High-strength and high-toughness modified plastic particles as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to high-strength and high-toughness modified plastic particles as well as a preparation method and application thereof. The preparation method of the high-strength and high-toughness modified plastic particles comprises the following steps: carrying out a reaction on MMT / CNTs and diisocyanate to prepare isocyanate-based MMT / CNTs; the preparation method comprises the following steps: reacting isocyanate-based MMT / CNTs with glycerol 1, 3-diglycerol alkyd diacrylate to prepare MMT / CNTs containing alkenyl groups; the preparation method comprises the following steps: carrying out grafting reaction on maleic anhydride, alkenyl-containing MMT / CNTs and POE (Polyolefin Elastomer) to prepare a modifier; and carrying out melt blending, extrusion, cooling and pelletizing on the modifier, the auxiliary agent and PA6 to obtain the high-strength and high-toughness modified plastic particles. The nano filler MMT / CNTs and the polyolefin elastomer POE are introduced, so that the modified plastic particles taking the PA6 as the matrix have high strength and high toughness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a modified plastic particle with high strength and high toughness, and a preparation method and application thereof. BACKGROUND

[0002] PA6 (polyamide 6) is widely used in many fields of the national economy due to its high mechanical strength, excellent heat resistance, wear resistance and oil resistance. However, its application is limited due to poor impact resistance. Therefore, it is necessary to modify PA6 to improve its toughness. The common method for toughening modification of PA6 is to add a flexible toughening polymer, such as POE (ethylene-octene copolymer).

[0003] Chinese patent CN103131168B discloses a permanent antistatic PA6 / POE alloy and a preparation method thereof. The preparation raw materials include antistatic masterbatch, PA6, POE and a compatibilizer. The prepared alloy material has good antistatic effect and high comprehensive mechanical properties. However, there is a large polarity difference between polar PA6 and non-polar polyolefin elastomer POE, and the compatibility between them is poor and the phase separation phenomenon is serious, resulting in a decrease in impact strength. In addition, the introduction of the flexible toughening polymer will cause a decrease in the tensile strength of the rigid polymer material PA6, that is, the PA6-based plastic material is difficult to have high strength and high toughness. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a modified plastic particle with high strength and high toughness, and a preparation method and application thereof, to solve the problem that the PA6-based modified plastic particle is difficult to have high strength and high toughness in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of a modified plastic particle with high strength and high toughness, comprising the following steps:

[0007] Step one, MMT / CNTs (montmorillonite / carbon nanotubes) are added to toluene, stirred and dispersed, then diisocyanate and a catalyst are added, reacted, centrifuged, washed and dried after the reaction is completed, to obtain isocyanate group MMT / CNTs;

[0008] Step two, glycerol 1,3-diglycerol diacrylate is added to toluene, stirred and dispersed, then isocyanate group MMT / CNTs and a catalyst are added, reacted, centrifuged, washed and dried after the reaction is completed, to obtain MMT / CNTs containing alkenyl groups;

[0009] Step three, maleic anhydride and an initiator are dissolved in acetone, and MMT / CNTs containing alkenyl groups are added, stirred and dispersed, to obtain a mixed solution;

[0010] The mixed solution is added into the POE, mixed, extruded through a double screw extruder, cooled, and granulated to obtain the modifier;

[0011] Step four, the modifier, the auxiliary agent and the PA6 are melt blended, extruded, cooled, and granulated to obtain the high-strength and high-toughness modified plastic particles.

[0012] Preferably, in the step one, the mass ratio of the MMT / CNTs, the diisocyanate, the catalyst and the toluene is 100:(50-70):(0.05-0.1):(400-600), and the reaction condition is that the reaction is carried out at 75-85℃ for 60-100min under nitrogen protection.

[0013] Preferably, the diisocyanate includes toluene-2,4-diisocyanate, and the catalyst includes stannous octoate.

[0014] Preferably, the MMT / CNTs in the step one is prepared by the following steps:

[0015] S1, DIC, HOBT and carboxylated multi-walled carbon nanotubes are added into N,N-dimethylformamide, ultrasonic dispersion is carried out to obtain a carbon nanotube dispersion liquid, triethylenetetramine is added into the carbon nanotube dispersion liquid, reaction is carried out, after the reaction is completed, filtration, washing and drying are carried out to obtain modified carbon nanotubes;

[0016] S2, the modified carbon nanotubes are added into deionized water, ultrasonic dispersion is carried out, hydrochloric acid is added dropwise under stirring, stirring reaction is carried out to obtain a carbon nanotube ammonium salt dispersion liquid;

[0017] Montmorillonite (MMT) is added into deionized water, ultrasonic dispersion is carried out, the carbon nanotube ammonium salt dispersion liquid is added, reaction is carried out, after the reaction is completed, filtration, washing and drying are carried out to obtain MMT / CNTs.

