CN115895072A - Application of supramolecular polymer in modification of carboxylated nitrile rubber, modified carboxylated nitrile rubber and preparation method thereof - Google Patents

Abstract

The invention discloses application of a supramolecular polymer in modification of carboxyl nitrile rubber, modified carboxyl nitrile rubber and a preparation method thereof, and belongs to the technical field of reinforced and toughened carboxyl nitrile rubber. The technical scheme comprises that the supramolecular polymer is a supramolecular polymer formed based on hydrogen bond interaction; the supermolecule polymer is used as a reinforcing agent and a toughening agent in the modification of the carboxyl nitrile rubber to modify the carboxyl nitrile rubber to obtain the modified carboxyl nitrile rubber. The invention is applied to the aspect of strengthening and toughening of the carboxyl nitrile rubber, solves the technical problems of difficult filler dispersion and complex interface design in the existing filler strengthening and toughening XNBR, and the technical problems of difficult processing caused by the introduction of metal cations and quick hardening and embrittlement of the rubber caused by accelerated aging of the rubber so as to lose the use value in the strengthening and toughening XNBR by metal salt, and has the characteristic of obviously improving the strength and toughness of the XNBR.

Description

Application of supramolecular polymer in modification of carboxylated nitrile rubber, modified carboxylated nitrile rubber and preparation method thereof

technical field

The invention belongs to the technical field of reinforced and toughened carboxylated nitrile butadiene rubber, and in particular relates to the application of a supramolecular polymer in the modification of carboxylated nitrile butadiene rubber, the modified carboxylated nitrile butadiene rubber and a preparation method thereof.

Background technique

Carboxylated nitrile rubber (XNBR) is formed by terpolymerization of butadiene, acrylonitrile and organic acid (acrylic acid, methacrylic acid, etc.) monomers. The introduction of carboxyl groups increases the polarity of XNBR, increases the compatibility with polar materials such as polyvinyl chloride and phenolic resin, and further improves the oil resistance; at the same time, the introduction of carboxyl groups also improves the tensile strength of the material, In particular, the tensile strength at high temperature is improved; in addition, XNBR has good adhesion and aging resistance, and improves the wear resistance and tear strength of the material. XNBR can be used alone or in combination with other elastomers to make rubber hoses, tape seals, O-rings, rubber rollers, rubber shoes and other products. Although the introduction of carboxyl groups has improved the basic mechanical properties of XNBR, it is still necessary to strengthen and toughen XNBR in order to obtain good use value.

In the rubber industry, rubber is usually reinforced and toughened by filling a large number of nano-reinforcing fillers (such as carbon black, silica, graphene, carbon nanotubes, etc.), but the addition of fillers also brings Other problems: On the one hand, the premise of XNBR reinforced and toughened by fillers is that the fillers are well dispersed in the rubber matrix. The performance of the material strongly depends on the rubber-filler interface strength, which usually requires complex design and optimization of the interface; finally, when the filler and rubber are mixed and processed, the filler nanoparticles fly, making the processing environment poor and damaging the health of the operator.

In order to strengthen and toughen XNBR, metal salts can also be introduced into the crosslinked network of XNBR, and the strength and toughness of XNBR can also be improved by in situ formation of metal coordination bonds between COOH groups in XNBR and metal ions. However, during rubber mixing and processing, the added metal cations will quickly form ionic bonds with the carboxyl groups in XNBR, making processing difficult, and the introduction of metal ions will also accelerate the aging of rubber, making the rubber rapidly harden and brittle so that it loses its use value .

Contents of the invention

Aiming at the deficiencies in the prior art, the technical problem to be solved by the present invention is to overcome the technical problems of difficult filler dispersion and complex interface design when the existing filler strengthens and toughens XNBR, and when the toughened XNBR is reinforced and toughened by metal salts, due to metal The introduction of cations leads to technical problems such as difficulty in processing and accelerated aging of rubber, making the rubber quickly hard and brittle so that it loses its use value. A supramolecular polymer that can significantly improve the strength and toughness of XNBR is proposed in the modified carboxylated nitrile rubber. The application of modified carboxylated nitrile rubber and its preparation method.

