CN115746233A - Modified graphene-enhanced repairable multifunctional asparagus polyurea elastomer composite material and preparation method thereof - Google Patents
Modified graphene-enhanced repairable multifunctional asparagus polyurea elastomer composite material and preparation method thereof Download PDFInfo
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Abstract
A modified graphene enhanced repairable multifunctional asparagus polyurea elastomer composite material and a preparation method thereof belong to the technical field of repairable elastomer materials. The composite material is prepared by mixing and reacting graphene solution with isocyanate to obtain isocyanate modified graphene, mixing and reacting the isocyanate with amino-terminated polyether, reacting with the isocyanate modified graphene to obtain prepolymer, and mixing and stirring the prepolymer and polyaspartic acid ester resin for reaction. The composite material takes isocyanate modified graphene as a reinforcing phase, and the obtained repairable multifunctional asparagus polyurea elastomer composite material has high-efficiency repairing performance and multiple performances such as impact resistance, electric conduction and heat conduction.
Description
Technical Field
The invention relates to the technical field of repairable elastomer materials, in particular to a modified graphene reinforced repairable multifunctional asparagus polyurea elastomer composite material and a preparation method thereof.
Background
In recent years, the advent of repairable elastomeric materials has attracted a great deal of attention from the industry and academia, as they can recover spontaneously from microcracks or damage during long-term use, which provides an effective means for extending the life cycle of polymer coatings, and is of profound significance in the fields of aerospace, automotive, flexible electronics, construction, and the like. The repairable elastomer material can be classified into an exo-type and an intrinsic type according to the different repairing mechanisms. The externally-applied repairable material is prepared by embedding microcapsules, liquid core fibers or capillary networks carrying the repairable agent in a polymer matrix, wherein when the polymer material is damaged, the microcapsules, the liquid core fibers or the capillary networks are broken to flow out of the repairable agent, and the repairable agent enters cracks and is solidified to repair the polymer material. Therefore, the repair frequency of the externally-applied repairable material is less, and the repair carrier is affected by the crack trend to influence the repair efficiency of the material. The intrinsic type repairable material is that the polymer material is repaired through one or more reversible dynamic chemical bonds in the polymer, and when the material is cracked or damaged, the dynamic bonds are subjected to reversible reaction to realize self-repair under the condition of external stimulation (such as heat, light, electricity, solvent and the like) or no external stimulation. Due to the capability of intrinsic type repairable materials to be repeatedly repaired, the main stream of the field of repairable materials is provided.
The polyurea is composed of isocyanate component (-NCO) and amino component (-NH) 2 ) The polymerization gives elastomeric polymers of urea groups whose molecular chains are composed of soft and hard segments. The glass transition temperature of the soft segment is lower than room temperature, mainly comprises long carbon chain, polyether, polyester and other flexible chain segments, and is easy to change conformation; and the hard section is mainly isocyanate, a chain extender, a cross-linking agent and the like, has higher glass transition temperature and is stiffer, and endows polyurea/polyurethane with higher modulus and strength. Due to the thermodynamic incompatibility between the soft and hard segments and the strong hydrogen bonding between the hard segments, the polyurea/polyurethane structure internally presents a unique morphology of microphase separation. The special microscopic morphology and the numerous urea bonds/carbamate bonds and hydrogen bonds existing on the molecular chain make the molecular chain have the potential of being a repairable material. Although the introduction of the dynamic reversible bond enables the polymer to have repairability, a great gap is still left in the aspect of improving the performance of repairable materials or enabling the repairable materials to have multiple functions. In many scenarios where polymeric materials are required to have healing properties, it is not possible to use the repairable materials due to their lack of versatility.
Graphene, as a two-dimensional nanocarbon material, is often used as a reinforcing phase of a multifunctional polymer nanocomposite due to its very excellent mechanical properties, as well as thermal and electrical conductivity. However, the addition of graphene often limits the repair of dynamic reversible bonds of self-repairing materials and the fluidity of molecular chains to hinder crack closure and healing processes. Therefore, the key point for preparing the multifunctional self-repairing graphene/polyurea elastomer composite material is how to ensure the dispersibility of graphene in a polyurea matrix and form a good interface effect by utilizing the interaction of the high specific surface area of the graphene and the polyurea matrix.
