Thermal-trigger in-situ reinforced polyolefin polymer material and preparation method thereof

Abstract

The invention discloses a heat-triggered in-situ reinforced polyolefin high polymer material and a preparation method thereof, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: carrying out a ring-opening metathesis polymerization reaction on 9-tosyl-9-azabicyclo [6.1. 0] nonyl-4-ene and cyclooctene under the catalysis of a ruthenium-based catalyst to obtain a ring-opening metathesis polymerization reaction product, mixing the ring-opening metathesis polymerization reaction product with elemental sulfur, and carrying out a cross-linking reaction under the catalysis of an organic alkali to obtain the thermal-trigger in-situ reinforced polyolefin polymer material. The heat-triggered in-situ reinforced polyolefin high polymer material provided by the invention has the characteristics of glass-like high polymers in an initial state, and can realize preliminary recycling of waste materials or precise molding of special-shaped parts; the thermosetting resin also has mechanical properties close to those of traditional thermosetting resin, and can be competent for high-load and high-temperature extreme service environments; the reinforcing process is spontaneously or inductively generated after the part is formed, and additional reinforcing fibers or fillers do not need to be added.

Description

A thermally triggered in-situ reinforced polyolefin polymer material and its preparation method Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a thermally triggered in-situ reinforced polyolefin polymer material and its preparation method. Background Technology

[0002] Polyolefin materials (such as polyethylene, polypropylene, and olefin copolymers) have become the most produced and widely used polymer materials globally due to their excellent chemical stability, low density, superior electrical insulation, and significant price advantage. However, linear polyolefins, as typical thermoplastics, suffer from inherent defects such as insufficient heat resistance, severe high-temperature creep, and limited mechanical strength. These limitations greatly restrict their widespread application in fields with extreme performance requirements, such as aerospace, automotive, and specialized electronic packaging.

[0003] To synergistically improve the overall service performance of polyolefins, the industry commonly employs crosslinking technology to transform their linear topology into a three-dimensional network. Although traditional chemical crosslinking techniques (such as peroxide radical crosslinking and silane hydrolysis crosslinking) can significantly enhance the modulus and heat resistance of materials, the covalent crosslinking points they form are irreversible "permanent networks." This irreversibility means that once crosslinked polyolefin materials are molded, they lose their ability to be reprocessed, and after disposal, they cannot be melted and recycled, resulting in enormous resource waste and environmental pressure.

[0004] In recent years, glass-like polymers with dynamic covalent bonds have provided a revolutionary solution to resolving the contradiction between "high performance" and "recyclability". Vitrimers, through thermally excited dynamic covalent bond exchange reactions (such as polysulfide bond exchange), enable the crosslinked network to exhibit controllable viscoelastic flow on a macroscopic scale. However, existing polyolefin-based vitrimers generally face the following technical bottlenecks in the pursuit of "infinitely many cycles": 1) Insufficient service thermal stability: The highly sensitive dynamic exchange characteristics lead to significant creep in high-temperature service environments, making it difficult to meet the requirements for precision dimensional stability; 2) The trade-off between strength and processing flexibility: To maintain remodeling capability, the crosslinking density of the system is usually limited, making it difficult to achieve a qualitative breakthrough in the tensile strength and modulus of the final product; 3) Thermally induced irreversible damage: In actual thermal remodeling processes, polysulfide bonds are prone to thermal rearrangement or uncontrollable side reactions caused by residual active sites in the polyolefin backbone, resulting in a "pathological" decline in the material's cycling performance.

[0005] On the other hand, directly utilizing elemental sulfur, a byproduct of the petrochemical industry, in chemical reactions to construct stable polymer materials has become a key pathway for the greening and low-cost transformation of the polymer industry. This involves sulfur-containing dynamic chemistry, particularly based on polysulfide bonds (−S−S).n The dynamic system of polysulfide (−S−) possesses unique advantages such as simple synthetic pathways, catalyst-free dynamic exchange, and a suitable exchange temperature window, making it an ideal choice for constructing high-performance glass-like polymers. However, how to cleverly introduce efficient polysulfide dynamic chemistry into linear polyolefin systems, and construct dynamic polysulfide bridges at specific sites to build polyethylene glass-like polymers that combine processing flexibility and final high performance, still lacks systematic research. In contrast, the networks generated by traditional polyolefin vulcanization processes are highly cross-linked, infusible, and lack dynamic reversibility, making recycling difficult.