In order to solve the technical problem, the technical solution adopted in the present invention is:

One aspect of the present invention provides a kind of supramolecular polymer in the application of carboxylated nitrile rubber modification, and described supramolecular polymer is the supramolecular polymer that forms based on hydrogen bond interaction; Described supramolecular polymer is in described In the modification of the carboxylated nitrile rubber, the carboxylated nitrile rubber is modified as a reinforcing agent and a toughening agent to obtain a modified carboxylated nitrile rubber.

Preferably, the supramolecular polymer is used in an amount of 4-7 phr.

Preferably, the supramolecular polymer is prepared by reacting 1,12-diaminododecane with acrylic acid.

Preferably, the molar ratio of the 1,12-diaminododecane to the acrylic acid is 1:2-4.

Another aspect of the present invention provides a modified carboxylated nitrile rubber based on the application of any one of the supramolecular polymers described above in the modification of carboxylated nitrile rubber.

Preferably, the modified carboxylated nitrile rubber is obtained by mixing the supramolecular polymer with the carboxylated nitrile rubber and vulcanizing it.

The present invention also provides a method for preparing the modified carboxylated nitrile rubber described in any one of the above, including a step of synthesizing a supramolecular polymer, and a step of modifying the carboxylated nitrile rubber with the supramolecular polymer.

Preferably, the supramolecular polymer synthesis step includes: dissolving 1,12-diaminododecane in dichloromethane, adding acrylic acid while stirring in an ice bath, and heating up to 55°C for reaction after stirring evenly , purified and dried to obtain the supramolecular polymer.

Preferably, the step of using the supramolecular polymer to modify the carboxylated nitrile rubber includes: mixing the supramolecular polymer, the carboxylated nitrile rubber and other rubber vulcanization aids except sulfur Putting it into an internal mixer and mixing to obtain a rubber compound, mixing the rubber compound with sulfur on an open mill at room temperature, and vulcanizing it by a flat vulcanizer to obtain the modified carboxylated nitrile rubber.

Preferably, the vulcanization temperature of the modified carboxylated nitrile rubber obtained by vulcanizing with a flat vulcanizer is 170° C., and the vulcanization pressure is 10 MPa.

Compared with prior art, the beneficial effect of the present invention is:

The invention provides an application of a supramolecular polymer in the modification of carboxylated nitrile rubber. The supramolecular polymer is used as a reinforcing agent and a toughening agent to modify carboxylated nitrile rubber. When the modified carboxylated nitrile rubber When stretched under force, the hydrogen bond between the supramolecular polymer itself and the hydrogen bond between the supramolecular polymer and carboxylated nitrile rubber is preferential to the covalent bond breaking to dissipate energy, and the breaking of the hydrogen bond will avoid the covalent bond crosslinking Carboxylated nitrile rubber is prematurely destroyed due to stress concentration, thereby significantly improving the strength and toughness of carboxylated nitrile rubber;

The invention provides a modified carboxylated nitrile rubber, which has strong strength and toughness;

The invention also provides a preparation method of the modified carboxylated nitrile rubber, which does not change the existing processing method of the carboxylated nitrile rubber and does not increase its processing difficulty, and has the characteristics of simple preparation method, low cost and convenient industrial production.

Description of drawings

Fig. 1 is the network structure schematic diagram of the modified carboxylated nitrile butadiene rubber provided by the embodiment of the present invention;

Fig. 2 is the modified carboxylated nitrile butadiene rubber preparation process flowchart provided by the embodiment of the present invention;

Fig. 3 is the state diagram of comparative samples 1, 2 and samples 1-6 provided by the embodiment of the present invention;

Fig. 4 is the cyclic stretching curve of comparative sample 1 and sample 1-3 provided by the embodiment of the present invention;

Fig. 5 is the cyclic tensile curves of the comparative sample 1 and samples 4-6 provided by the embodiment of the present invention.

Detailed ways

The technical solutions in specific embodiments of the present invention will be described in detail and completely below in conjunction with the accompanying drawings. Apparently, the described embodiments are only some specific implementations of the general technical solution of the present invention, but not all implementations. All other embodiments obtained by those skilled in the art based on the general concept of the present invention fall within the protection scope of the present invention.

