Interface modifier and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to an interface modifier and a preparation method thereof. According to the preparation method provided by the invention, a carbon free radical is formed on a molecular chain of polyolefin through initiation of an initiator, and then the carbon free radical and vinyl in maleic anhydride or alkoxy silane are subjected to a free radical addition reaction, so that an anhydride group or an alkoxy silane group is introduced on the molecular chain of polyolefin. The anhydride group can improve the interface between the plant fiber powder and polyolefin, and is used for toughening a polar high polymer material due to good compatibility; the alkoxy silane group can react with a polar group on the surface of the inorganic filler to form a covalent bond, so that the compatibility of the inorganic filler and a resin matrix is enhanced, the purpose of improving the material performance is achieved, and the performance of a polymer composite material added with various different types of fillers can be improved. Therefore, the technical problem that the existing interface modifier cannot well improve the performance of the polymer composite material added with various different types of fillers is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to an interfacial modifier and a preparation method thereof. Background Art

[0002] To meet the requirements of different application scenarios for the performance of polymer materials, it is often necessary to add other polymers or fillers to the polymer matrix for blending or composite modification. The compatibility between the filler and the polymer matrix is a key factor restricting the material performance. Therefore, it is necessary to additionally add a suitable interfacial modifier to ensure the compatibility between the filler and the polymer matrix, so as to prepare a polymer blend material or a polymer composite material that meets the performance requirements.

[0003] Common interfacial modifiers for polymer materials include, one is small molecule coupling agents, mainly silane coupling agents, titanate coupling agents, etc., and it is often necessary to perform an infiltration treatment on the filler before preparing the composite material. The other is to add macromolecular compatibilizers, various functional monomer grafted polymers, such as maleic anhydride grafted polyolefins, copolymers of acrylate monomers and olefins, etc., which are suitable for the one-step preparation of polymer composite materials by melt processing. Common interfacial modifiers on the market generally only apply to specific resin matrices and fillers. Small molecule coupling agents are more suitable for inorganic or metal fillers, and macromolecular compatibilizers are suitable for interfacial modification of resins with large polarity differences or resins with specific fillers. For multi-component composite materials, especially polymer composite materials filled with multi-category fillers, the modification effect of conventional single interfacial modifiers is difficult to achieve the best. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide an interfacial modifier and a preparation method thereof, which solve the technical problem that the existing interfacial modifiers have poor performance improvement for polymer composite materials added with multiple different types of fillers.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention provides a preparation method of an interfacial modifier, including the following steps: Using alkoxysilane, maleic anhydride, initiator and polyolefin as raw materials, after mixing the raw materials evenly, performing melt mixing, under the action of the initiator, grafting acid anhydride groups and alkoxysilyl groups onto the molecular chain of the polyolefin to obtain an interfacial modifier containing acid anhydride groups and alkoxysilyl groups. Among them, based on the weight of the polyolefin, the dosage of alkoxysilane is 0.1% - 5%, the dosage of maleic anhydride is 0.5% - 5%, and the dosage of the initiator is 0.1% - 2%.

[0006] Carbon free radicals are formed on the main chain, side groups or end groups of polyolefins by initiators, and then the carbon free radicals undergo free radical addition reactions with the vinyl groups in maleic anhydride or alkoxysilane molecules, thereby introducing anhydride groups or alkoxysilyl groups on the main chain, side chain or end groups of polyolefins. The anhydride groups in the structure of the interfacial modifier have excellent improvement effects on the interface between plant fiber powder and polyolefins, and it also has good compatibility with polar polymer materials and can be used for toughening polar polymer materials; the alkoxysilyl groups in the structure of the interfacial modifier can react with the polar groups on the surface of inorganic fillers such as glass fiber or carbon fiber to form covalent bonds, enhancing the compatibility between the filler and the resin matrix, achieving the purpose of improving material properties, thereby being able to improve the properties of polymer composites filled with various different types of fillers, and further solving the technical problem that the existing interfacial modifiers have poor performance improvement for polymer composites filled with various different types of fillers.

[0007] See Figure 1 Taking the synthesis route of Figure 1 as an example, using vinyltrimethoxysilane, maleic anhydride, diisopropylbenzene peroxide and linear low density polyethylene as raw materials, wherein, diisopropylbenzene peroxide is used as an initiator, and under the action of the initiator, anhydride groups and trimethoxysilyl groups are grafted onto the molecular chain of linear low density polyethylene to obtain an interfacial modifier containing anhydride groups and alkoxysilyl groups.