Disclosure of Invention
Based on the problems faced by the application fields, the invention provides a modified graphene reinforced repairable multifunctional asparagus polyurea elastomer composite material and a preparation method thereof, wherein isocyanate modified graphene is used as a reinforcing phase, and the obtained repairable multifunctional asparagus polyurea elastomer composite material has high-efficiency repairing performance and multiple performances such as impact resistance, electric conduction and heat conduction.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the modified graphene reinforced repairable multifunctional asparagus polyurea elastomer composite material has repairable performance, wherein the tensile strength is 7.69-12.58 Mpa, the elongation at break is 375.15-402.51%, the repairable tensile strength is 5.97-10.15 Mpa, the repairable elongation at break is 319.67-358.64%, the electric conductivity is 7.46E-15-2.35E-4S/cm, the heat conductivity coefficient is 0.12-28.49W/m.K, and the impact strength is 41.35-64.73 KJ/m 2 。
The modified graphene reinforced repairable multifunctional aspartyl polyurea elastomer composite material is prepared by mixing and reacting a graphene solution with isocyanate to obtain isocyanate modified graphene, mixing and reacting the isocyanate with amino-terminated polyether, reacting with the isocyanate modified graphene to obtain a prepolymer, and mixing and stirring the prepolymer and polyaspartic ester resin for reaction.
The invention discloses a preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material, which comprises the following steps:
s1: preparation of isocyanate modified graphene
(1) Carrying out ultrasonic dispersion on few-layer graphene in a solvent to obtain a graphene solution;
(2) Reacting the graphene solution with isocyanate at 75-95 ℃ for 12-30 h to obtain a reaction solution; according to the mass ratio, graphene: isocyanate =1: (5-25).
(3) Carrying out solid-liquid separation on the reaction solution, washing and drying a solid product to obtain isocyanate modified graphene;
s2: preparation of modified graphene-enhanced repairable multifunctional asparagus polyurea elastomer composite material
(1) Placing isocyanate modified graphene in an organic solvent, and performing ultrasonic dispersion to obtain a uniformly dispersed isocyanate modified graphene solution;
(2) Under the nitrogen environment, uniformly mixing isocyanate and amino-terminated polyether, controlling the temperature at 10 +/-5 ℃ and the stirring speed at 10-50 rpm in the mixing process, stirring and reacting for 20-40 min after mixing is finished, and then heating to 80-90 ℃ and stirring and reacting for 20-40 min at 120-300 rpm to obtain a mixture;
wherein, according to the mass ratio, the amino-terminated polyether: isocyanate = (10 to 25): (5-12);
(3) Adding the uniformly dispersed isocyanate modified graphene solution into the mixture at the speed of (2-5) mL/min, and reacting for 3-5 h at the stirring speed of 120-300 rpm and the temperature of 80-90 ℃ after the addition is finished to obtain an isocyanate modified graphene/aspartyl polyurea prepolymer; wherein the mass fraction of the isocyanate modified graphene in the isocyanate modified graphene/aspartyl polyurea prepolymer is 0.1-20 wt%;
(4) Mixing the isocyanate modified graphene/aspartyl polyurea prepolymer and polyaspartic acid ester resin, stirring at a stirring speed of 10-90 rpm for 5-10 min, vacuumizing at 50-60 ℃ for 5-20 min, evaporating to remove the solvent, and drying to obtain a completely cured modified graphene reinforced repairable multifunctional aspartyl polyurea elastomer composite material; wherein, according to the mass ratio, the isocyanate modified graphene/asparagus polyurea prepolymer: polyaspartic acid ester resin = (15 to 30): (10 to 22).
In the step (1) of S1, the few-layer graphene is prepared by the following preparation method.
i) Placing the expandable graphite raw material at the constant temperature of 600-800 ℃ for expansion stripping to obtain vermicular expanded graphite;
in the above i), the swelling and peeling time is preferably 1 to 5min.
ii) carrying out wet ball milling on the expanded graphite for 8-24 h to obtain a ball-milled solution;
iii) Performing solid-liquid separation on the ball-milled solution, and drying to obtain few-layer graphene;
in the step i), the expandable graphite raw material is a graphite intercalation compound.
In the step ii), the ball milling adopts planetary ball milling and revolution: rotation =1:2, the ball milling speed is 400-600 rpm, and the ball milling medium is preferably zirconia balls; the material-to-ball ratio is expanded graphite: solvent: the proportion of zirconia balls is 1g: 40-80 mL: 50-100 g; the ball milling solvent adopted by the wet ball milling is selected from one of deionized water, absolute ethyl alcohol and acetone, and is preferably absolute ethyl alcohol.
In the step iii), the drying temperature is 60-90 ℃, and the drying time is 6-10 h.
In the above (1) of S1, the solvent is preferably a high boiling point solvent, more preferably Dimethylformamide (DMF) or dimethylacetamide (DMAc).
In the step (1) of S1, the ultrasonic dispersion time is preferably 10 to 30min.