One aspect of the present invention provides a kind of supramolecular polymer in the application of carboxylated nitrile rubber modification, and described supramolecular polymer is the supramolecular polymer that forms based on hydrogen bond interaction; Described supramolecular polymer is in described In the modification of the carboxylated nitrile rubber, the carboxylated nitrile rubber is modified as a reinforcing agent and a toughening agent to obtain a modified carboxylated nitrile rubber. This technical scheme utilizes supramolecular polymer as reinforcing agent and toughener to modify carboxyl nitrile butadiene rubber, when the carboxylated nitrile butadiene rubber after modification is stretched, the hydrogen bond of supramolecular polymer itself and supermolecular The hydrogen bond between the molecular polymer and the carboxylated nitrile rubber dissipates energy prior to the covalent bond breaking, and the breaking of the hydrogen bond will avoid the premature destruction of the covalently bonded carboxylated nitrile rubber due to stress concentration, thereby Significantly improves the strength and toughness of carboxylated nitrile rubber.

It should be noted that supramolecular polymers include polymers formed based on a variety of intermolecular interactions and their synergistic or multiple interactions, such as coordination, host-guest interactions, charge transfer interactions, π-π interactions , the present invention specifically defines supramolecular polymers as supramolecular polymers formed based on hydrogen bond interactions, because the supramolecular polymers formed based on hydrogen bond interactions are formed through primary and secondary amine groups at the ends of small molecules It is formed by the hydrogen bond interaction between the carboxyl groups at the ends of small molecules. Among them, the primary amines, secondary amines, and carboxyl groups in the supramolecular polymers can also form hydrogen bonds with the carboxyl groups in XNBR. Since the bond energy of hydrogen bonds is lower than that of covalent bonds, hydrogen bonds will break preferentially over covalent bonds when the material is stretched. The mechanism of supramolecular polymer strengthening and toughening XNBR is divided into two aspects. On the one hand, the hydrogen bond of the supramolecular polymer itself breaks and dissipates energy; on the other hand, the hydrogen bond between the supramolecular polymer and XNBR also breaks and dissipates energy. Hydrogen bonds are preferentially broken over covalent bonds to avoid premature destruction of covalently bonded XNBR due to stress concentration, thereby significantly improving the strength and toughness of the material. In addition, the present invention utilizes the supramolecular polymer as a reinforcing agent and a toughening agent to modify the carboxylated nitrile rubber. Due to the reversible characteristics of the hydrogen bond, after the modified carboxylated nitrile rubber is stretched, the broken hydrogen bond It can be connected and formed again, so as to achieve the effect of repeated toughening, and further ensure the strength and toughness of the modified carboxylated nitrile rubber.

Further, the supramolecular polymer is very easy to disperse in the XNBR matrix and will not affect the mixing process. This is because the supramolecular polymer and XNBR are both polar and similarly compatible. In addition, the supramolecular polymer defined in the present invention Polymers are formed based on hydrogen bonds between monomers. The hydrogen bonds will be dissociated during the blending process of supramolecular polymers, XNBR and rubber crosslinking aids. The supramolecular polymers are dispersed in the form of monomer molecules. In the XNBR matrix, after the vulcanization of the sample, these monomer molecules re-associate together through hydrogen bonds to form supramolecular polymers in situ in the XNBR matrix. Therefore, there will be no problem of supramolecular polymer agglomeration deteriorating material properties.

In a preferred embodiment, the supramolecular polymer is used in an amount of 4-7 phr. This technical solution specifically limits the dosage of supramolecular polymers, which not only can achieve the optimal strengthening and toughening effect on XNBR, but also is more conducive to reducing the impact of supramolecular polymers on the original XNBR system, ensuring that other properties of XNBR are not affected. Influence. It can be understood that the amount of the supramolecular polymer can also be 5phr, 6phr and any point value within the range. Among them, phr represents the percentage content of additives in rubber, for example: 4phr represents 4g of supramolecular polymer per 100g of equal mass of rubber, of course, g can also be replaced by kg, t, etc.