[0006] Therefore, developing an "in-situ reinforced" polyolefin network using elemental sulfur, capable of complex reshaping during processing by leveraging dynamic bond properties and achieving network topology locking and significant mechanical property enhancement through a thermal triggering process after molding, possesses extremely high scientific value and industrial prospects. This material enables an intrinsic leap from "low modulus and easy molding" to "high strength and creep resistance," providing a novel technological path for the fabrication of high-performance, dimensionally stable specialty polyolefin engineering components. Summary of the Invention

[0007] The purpose of this invention is to provide a thermally triggered in-situ reinforced polyolefin polymer material and its preparation method, overcoming the shortcomings of existing cross-linked polyolefin materials that cannot simultaneously achieve processing flexibility and service rigidity, as well as the poor high-temperature creep resistance of traditional glass-like polymers. The provided thermally triggered in-situ reinforced polyolefin polymer material possesses dynamic covalent network characteristics in the early stages of molding, allowing for complex morphological processing; under specific thermal triggering conditions, through the locking and recombination of the network topology, a significant in-situ improvement in the material's modulus and strength is achieved.

[0008] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of the present invention is to provide a thermally triggered in-situ reinforced polyolefin polymer material, the structural formula of which is as follows: In the above formula, x is independently selected from integers from 50 to 2000, y is independently selected from integers from 10 to 400, and n is independently selected from integers from 0 to 8.

[0009] The second technical solution of the present invention provides a method for preparing the above-mentioned thermally triggered in-situ reinforced polyolefin polymer material, comprising the following steps: 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene and cyclooctene undergo ring-opening metathesis polymerization under the catalysis of a ruthenium-based catalyst; the ring-opening metathesis polymerization product is mixed with elemental sulfur and then subjected to crosslinking reaction under the catalysis of an organic base to obtain the thermally triggered in-situ reinforced polyolefin polymer material.

[0010] The structural formula of 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene used in this invention is: .

[0011] Preferably, the molar ratio of 9-p-toluene-9-azabicyclo[6.1.0]non-4-ene to cyclooctene is 1:(5~20); more preferably, it is 1:10.

[0012] Preferably, the ruthenium-based catalyst is a second-generation Grubbs catalyst.

[0013] Preferably, the reaction temperature of the ring-opening metathesis polymerization reaction is room temperature, and the reaction time is 9-12 hours; more preferably, the reaction time is 9 hours.

[0014] Preferably, the organic base is 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0015] Preferably, the crosslinking reaction is carried out at a temperature of 100-120°C for 4-6 hours; more preferably, the crosslinking reaction conditions are a temperature of 100°C and a time of 5 hours.

[0016] Preferably, the amount of elemental sulfur added is three times the molar amount of 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene.

[0017] The in-situ enhancement mechanism of the thermally triggered in-situ enhanced polyolefin polymer material provided by the present invention is as follows: In the first stage of heat treatment (processing stage), the low activation energy exchange characteristics of polysulfide bonds are used to impart fluidity to the material; in the second stage of thermal triggering (locking stage), by increasing the temperature or extending the heat treatment time, irreversible topological locking reactions (such as thermal conversion of polysulfide bonds to mono / disulfide bonds, secondary crosslinking of residual active sites, etc.) are induced in the system.