In the step (2) of S1, the isocyanate is diisocyanate, more specifically at least one of IPDI, MDI, TDI and PAPI.
In the step (3) of S1, the drying temperature is 50-80 ℃.
In the above (1) of S2, the organic solvent is preferably a high-boiling organic solvent, and more preferably DMF or DMAc.
In the step (1) of S2, the ultrasonic dispersion time is preferably 20 to 30min.
In the step (2) in S2, the amino-terminated polyether is a binary amino-terminated polyoxypropylene ether or a ternary amino-terminated polyoxypropylene ether, and preferably, the amino-terminated polyether is at least one of D2000, D230, T403, T300 and T5000; the isocyanate is diisocyanate, and more specifically at least one of Hexamethylene Diisocyanate (HDI), polyphenyl polymethylene polyisocyanate (PAPI), and isophorone diisocyanate (IPDI).
In the step (2) of S2, the dripping rate of the isocyanate is 5-10 mL/min in the process of mixing the isocyanate and the amine-terminated polyether.
In the step (4) of S2, the temperature for evaporation is 90-100 ℃, and the evaporation time is 10-12 h; the temperature for drying is 50-60 ℃, and the drying time is 20-24 h.
In the step (4) of S2, the polyaspartic acid ester resin includes at least one of NH 1420, NH 1520, HN 3300, HN3400, NH3390, and NH 3800.
In the preparation method of the modified graphene reinforced repairable multifunctional asparagus polyurea elastomer composite material, the adopted amino-terminated polyether, diisocyanate and polyaspartic ester resin raw materials are all put into an oven with the temperature of 50-70 ℃ for dehydration for 2-4 h.
The invention relates to a formula of a multifunctional asparagus polyurea elastomer with self-repairing capability, which has the following beneficial effects compared with the prior art:
(1) The invention provides a preparation method of an asparagus polyurea elastomer with high-efficiency self-healing efficiency;
(2) The invention provides a method for preparing graphene with oxygen-containing functional groups on the surface by utilizing mechanochemical energy, and isocyanate functional groups are connected to the surface of the graphene through bonding reaction, so that graphene particles can be inserted into polyurea molecular chains to establish chemical bond connection with a polyurea matrix, and a more stable interface effect is formed.
(3) The reinforcing phase filler graphene is subjected to isocyanate functionalization treatment to become a part of a self-repairing network, so that the problem that the addition of the nano filler can limit the repair of dynamic reversible bonds and the mobility of molecular chains to hinder the crack closing and healing processes is solved.
(4) The isocyanate modified graphene nanosheet has excellent mechanical property, heat conducting property, electric conductivity and the like, and is added into a polyurea matrix as a reinforcing phase, so that the asparagus polyurea elastomer composite material is endowed with multifunctionality, and the possibility of applying the self-repairing material to more fields is provided.
Drawings
Fig. 1 is a graph comparing the data on the mechanical properties of the modified graphene reinforced repairable polyaspartic polyurea elastomer composite in each example.
Fig. 2 is a diagram showing the self-repairing effect of the modified graphene enhanced repairable multifunctional aspartyl polyurea elastomer composite.
FIG. 3 is a data comparison graph of the self-healing performance of the modified graphene enhanced repairable multifunctional aspartyl polyurea elastomer composite of the examples.
FIG. 4 is a graph comparing data for impact resistance of modified graphene enhanced repairable polyaspartic polyurea elastomer composite in various examples.
FIG. 5 is a data comparison graph of the thermal conductivity of modified graphene enhanced repairable polyaspartic polyurea elastomer composite of various examples.
Fig. 6 is a graph comparing conductivity data for modified graphene enhanced repairable polyaspartic polyurea elastomer composites of various examples.
Detailed Description
The present invention will be described in further detail with reference to examples.
In the following examples, the test method of the obtained modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material is as follows:
(1) According to GB 228-87, a universal tester is adopted to determine the mechanical properties of the modified graphene enhanced repairable multifunctional asparagus polyurea elastomer composite material and the mechanical properties after self-repair.
(2) According to GB/T229-2020, an epoxy resin impact sample is prepared, 2mm of modified graphene-reinforced repairable multifunctional aspartyl polyurea elastomer composite material is coated on the surface of the epoxy resin impact sample, and a Charpy impact tester is adopted to test the impact resistance of the polyurea coating.
Wherein, the epoxy resin impact sample is prepared by mixing epoxy resin and a D230 curing agent in a mass ratio of 10:3.3, obtaining the product.