In a preferred embodiment, the supramolecular polymer is prepared by reacting 1,12-diaminododecane (DDA) with acrylic acid (AA). Optionally, the molar ratio of the 1,12-diaminododecane to the acrylic acid is 1:2-4. This embodiment defines that the supramolecular polymer is composed of a series of small molecules with different structures, and as the amount of AA increases, the content of carboxyl groups in the synthesized supramolecular polymer material increases. Among them, the reaction formula of 1,12-diaminododecane (DDA) and acrylic acid (AA) is as follows:

The above-mentioned examples specifically limit the molar ratio of 1,12-diaminododecane to acrylic acid to 1:2-4, because it is proved by experiments that when the ratio of the above-mentioned monomers is higher than 1:2, the supramolecular polymerization The sample obtained after blending and vulcanizing the supramolecular polymer with XNBR is uneven, the shrinkage rate is too large, and the sample preparation is unqualified; when the ratio of the above monomers is lower than 1:4, the sample obtained after the blending and vulcanizing of the supramolecular polymer and XNBR Decreased strength and toughness. It can be understood that the molar ratio of 1,12-diaminododecane to acrylic acid can also be 1:3 and any point value ratio within the range.

Another aspect of the present invention provides a kind of modified carboxylated nitrile rubber obtained based on the application of supramolecular polymer described in any one of the above in the modification of carboxylated nitrile butadiene rubber, the modified carboxylated nitrile butadiene rubber has as shown in Figure 1 The network structure shown. In a preferred embodiment, the modified carboxylated nitrile rubber is obtained by mixing and vulcanizing the supramolecular polymer with the carboxylated nitrile rubber. The modified carboxylated nitrile rubber has strong strength and toughness while retaining the original properties of the carboxylated nitrile rubber. The modified carboxylated nitrile rubber constructs a supramolecular polymer in situ in the sulfur-cured XNBR matrix. Prioritize fracture to dissipate energy and avoid premature destruction of the material due to covalent bond breakage of the XNBR main chain, thereby strengthening and toughening XNBR. However, it is difficult to improve both strength and toughness at the same time with filler-reinforced XNBR.

The present invention also provides the preparation method of the modified carboxylated nitrile butadiene rubber described in any one of the above, as shown in Figure 2, comprising a supramolecular polymer synthesis step, and utilizing the supramolecular polymer to treat the carboxylated nitrile butadiene rubber Steps to modify. The supramolecular polymer of this embodiment is very easy to disperse in the XNBR matrix and will not affect the mixing process. The reason is that, on the one hand, since the supramolecular polymer and XNBR are polar, they are similarly compatible; on the other hand , polar supramolecular polymers are formed based on hydrogen bonds between monomers, and the hydrogen bonds of supramolecular polymers themselves will dissociate during the blending process of supramolecular polymers, XNBR and rubber additives, and form The form of monomer molecules is dispersed in the polar XNBR matrix. After the vulcanization of the sample, these monomer molecules are re-associated together through hydrogen bonds to form supramolecular polymers in situ in the XNBR matrix, thus ensuring the supramolecular polymers Dispersion in XNBR matrix.

In a preferred embodiment, the supramolecular polymer synthesis step includes: dissolving 1,12-diaminododecane in dichloromethane, adding acrylic acid while stirring under ice-bath conditions, stirring evenly, and heating React at 55°C, purify and dry to obtain the supramolecular polymer. The synthesis method of the supramolecular polymer is simple, the yield is higher than 90%, and the solvent used in the synthesis process is nontoxic and recyclable. The synthesis method specifically includes: dissolving DDA in dichloromethane, adding AA (nDDA:nAA=1:2-4) dropwise to the above solution while stirring under ice bath conditions, and continuing to Stir the solution for 0.5h, raise the temperature of the solution to 55°C, and react at this temperature for 8h. After the reaction, the product is purified by absolute ethanol, and the purified product is vacuum-dried at 80°C for 12h to obtain a supramolecular polymer. Wherein the yield of the supramolecular polymer is >90%.