[0018] The advantages of the technical solution of this invention are: 1) Controllable transformation of topology: The material possesses the intrinsic property of transforming from a "dynamic cross-linked network" to a "static reinforced network," and the processing life of the material can be precisely controlled through thermal history. 2) Leapfrog performance improvement: After thermally triggered reinforcement, the modulus of the material increases significantly, and the creep resistance is significantly improved. 3) Excellent dimensional stability: The reinforced network is transformed into a high-density static cross-linked structure, which completely solves the problem of easy creep of traditional Vitrimers at high temperatures.

[0019] The beneficial technical effects of the present invention are as follows: 1) Processing flexibility: The thermally triggered in-situ reinforced polyolefin polymer material provided by the present invention has glass-like polymer characteristics in the initial state, which can realize the initial recycling of waste materials or the precision molding of irregular parts.

[0020] 2) High strength and high modeling properties: The thermally triggered in-situ reinforced polyolefin polymer material provided by this invention has mechanical properties close to those of traditional thermosetting resins, and can withstand extreme service environments with high loads and high temperatures.

[0021] 3) In-situ properties: The reinforcement process of the thermally triggered in-situ reinforced polyolefin polymer material provided by the present invention occurs spontaneously or induced after the component is formed, without the need to add additional reinforcing fibers or fillers, thus maintaining the lightweight characteristics of the polyolefin polymer material. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 shows the 1H NMR spectrum of 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene used in the embodiments and comparative examples of this invention.

[0024] Figure 2 shows the X-ray diffraction patterns of the thermally triggered in-situ enhanced polyolefin polymer material prepared in Example 1 and elemental sulfur.

[0025] Figure 3 shows the C1s XPS spectrum of the thermally triggered in-situ enhanced polyolefin polymer material prepared in Example 1.

[0026] Figure 4 shows the S 2p XPS spectrum of the thermally triggered in-situ enhanced polyolefin polymer material prepared in Example 1.

[0027] Figure 5 shows the thermogravimetric analysis curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1.

[0028] Figure 6 shows the stress-strain curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1.

[0029] Figure 7 shows the frequency scan curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1.

[0030] Figure 8 shows the frequency scan curves of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Comparative Example 1.

[0031] Figure 9 shows the creep strain-time curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1.

[0032] Figure 10 shows the creep strain-time curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Comparative Example 1. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0034] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0035] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0036] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] The preparation method of the thermally triggered in-situ reinforced polyolefin polymer material of the present invention includes the following steps: a cyclopropane-substituted olefin and cyclooctene undergo a ring-opening metathesis polymerization reaction under the catalysis of a ruthenium-based catalyst; the ring-opening metathesis polymerization product is mixed with elemental sulfur and then subjected to a crosslinking reaction under the catalysis of an organic base to obtain the thermally triggered in-situ reinforced polyolefin polymer material.

[0039] In this invention, the thermally triggered in-situ reinforced polyolefin polymer contains dynamic covalent sulfur-sulfur bonds, enabling reversible dynamic exchange of these bonds within a certain temperature range, allowing for complex morphological processing. Under specific thermal triggering conditions, the locking and recombination of the network topology overcomes the shortcomings of existing cross-linked polyolefin materials that cannot simultaneously achieve processing flexibility and service rigidity. This preparation method is relatively simple and highly controllable, allowing precise control of key parameters. By adjusting these parameters, the degree of cross-linking and the density of the cross-linked network can be flexibly controlled, thereby adjusting the chemical composition and mechanical properties of the material. The polysulfide structure in the product can form stable covalent cross-links, providing excellent mechanical properties and chemical resistance. These characteristics give the thermally triggered in-situ reinforced polyolefin polymer high tensile strength, creep resistance, and durability in applications, making it a promising candidate for the market.

[0040] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0041] All raw materials used in the following embodiments of the present invention were purchased commercially.

[0042] The preparation steps of 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene used in this embodiment of the invention are as follows: 1,5-cyclooctadiene (12.2 mL, 100 mmol, 1.0 equivalent), hydroxylamine sulfonic acid (22.6 g, 200 mmol, 2.0 equivalent), and piperidine (19.8 mL, 200 mmol, 2.0 equivalent) were mixed in hexafluoroisopropanol (80 mL). The resulting mixture was stirred at room temperature for 24 h under nitrogen protection. Then, the mixture was quenched with saturated sodium bicarbonate solution and extracted three times with dichloromethane and saturated brine. The organic phase was concentrated to obtain 8.5 g of oily product.