[0008] Optionally, the temperature of the melt mixing is 160 °C to 220 °C.

[0009] Preferably, based on the weight of the polyolefin, the dosage of the alkoxysilane is 0.5% - 1%, the dosage of maleic anhydride is 1% - 2%, and the dosage of the initiator is 0.2% - 0.5%.

[0010] Optionally, the polyolefin is any one of polyethylene, polypropylene and polyolefin elastomer.

[0011] Optionally, the alkoxysilane is at least one of vinyltrimethoxysilane and vinyltriethoxysilane.

[0012] Optionally, the initiator is any one of diisopropylbenzene peroxide, benzoyl peroxide, di-tert-butylperoxyisopropylbenzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0013] The present invention provides an interfacial modifier prepared by using the above-mentioned preparation method of the interfacial modifier.

[0014] The beneficial effects of the present invention are as follows. Compared with the prior art, the preparation method provided by the present invention forms carbon free radicals on the main chain, side groups or end groups of polyolefins through the initiation of initiators, and then the carbon free radicals undergo free radical addition reactions with the vinyl groups in maleic anhydride or alkoxysilane molecules, thereby introducing anhydride groups or alkoxysilyl groups on the main chain, side chains or end groups of polyolefins. The anhydride groups in the structure of the interfacial modifier have excellent improvement effects on the interface between plant fiber powder and polyolefins, and it also has good compatibility with polar polymer materials and can be used for toughening polar polymer materials; the alkoxysilyl groups in the structure of the interfacial modifier can react with the polar groups on the surface of inorganic fillers such as glass fiber or carbon fiber to form covalent bonds, enhancing the compatibility between the filler and the resin matrix, achieving the purpose of improving material properties, thereby being able to improve the properties of polymer composites filled with various different types of fillers, and further solving the technical problem that the existing interfacial modifiers have poor performance improvement for polymer composites filled with various different types of fillers.

[0015] In addition, the alkoxysilyl groups can further form covalent bonds or generate self-crosslinking with the polar interface under the action of moisture and heat, which can further improve the interfacial effect or increase the material strength. Alkoxysilanes are all liquids, and after infiltrating the surface of polyolefin particles, they can play the role of adhering maleic anhydride and initiators, ensuring that each component can be mixed evenly, simplifying the process steps, avoiding the exhaust gas generated by additional addition of solvents or heating, improving the working environment, and alleviating the pressure of exhaust gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the synthesis route of an interfacial modifier provided by the present invention.

[0017] Figure 2 It is an infrared spectrogram of the multifunctional LLDPE interfacial modifier and LLDPE prepared in Example 2 of the present invention.

[0018] Figure 3 It is a cross-sectional morphology diagram of a composite material formed by adding LLDPE to carbon fiber reinforced nylon 66.

[0019] Figure 4 It is a cross-sectional morphology diagram of a composite material formed by adding the multifunctional LLDPE interfacial modifier prepared in Example 2 to carbon fiber reinforced nylon 66. DETAILED DESCRIPTION OF THE INVENTION

[0020] To solve the above technical problems, the present invention provides an interfacial modifier and its preparation method. Now, the technical solutions and embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] PE, Polyethylene, polyethylene.

[0022] POE, Poly Olefin Elastomer, is a polyolefin elastomer.

[0023] LLDPE, Linear Low Density Polyethylene, is linear low density polyethylene.

[0024] HDPE, High Density PolyEthylene, is high density polyethylene.

[0025] PP, Polypropylene, is polypropylene.

[0026] The technical solution adopted in the present invention is as follows: First, the initiator is dispersed in alkoxysilane to obtain a mixed solution.

[0027] Then, the mixed solution of the initiator and alkoxysilane, together with the polyolefin and maleic anhydride, is added to a mixer and mixed evenly.

[0028] Finally, the uniformly mixed material is added to a polymer melt kneader for high-temperature melt kneading, and the interfacial modifier can be obtained after sufficient reaction.

[0029] Specifically, the polymer melt kneader can be a co-rotating parallel twin-screw extruder, an internal mixer or a multi-screw extruder. Preferably, a co-rotating parallel twin-screw extruder is used.