(3) According to GB/T3399-1982, the thermal conductivity coefficient of the modified graphene enhanced repairable multifunctional aspartyl polyurea elastomer composite material is measured by adopting a Hot Disk TPS 2500S instrument.
(4) According to GB/T15662-1995, the conductivity of the modified graphene reinforced repairable multifunctional aspartyl polyurea elastomer composite material is measured by an Agilent 4339B high resistivity instrument.
In the following examples, the mechanical testing scheme for the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite specifically includes the following steps:
(1) The modified graphene-reinforced repairable multifunctional aspartyl polyurea elastomer composite material is prepared into a standard tensile test piece according to GB 228-87.
(2) The tensile test piece was tested using a universal testing machine, and the tensile strength and elongation at break of the tensile test piece were collected.
In the following examples, a self-healing test protocol for a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite includes the following steps:
(1) The modified graphene-reinforced repairable multifunctional aspartyl polyurea elastomer composite material is prepared into a standard tensile test piece according to GB 228-87.
(2) And (3) cutting the test piece by using a surgical blade to stretch the middle section of the test piece along the central line at 45 degrees, aligning the cuts, and heating the aligned cuts in an oven at 60-100 ℃ for 3-10 hours.
(3) And testing the test tensile test piece which is repaired after being cut off by using a universal testing machine, and collecting the self-repairing tensile strength and the self-repairing elongation at break of the tensile test piece.
In the following examples, the impact test protocol for the modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite includes the following steps:
(1) Mixing epoxy resin and a D230 curing agent in a mass ratio of 10:3.3 preparing the epoxy resin block.
(2) And (3) sticking the modified graphene-reinforced repairable multifunctional aspartyl polyurea elastomer composite material on an epoxy resin block through epoxy resin glue.
(3) According to GB/T229-2020, a Charpy impact tester is used to test the impact properties of an epoxy resin block coated with a modified graphene enhanced repairable multifunctional aspartyl polyurea elastomer composite coating.
In the following examples, the thermal conductivity test protocol for the modified graphene enhanced repairable multifunctional aspartyl polyurea elastomer composite includes the following steps:
(1) The modified graphene-reinforced repairable multifunctional aspartyl polyurea elastomer composite coating is prepared into a standard heat conduction test piece according to GB/T3399-1982.
(2) And measuring the thermal conductivity coefficient of the modified graphene enhanced repairable multifunctional aspartic polyurea elastomer composite material elastomer by adopting a Hot Disk TPS 2500S instrument.
Example 1
The preparation method of the isocyanate modified graphene comprises the following steps:
(1) Weighing 0.1 part by mass of expandable graphite raw material, placing the expandable graphite raw material in a muffle furnace at 700 ℃ for heating and expanding for 1min, transferring the obtained expandable graphite into a ball milling tank, taking absolute ethyl alcohol as a ball milling medium, and adding zirconia balls and expandable graphite: absolute ethanol: zirconia balls =1g:50mL of: and 100g, setting the ball milling rotation speed to be 400rpm, carrying out ball milling for 8 hours, and carrying out suction filtration and drying treatment on the finally obtained graphene solution to obtain the ball-milled and stripped few-layer Graphene (GNP).
(2) And adding the few-layer graphene obtained in the last step into 20mL of DMF solution, putting the solution into an ultrasonic cleaner for ultrasonic treatment for 10min, dropwise adding 10mL of IPDI, and transferring the obtained mixed solution into an oil bath kettle at 85 ℃ for reaction for 12h. And then carrying out suction filtration on the solution after the reaction is finished, adding 20mL of DMF solution, repeatedly washing and carrying out suction filtration twice, and putting the finally obtained suction filtration product into a 65 ℃ drying oven for 12 hours to obtain the isocyanate modified graphene (IP-GNP).
(3) When preparing the graphene/asparagus polyurea elastomer composite material with other components, the mass parts of the expandable graphite in the step (1) are replaced by the required mass parts, and the rest steps are not changed.
Comparative example 1
A preparation method of an aspartic polyurea elastomer composite material comprises the following steps:
and (1) uniformly mixing 15g D2000 and 2g T5000, transferring the mixture into a three-neck flask, then placing the mixture into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 7g IPDI at a dropwise adding speed of 5g/min, setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 25rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 4h to obtain the asparagus polyurea prepolymer.
And (2) adding 1691 NH 1420 into the asparagus polyurea prepolymer, stirring at a low speed of 20rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mould, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the completely cured asparagus polyurea elastomer coating.
Example 2
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
step (1) 0.4g of the IP-GNP prepared in example 1 was placed in a beaker, 10mL of DMF was added as a solvent, and sonication was carried out for 20min to obtain a uniformly dispersed IP-GNP solution.
