resulting from a method of making the recyclable polyacrylate emulsion coating.
In a third aspect, the present invention provides the use of the recyclable polyacrylate emulsion coating in a water repellent material or shape memory material.
Some exemplary embodiments are described below.
In the following examples, the preparation scheme for monomer B is as follows:
the specific operation can be as follows: hydroxyethyl methacrylate (13.01 g, 100 mmol), p-toluenesulfonic acid (8.61 g, 100 mmol) and propiolic acid (7 g, 100 mmol) were added to a 250 mL round bottom flask, and then 30 mL chloroform was added to dissolve; after reacting for 18 hours at 60 ℃, washing the mixture for 2-3 times by deionized water and saturated sodium bicarbonate, drying the organic phase, and evaporating the organic phase to obtain a first-step product of ethyl 2- (propiolate) methacrylate; then, ethyl 2- (propiolate) methacrylate (9.11 g, 50 mmol) and diethylamine (3.66 g, 50 mmol) were dissolved with 20 mL dichloromethane respectively, and the diethylamine solution was added dropwise to the ethyl 2- (propiolate) methacrylate solution by means of dropwise addition, and after reacting for 18 hours, the dichloromethane was removed by rotary evaporation to obtain monomer B.
Example 1
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
204.96 mmol methyl methacrylate, 409.92 mmol butyl acrylate (the ratio of methyl methacrylate to butyl acrylate is 1:2), 19.01 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250 r/min for 30min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting for 10-15min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3 mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; centrifuging the prepared emulsion at 4000 r/min for 15: 15min, and observing the change of the emulsion;
The obtained polypropylene emulsion was placed in a polytetrafluoroethylene mold, and the water was volatilized at 100 ℃ to obtain a coating 1.
After the coating 1 was sheared by scissors, the recovered sample was obtained by hot-pressing 1: 1h at 150℃and 10 MPa.
Example 2
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
245.95 mmol methyl methacrylate, 368.93 mmol butyl acrylate (ratio of methyl methacrylate to butyl acrylate is 1:1.5), 19.01 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250 r/min for 30 min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
Adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting 10-15 min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; centrifuging the prepared emulsion at 4000 r/min for 15: 15 min, and observing the change of the emulsion;
The obtained polypropylene emulsion is placed in a polytetrafluoroethylene mould, and the moisture is volatilized at 100 ℃ to obtain a coating 2.
After the coating 2 is sheared by scissors, the recovered sample is obtained by hot pressing for 1h at 150 ℃ and 10 MPa ℃.
Example 3
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
307.44 mmol methyl methacrylate, 307.44 mmol butyl acrylate (ratio of methyl methacrylate to butyl acrylate is 1:1), 19.01 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250 r/min for 30min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting 10-15 min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; the emulsion prepared was centrifuged at 4000 r/min for 15: 15 min and the emulsion was observed for changes.
The obtained polypropylene emulsion is placed in a polytetrafluoroethylene mould, and the moisture is volatilized at 100 ℃ to obtain a coating 3.
The coating 3 was crushed by scissors and hot-pressed at 150℃and 10 MPa for 1 hour to obtain a recovered sample.
Example 4
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
368.93 mmol methyl methacrylate, 245.95 mmol butyl acrylate (the ratio of methyl methacrylate to butyl acrylate is 1.5:1), 19.01 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250r/min for 30 min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
Adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting 10-15 min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; centrifuging the prepared emulsion at 4000 r/min for 15: 15 min, and observing the change of the emulsion;
the obtained polypropylene emulsion was placed in a polytetrafluoroethylene mold, and the water was volatilized at 100 ℃ to obtain a coating layer 4.
After the coating 4 was sheared by scissors, the recovered sample was obtained by hot-pressing at 150℃and 10 MPa under heat and pressure of 1:1 h.
Example 5
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
409.92mmol of methyl methacrylate, 204.96 mmol butyl acrylate (the ratio of methyl methacrylate to butyl acrylate is 2:1), 19.01 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250 r/min for 30 min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
Adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting 10-15 min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; centrifuging the prepared emulsion at 4000 r/min for 15: 15 min, and observing the change of the emulsion;
The obtained polypropylene emulsion is placed in a polytetrafluoroethylene mould, and the moisture is volatilized at 100 ℃ to obtain a coating 5.
The coating 5 was crushed by scissors and hot-pressed at 150℃and 10 MPa for 1 hour to obtain a recovered sample.
Example 6
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
297.93 mmol methyl methacrylate, 297.93 mmol butyl acrylate, 38.03 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250 r/min for 30 min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
Adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting 10-15 min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; centrifuging the prepared emulsion at 4000 r/min for 15: 15 min, and observing the change of the emulsion;
The obtained polypropylene emulsion was placed in a polytetrafluoroethylene mold, and the water was volatilized at 100 ℃ to obtain a coating 6.