In a preferred embodiment, the step of using the supramolecular polymer to modify the carboxylated nitrile rubber includes: mixing the supramolecular polymer, the carboxylated nitrile rubber and other compounds except sulfur The rubber vulcanization aid is added into an internal mixer and mixed to obtain a rubber compound, which is mixed with sulfur on an open mill at room temperature, and vulcanized by a flat vulcanizer to obtain the modified carboxylated nitrile rubber. In this process, polar supramolecular polymers are formed based on hydrogen bonds between monomers, and hydrogen bonds will dissociate during the blending process of supramolecular polymers, XNBR and rubber additives, making supramolecular polymers Dispersed in the XNBR matrix in the form of monomer molecules, after the vulcanization of the sample, these monomer molecules are re-associated together through hydrogen bonds, forming supramolecular polymers in situ in the XNBR matrix, ensuring that the supramolecular polymers in XNBR Dispersion in the matrix. The preparation process is simple and operable. Adding supramolecular polymers to strengthen and toughen XNBR does not change the processing method of XNBR nor increase its processing difficulty. The processing equipment is general rubber processing equipment, which can realize large-scale industrial production and is beneficial to Achieve marketing. In a preferred embodiment, the vulcanization temperature of the modified carboxylated nitrile rubber obtained by vulcanizing with a flat vulcanizer is 170° C., and the vulcanization pressure is 10 MPa.

In order to introduce in detail the application of the supramolecular polymer provided in the embodiments of the present invention in the modification of carboxylated nitrile rubber, the modified carboxylated nitrile rubber and its preparation method, the following will be described in conjunction with specific examples.

Example 1

Synthesis of supramolecular polymer (DDA1AA2):

(1) 10g DDA was dissolved in 100mL methylene chloride in a 150mL three-necked flask;

(2) Under the condition of ice bath, add 7.2g AA (nDDA:nAA=1:2) dropwise to the above solution while stirring, and continue to stir the solution for 0.5h after the addition of AA is completed;

(3) The temperature of the solution was raised to 55° C., and reacted at this temperature for 8 hours;

(4) After the reaction, the product was purified by absolute ethanol, and the purified product was vacuum-dried at 80° C. for 12 hours to obtain DDA1AA2 (yield>90%).

Preparation of carboxylated nitrile rubber/supramolecular polymer vulcanizate:

Set the initial temperature of the mixer to 60°C and the rotor speed to 70rpm; add 100kg of carboxylated nitrile rubber, 5kg of zinc oxide, 1kg of stearic acid, 1kg of accelerator MBTS, and 4kg of supramolecular polymer DDA1AA2 into the mixer for 8 minutes; Mix the obtained mixed rubber with 1.5kg of sulfur on the open mill at room temperature, and then make a thin triangle bag for 6 times, and then make a thin slice of about 2mm; Carry out vulcanization, the vulcanization pressure is 10MPa, obtain sample 1 after vulcanization.

Example 2

Synthesis of supramolecular polymer (DDA1AA3):

(1) 10g DDA was dissolved in 100mL methylene chloride in a 150mL three-necked flask;

(2) Under the condition of ice bath, add 10.8g AA (nDDA:nAA=1:3) dropwise into the above solution while stirring, and continue to stir the solution for 0.5h after the addition of AA is completed;

(3) The temperature of the solution was raised to 55° C., and reacted at this temperature for 8 hours;

(4) After the reaction, the product was purified by absolute ethanol, and the purified product was vacuum-dried at 80° C. for 12 hours to obtain DDA1AA3 (yield>90%).

Preparation of carboxylated nitrile rubber/supramolecular polymer vulcanizate:

Set the initial temperature of the mixer to 60°C and the rotor speed to 70rpm; add 100kg of carboxylated nitrile rubber, 5kg of zinc oxide, 1kg of stearic acid, 1kg of accelerator MBTS, and 4kg of supramolecular polymer DDA1AA3 into the mixer for 8 minutes; Mix the obtained mixed rubber with 1.5kg of sulfur on the open mill at room temperature, and then make a thin triangle bag for 6 times, and then make a thin slice of about 2mm; Carry out vulcanization, the vulcanization pressure is 10MPa, obtain sample 2 after vulcanization.