[0018] Preferably, in the S1, the mass ratio of the DIC, the HOBT, the carboxylated multi-walled carbon nanotubes, the N,N-dimethylformamide and the triethylenetetramine is (0.01-0.03):(0.01-0.03):(0.8-1.2):(95-105):(0.4-0.6), and the reaction condition is that the reaction is carried out at room temperature for 20-30h under stirring.

[0019] Preferably, in the S2, when the carbon nanotube ammonium salt dispersion liquid is prepared, the mass ratio of the modified carbon nanotubes, the deionized water and the hydrochloric acid is (1-2):(80-120):(10-15), and the reaction condition is that the reaction is carried out at room temperature for 20-40min under stirring.

[0020] Preferably, the hydrochloric acid comprises 36.5wt% hydrochloric acid.

[0021] Preferably, in the S2, when preparing the MMT / CNTs, the mass ratio of the montmorillonite, deionized water and carbon nanotube ammonium salt dispersion is (8-12):(150-250):(91-137), and the reaction condition is stirring reaction at 70-90℃ for 20-30h.

[0022] Preferably, in the step two, the mass ratio of the glycerol 1,3-diglycerol diacrylate, isocyanate group MMT / CNTs, catalyst and toluene is (34.8-36.5):(15-17):(0.02-0.04):(300-500), and the reaction condition is reaction under nitrogen protection at 70-90℃ for 60-100min.

[0023] Preferably, the catalyst comprises dibutyl tin laurate.

[0024] Preferably, in the step three, the mass ratio of the maleic anhydride, initiator, acetone, alkenyl-containing MMT / CNTs and POE is (2-4):(0.5-1):(30-40):(3-5):100, the extrusion temperature is 180-200℃, and the screw rotation speed is 150-250r / min.

[0025] Preferably, the initiator comprises dicumyl peroxide.

[0026] Preferably, in the step four, the mass ratio of the modifier, auxiliary agent and PA6 is (8-12):(1-2):100, and the temperature of the melt blending is 260-280℃.

[0027] The auxiliary agent comprises a lubricant and an antioxidant.

[0028] Preferably, the mass ratio of the lubricant and the antioxidant is 1:1.

[0029] The lubricant comprises calcium stearate, and the antioxidant comprises antioxidant 1010 (tetra[p-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester).

[0030] The application further discloses a high-strength and high-toughness modified plastic particle prepared by the preparation method of the high-strength and high-toughness modified plastic particle.

[0031] The application further discloses an application of the high-strength and high-toughness modified plastic particle.

[0032] Compared with the prior art, the application has the beneficial effects that:

[0033] In the present application, PA6 is used as the base material, the modified plastic particles have high strength, the tubular structure of carbon nanotubes and the sheet structure of montmorillonite in the nano filler MMT / CNTs can synergistically enhance and toughen PA6, the polyolefin elastomer POE molecule contains both crystalline ethylene chain and amorphous octene soft chain curling structure, and has good toughening modification ability, and the strength and toughness of PA6 can be effectively improved by introducing the nano filler MMT / CNTs and the polyolefin elastomer POE, wherein the nano filler MMT / CNTs is modified and treated, can be chemically grafted with the polyolefin elastomer POE, so as to realize the construction of the synergistic network of the reinforcing and toughening nano filler and the toughening elastomer, and the prepared modified plastic particles have high strength and high toughness.

[0034] In the process of preparing the modifier of the nano filler MMT / CNTs and the polyolefin elastomer POE, the MMT / CNTs is reacted with diisocyanate through the surface hydroxyl group to prepare isocyanate group MMT / CNTs, the isocyanate group is introduced on the surface of the MMT / CNTs, and then the isocyanate group is reacted with the hydroxyl group on the molecule of glycerol 1,3-diglycerol acid dipropylene ester to obtain MMT / CNTs containing alkenyl, the carbon-carbon double bond introduced on the surface of the MMT / CNTs and the carbon-carbon double bond on the molecule of maleic anhydride are grafted and bonded with the molecular chain of POE under the action of an initiator, the access of maleic anhydride can react with the amino group at the end of the molecular chain of PA6, so as to improve the compatibility of POE and PA6, and then improve the compatibility of the nano filler MMT / CNTs grafted on the molecular chain of POE and PA6.