After the coating 6 is sheared by scissors, the recovered sample is obtained by hot pressing for 1h at 150 ℃ and 10 MPa ℃.
Example 7
The recyclable polyacrylate emulsion coating is prepared according to the following steps:
288.42 mmol methyl methacrylate, 288.42 mmol butyl acrylate, 57.05 mmol monomer B, deionized water, 2.1 g emulsifier OP-10 and 2.1 g sodium dodecyl sulfate are added into a round bottom flask, and stirred at 250 r/min for 30 min to obtain a pre-emulsion;
Dissolving 0.6 g potassium persulfate in 30 mL deionized water to obtain a potassium persulfate solution; dissolving 0.5g sodium bicarbonate in 10 mL deionized water to obtain sodium bicarbonate solution;
Adding 20 mL of pre-emulsion into a three-neck round bottom flask, heating to 80 ℃, adding 6 mL of potassium persulfate solution and 10mL of sodium bicarbonate solution, and reacting 10-15 min (emulsion bluing); adding the rest pre-emulsion and the initiator solution, and finishing the addition in a period of 2 h; finally, adding 3mL of initiator solution, then reacting 2 h, cooling to room temperature, and adding m-xylylenediamine to obtain polypropylene emulsion; centrifuging the prepared emulsion at 4000 r/min for 15: 15 min, and observing the change of the emulsion;
The obtained polypropylene emulsion was placed in a polytetrafluoroethylene mold, and the water was volatilized at 100℃to obtain a coating 7.
The coating 7 was crushed by scissors and hot-pressed at 150℃and 10 MPa for 1 hour to obtain a recovered sample.
FIG. 1 shows photographs of the polyacrylic emulsion prepared in example 1 and photographs after centrifugation 15 min. As can be seen from FIG. 1, the prepared polyacrylate emulsion has no obvious precipitation after being centrifuged at 4000 r/min for 15: 15min, which indicates that the prepared polyacrylate emulsion has good stability.
Fig. 2 shows stress-strain curves of the acrylic emulsion coatings prepared in examples 1 to 5. The Young's modulus of the coatings of examples 1-5 increased with increasing ratio of methyl methacrylate to butyl acrylate in monomer A, with increasing and decreasing tensile break length, indicating that increasing the methyl methacrylate content of the monomer increases the stiffness of the polymer when methyl methacrylate and butyl acrylate are 1:1, the coating exhibits the best flexibility. It can be seen that by adjusting the hard and soft acrylic monomers, a coating material of suitable flexibility can be obtained.
Fig. 3 shows stress-strain curves of the polyolefin emulsion coatings prepared in examples 3, 6 and 7. Examples 3, 6 and 7 increased the amount of monomer B, which resulted in an increase in the young's modulus of the coating, with a subsequent decrease in elongation at break, indicating that the coating was most flexible at 6% of monomer B. It can be seen that varying the monomer B content can adjust the mechanical properties of the material.
FIG. 4 is a schematic view of hot press recovery of the acrylic emulsion-prepared coating prepared in example 6. As can be seen from fig. 4, the coating appearance before and after recovery was unchanged.
Fig. 5 shows stress-strain curves of three recoveries of the acrylic emulsion preparation coating prepared in example 6. As can be seen from FIG. 5, the mechanical properties of the prepared coating before and after recovery are not greatly changed, which indicates that the material has excellent recoverable function.
FIG. 6 shows the shape memory performance test curves of the acrylic emulsion prepared in example 6. As can be seen in fig. 6, 55 s is required for the coating to recover from the zero-time shape to the original shape at 70 ℃.
The shape memory performance of the coating was tested in a tensile mode using a DMA Q800 dynamic mechanical analyzer, with a controlled load of 0.2N, a cycling temperature of 20-120 ℃, and a test of 4 cycles, with the shape retention and shape recovery of the 2 nd cycle evaluating the shape memory performance. FIG. 7 is a graph showing the shape memory cycle of the coating layer prepared from the acrylic emulsion prepared in example 6 of the present invention. As can be seen from fig. 7, the shape fixation rate is 88% and the shape recovery rate is 91%, which indicates that the coating material prepared according to the present invention has good shape memory properties.
The present invention is not limited to the above embodiments, but is merely preferred embodiments of the present invention, and the present invention should be considered as being within the scope of the present invention as long as the technical effects of the present invention are achieved by the same or equivalent means. Various modifications and variations are possible in the technical solution and/or in the embodiments within the scope of the invention.