[0043] The oily product (8.5 g, 69 mmol, 3.0 equivalent) was mixed with p-toluenesulfonyl chloride (4.4 g, 23 mmol, 1.0 equivalent) and triethylamine (8.0 mL, 58 mmol, 2.5 equivalent) in dichloromethane and stirred overnight at room temperature under nitrogen protection. The resulting mixture was extracted three times with dichloromethane and saturated brine. The organic phase was collected and purified by column chromatography on a silica gel column. The product was eluted with petroleum ether / ethyl acetate (16 / 1, v / v) to give a white solid, namely 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene, in 52% yield.

[0044] The proton NMR spectrum of the prepared 9-p-toluene-9-azabicyclo[6.1.0]non-4-ene is shown in Figure 1.

[0045] As can be seen from Figure 1, the structure of this compound is consistent with the target product 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene.

[0046] Example 1 Preparation of thermally triggered in-situ enhanced polyolefin polymer: (1) 0.221 g of 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene, 1.0 mL of cyclooctene and 8 mL of dichloromethane were added to a reaction flask under a nitrogen atmosphere. 0.013 g of Grubbs second-generation catalyst was added and the reaction was carried out at room temperature for 9 hours. After the reaction was completed, 25 mL of dichloromethane was added to dilute the product and then the product was added to 600 mL of ice-cold methanol to precipitate the product. The obtained solid was filtered out and dried under vacuum. The solid obtained was 0.95 g of the ring-opening metasomatic polymerization product (number average molecular weight of 166.4 kDa, weight average molecular weight of 342.2 kDa, and dispersion of 2.06).

[0047] (2) Add 0.6 g of ring-opening metathesis polymerization product, 0.038 g of elemental sulfur and 4.5 mL of toluene to a flask, raise the temperature to 100 °C, and stir continuously until the mixture is homogeneous. Then add 6 μL of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and react for 4 hours. The solid obtained after vacuum drying is the thermally triggered in-situ reinforced polyolefin polymer material (named V2).

[0048] The structural formula of V2 is: Where x is independently selected from integers from 50 to 2000, y is independently selected from integers from 10 to 400, and n is independently selected from integers from 0 to 8; according to organic element analysis, its sulfur content is 6.49%.

[0049] Comparative Example 1: Preparation of thermally triggered in-situ enhanced polyolefin polymer: (1) 0.221 g of 9-p-toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene, 1.0 mL of cyclooctene and 8 mL of dichloromethane were added to a reaction flask under a nitrogen atmosphere. 0.013 g of Grubbs second-generation catalyst was added and the reaction was carried out at room temperature for 9 hours. After the reaction was completed, 25 mL of dichloromethane was added for dilution, and then precipitated by adding it to 600 mL of ice-cold methanol. The obtained solid was filtered out and dried under vacuum. The solid obtained was 0.95 g of ring-opening metathesis polymerization product (number average molecular weight of 166.4 kDa, weight average molecular weight of 342.2 kDa, and dispersion of 2.06).

[0050] (2) Under a nitrogen atmosphere, 0.8 g of the obtained ring-opening metathesis polymerization product, 2.7 g of p-toluenesulfonyl hydrazine and 15 mL of xylene were added to a flask, and 2.9 mL of tripropylamine was added. The temperature was raised to 135 °C and the reaction was refluxed for 6 hours. After the reaction was completed, 20 mL of xylene was added to dilute the product, and then the product was added dropwise to 600 mL of ice-cold methanol to precipitate the product. The obtained solid was filtered out and dried under vacuum. The solid obtained was 0.72 g of the hydrogenation reaction product.