[0035] In addition, glycerol 1,3-diglycerol acid dipropylene ester is a polyene compound, which can realize the moderate crosslinking between the molecular chains of POE and form a three-dimensional crosslinking network structure while grafting the nano filler MMT / CNTs to the molecular chain of POE, so as to further improve the toughness of the PA6-based modified plastic particles. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a reaction schematic diagram of MMT / CNTs and toluene-2,4-diisocyanate in example 1 of the present application to prepare isocyanate group MMT / CNTs;

[0037] Figure 2 It is a reaction schematic diagram of isocyanate group MMT / CNTs and glycerol 1,3-diglycerol acid dipropylene ester in example 1 of the present application to prepare MMT / CNTs containing alkenyl;

[0038] Figure 3 It is a tensile property test result diagram of the modified plastic particles prepared in examples 1-5 and comparative examples 1-2 of the present application;

[0039] Figure 4 Figure for impact resistance test results of modified plastic particles prepared in Examples 1-5 and Comparative Examples 1-2 of the present application. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0041] Example 1

[0042] The present embodiment discloses a preparation method of high-strength and high-toughness modified plastic particles, comprising the following steps:

[0043] Step one, MMT / CNTs is added to toluene, stirred and dispersed at a stirring speed of 300 r / min for 30 min, then toluene-2,4-diisocyanate and stannous octoate are added, the mass ratio of MMT / CNTs, toluene-2,4-diisocyanate, stannous octoate, and toluene is 100:50:0.05:400, reaction is carried out under nitrogen protection at a temperature of 75℃ for 100 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ for drying to constant weight, to obtain isocyanate group MMT / CNTs;

[0044] The MMT / CNTs is prepared by the following steps:

[0045] S1, N,N'-diisopropyl carbodiimide, 1-hydroxybenzotriazole, and carboxylated multi-walled carbon nanotubes are added to N,N-dimethylformamide, ultrasonic dispersion is carried out at a frequency of 50kH for 30 min to obtain a carbon nanotube dispersion liquid, triethylenetetramine is added to the carbon nanotube dispersion liquid, the mass ratio of N,N'-diisopropyl carbodiimide, 1-hydroxybenzotriazole, carboxylated multi-walled carbon nanotubes, N,N-dimethylformamide, and triethylenetetramine is 0.02:0.02:1:95:0.5, stirring reaction is carried out at room temperature and a stirring speed of 200 r / min for 24 h, after the reaction is completed, filtration is carried out, washing is carried out with toluene for 3 times, and then placed in a vacuum drying box at 50℃ for drying to constant weight to obtain modified carbon nanotubes;

[0046] S2, the modified carbon nanotubes are added into deionized water, ultrasonic dispersion is carried out for 30 min under 50 kH frequency, 36.5 wt% hydrochloric acid is added dropwise under stirring condition at a stirring speed of 200 r / min, the mass ratio of the modified carbon nanotubes, deionized water and 36.5 wt% hydrochloric acid is 1.5:100:12, stirring reaction is carried out at room temperature and a stirring speed of 200 r / min for 24 h, and a carbon nanotube ammonium salt dispersion liquid is obtained;

[0047] The montmorillonite is added into deionized water, ultrasonic dispersion is carried out for 30 min under 50 kH frequency, the carbon nanotube ammonium salt dispersion liquid is added, the mass ratio of the montmorillonite, deionized water and the carbon nanotube ammonium salt dispersion liquid is 10:200:113.5, stirring reaction is carried out at a temperature of 80℃ and a stirring speed of 200 r / min for 24 h, after the reaction is completed, filtration is carried out, washing is carried out with ethanol for 3 times, and then drying is carried out in a vacuum drying box at 50℃ until the weight is constant, and MMT / CNTs is obtained.

[0048] Step two, glycerol 1,3-diglycerol acid diacrylate is added into toluene, stirring dispersion is carried out for 30 min at a stirring speed of 300 r / min, isocyanate group MMT / CNTs and dibutyl tin laurate are added, the mass ratio of glycerol 1,3-diglycerol acid diacrylate, isocyanate group MMT / CNTs, dibutyl tin laurate and toluene is 34.8:15:0.02:300, reaction is carried out under nitrogen protection at a temperature of 70℃ for 100 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then drying is carried out in a vacuum drying box at 40℃ until the weight is constant, and MMT / CNTs containing alkenyl groups is obtained.

[0049] Step three, maleic anhydride and dicumyl peroxide are dissolved in acetone, MMT / CNTs containing alkenyl groups is added, stirring dispersion is carried out for 30 min at a stirring speed of 300 r / min, and a mixed liquid is obtained.

[0050] The mixed liquid is added into POE, the mass ratio of maleic anhydride, dicumyl peroxide, acetone, MMT / CNTs containing alkenyl groups and POE is 2:0.5:30:3:100, mixing is carried out, extrusion is carried out through a double-screw extruder, the extrusion temperature is 180℃, the screw rotation speed is 250 r / min, cooling is carried out, and pelletization is carried out, and a modifier is obtained.

