Filler-free rubber composite material reinforced by multiple hydrogen bonds as well as preparation method and application of filler-free rubber composite material

Abstract

The invention discloses a filler-free rubber composite material reinforced by multiple hydrogen bonds as well as a preparation method and application of the filler-free rubber composite material. The method for introducing sacrificial bonds into non-polar rubber through simple processing comprises the following steps: firstly, preparing a micromolecular cross-linking agent (dCB) with multiple hydrogen bond donors / receptors; secondly, the dCB is grafted to an ENR molecular chain to form a unique eight-fold hydrogen bond structure; and finally, dispersing ENR / dCBx into SSBR in the form of organic filler through simple processing technologies such as internal mixing-open mixing, and reacting with double bonds of ENR and SSBR through sulfur vulcanization. The strength, the ductility, the wear resistance and the fatigue resistance of the rubber composite material are obviously improved. It is worthy of noting that the novel method provided in the research has good universality, is not only suitable for an SSBR system, but also can be further popularized to other types of rubber systems, and the preparation process is completely compatible with an existing rubber industrial production line and has good industrial application potential.

Description

Technical Field

[0001] The present invention relates to the field of rubber industry, and in particular to a rubber composite material reinforced by multiple hydrogen bonds without the need for fillers, and a preparation method and application thereof. Background Art

[0002] Due to their unique high elasticity and flexibility, rubber materials play an irreplaceable role in tires, transportation, construction, aviation and other fields. However, even after cross-linking with sulfur, the mechanical properties of most rubbers are still very low, and fillers are usually added to enhance the mechanical properties. Currently, the most commonly used reinforcing fillers in rubber composites are carbon black, silica, clay, etc. However, the addition of large amounts of fillers will complicate the processing process, increase energy consumption, and cause environmental pollution, which is contrary to the concept of modern green chemistry. Materials in nature often have extraordinary strength and toughness, such as spider silk, mussel byssus, and bone. Studies have shown that these materials have structures that can dissipate energy, such as the ionic coordination bonds in bones and the multi-hydrogen bond structure in mussel byssus. These energy-dissipating structural units are called sacrificial bonds. When the material is subjected to external force, the sacrificial bonds will break before the covalent bonds in the molecular chain break, and dissipate some energy, thereby achieving the effect of strengthening and toughening. Inspired by natural materials, researchers have attempted to introduce non-covalent bonds into rubber materials to achieve rubber reinforcement. This method dissipates energy by constructing sacrificial bonds within the rubber composite, achieving a good reinforcement effect without the need to add fillers. Currently, in most studies on the introduction of sacrificial bonds into rubber composites, researchers have mainly introduced sacrificial bonds into rubbers with polar groups. There are relatively few reports on the introduction of sacrificial bonds into non-polar rubbers (such as solution-polymerized styrene-butadiene rubber). In the research reports on the introduction of sacrificial bond structures into non-polar rubbers, the rubber molecular chains are usually structurally modified. The production and preparation process is complex and difficult, the production cost is relatively high, and it is difficult to achieve large-scale application in industry. Therefore, it is of great significance to develop a non-polar rubber material that does not require fillers and uses sacrificial bonds to reinforce it. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a rubber composite material reinforced by multiple hydrogen bonds without fillers, and its preparation method and application. The rubber material has good tensile strength, excellent elongation at break, and good wear resistance and fatigue resistance.

[0004] In order to achieve the above-mentioned object, the present invention adopts the following technical scheme: a rubber composite material reinforced by multiple hydrogen bonds without filler, which includes, by mass fraction, 20 parts of epoxy natural rubber, 80 parts of solution-polymerized styrene-butadiene rubber, 5 parts of zinc oxide, 4 parts of stearic acid, 0.5 parts of diphenylguanidine, 2.2 parts of 2-thiolbenzothiazole, 1.96 parts of benzothiazole disulfide, 1.5 parts of N-cyclohexyl-N'-phenyl-p-phenylenediamine, 0.32 parts of dithiocarbonyldimethylamine disulfide, 1 part of sulfur and 1-4 parts of a multiple hydrogen bond crosslinking agent as preparation raw materials.

[0005] The multiple hydrogen bond crosslinker is prepared using 1,4-bis(acryloyloxy)butane, cytosine, potassium carbonate and dimethyl sulfoxide as raw materials, and the mass ratio of butane, cytosine, potassium carbonate and dimethyl sulfoxide is 10:12.34:1:250.