[0051] (3) Add 0.6 g of hydrogenation reaction product, 0.038 g of elemental sulfur and 4.5 mL of toluene to a flask, raise the temperature to 100 °C, and stir continuously until the mixture is homogeneous. Then add 6 μL of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and react for 4 hours. The solid obtained after vacuum drying is the thermally triggered in-situ reinforced polyolefin polymer material (named V2H).

[0052] The structural formula of the obtained V2H is: Where x is independently selected from integers from 50 to 2000, y is independently selected from integers from 10 to 400, and n is independently selected from integers from 0 to 8; according to organic element analysis, its sulfur content is 7.52%.

[0053] The X-ray diffraction patterns of the thermally triggered in-situ enhanced polyolefin polymer material prepared in Example 1 and elemental sulfur are shown in Figure 2.

[0054] As can be seen from Figure 2, the thermally triggered in-situ reinforced polyolefin polymer material (V2) prepared in Example 2 does not have an absorption peak of elemental sulfur.

[0055] The C1s XPS spectrum of the thermally triggered in-situ enhanced polyolefin polymer material prepared in Example 1 is shown in Figure 3.

[0056] As can be seen from Figure 3, V2 has a characteristic peak of CC bond at a binding energy of 284.8 eV, a characteristic peak of CS bond at 285.8 eV, and a characteristic peak of CN bond at 286.7 eV.

[0057] The S 2p XPS spectrum of the thermally triggered in-situ enhanced polyolefin polymer material prepared in Example 1 is shown in Figure 4.

[0058] As can be seen from Figure 4, V2 has a characteristic peak of SC bond at a binding energy of 164.6 eV, a characteristic peak of SS bond at 166.0 eV, and a characteristic peak of O=S=O bond at 168.5 eV.

[0059] The thermogravimetric analysis curves of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1 are shown in Figure 5.

[0060] As can be seen from Figure 5, when the mass loss of V2 is 5%, the temperature is 343.9℃, which is the decomposition temperature.

[0061] Tensile testing was performed on the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1. The specific test method for the tensile test is as follows: S1. A smooth polyethylene terephthalate film and a smooth perforated stainless steel mold were laid flat on a smooth pressing plate. S2. The prepared thermally triggered in-situ reinforced polyolefin was cut into small pieces and evenly spread in the groove of the perforated stainless steel mold. S3. Another layer of polyethylene terephthalate film and a smooth pressing plate were laid flat in sequence. S4. The prepared sample was placed in a pressing machine at <120 ℃ and preheated at normal pressure for <5 minutes. S5. After preheating, the pressure was increased to 10 MPa and held in the pressing machine for <15 minutes. S6. After holding the pressure, the sample was cooled to room temperature in a water-cooling cycle, the pressing machine was opened, and the sample was taken out. S7. The hot-pressed sample was demolded and can be used as a tensile test strip. S8. The strips after the tensile test can be repeated in steps S1 to S7 to make repeatable processability test strips.

[0062] The test specimen for the tensile test was 50 mm long, 10.0 mm wide, and 2 mm thick. The mechanical properties were tested according to GB / T1040.3 / 2 / 50. The specimen used was a type 3 specimen. The tensile rate of the test was 10 mm / min. The stress-strain tensile test was carried out at room temperature.

[0063] The stress-strain curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1 is shown in Figure 6.

[0064] As can be seen from Figure 6, the breaking strength of V2 is 5.8 MPa and the elongation at break is 390%.

[0065] Creep tests were conducted on the thermally triggered in-situ reinforced polyolefin polymers prepared in Example 2 and Comparative Example 1 using an Anton Paar MCR 302e rheometer, with measurements taken using an 8 mm parallel plate. The frequency scanning test mode was dynamic frequency scanning, with a frequency range of 100~0.01 rad / s. The creep test was performed under a constant tensile stress of 3 kPa, with loading for 15 min and unloading for 15 min.

[0066] The frequency scan curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1 is shown in Figure 7.