[0051] Step four, the modifier, calcium stearate and antioxidant 1010 are melt blended with PA6, the mass ratio of the modifier, calcium stearate, antioxidant 1010 and PA6 is 8:0.5:0.5:100, the temperature of melt blending is 260℃, extrusion is carried out, cooling is carried out, and pelletization is carried out, and high-strength and high-toughness modified plastic particles are obtained.

[0052] Example 2

[0053] The embodiment discloses a preparation method of modified plastic particles with high strength and high toughness.

[0054] Step one, MMT / CNTs is added into toluene, stirred and dispersed at a stirring speed of 250 r / min for 30 min, then toluene-2,4-diisocyanate and stannous octoate are added, the mass ratio of MMT / CNTs, toluene-2,4-diisocyanate, stannous octoate, toluene is 100:70:0.1:600, reaction is carried out under nitrogen protection at 85 DEG C for 60 min, after reaction, centrifugal separation is carried out, the centrifugal precipitate is washed with toluene for three times, then is placed in a vacuum drying box at 40 DEG C to dry until constant weight, and isocyanate group MMT / CNTs is obtained;

[0055] In the embodiment, the preparation method of MMT / CNTs is same as that in the embodiment 1.

[0056] Step two, glycerol 1,3-diglycerol acid diacrylate is added into toluene, stirred and dispersed at a stirring speed of 300 r / min for 30 min, then isocyanate group MMT / CNTs and dibutyltin laurate are added, the mass ratio of glycerol 1,3-diglycerol acid diacrylate, isocyanate group MMT / CNTs, dibutyltin laurate, toluene is 36.5:17:0.04:500, reaction is carried out under nitrogen protection at 90 DEG C for 60 min, after reaction, centrifugal separation is carried out, the centrifugal precipitate is washed with toluene for three times, then is placed in a vacuum drying box at 40 DEG C to dry until constant weight, and MMT / CNTs containing alkenyl groups is obtained;

[0057] Step three, maleic anhydride and dicumyl peroxide are dissolved in acetone, MMT / CNTs containing alkenyl groups is added, stirring and dispersion is carried out at a stirring speed of 300 r / min for 30 min, and a mixed solution is obtained;

[0058] The mixed solution is added into POE, the mass ratio of maleic anhydride, dicumyl peroxide, acetone, MMT / CNTs containing alkenyl groups, POE is 4:1:40:5:100, mixing is carried out, extrusion is carried out through a double-screw extruder, the extrusion temperature is 200 DEG C, the screw rotating speed is 150 r / min, cooling is carried out, and pelletizing is carried out, and a modifier is obtained;

[0059] Step four, the modifier, calcium stearate and antioxidant 1010 are melt-blended with PA6, the mass ratio of the modifier, calcium stearate, antioxidant 1010, PA6 is 12:1:1:100, the temperature of melt-blending is 280 DEG C, extrusion is carried out, cooling is carried out, and pelletizing is carried out, and modified plastic particles with high strength and high toughness are obtained.

[0060] Embodiment 3

[0061] The embodiment discloses a preparation method of modified plastic particles with high strength and high toughness.

[0062] Step one, MMT / CNTs is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 250 r / min, toluene-2, 4-diisocyanate and stannous octoate are added, the mass ratio of MMT / CNTs, toluene-2, 4-diisocyanate, stannous octoate and toluene is 100:55:0.06:450, the reaction is carried out at 80℃ under nitrogen protection for 80 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain isocyanate group MMT / CNTs;

[0063] In the method, the MMT / CNTs are prepared by the method of Example 1.

[0064] Step two, glycerol 1, 3-diglycerol acid diacrylate is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 300 r / min, isocyanate group MMT / CNTs and dibutyltin laurate are added, the mass ratio of glycerol 1, 3-diglycerol acid diacrylate, isocyanate group MMT / CNTs, dibutyltin laurate and toluene is 35.3:15.5:0.03:350, the reaction is carried out at 80℃ under nitrogen protection for 80 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain alkenyl-containing MMT / CNTs.