[0006] The method for preparing the rubber composite material reinforced by multiple hydrogen bonds without fillers comprises the following steps:

[0007] 1) Preparation of a multiple hydrogen bond crosslinker: 1,4-bis(acryloyloxy)butane, cytosine, and dimethyl sulfoxide are thoroughly mixed, followed by addition of potassium carbonate. After thorough stirring, the mixture is filtered, washed, and finally dried at 55-65°C to obtain a multiple hydrogen bond crosslinker for use.

[0008] 2) Preparation of Epoxidized Natural Rubber / Multiple Hydrogen Bond Crosslinker: The components were taken according to the above mass fractions, and the Epoxidized Natural Rubber was added to an internal mixer and kneaded for 5 minutes. The multiple hydrogen bond crosslinker was added and thoroughly mixed. The Epoxidized Natural Rubber mixed with the multiple hydrogen bond crosslinker was then placed in a flat vulcanizer and hot pressed at 120°C and 10 MPa for 20 minutes to obtain the Epoxidized Natural Rubber / Multiple Hydrogen Bond Crosslinker.

[0009] 3) Preparation of a rubber composite material reinforced by multiple hydrogen bonds without fillers: Epoxy natural rubber / multiple hydrogen bond crosslinking agent and solution-polymerized styrene-butadiene rubber were added to a mixer and kneaded for 5 minutes, followed by the addition of zinc oxide and stearic acid, mixed evenly, and then taken out; after cooling, the mixture was put on an open mill for refining, and diphenylguanidine, 2-mercaptobenzothiazole, benzothiazole disulfide, N-cyclohexyl-N'-phenyl-p-phenylenediamine, dimethyldithiocarbonyl disulfide, and sulfur were added in sequence, mixed evenly, and then hot-pressed to obtain a rubber composite material reinforced by multiple hydrogen bonds without fillers.

[0010] The rubber composite material reinforced by multiple hydrogen bonds without the need for fillers is used in the preparation of sole rubber materials.

[0011] Compared with the prior art, the present invention does not require the addition of any filler, and only a small amount of polar rubber is needed to achieve the reinforcement and toughening of traditional non-polar rubber. First, an octahydrogen bond structure is constructed in epoxidized natural rubber (ENR), which is then dispersed into solution-polymerized styrene-butadiene rubber (SSBR) as a filling phase, and the ENR and SSBR main chains are connected by sulfur bonds to form an interpenetrating network structure, successfully achieving a significant improvement in the strength and ductility of the composite material. The rubber composite material preparation process is simple, requiring only conventional rubber processing methods such as open mixing and banburying, and is fully compatible with existing rubber industrial production lines. The method can be further extended to other types of rubber, providing a new research idea for the development of high-strength and high-toughness rubber composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The structural characterization diagram of dCB, including Fourier transform infrared spectrum, nuclear magnetic hydrogen spectrum, nuclear magnetic carbon spectrum and thermogravimetric analysis diagram;

[0013] Figure 2 The RPA test results of SSBR / ENR / dCBx compounds with different dCB contents are shown in Figure 1, where x represents the number of dCB added per 100 parts of rubber material, which are SSBR / ENR / dCB0, SSBR / ENR / dCB1, SSBR / ENR / dCB2, SSBR / ENR / dCB3, SSBR / ENR / dCB4, Figure 2 The figure includes the relationship between the storage modulus (G'), loss modulus (G") and loss factor (tanδ) of SSBR / ENR / dCBx rubber compounds as a function of strain;

[0014] Figure 3 is the vulcanization characteristic curve of SSBR / ENR / dCBx;

[0015] Figure 4 is the crosslink density of SSBR / ENR / dCBx composite;

[0016] Figure 5 Mechanical properties of SSBR / ENR / dCBx composites, including stress-strain curves of SSBR / ENR / dCBx composites, toughness of SSBR / ENR / dCBx composites, and cyclic tensile curves of SSBR / ENR / dCB4 ​​composites;

[0017] Figure 6 This is the scanning electron microscopy (SEM) image of the tensile cross section of the SSBR / ENR / dCBx composite material;

[0018] Figure 7Akron wear volume diagram of SSBR / ENR / dCBx composite material and 60℃ creep curve diagram of SSBR / ENR / dCBx composite material;

[0019] Figure 8 SEM image of the Akron worn surface of SSBR / ENR / dCBx composite;

[0020] Figure 9 is the fatigue performance diagram of SSBR / ENR / dCBx composite material; DETAILED DESCRIPTION

[0021] In order to demonstrate the application of the rubber composite material reinforced by multiple hydrogen bonds without fillers of the present invention, the present invention is further described below with reference to specific examples, but the protection scope of the present invention is not limited thereto.