And (2) uniformly mixing 15g D2000 and 2g T5000, transferring the mixture into a three-neck flask, then placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 7g IPDI at a dropwise adding speed of 5g/min, setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 30rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ and reacting for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask at 5mL/min, increasing the stirring speed to 120rpm, and continuously reacting for 5 hours under the oil bath condition of 85 ℃ to obtain the isocyanate modified graphene/asparagus polyurea prepolymer.
And (4) adding 169g of NH 1420 into the isocyanate modified graphene/asparagus polyurea prepolymer, stirring at a low speed of 20rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the IP-GNP/asparagus polyurea elastomer composite material coating with the mass part of 1 wt%.
Example 3
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
step (1), 0.8g of the IP-GNP prepared in example 1 is placed in a beaker, 10mL of DMF is added as a solvent, and the mixture is subjected to ultrasonic treatment for 20min to obtain a uniformly dispersed IP-GNP solution.
And (2) uniformly mixing 15g D2000 and 2g T5000, transferring the mixture into a three-neck flask, then placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, then slowly dropwise adding 7g IPDI, setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 25rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask, increasing the stirring speed to 200rpm, and continuously reacting for 3-5 hours under the condition of an oil bath at 85 ℃ to obtain the isocyanate modified graphene/asparagus polyurea prepolymer.
And (4) adding 169g NH 1420 into the prepolymer, stirring at a low speed of 20rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the IP-GNP/asparagus polyurea nano composite material coating with the mass part of 2 wt%.
Example 4
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
step (1) 1.52g of the IP-GNP prepared in example 1 was placed in a beaker, 10mL of DMF was added as a solvent, and sonication was carried out for 20min to obtain a uniformly dispersed IP-GNP solution.
And (2) uniformly mixing 22g of D230 and 3g of T403, transferring the mixture into a three-neck flask, placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 7.5g of HDI, stirring at a low speed of 30rpm while setting the temperature of the oil bath pot at 10 ℃, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask at 2mL/min, increasing the stirring speed to 220rpm, and continuously reacting for 4 hours under the condition of an oil bath at 85 ℃ to obtain the isocyanate modified graphene/asparagus polyurea prepolymer.
And (4) adding 18g NH 3300 into the isocyanate modified graphene/asparagus polyurea prepolymer, stirring at a low speed of 20rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mould, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the IP-GNP/asparagus polyurea nanocomposite coating with the mass part of 3 wt%.
Example 5
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
and (1) putting 2.5g of the IP-GNP prepared in the example 1 into a beaker, adding 10ml of DMF serving as a solvent, and carrying out ultrasonic treatment for 20min to obtain a uniformly dispersed IP-GNP solution.
And (2) uniformly mixing 18g D2000 and 3g T300, transferring the mixture into a three-neck flask, placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 9g IPDI (isophorone diisocyanate), setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 20rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask, increasing the stirring speed to 200rpm, and continuously reacting for 3-5 hours under the condition of an oil bath at 85 ℃ to obtain the isocyanate modified graphene/asparagus polyurea prepolymer.
And (4) adding 20g NH 1520 into the prepolymer, stirring at a low speed of 30rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the IP-GNP/asparagus polyurea nano composite material coating with the mass part of 5 wt%.
Example 6
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
step (1) 4.7g of the IP-GNP prepared in example 1 was placed in a beaker, 10mL of DMF was added as a solvent, and sonication was carried out for 20min to obtain a uniformly dispersed IP-GNP solution.
And (2) uniformly mixing 17g D2000 and 4g T403, transferring the mixture into a three-neck flask, then placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 8.3g IPDI, setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 30rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask, increasing the stirring speed to 180rpm, and continuously reacting for 3-5 hours under the condition of an oil bath at 85 ℃ to obtain the isocyanate modified graphene/asparagus polyurea prepolymer.
And (4) adding 18g of NH 1420 to the prepolymer, stirring at a low speed of 20rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the IP-GNP/asparagus polyurea nano composite material coating with the mass part of 10 wt%.
Example 7
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
and (1) putting 9.3g of the IP-GNP prepared in the example 1 into a beaker, adding 10ml of DMF as a solvent, and carrying out ultrasonic treatment for 20min to obtain a uniformly dispersed IP-GNP solution.
And (2) uniformly mixing 25g of D230 and 5g of T403, transferring the mixture into a three-neck flask, placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 12g of PAPI, setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 25rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask, increasing the stirring speed to 160rpm, and continuously reacting for 3-5 hours under the condition of an oil bath at 85 ℃ to obtain the isocyanate modified graphene/asparagus polyurea prepolymer.