[0065] Step three, maleic anhydride and dicumyl peroxide are dissolved in acetone, and alkenyl-containing MMT / CNTs is added, stirring and dispersing is carried out at a stirring speed of 300 r / min for 30 min, to obtain a mixed solution;

[0066] The mixed solution is added into POE, the mass ratio of maleic anhydride, dicumyl peroxide, acetone, alkenyl-containing MMT / CNTs and POE is 2.5:0.6:32:3.5:100, mixing is carried out, extrusion is carried out through a double-screw extruder, the extrusion temperature is 190℃, the screw rotation speed is 200 r / min, cooling is carried out, and pelletizing is carried out, to obtain a modifier;

[0067] Step four, the modifier, calcium stearate and antioxidant 1010 are melt-blended with PA6, the mass ratio of the modifier, calcium stearate, antioxidant 1010 and PA6 is 9:0.6:0.6:100, the temperature of melt-blending is 270℃, extrusion is carried out, cooling is carried out, and pelletizing is carried out, to obtain high-strength and high-toughness modified plastic particles.

[0068] Example 4

[0069] The embodiment discloses a preparation method of high-strength and high-toughness modified plastic particles, which comprises the following steps:

[0070] Step one, MMT / CNTs is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 250 r / min, toluene-2, 4-diisocyanate and stannous octoate are added, the mass ratio of MMT / CNTs, toluene-2, 4-diisocyanate, stannous octoate, and toluene is 100:60:0.075:500, the reaction is carried out at 80℃ under nitrogen protection for 80 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain isocyanate group MMT / CNTs;

[0071] The preparation method of MMT / CNTs is same as that in Example 1.

[0072] Step two, glycerol 1, 3-diglycerol acid dipropylene acrylate is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 300 r / min, isocyanate group MMT / CNTs and dibutyltin laurate are added, the mass ratio of glycerol 1, 3-diglycerol acid dipropylene acrylate, isocyanate group MMT / CNTs, dibutyltin laurate, and toluene is 35.7:16:0.03:400, the reaction is carried out at 80℃ under nitrogen protection for 80 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain alkenyl-containing MMT / CNTs.

[0073] Step three, maleic anhydride and dicumyl peroxide are dissolved in acetone, and alkenyl-containing MMT / CNTs is added, stirring and dispersing is carried out at a stirring speed of 300 r / min for 30 min, to obtain a mixed solution;

[0074] The mixed solution is added into POE, the mass ratio of maleic anhydride, dicumyl peroxide, acetone, alkenyl-containing MMT / CNTs, and POE is 3:0.75:35:4:100, mixing is carried out, extrusion is carried out through a double-screw extruder, the extrusion temperature is 190℃, the screw rotation speed is 200 r / min, cooling is carried out, and pelletizing is carried out, to obtain a modifier;

[0075] Step four, the modifier, calcium stearate, and antioxidant 1010 are melt blended with PA6, the mass ratio of the modifier, calcium stearate, antioxidant 1010, and PA6 is 10:0.75:0.75:100, the temperature of melt blending is 270℃, extrusion is carried out, cooling is carried out, and pelletizing is carried out, to obtain high-strength and high-toughness modified plastic particles.

[0076] Example 5

[0077] The embodiment discloses a preparation method of high-strength and high-toughness modified plastic particles, which comprises the following steps:

[0078] Step one, MMT / CNTs is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 250 r / min, toluene-2, 4-diisocyanate and stannous octoate are added, the mass ratio of MMT / CNTs, toluene-2, 4-diisocyanate, stannous octoate, and toluene is 100:65:0.09:550, the reaction is carried out at 80℃ under nitrogen protection for 80 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain isocyanate group MMT / CNTs;

[0079] The preparation method of MMT / CNTs is same as that in Example 1.

[0080] Step two, glycerol 1, 3-diglycerol diacrylate is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 300 r / min, isocyanate group MMT / CNTs and dibutyltin laurate are added, the mass ratio of glycerol 1, 3-diglycerol diacrylate, isocyanate group MMT / CNTs, dibutyltin laurate, and toluene is 36.2:16.5:0.03:450, the reaction is carried out at 80℃ under nitrogen protection for 80 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain alkenyl-containing MMT / CNTs;

[0081] Step three, maleic anhydride and dicumyl peroxide are dissolved in acetone, and alkenyl-containing MMT / CNTs is added, stirring and dispersing is carried out at a stirring speed of 300 r / min for 30 min, to obtain a mixed solution;

[0082] The mixed solution is added into POE, the mass ratio of maleic anhydride, dicumyl peroxide, acetone, alkenyl-containing MMT / CNTs, and POE is 3.5:0.9:38:4.5:100, mixing is carried out, extrusion is carried out through a double-screw extruder, the extrusion temperature is 190℃, the screw rotation speed is 200 r / min, cooling is carried out, and pelletizing is carried out, to obtain a modifier;

[0083] Step four, the modifier, calcium stearate, and antioxidant 1010 are melt blended with PA6, the mass ratio of the modifier, calcium stearate, antioxidant 1010, and PA6 is 11:0.9:0.9:100, the temperature of melt blending is 270℃, extrusion is carried out, cooling is carried out, and pelletizing is carried out, to obtain high-strength and high-toughness modified plastic particles.