[0030] The present invention will be described in detail below through specific examples. The examples are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0031] In the embodiments of the present application, the polyolefin elastomer used is produced by Dow Chemical Company in the United States, and the model is ENGAGE TM 8200. The linear low density polyethylene used is produced by Zhenhai Refining & Chemical Company, and the model is DFDA-7042. The high density polyethylene used is produced by Dushanzi Petrochemical Company, and the model is DMDA-8008. The PP used is produced by Shanghai Petrochemical Company, and the model is T300.

[0032] Example 1 Using vinyltriethoxysilane, maleic anhydride, di-tert-butyl peroxyisopropylbenzene and polyolefin elastomer as raw materials, wherein, based on the weight of the polyolefin elastomer, the amount of vinyltriethoxysilane is 0.5%, the amount of maleic anhydride is 1%, and the amount of di-tert-butyl peroxyisopropylbenzene is 0.2%.

[0033] First, dissolve di - tert - butyl peroxyisopropylbenzene in vinyltriethoxysilane to obtain a mixed solution. Then, mix the mixed solution, polyolefin elastomer, and powdered maleic anhydride evenly with a mixer to obtain a mixture.

[0034] Add the mixture into a co - rotating parallel twin - screw extruder and conduct melt mixing at a temperature of 190 °C, then extrude and pelletize to obtain a multi - functionalized POE interfacial modifier. This interfacial modifier can be applied to hot - melt adhesives and can also be used for toughening various rigid polymer composites.

[0035] Comparative Example 1 The polyolefin elastomer in Example 1.

[0036] Example 2 Using vinyltrimethoxysilane, maleic anhydride, di - isopropylbenzene peroxide, and linear low - density polyethylene as raw materials. Among them, based on the weight of linear low - density polyethylene, the amount of vinyltrimethoxysilane is 1%, the amount of maleic anhydride is 2%, and the amount of di - isopropylbenzene peroxide is 0.3%.

[0037] First, dissolve di - isopropylbenzene peroxide in vinyltrimethoxysilane to obtain a mixed solution. Then, mix the mixed solution, LLDPE, and powdered maleic anhydride evenly with a mixer to obtain a mixture.

[0038] Add the mixture into a co - rotating parallel twin - screw extruder and conduct melt mixing at a temperature of 180 °C, then extrude and pelletize to obtain a multi - functionalized LLDPE interfacial modifier. This interfacial modifier is suitable for various PE - based composites and can also be used for toughening polyamide composites.

[0039] Figure 2 The infrared spectra of the multi - functionalized LLDPE interfacial modifier prepared in Example 2 and LLDPE. Through Figure 2 It can be seen that the multi - functionalized LLDPE interfacial modifier prepared in this example successfully grafts anhydride groups and alkoxysilyl groups onto LLDPE.

[0040] Comparative Example 2 The linear low - density polyethylene in Example 2.

[0041] Example 3 Using vinyltriethoxysilane, maleic anhydride, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane, and high - density polyethylene as raw materials. Among them, based on the weight of high - density polyethylene, the amount of vinyltriethoxysilane is 0.5%, the amount of maleic anhydride is 1%, and the amount of 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane is 0.3%.

[0042] First, dissolve 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane in vinyltriethoxysilane, and then mix the above solution evenly with high-density polyethylene, powdered maleic anhydride using a mixer to obtain a mixture.

[0043] Add the mixture to a co-rotating parallel twin-screw extruder and carry out melt mixing at a temperature of 180 °C, and then extrude and pelletize to obtain a multifunctional grafted HDPE interfacial modifier. This interfacial modifier is suitable for the compatibilization of various polymer composites, especially for PE-based wood-plastic composites filled with inorganic fillers and wood powder.

[0044] Comparative Example 3 The high-density polyethylene in Example 3.

[0045] Example 4 Using vinyltrimethoxysilane, maleic anhydride, benzoyl peroxide and PP as raw materials, among which, based on the amount of PP by weight, the amount of vinyltrimethoxysilane is 1%, the amount of maleic anhydride is 2%, and the amount of benzoyl peroxide is 0.5%.

[0046] First, disperse benzoyl peroxide in vinyltrimethoxysilane to obtain a mixed solution, and then mix the mixed solution evenly with PP and powdered maleic anhydride using a mixer to obtain a mixture.

[0047] Add the mixture to a co-rotating parallel twin-screw extruder and carry out melt mixing at a temperature of 200 °C, and then extrude and pelletize to obtain a multifunctional grafted PP interfacial modifier. This interfacial modifier is suitable for the compatibilization of various PP-based composites. Especially suitable for PP-based wood-plastic composites filled with inorganic fillers and wood powder, and also suitable for glass fiber-reinforced PP composites or PP flame-retardant composites.