Example 3

Synthesis of supramolecular polymer (DDA1AA4):

(1) 10g DDA was dissolved in 100mL methylene chloride in a 150mL three-necked flask;

(2) Under the condition of ice bath, add 14.4g AA (nDDA:nAA=1:4) to the above solution dropwise while stirring, and continue to stir the solution for 0.5h after the addition of AA is completed;

(3) The temperature of the solution was raised to 55° C., and reacted at this temperature for 8 hours;

(4) After the reaction, the product was purified by absolute ethanol, and the purified product was vacuum-dried at 80° C. for 12 hours to obtain DDA1AA4 (yield>90%).

Preparation of carboxylated nitrile rubber/supramolecular polymer vulcanizate:

Set the initial temperature of the internal mixer to 60°C and the rotor speed to 70rpm; add 100kg of carboxylated nitrile rubber, 5kg of zinc oxide, 1kg of stearic acid, 1kg of accelerator MBTS, and 4kg of supramolecular polymer DDA1AA4 to the internal mixer and mix for 8 minutes; Mix the obtained mixed rubber with 1.5kg of sulfur on the open mill at room temperature, and then make a thin triangle bag for 6 times, and then make a thin slice of about 2mm; Carry out vulcanization, the vulcanization pressure is 10MPa, obtain sample 3 after vulcanization.

Example 4

The supramolecular polymer (DDA1AA3) was synthesized according to Example 2.

Preparation of carboxylated nitrile rubber/supramolecular polymer vulcanizate:

Set the initial temperature of the internal mixer to 60°C and the rotor speed to 70rpm; add 100kg of carboxylated nitrile rubber, 5kg of zinc oxide, 1kg of stearic acid, 1kg of accelerator MBTS, and 3kg of supramolecular polymer DDA1AA4 into the internal mixer and mix for 8 minutes; Mix the obtained mixed rubber with 1.5kg of sulfur on the open mill at room temperature, and then make a thin triangle bag for 6 times, and then make a thin slice of about 2mm; Carry out vulcanization, the vulcanization pressure is 10MPa, obtain sample 4 after vulcanization.

Example 5

The supramolecular polymer (DDA1AA3) was synthesized according to Example 2.

Preparation of carboxylated nitrile rubber/supramolecular polymer vulcanizate:

Set the initial temperature of the internal mixer to 60°C and the rotor speed to 70rpm; add 100kg of carboxylated nitrile rubber, 5kg of zinc oxide, 1kg of stearic acid, 1kg of accelerator MBTS, and 5kg of supramolecular polymer DDA1AA4 into the internal mixer and mix for 8 minutes; Mix the obtained mixed rubber with 1.5kg of sulfur on the open mill at room temperature, and then make a thin triangle bag for 6 times, and then make a thin slice of about 2mm; Carry out vulcanization, the vulcanization pressure is 10MPa, obtain sample 5 after vulcanization.

Example 6

The supramolecular polymer (DDA1AA3) was synthesized according to Example 2.

Preparation of carboxylated nitrile rubber/supramolecular polymer vulcanizate:

Set the initial temperature of the mixer to 60°C and the rotor speed to 70rpm; add 100kg of carboxylated nitrile rubber, 5kg of zinc oxide, 1kg of stearic acid, 1kg of accelerator MBTS, and 7kg of supramolecular polymer DDA1AA4 into the mixer for 8 minutes; Mix the obtained mixed rubber with 1.5kg of sulfur on the open mill at room temperature, and then make a thin triangle bag for 6 times, and then make a thin slice of about 2mm; Carry out vulcanization, the vulcanization pressure is 10MPa, obtain sample 6 after vulcanization.

Comparative example 1

Same as Example 1, the difference is that the synthesis step of the supramolecular polymer (DDA1AA2) is not included, and the supramolecular polymer (DDA1AA2) is not added during the preparation of the carboxylated nitrile rubber/supramolecular polymer vulcanizate.

Comparative example 2

Same as Example 1, the difference is: in the synthesis step of the supramolecular polymer (DDA1AA2), the molar ratio of DDA to AA is 1:1.