[0084] Comparative Example 1

[0085] This comparative example discloses a preparation method of high-strength and high-toughness modified plastic particles, which comprises the following steps:

[0086] Step one, MMT / CNTs is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 300 r / min, toluene-2, 4-diisocyanate and stannous octoate are added, the mass ratio of MMT / CNTs, toluene-2, 4-diisocyanate, stannous octoate, and toluene is 100:50:0.05:400, the reaction is carried out at 75℃ under nitrogen protection for 100 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain isocyanate group MMT / CNTs;

[0087] The preparation method of MMT / CNTs is the same as that in Example 1.

[0088] Step two, 3-hydroxypropyl acrylate is added into toluene, after stirring and dispersing for 30 min at a stirring speed of 300 r / min, isocyanate group MMT / CNTs and dibutyltin laurate are added, the mass ratio of 3-hydroxypropyl acrylate, isocyanate group MMT / CNTs, dibutyltin laurate, and toluene is 13:15:0.02:300, the reaction is carried out at 70℃ under nitrogen protection for 100 min, after the reaction is completed, centrifugation is carried out, the centrifugation precipitate is washed with toluene for 3 times, and then placed in a vacuum drying box at 40℃ to dry to constant weight, to obtain alkenyl-containing MMT / CNTs.

[0089] Step three, maleic anhydride and dicumyl peroxide are dissolved in acetone, and alkenyl-containing MMT / CNTs is added, stirring and dispersing is carried out at a stirring speed of 300 r / min for 30 min, to obtain a mixed solution;

[0090] The mixed solution is added into POE, the mass ratio of maleic anhydride, dicumyl peroxide, acetone, alkenyl-containing MMT / CNTs, and POE is 2:0.5:30:1.9:100, mixing is carried out, extrusion is carried out through a double-screw extruder, the extrusion temperature is 180℃, the screw rotation speed is 250 r / min, cooling is carried out, and pelletizing is carried out, to obtain a modifier;

[0091] Step four, the modifier, calcium stearate, and antioxidant 1010 are melt blended with PA6, the mass ratio of the modifier, calcium stearate, antioxidant 1010, and PA6 is 7.9:0.5:0.5:100, the temperature of melt blending is 260℃, extrusion is carried out, cooling is carried out, and pelletizing is carried out, to obtain high-strength and high-toughness modified plastic particles.

[0092] Comparative Example 2

[0093] This comparative example discloses a preparation method of high-strength and high-toughness modified plastic particles, which comprises the following steps:

[0094] Step 1: Add MMT / CNTs to toluene, stir and disperse at a stirring speed of 300 r / min for 30 minutes, then add toluene-2,4-diisocyanate and stannous octoate, the mass ratio of MMT / CNTs, toluene-2,4-diisocyanate, stannous octoate and toluene is 100:50:0.05:400, react at 75°C under nitrogen protection for 100 minutes, centrifuge after completion of the reaction, wash the centrifugal precipitate with toluene three times, and then dry it in a vacuum drying oven at 40°C to constant weight to obtain isocyanate-based MMT / CNTs;

[0095] Wherein, the preparation method of MMT / CNTs is the same as that of Example 1;

[0096] Step 2: Add 1,3-diglycerol alcohol diacrylate to toluene, stir and disperse at a stirring speed of 300 r / min for 30 minutes, then add isocyanate MMT / CNTs and dibutyltin laurate, the mass ratio of 1,3-diglycerol alcohol diacrylate, isocyanate MMT / CNTs, dibutyltin laurate and toluene is 34.8:15:0.02:300, react at 70°C under nitrogen protection for 100 minutes, centrifuge after completion of the reaction, wash the centrifugal precipitate with toluene three times, and then dry it in a vacuum drying oven at 40°C to constant weight to obtain alkenyl-containing MMT / CNTs;

[0097] Step 3: dissolving dicumyl peroxide in acetone, adding alkenyl-containing MMT / CNTs, and stirring and dispersing at a stirring speed of 300 r / min for 30 minutes to obtain a mixed solution;

[0098] The mixed solution was added to POE, with the mass ratio of dicumyl peroxide, acetone, alkenyl-containing MMT / CNTs and POE being 0.5:30:3:100, mixed, and extruded through a twin-screw extruder at an extrusion temperature of 180°C and a screw speed of 250 r / min, cooled, and pelletized to obtain a modifier;

[0099] Step 4: melt-blending the modifier, calcium stearate, antioxidant 1010 and PA6. The mass ratio of the modifier, calcium stearate, antioxidant 1010 and PA6 is 7.8:0.5:0.5:100. The melt-blending temperature is 260°C. Extrusion, cooling, and pelletizing are performed to obtain modified plastic particles with high strength and high toughness.