[0067] As shown in Figure 7, the energy storage modulus G' of V2 at 120 ℃ decreases slowly with decreasing test frequency (from high frequency to low frequency); when the thermal trigger temperature increases to 160 ℃ and 180 ℃, the energy storage modulus G' increases significantly and remains basically constant across the entire frequency test range. Meanwhile, the loss modulus G'' is consistently lower than the energy storage modulus G', indicating that V2 still exhibits a predominantly elastic response after thermal triggering in-situ reinforcement, fully demonstrating its excellent resistance to elastic deformation.

[0068] The frequency scan curves of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Comparative Example 1 are shown in Figure 8.

[0069] As shown in Figure 8, the storage modulus G' of V2H after thermal triggering treatment at 120 ℃, 160 ℃, and 180 ℃ shows minimal difference. Within the frequency range, the modulus only decreases slowly with frequency (from high to low frequencies), without exhibiting the characteristic of a significant increase in modulus at high temperatures and no change with frequency seen in V2. This indicates that the molecular network structure of V2H is insensitive to the thermal triggering temperature, and its performance cannot be significantly improved through temperature control.

[0070] The creep strain-time curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Example 1 is shown in Figure 9.

[0071] As shown in Figure 9, the creep resistance of V2 significantly increases with increasing thermal trigger temperature. After applying an axial stress of 3 kPa at 120 ℃, the maximum creep strain is 6.35%, and the residual strain after stress release is 3.57%. At 160 ℃, the maximum creep strain decreases to 4.17%, and the residual strain decreases to 3.09%. At 180 ℃, the maximum creep strain is only 1.02%, and the residual strain is as low as 0.42%, which are 84% and 88% lower than at 120 ℃, respectively, representing a qualitative leap in creep resistance.

[0072] The creep strain-time curve of the thermally triggered in-situ reinforced polyolefin polymer material prepared in Comparative Example 1 is shown in Figure 10.

[0073] As shown in Figure 10, the creep resistance of V2H deteriorates significantly with increasing thermal trigger temperature. At 120 °C, the maximum creep strain is 6.19%, and the residual strain after stress release is 3.26%. When the thermal trigger temperature rises to 160 °C, the maximum creep strain increases sharply to 19.7%, and the residual strain increases to 12.9%. When the thermal trigger temperature is further increased to 180 °C, the maximum creep strain reaches as high as 28.2%, and the residual strain increases to 19.4%, indicating that the material has lost its effective creep resistance.

[0074] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A thermally triggered in-situ reinforced polyolefin polymer material, characterized in that, The structural formula of the thermally triggered in-situ reinforced polyolefin polymer material is as follows: In the above formula, x is independently selected from integers from 50 to 2000, y is independently selected from integers from 10 to 400, and n is independently selected from integers from 0 to 8.

2. A method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 1, characterized in that, Includes the following steps: 9-p-Toluenesulfonyl-9-azabicyclo[6.1.0]non-4-ene and cyclooctene were subjected to ring-opening metathesis polymerization under the catalysis of a ruthenium-based catalyst; the product of the ring-opening metathesis polymerization was mixed with elemental sulfur and then subjected to cross-linking reaction under the catalysis of an organic base to obtain the thermally triggered in-situ reinforced polyolefin polymer material.

3. The method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 2, characterized in that, The molar ratio of 9-p-toluene-9-azabicyclo[6.1.0]non-4-ene to cyclooctene is 1:(5~20).

4. The method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 2, characterized in that, The ruthenium-based catalyst is a second-generation Grubbs catalyst.

5. The method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 2, characterized in that, The ring-opening metathesis polymerization reaction was carried out at room temperature for 9-12 hours.

6. The method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 2, characterized in that, The organic base is 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene.

7. The method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 2, characterized in that, The cross-linking reaction is carried out at a temperature of 100-120°C for 4-6 hours.

8. The method for preparing the thermally triggered in-situ reinforced polyolefin polymer material according to claim 2, characterized in that, The amount of elemental sulfur added is three times the molar amount of 9-p-toluene-9-azabicyclo[6.1.0]non-4-ene.

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