Comparative example 3

Same as Example 1, the difference is: in the synthesis step of the supramolecular polymer (DDA1AA2), the molar ratio of DDA to AA is 1:5.

Comparative example 4

Same as Example 4, the difference is that the amount of supramolecular polymer (DDA1AA3) in the preparation process of carboxylated nitrile rubber/supramolecular polymer vulcanizate is 2 phr.

Comparative example 5

Same as Example 4, the difference is that the amount of supramolecular polymer (DDA1AA3) in the preparation process of carboxylated nitrile rubber/supramolecular polymer vulcanizate is 8 phr.

The proportions of DDA and AA monomers for synthesizing supramolecular polymers, and the dosage of supramolecular polymers in Examples 1-6 and Comparative Examples 1-5 are shown in Table 1 and Table 2.

Supramolecular polymer synthesis monomer ratio and supramolecular polymer consumption in the embodiment 1-6 of table 1

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 DDA:AA (molar ratio) 1:2 1:3 1:4 1:3 1:3 1:3 Number of copies (phr) 4 4 4 3 5 7

Supramolecular polymer synthesis monomer ratio and supramolecular polymer consumption in Table 2 comparative examples 1-5

Comparative sample 1 Comparative sample 2 Comparative sample 3 Comparative sample 4 Comparative sample 5 DDA:AA (molar ratio) - 1:1 1:5 1:3 1:3 Number of copies (phr) 0 4 4 2 8

It can be seen from Figure 3 that no supramolecular polymer was added in the comparative sample 1, and the sample was flat and had a certain degree of transparency. The wrinkle is uneven. Since the wrinkle of the comparative sample 2 is uneven, it will not be studied in the future. Samples 1-6 added with supramolecular polymers are flat and highly transparent, indicating that the synthesized supramolecular polymers can be uniformly dispersed in the XNBR matrix through general rubber processing methods without special treatment.

Table 3 and Table 4 are the tensile strength and breaking energy of samples 1-6 and comparative samples 1-5. The fracture energy is the integral area under the stress-strain curve. The fracture energy can reflect the toughness of the material. The higher the fracture energy, the greater the toughness of the material. From the properties of samples 1-3, it can be seen that when the amount of supramolecular polymer added is fixed at 4 phr, the tensile strength and toughness of the material gradually increase with the increase of the ratio of the synthetic supramolecular polymer monomer AA. increase, and are higher than XNBR (comparative sample 1) without adding supramolecular polymer sulfur vulcanization. However, when continuing to increase the ratio of monomer AA for the synthesis of supramolecular polymers, the tensile strength and toughness of the comparison sample 3 added to this supramolecular polymer XNBR are lower than that of sample 3, so continue to improve the synthesis of supramolecular polymers The use ratio of the monomer AA of the compound is not necessary. From the performance of samples 4-6, it can be seen that when the monomer ratio of the synthetic supramolecular polymer is fixed at 1:3 (that is, the supramolecular polymer is DDA1AA3), as the amount of supramolecular polymer gradually increases, The tensile strength and fracture energy of the XNBR vulcanizate added with supramolecular polymer gradually increased, which were also higher than those of the comparative sample 1. When the amount of DDA1AA3 is 2phr (comparative sample 4), the tensile strength and fracture energy of the sample are not significantly improved compared with the sample without any supramolecular polymer (comparative sample 1), which is due to the hydrogen bond itself. It needs to accumulate to a certain amount to significantly improve the strength and toughness of the material. When the amount of DDA1AA3 is 8phr (comparative sample 5), the tensile strength and fracture energy of the sample do not increase but decrease compared with sample 6, which proves that when the amount of supramolecular polymer is about 7phr, the performance of the material is optimal.