[0100] In the above examples and comparative examples, the particle size of the carboxylated multi-walled carbon nanotubes is 30-50 nm and the length is 10-20 μm; the particle size of the montmorillonite is 2000 mesh; the octene content in the POE is 24% to 28% and the density is 0.87 g / cm 3 ;The tensile strength of PA6 is 71.4MPa and the melting point is 225℃.

[0101] Test Example

[0102] (1) Tensile property: The modified plastic particles prepared in Examples 1-5 and Comparative Examples 1-2 were melted and injection molded to obtain test samples, and the tensile strength of the test samples was determined according to the standard ASTM D638-2014 "Standard Test Methods for Tensile Properties of Plastics", the test sample was Type IV sample, the total length of the test sample was 115 mm, the length of the narrow part was 33 mm, the total width was 19 mm, the width of the narrow part was 6 mm, the thickness was 4 mm, and the tensile speed was 10 mm / min. The determination results are shown in Table 1:

[0103] Table 1

[0104]

[0105] As can be seen from Table 1, the modified plastic particles prepared by the present application have high strength. Using PA6 as the base material, the modified plastic particles have high strength, and the tubular structure of carbon nanotubes and the lamellar structure of montmorillonite in the rigid nanofiller MMT / CNTs can synergistically enhance PA6, which can effectively compensate for the problem of the decrease of the tensile strength of the rigid polymer material PA6 caused by the introduction of the flexible toughening polymer POE, and the modifier can react with the amino group at the molecular chain end of PA6 through the grafted maleic anhydride group, thereby improving the compatibility of the modifier with PA6, and further improving the compatibility of the nanofiller MMT / CNTs grafted on the molecular chain of POE with PA6, and the tensile strength is further improved. Compared with Example 1, in Comparative Example 1, 3-hydroxypropyl acrylate was used instead of glycerol 1,3-diglyceryl acid dipropyl acrylate when preparing the modifier, i.e. the POE molecular chains cannot be crosslinked, avoiding the potential interfacial defects caused by the crosslinking network limiting the deformation of the POE matrix, and the tensile strength of the modified plastic particles is actually increased; in Comparative Example 2, maleic anhydride is not grafted when preparing the modifier, the modifier cannot be chemically bonded with PA6, the compatibility of the rigid nanofiller MMT / CNTs with PA6 is reduced, and the tensile strength of the modified plastic particles is decreased.

[0106] (2) Impact resistance: The notched Izod impact strength of the modified plastic particles prepared in Examples 1-5 and Comparative Examples 1-2 was determined according to the standard GB / T1843-2008 "Determination of the Izod Impact Strength of Plastics", and the determination results are shown in Table 2:

[0107] Table 2

[0108]

[0109] As shown in Table 2, the modified plastic particles prepared by the application have high toughness. In the preparation of the modified plastic particles, PA6 is used as the base material, and by introducing flexible toughening polymer POE into PA6, the toughness of PA6 can be effectively improved. The tubular carbon nanotubes and the layered montmorillonite in the nanofiller MMT / CNTs can synergistically toughen PA6. In addition, in the preparation process of the modifier, the introduced glycerol 1,3-diglycerol acid diacrylate is a polyene compound, which can not only realize the grafting of the nanofiller MMT / CNTs and the POE molecular chain, but also realize the moderate crosslinking between the POE molecular chains to form a three-dimensional crosslinking network structure. The crosslinking structure more effectively induces the shear yielding or cavitation of the matrix, promotes the PA6 matrix to occur plastic deformation such as silver streaks and shear bands, and absorbs impact energy, thereby further improving the toughness of the PA6-based modified plastic particles. Compared with Example 1, in Comparative Example 1, 3-hydroxypropyl acrylate is used instead of glycerol 1,3-diglycerol acid diacrylate in the preparation of the modifier, that is, the crosslinking between the POE molecular chains does not occur, the toughness of the modified plastic particles decreases, and the impact strength decreases. In Comparative Example 2, maleic anhydride is not introduced in the preparation of the modifier, the modifier cannot be chemically bonded with PA6, the compatibility of the rigid nanofiller MMT / CNTs with PA6 decreases, and the impact strength also decreases.