[0022] Example 1:

[0023] A rubber composite material reinforced by multiple hydrogen bonds without filler is prepared, calculated by mass, including 20 parts of epoxy natural rubber, 80 parts of solution-polymerized styrene-butadiene rubber, 5 parts of zinc oxide, 4 parts of stearic acid, 0.5 parts of diphenylguanidine, 2.2 parts of 2-thiolbenzothiazole, 1.96 parts of benzothiazole disulfide, 1.5 parts of N-cyclohexyl-N'-phenyl-p-phenylenediamine, 0.32 parts of dimethyldithiocarbonylamine disulfide, 1 part of sulfur and 1-4 parts of dCB; wherein the dCB is prepared from 10 parts of 1,4-bis(acryloyloxy)butane, 12.34 parts of cytosine, 1 part of potassium carbonate and 250 parts of dimethyl sulfoxide; after preparation, 1 part, 2 parts, 3 parts and 4 parts of dCB are respectively taken as raw materials for preparing different material proportions.

[0024] Preparation of dCB: 1,4-bis(acryloyloxy)butane (10 g, 50.44 mmol), cytosine (12.34 g, 111 mmol), and K2CO3 (1 g, 3.62 mmol) were placed in a 500 mL round-bottom flask at room temperature. 250 mL of DMSO was then added to the round-bottom flask, and the suspension was stirred at room temperature overnight. The reaction mixture was poured into 1.2 L of deionized water and allowed to stand for 1 hour. The white precipitate was isolated by vacuum filtration, purified by multiple washings, and then dried in an oven to obtain dCB for later use.

[0025] Preparation of ENR / dCBx: Epoxidized natural rubber (ENR) was added to an internal mixer and kneaded for 5 minutes. A multi-hydrogen bond crosslinker (dCB) was added according to the ratio of claim 1 and thoroughly mixed. The ENR mixed with dCB was then placed in a flat vulcanizer and hot-pressed at 120°C and 10 MPa for 20 minutes to obtain ENR / dCBx.

[0026] Preparation of SSBR / ENR / dCBx: According to the ratio in claim 1, ENR / dCBx and solution-polymerized styrene-butadiene rubber (SSBR) are added to a mixer and kneaded for 5 minutes, and then zinc oxide and stearic acid are added in sequence. After mixing evenly, the mixture is taken out. After cooling, the mixture is mixed on an open mill, and diphenylguanidine, 2-mercaptobenzothiazole, benzothiazole disulfide, N-cyclohexyl-N'-phenyl-p-phenylenediamine, dimethyldithiocarbonyl disulfide and sulfur are added in sequence. After finally mixing evenly, the mixture is hot-pressed using a flat-plate vulcanizer according to the positive vulcanization time of different samples to obtain an SSBR / ENR / dCBx composite material.

[0027] Figure 1 The successful synthesis of dCB was demonstrated by various characterization methods, and the thermal stability of dCB met the rubber processing temperature requirements.

[0028] according to Figure 2 It can be seen that hydrogen bonds have been successfully introduced into the SSBR / ENR / dCBx material.

[0029] according to Figure 3 It can be seen that the addition of dCB can improve the vulcanization efficiency. The vulcanization time is increased from 265 seconds for SSBR / ENR / dCB0 to 235 seconds for SSBR / ENR / dCB4, and the vulcanization efficiency is increased by 11.3%.

[0030] according to Figure 4 It can be seen that the addition of dCB increases the crosslinking density of SSBR / ENR / dCBx composites from 1.7×10 -4 mol / cm 3 Improved to 1.82×10 for SSBR / ENR / dCB4 -4 mol / cm 3 .