And (4) adding 20g NH3800 into the prepolymer, stirring at a low speed of 15rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the IP-GNP/asparagus polyurea nano composite material coating with the mass part of 15 wt%.
Example of detection
(1) An aspartyl polyurea coated stretch (stretch 1) and an aspartyl polyurea coated stretch (stretch 2) to which a black colorant was added were prepared separately.
(2) The stretching member 1 and the stretching member 2 are cut along the middle line of 45 degrees from the middle section of the stretching part by using a surgical knife, and then, one half of the stretching member 1 and the other half of the stretching member 2 are aligned to be cut and placed into an oven at 60-100 ℃ to be heated for 3-10 hours.
(3) The tensile member 1 and the tensile member 2 are self-repaired to form a complete tensile specimen. The repaired tensile test piece can be easily hung with a 4LB dumbbell piece, and the effect diagram is shown in figure 2.
Comparative example 2
A preparation method of an aspartic polyurea nano elastomer composite material added with graphene comprises the following steps:
step (1) 0.8g of GNP prepared in example 1 was placed in a beaker, 10ml of DMF was added as solvent and sonicated for 20min to give a uniformly dispersed GNP solution.
And (2) uniformly mixing 15g of D2000 and 2g of T5000, transferring the mixture into a three-neck flask, then placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 7g of IPDI (isophorone diisocyanate), setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 25rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ and reacting for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask, increasing the stirring speed to 200rpm, and continuously reacting for 3-5 hours under the condition of oil bath at 85 ℃ to obtain the graphene/asparagus polyurea prepolymer.
And (4) adding 169g of NH 1420 into the prepolymer, stirring at a low speed of 20rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the GNP/asparagus polyurea nano composite material coating with the mass part of 2 wt%.
Comparative example 3
A preparation method of a modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material comprises the following steps:
step (1), 9.3g of GNP prepared in example 1 was placed in a beaker, 10ml of DMF was added as solvent, and sonication was carried out for 20min to obtain a uniformly dispersed GNP solution.
And (2) uniformly mixing 25g of D230 and 5g of T403, transferring the mixture into a three-neck flask, placing the three-neck flask into a constant-temperature magnetic stirring oil bath pot, introducing nitrogen, slowly dropwise adding 12g of PAPI, setting the temperature of the oil bath pot to be 10 ℃ in the dropwise adding process, stirring at a low speed of 30rpm, and after the mixture reacts for 30min, adjusting the temperature of the oil bath to 85 ℃ for reaction for 30min.
And (3) dropwise adding the prepared isocyanate modified graphene solution into a three-neck flask, increasing the stirring speed to 200rpm, and continuously reacting for 3-5 hours under the condition of an oil bath at 85 ℃ to obtain the graphene/asparagus polyurea prepolymer.
And (4) adding 20g NH3800 into the prepolymer, stirring at a low speed of 25rpm for 5min, vacuumizing in a vacuum oven at 60 ℃ for 10min, pouring into a polytetrafluoroethylene mold, placing in an oven at 90 ℃ for 12h, evaporating the solvent in the system, and drying in the oven at 60 ℃ for 24h to obtain the GNP/asparagus polyurea nano composite material coating with the mass part of 15 wt%.
The test data obtained for examples 1-7 and comparative examples 1-3 are tabulated below:
TABLE 1 tensile Properties of the respective aspartic polyurea nanocomposite coatings of examples 2 to 7 and comparative examples 1 to 3
| Examples | Polyurea component | Tensile strength (Mpa) | Fracture growth Rate (%) |
| Comparative example 1 | Asparagus polyurea | 6.52 | 367.42 |
| Example 2 | Adding 1wt% of IP-GNP | 8.47 | 384.74 |
| Example 3 | Adding 2wt% of IP-GNP | 12.58 | 402.51 |
| Example 4 | Addition of 3wt% of IP-GNP | 11.42 | 392.42 |
| Example 5 | Adding 5wt% of IP-GNP | 10.03 | 385.11 |
| Example 6 | Adding 10wt% of IP-GNP | 8.58 | 378.89 |
| Example 7 | Adding 15wt% of IP-GNP | 7.69 | 375.15 |
| Comparative example 2 | Adding 2wt% of GNP | 4.72 | 312.75 |
| Comparative example 3 | Adding 15wt% of GNP | 3.36 | 208.13 |
The data in table 1 and fig. 1 show that the mechanical properties of the coating of the winter polyurea elastomer composite material after the addition of the IP-GNP are improved, wherein the mechanical properties of the component with the graphene content of 2wt% are improved to the maximum, the tensile strength reaches 12.58MPa, and the elongation at break reaches 402.51%. The use of unmodified Graphene (GNP) results in a small reduction in the mechanical properties of the polyurea matrix.