[0048] Comparative Example 4 The PP in Example 4.

[0049] It should be noted that in the preparation steps of Examples 1 to 4, since the raw materials contain a variety of polymer materials, and the melting behavior of the polymer materials is completed within a certain temperature range, the temperature during the melt mixing process is an interval value, rather than a fixed value.

[0050] Example 5 The difference from Example 2 is that the amount of vinyltrimethoxysilane is 0.1%.

[0051] Example 6 The difference from Example 2 is that the amount of vinyltrimethoxysilane is 5%.

[0052] Example 7 The difference from Example 2 is that the amount of maleic anhydride is 0.5%.

[0053] Example 8 The difference from Example 2 is that the dosage of maleic anhydride is 5%.

[0054] Example 9 The difference from Example 2 is that the dosage of dicumyl peroxide is 0.1%.

[0055] Example 10 The difference from Example 2 is that the dosage of dicumyl peroxide is 2%.

[0056] Example 11 The difference from Example 2 is that the temperature of melt mixing is 160 °C.

[0057] Example 12 The difference from Example 2 is that the temperature of melt mixing is 220 °C.

[0058] It should be noted that compared with Example 2, there are no obvious differences in the performance of the interfacial modifiers prepared in Examples 5 to 10.

[0059] The application effects of the multifunctional interfacial modifiers in the following specific examples and the non-functionalized polymer materials in the corresponding composite materials were compared, and the statistical results are shown in Table 1.

[0060] Table 1 Statistical Table of Application Effects Figure 3 It is a cross-sectional morphology diagram of a composite material formed by adding LLDPE to carbon fiber reinforced nylon 66. Figure 4 It is a cross-sectional morphology diagram of a composite material formed by adding the multifunctional LLDPE interfacial modifier prepared in Example 2 to carbon fiber reinforced nylon 66.

[0061] Combined Figure 3 、 Figure 4 And the data in Table 1 show that compared with the conventional polymer interfacial modifiers, the interfacial modifiers prepared in Examples 1 to 4 of this application can significantly improve the impact strength and flexural strength of the base material, indicating that the interfacial modifier and its preparation method provided in this application can solve the technical problem that the existing interfacial modifiers have poor performance improvement for polymer composite materials filled with multiple different types of fillers.

[0062] The above-described are only the preferred embodiments of the present invention, and the above specific embodiments are not limitations on the present invention. Various deformations and modifications can occur within the scope of the technical idea of the present invention. Any retouching, modification, or equivalent replacement made by those of ordinary skill in the art according to the above description shall fall within the scope protected by the present invention.

Claims

1. A method for preparing an interfacial modifier, characterized in that: The steps include: Alkoxysilane, maleic anhydride, initiator and polyolefin are used as raw materials, the raw materials are mixed evenly, and then melt-kneaded. Under the action of the initiator, anhydride groups and alkoxysilane groups are grafted on the molecular chain of polyolefin to obtain an interface modifier containing anhydride groups and alkoxysilane groups; Wherein, based on the amount of polyolefin used, the amount of alkoxysilane used is 0.1% to 5%, the amount of maleic anhydride used is 0.5% to 5%, and the amount of initiator used is 0.1% to 2%.

2. The method for preparing the interface modifier according to claim 1, characterized in that: The temperature of the melt kneading is 160°C to 220°C.

3. The method for preparing the interface modifier according to claim 1, characterized in that: Based on the weight of polyolefin, the amount of alkoxysilane is 0.5% to 1%, the amount of maleic anhydride is 1% to 2%, and the amount of initiator is 0.2% to 0.5%.

4. The method for preparing an interface modifier according to claim 1, characterized in that: The polyolefin is any one of polyethylene, polypropylene and polyolefin elastomer.

5. The method for preparing an interface modifier according to claim 1, characterized in that: The alkoxysilane is at least one of vinyltrimethoxysilane and vinyltriethoxysilane.

6. The method for preparing an interface modifier according to claim 1, characterized in that: The initiator is any one of dicumyl peroxide, benzoyl peroxide, di-tert-butylcumyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

7. An interface modifier, characterized in that The interface modifier is prepared by the preparation method of the interface modifier according to any one of claims 1 to 6.

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