[0031] according to Figure 5 It can be seen that when the dCB addition amount increases from 0phr to 4phr, the tensile strength of the rubber composite material increases from 2.1MPa to 4.88MPa (an increase of 132%), the elongation at break jumps from 240% to 500% (an increase of 108%), and the fracture toughness increases from 3.2MJ / m 3 Significantly increased to 12.4MJ / m 3 (Increase of 288%). Figure 6 It can be seen that the cross-section of SSBR / ENR / dCBx composites shows a typical river-like pattern. As the dCB content increases, the cross-sectional morphology of the composite material changes significantly. The river-like pattern gradually decreases and the cross-sectional flatness is significantly improved. This cross-sectional morphology usually reflects that the vulcanized rubber has excellent mechanical strength and anti-destruction properties.

[0032] according to Figure 7 It can be seen that after adding dCB, the Akron wear volume of the rubber composite material is reduced from 1.37 cm 3 to 1.26 cm 3 , and the wear resistance is improved by 8%. After the creep test at 60°C for 30 min, the creep value of the SSBR / ENR / dCB0 composite material is 6.4%, while the creep value of the SSBR / ENR / dCB4 composite material is 5.8%, which is improved by 9.4%. According to Figure 8 It can be seen that after adding dCB to introduce eight hydrogen bonds, the wear trace of the material is gradually flat, the ridge distance is smaller and smaller, the wear trace is shallower and shallower, and the wear resistance of the material is improved.

[0033] According to Figure 9 It can be seen that after adding dCB to introduce sacrifice bond, the fatigue resistance of the SSBR / ENR / dCBx composite material is improved, and the service life can be effectively improved.

Claims

1. A rubber composite material reinforced by multiple hydrogen bonds without filler, characterized in that: The preparation raw materials, calculated by mass fraction, include 20 parts of epoxy natural rubber, 80 parts of solution-polymerized styrene-butadiene rubber, 5 parts of zinc oxide, 4 parts of stearic acid, 0.5 parts of diphenylguanidine, 2.2 parts of 2-thiolbenzothiazole, 1.96 parts of benzothiazole disulfide, 1.5 parts of N-cyclohexyl-N'-phenyl-p-phenylenediamine, 0.32 parts of dimethyldithiocarbonylamine disulfide, 1 part of sulfur and 1-4 parts of a multiple hydrogen bond crosslinking agent.

2. The rubber composite material according to claim 1, wherein: The multiple hydrogen bond crosslinker is prepared using 1,4-bis(acryloyloxy)butane, cytosine, potassium carbonate and dimethyl sulfoxide as raw materials, and the mass ratio of butane, cytosine, potassium carbonate and dimethyl sulfoxide is 10:12.34:1:

250.

3. A method for preparing a rubber composite material reinforced by multiple hydrogen bonds without fillers as claimed in claim 1 or 2, characterized in that: The steps include: 1) Preparation of a multiple hydrogen bond crosslinker: 1,4-bis(acryloyloxy)butane, cytosine, and dimethyl sulfoxide are thoroughly mixed, followed by addition of potassium carbonate. After thorough stirring, the mixture is filtered, washed, and finally dried at 55-65°C to obtain a multiple hydrogen bond crosslinker for use. 2) Preparation of Epoxidized Natural Rubber / Multiple Hydrogen Bond Crosslinker: The components were taken according to the above mass fractions, and the Epoxidized Natural Rubber was added to an internal mixer and kneaded for 5 minutes. The multiple hydrogen bond crosslinker was added and thoroughly mixed. The Epoxidized Natural Rubber mixed with the multiple hydrogen bond crosslinker was then placed in a flat vulcanizer and hot pressed at 120°C and 10 MPa for 20 minutes to obtain the Epoxidized Natural Rubber / Multiple Hydrogen Bond Crosslinker. 3) Preparation of a rubber composite material reinforced by multiple hydrogen bonds without fillers: Epoxy natural rubber / multiple hydrogen bond crosslinking agent and solution-polymerized styrene-butadiene rubber were added to a mixer and kneaded for 5 minutes, followed by the addition of zinc oxide and stearic acid, mixed evenly, and then taken out; after cooling, the mixture was put on an open mill for refining, and diphenylguanidine, 2-mercaptobenzothiazole, benzothiazole disulfide, N-cyclohexyl-N'-phenyl-p-phenylenediamine, dimethyldithiocarbonyl disulfide, and sulfur were added in sequence, mixed evenly, and then hot-pressed to obtain a rubber composite material reinforced by multiple hydrogen bonds without fillers.

4. Use of the rubber composite material reinforced by multiple hydrogen bonds without fillers as claimed in claim 1 in preparing a rubber material for a shoe sole.

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