Table 3 Tensile strength and fracture energy of samples 1-6

sample 1 sample 2 sample 3 Sample 4 Sample 5 Sample 6 Tensile strength (MPa) 14.0 20.5 22.3 19.1 21.5 23.7 <![CDATA[Fracture Energy (MJ m^-3)]]> 23.2 30.7 38.5 27.3 35.6 44.7

Tensile strength and fracture energy of comparative sample 1-5 of table 4

Comparative sample 1 Comparative sample 2 Comparative sample 3 Comparative sample 4 Comparative sample 5 Tensile strength (MPa) 10.8 12.9 17.6 11.1 20.9 <![CDATA[Fracture Energy (MJ m^-3)]]> 14.1 19.6 26.3 15.2 33.2

Figures 4 and 5 are the cyclic stretching curves of Comparative Sample 1 and Samples 4-6. It can be seen from Figure 4 that when the amount of supramolecular polymer added is fixed at 4phr, the hysteresis circle area of Samples 1-3 averages It is larger than that of the comparative sample 1, and with the increase of the ratio of the synthetic supramolecular polymer monomer AA, the area of the hysteresis ring in the cyclic stretching of the sample gradually increases, indicating that the toughness of the material is gradually improved. The larger the area of the hysteresis ring, the more energy is dissipated in the forging of the hydrogen bond of the sample during stretching, and the toughness of the material is improved. It can be seen from Figure 5 that when the monomer ratio of the synthetic supramolecular polymer is fixed at 1:3, the areas of the hysteresis circles of samples 4-6 are all higher than those of the comparative sample 1, and with the increase in the amount of supramolecular polymer The area of the hysteresis zone in the cyclic stretching of the sample gradually increases, indicating that the toughness of the material is gradually improved.

Claims (10)

1. The application of the supramolecular polymer in modification of the carboxyl nitrile rubber is characterized in that the supramolecular polymer is formed based on hydrogen bond interaction; and the supermolecule polymer is used as a reinforcing agent and a toughening agent in the modification of the carboxyl nitrile rubber to modify the carboxyl nitrile rubber to obtain the modified carboxyl nitrile rubber.

2. Use of the supramolecular polymer in the modification of carboxylated nitrile rubber according to claim 1, wherein the supramolecular polymer is present in an amount of 4-7phr.

3. Use of the supramolecular polymer in the modification of carboxylated nitrile rubber according to claim 1, characterized in that the supramolecular polymer is prepared by reacting 1, 12-diaminododecane with acrylic acid.

4. Use of the supramolecular polymer in the modification of carboxylated nitrile rubber according to claim 3, characterized in that the molar ratio of 1, 12-diaminododecane to acrylic acid is from 1.

5. Modified carboxylated nitrile rubber obtained on the basis of the use of a supramolecular polymer as claimed in any of claims 1 to 4 for the modification of carboxylated nitrile rubbers.

6. The modified carboxylated nitrile rubber according to claim 5, wherein said modified carboxylated nitrile rubber is obtained by mixing said supramolecular polymer with said carboxylated nitrile rubber and vulcanizing said mixture.

7. Process for the preparation of modified carboxylated nitrile rubber according to any of the claims from 5 to 6, characterized in that it comprises a step of synthesis of supramolecular polymers and a step of modification of said carboxylated nitrile rubber by means of said supramolecular polymers.

8. The process for the preparation of modified carboxylated nitrile rubber according to claim 7, wherein said supramolecular polymer synthesis step comprises: dissolving 1, 12-diaminododecane in dichloromethane, adding acrylic acid while stirring under an ice bath condition, uniformly stirring, heating to 55 ℃ for reaction, purifying and drying to obtain the supramolecular polymer.

9. The process for the preparation of modified carboxylated nitrile rubber according to claim 7, wherein said step of modifying said carboxylated nitrile rubber with said supramolecular polymer comprises: adding the supramolecular polymer, the carboxyl nitrile rubber and other rubber vulcanization auxiliaries except sulfur into an internal mixer to be mixed to obtain a mixed rubber, mixing the mixed rubber with the sulfur on an open mill at room temperature, and vulcanizing by a flat vulcanizing machine to obtain the modified carboxyl nitrile rubber.

10. The process for preparing modified carboxylated nitrile rubber according to claim 9, wherein the vulcanization temperature of said modified carboxylated nitrile rubber obtained by vulcanization in a press is 170 ℃ and the vulcanization pressure is 10MPa.

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