TABLE 2 tensile Properties of the Aspartame nanocomposites coatings repaired in examples 2 to 7 and comparative examples 1 to 3
The data in Table 2 and FIG. 3 show that the mechanical properties of the repaired coating can reach 80% of those of the original coating, which indicates that the polyurea elastomer composite coating has a certain self-repairing ability. The unmodified Graphene (GNP) is used, and the mechanical property of the repaired coating is seriously reduced and only reaches about 50 percent of that of the original coating.
TABLE 3 impact resistance of the respective aspartic polyurea nanocomposite coatings of examples 2 to 7 and comparative examples 1 to 3
The data in the table 3 and the data in fig. 4 show that the anti-impact performance of the asparagus polyurea elastomer composite material coating is improved after the IP-GNP is added, and similarly, the asparagus polyurea elastomer composite material coating with the graphene content of 2wt% shows better anti-impact performance, and the impact strength of the asparagus polyurea elastomer composite material coating reaches 64.73KJ/m 2 Compared with pure epoxy blocks, the improvement is 348.89%. And the impact resistance of the winter polyurea elastomer composite material coating is reduced after the unmodified Graphene (GNP) is used.
TABLE 4 thermal conductivity of the respective aspartic polyurea nanocomposite coatings of examples 2 to 7 and comparative examples 1 to 3
As can be seen from the data in Table 4 and FIG. 5, the thermal conductivity of the winter polyurea elastomer composite material after the addition of the IP-GNP is greatly improved, wherein the thermal conductivity coefficient of the composition added with 15wt% of the IP-GNP reaches 28.49W/m.K. And the heat conductivity of the asparagus polyurea elastomer composite material added with the unmodified Graphene (GNP) is slowly improved.
TABLE 5 conductive Properties of the various aspartic polyurea nanocomposite coatings of examples 2-7 and comparative examples 1-3
| Examples | Polyurea component | Conductivity (S/cm) |
| Comparative example 1 | Asparagus polyurea | 3.72E-16 |
| Example 2 | Adding 1wt% of IP-GNP | 7.46E-15 |
| Example 3 | Adding 2wt% of IP-GNP | 1.74E-14 |
| Example 4 | Addition of 3wt% of IP-GNP | 5.46E-11 |
| Example 5 | Adding 5wt% of IP-GNP | 2.46E-7 |
| Example 6 | Adding 10wt% of IP-GNP | 5.62E-5 |
| Example 7 | Adding 15wt% of IP-GNP | 2.35E-4 |
| Comparative example 2 | Adding 2wt% of GNP | 1.14E-15 |
| Comparative example 3 | Adding 15wt% of GNP | 5.48E-13 |
As can be seen from the data in Table 5 and FIG. 6, the conductivity of the winter polyurea elastomer composite material after the addition of the IP-GNP is greatly improved, wherein the conductivity of the composition with the addition of 15wt% of the IP-GNP reaches 2.35E-4S/cm. And the conductivity of the asparagus polyurea elastomer composite material added with the unmodified Graphene (GNP) is slowly improved.
By combining the data, the mechanical property, the self-repairing property, the shock resistance and the heat and electricity conducting property of the asparagus polyurea elastomer composite material using the modified graphene are superior to those of the unmodified graphene. The reason is that the modified graphene nanosheets and the polyurea matrix form chemical bond connection, so that a stable interface effect is established between the filler phase and the matrix phase, and the graphene/asparagus polyurea elastomer composite coating has excellent performance. The patent provides a simple and effective method for preparing the graphene/asparagus polyurea elastomer composite material with high self-healing performance and multiple functionalities, and provides possibility for applying the polyurea elastomer material to more fields.
Claims (10)
1. The modified graphene reinforced repairable multifunctional aspartyl polyurea elastomer composite material is characterized by having repairability.