[0110] Although the embodiments of the application have been shown and described, it is to be understood that for the purpose of the present application, the changes in the embodiments, the modifications, the replacements and the variations can be made by those skilled in the art without departing from the principles and the spirit of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a modified plastic particle having high strength and high toughness, characterized by comprising the steps of: It comprises the following steps: ​ Step one, MMT / CNTs is added into toluene, after stirring and dispersing, diisocyanate and catalyst are added, reaction, after reaction, centrifugal, washing, drying, isocyanate group MMT / CNTs is obtained; Step two, glycerol 1, 3-diglycerol diacrylate is added into toluene, after stirring and dispersing, isocyanate group MMT / CNTs and catalyst are added, reaction, after reaction, centrifugal, washing, drying, MMT / CNTs containing alkenyl is obtained; Step three, maleic anhydride and initiator are dissolved in acetone, MMT / CNTs containing alkenyl is added, stirring and dispersing, a mixed solution is obtained; The mixed solution is added into POE, mixing, extruding through double screw extruder, cooling, granulating, a modifier is obtained; Step four, the modifier, auxiliary agent and PA6 are melt blended, extruding, cooling, granulating, high strength and high toughness modified plastic particles are obtained.

2. The method of claim 1, wherein the modified plastic particle has a high strength and a high toughness. In the step one, the mass ratio of MMT / CNTs, diisocyanate, catalyst and toluene is 100: (50-70) : (0.05-0.1) : (400-600), the reaction condition is that the reaction is carried out under nitrogen protection at 75-85℃ for 60-100min.

3. The method of claim 1, wherein the modified plastic particles have a high strength and a high toughness. The MMT / CNTs in the step one, It is prepared by the following steps: S1, N, N'-diisopropyl carbodiimide, 1-hydroxybenzotriazole, carboxylated multi-walled carbon nanotube are added into N, N-dimethylformamide, ultrasonic dispersion, a carbon nanotube dispersion solution is obtained, triethylenetetramine is added into the carbon nanotube dispersion solution, reaction, after reaction, filtration, washing, drying, modified carbon nanotube is obtained; S2, the modified carbon nanotube is added into deionized water, after ultrasonic dispersion, hydrochloric acid is added dropwise under stirring condition, stirring reaction, a carbon nanotube ammonium salt dispersion solution is obtained; Montmorillonite is added into deionized water, after ultrasonic dispersion, the carbon nanotube ammonium salt dispersion solution is added, reaction, after reaction, filtration, washing, drying, MMT / CNTs is obtained.

4. The method of claim 3, wherein the modified plastic particles have a high strength and a high toughness. In the S1, the mass ratio of N, N'-diisopropyl carbodiimide, 1-hydroxybenzotriazole, carboxylated multi-walled carbon nanotube, N, N-dimethylformamide, triethylenetetramine is (0.01-0.03) : (0.01-0.03) : (0.8-1.2) : (95-105) : (0.4-0.6), the reaction condition is that the reaction is carried out under stirring at room temperature for 20-30h.

5. The method of claim 3, wherein the modified plastic particles have a high strength and a high toughness. In the S2, when the carbon nanotube ammonium salt dispersion solution is prepared, the mass ratio of modified carbon nanotube, deionized water, hydrochloric acid is (1-2) : (80-120) : (10-15), the reaction condition is that the reaction is carried out under stirring at room temperature for 20-40min; When MMT / CNTs is prepared, the mass ratio of montmorillonite, deionized water, carbon nanotube ammonium salt dispersion solution is (8-12) : (150-250) : (91-137), the reaction condition is that the reaction is carried out under stirring at 70-90℃ for 20-30h.

6. The method of claim 1, wherein the modified plastic particles have a high strength and a high toughness. The mass ratio of glycerol 1,3-diglycerol acid diacrylate, isocyanate-based MMT / CNTs, catalyst and toluene in the second step is (34.8-36.5):(15-17):(0.02-0.04):(300-500), and the reaction condition is 60-100 min under nitrogen protection at 70-90℃. The catalyst comprises dibutyl tin laurate.

7. The method of claim 1, wherein the modified plastic particles have a high strength and a high toughness. The mass ratio of maleic anhydride, initiator, acetone, alkenyl-containing MMT / CNTs and POE in the third step is (2-4):(0.5-1):(30-40):(3-5):100, the extrusion temperature is 180-200℃, and the screw rotation speed is 150-250r / min. The initiator comprises dicumyl peroxide.

8. The method of claim 1, wherein the modified plastic particle has a high strength and a high toughness. The mass ratio of modifier, auxiliary agent and PA6 in the fourth step is (8-12):(1-2):100, and the temperature of melt blending is 260-280℃. The auxiliary agent comprises lubricant and antioxidant. 9.A high-strength and high-toughness modified plastic particle prepared by the method of any one of claims 1-8. 10.A use of the high-strength and high-toughness modified plastic particle of claim 9.

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