2. The modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material is characterized in that the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material has the tensile strength of 7.69-12.58 Mpa, the elongation at break of 375.15-402.51%, the repair tensile strength of 5.97-10.15 Mpa, the elongation at break of 319.67-358.64%, the electric conductivity of 7.46E-15-2.35E-4S/cm, the heat conductivity of 0.12-28.49W/m.K, and the impact strength of 41.35-64.73 KJ/m.K 2 。
3. The preparation method of the modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 1 or 2, which comprises the following steps:
s1: preparation of isocyanate modified graphene
(1) Ultrasonically dispersing few-layer graphene in a solvent to obtain a graphene solution;
(2) Reacting the graphene solution with isocyanate at 75-95 ℃ for 12-30 h to obtain a reaction solution; according to the mass ratio, graphene: isocyanate =1: (5-25);
(3) Carrying out solid-liquid separation on the reaction solution, washing and drying a solid product to obtain isocyanate modified graphene;
s2: preparation of modified graphene-reinforced repairable multifunctional asparagus polyurea elastomer composite material
(1) Placing isocyanate modified graphene in an organic solvent, and performing ultrasonic dispersion to obtain a uniformly dispersed isocyanate modified graphene solution;
(2) Under the nitrogen environment, uniformly mixing isocyanate and amino-terminated polyether, controlling the temperature at 10 +/-5 ℃ and the stirring speed at 10-50 rpm in the mixing process, stirring and reacting for 20-40 min after mixing is finished, and then heating to 80-90 ℃ and stirring and reacting for 20-40 min at 120-300 rpm to obtain a mixture;
wherein, according to the mass ratio, the amino-terminated polyether: isocyanate = (10 to 25): (5-12);
(3) Adding the uniformly dispersed isocyanate modified graphene solution into the mixture at the speed of (2-5) mL/min, and reacting for 3-5 h at the temperature of 80-90 ℃ at the stirring speed of 120-300 rpm after the addition is finished to obtain an isocyanate modified graphene/aspartyl polyurea prepolymer; wherein the mass fraction of the isocyanate modified graphene in the isocyanate modified graphene/aspartyl polyurea prepolymer is 0.1-20 wt%;
(4) Mixing the isocyanate modified graphene/aspartyl polyurea prepolymer and polyaspartic acid ester resin, stirring at a stirring speed of 10-90 rpm for 5-10 min, vacuumizing at 50-60 ℃ for 5-20 min, evaporating to remove the solvent, and drying to obtain a completely cured modified graphene reinforced repairable multifunctional aspartyl polyurea elastomer composite material; wherein, according to the mass ratio, the isocyanate modified graphene/asparagus polyurea prepolymer: polyaspartic acid ester resin = (15 to 30): (10 to 22).
4. The method for preparing the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 3, wherein in the step (1) of S1, the few-layer graphene is prepared by the following preparation method:
i) Placing the expandable graphite raw material at the constant temperature of 600-800 ℃ for expansion stripping to obtain vermicular expanded graphite;
ii) carrying out wet ball milling on the expanded graphite for 8-24 h to obtain a ball-milled solution;
iii) And (4) carrying out solid-liquid separation on the solution subjected to ball milling, and drying to obtain the few-layer graphene.
5. The preparation method of the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 4, wherein in the step ii), the ball milling is planetary ball milling, revolution: autorotation =1:2, the ball milling rotating speed is 400-600 rpm, and the ball milling medium is zirconia balls; the material-to-ball ratio is expanded graphite: solvent: the proportion of zirconia balls is 1g: 40-80 mL: 50-100 g; the ball milling solvent adopted by the wet ball milling is selected from one of deionized water, absolute ethyl alcohol and acetone.
6. The preparation method of the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 3, wherein in the step (1) of S1, the solvent is a high boiling point solvent, and the ultrasonic dispersion time is 10-30 min;
in (1) of S2, the organic solvent is a high-boiling point organic solvent; the ultrasonic dispersion time is 20-30 min.
7. The preparation method of the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 3, wherein the amino-terminated polyether is a binary amino-terminated polyoxypropylene ether and/or a ternary amino-terminated polyoxypropylene ether, and the isocyanate is diisocyanate; the polyaspartic acid ester resin comprises at least one of NH 1420, NH 1520, HN 3300, HN3400, NH3390 and NH 3800.
8. The method for preparing the modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 3, wherein in the step (2) of S2, the dripping rate of the isocyanate is 5-10 mL/min during the mixing process of the isocyanate and the amine-terminated polyether.
9. The preparation method of the modified graphene-reinforced repairable multifunctional aspartic polyurea elastomer composite material according to claim 3, wherein in the step (4) of S2, the temperature for evaporation is 90-100 ℃, and the evaporation time is 10-12 h; the temperature for drying is 50-60 ℃, and the drying time is 20-24 h.
10. The preparation method of the modified graphene reinforced repairable multifunctional aspartic polyurea elastomer composite material as claimed in claim 3, wherein the adopted raw materials of the amino-terminated polyether, the isocyanate and the polyaspartic ester resin are all put into an oven with a temperature of 50-70 ℃ for dehydration for 2-4 h.
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