A polyimide in-situ reinforced polydicyclopentadiene composite and a method of making the same
By preparing polyimide-reinforced polydicyclopentadiene composites by copolyimide monomers and dicyclopentadiene, the problems of insufficient material rigidity and heat resistance are solved, and high-performance material modification is achieved, which is suitable for the electronics, automotive and construction industries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2023-06-15
- Publication Date
- 2026-06-02
AI Technical Summary
Polydicyclopentadiene materials lack rigidity and heat resistance, which limits their application in the fields of optics and microelectronics.
Polyimide-reinforced polydicyclopentadiene composites were prepared by copolymerizing imide monomers containing norbornene groups with dicyclopentadiene using a ring-opening metathesis polymerization method. Grubbs series catalysts and phosphite inhibitors were added to control the polymerization process.
It significantly improves the tensile modulus, tensile strength, flexural modulus and flexural strength of composite materials, increases the glass transition temperature by 109℃, and increases the thermal decomposition temperature by more than 400℃, meeting the application needs of the electronics, automotive and construction industries.
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Figure CN116535621B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials technology, specifically relating to a polyimide in-situ reinforced polydicyclopentadiene composite material and its preparation method. Background Technology
[0002] Polydicyclopentadiene (PDCPD) is a high-molecular-weight material that combines rigidity and flexibility. It is produced by the ring-opening metathesis polymerization of dicyclopentadiene (DCPD). The monomer DCPD mainly comes from the C5 fraction of petroleum cracking for ethylene production and coal coking byproducts, offering advantages such as wide availability and low price. With the increasing demand for ethylene, the development and utilization of dicyclopentadiene, as a byproduct of industrial production, is receiving increasing attention. DCPD can be used as a polymerization monomer due to its low viscosity and high reactivity, making it particularly suitable for producing complex, large, thin-walled parts through reaction injection molding. The polymerization process is exothermic, requiring minimal energy consumption during molding, and the reaction can be completed within minutes, resulting in a short production cycle. Furthermore, PDCPD has low density and relatively light weight, making it widely used in automobiles, home appliances, and sporting goods.
[0003] Polydicyclopentadiene (PDCPD) possesses a combination of flexible double bonds, a rigid cyclic structure, and controllable crosslinking, characteristics that are maintained even under extreme conditions such as low temperatures. It also exhibits excellent acid and alkali resistance, water resistance, and superior electrical and mechanical properties. These advantages give PDCPD enormous application potential. However, unmodified PDCPD's basic mechanical properties are not outstanding, exhibiting low rigidity and modulus, moderate tensile and flexural strength, and insufficient heat resistance, among other mechanical and thermodynamic issues. This limits its application in optics and microelectronics. To improve the performance of PDCPD and obtain materials with specific functions, it can be modified by copolymerizing it with olefin monomers of a functional matrix. Current research indicates that introducing compounds such as alkoxysilanes, acrylates, and norbornene derivatives can improve the mechanical properties of PDCPD to varying degrees, but with minimal effect and little improvement, or even a decrease, in heat resistance.
[0004] Imide compounds, whose structural units contain two carbonyl groups bonded to a nitrogen atom, with the carbonyl oxygen acting as an electron acceptor and the nitrogen as an electron donor, exhibit strong intermolecular forces. They are typically prepared by reacting primary amines with acid anhydrides or carboxylic acids, making the raw materials extremely abundant. Polyimide materials prepared from these compounds are widely used as specialty engineering plastics in aerospace, electronics, and architectural design. By referencing and designing based on the molecular structure of polyimide, its use as a modifier for PDCPD can significantly improve the material's thermal properties. This novel high-performance polydicyclopentadiene material can effectively improve the mechanical and heat resistance properties of PDCPD for various applications in electronics, automotive, and construction, breaking the monopoly of foreign products and technologies and possessing broad market prospects.
[0005] This invention proposes a polyimide-reinforced polydicyclopentadiene composite material and its preparation method by combining the properties of special engineering plastic polyimide and engineering plastic polydicyclopentadiene through molecular design. Summary of the Invention
[0006] To address the issues of insufficient rigidity and heat resistance in polydicyclopentadiene materials, this invention provides a polyimide-reinforced polydicyclopentadiene composite material and its preparation method. The method involves dissolving an imide monomer containing norbornene groups in dicyclopentadiene and copolymerizing it with dicyclopentadiene via ring-opening metathesis polymerization, thereby imparting adjustable mechanical and heat resistance properties to the material.
[0007] The present invention discloses a method for preparing a polyimide in-situ reinforced polydicyclopentadiene composite material, which involves melting dicyclopentadiene, then adding a small amount of an imide monomer containing norbornene groups in batches under heating and stirring at 60-80°C. After the monomer is fully dissolved, a catalyst and an inhibitor are added, the mixture is mixed and degassed, and the resulting mixture is then cured. After complete curing, the mixture is removed to obtain the polyimide in-situ reinforced polydicyclopentadiene composite material of the present invention.
[0008] Furthermore, the catalyst is a ruthenium-based catalyst, preferably a Grubbs series catalyst, such as a Grubbs 2 catalyst; the amount of catalyst used is 0.05 to 0.2 mol% of the sum of the amounts of dicyclopentadiene and the imide monomer containing norbornene groups.
[0009] Furthermore, the inhibitor is a phosphite compound, preferably tributyl phosphite; the molar ratio of inhibitor to catalyst is 0.1 to 10:1;
[0010] Furthermore, the curing process can be carried out using temperature-controlled heating devices such as ovens, heating tables, and heating blankets, with curing conditions of 35-45℃ for 1-2 hours, 55-65℃ for 2-4 hours, and 75-85℃ for 2-10 hours.
[0011] Furthermore, the mass of dicyclopentadiene and the imide monomer containing norbornene groups is calculated as 100%, with the imide monomer containing norbornene groups accounting for 1-30% of the mass, and the remainder being dicyclopentadiene.
[0012] Furthermore, the imide monomer containing the norbornene group is synthesized from an acid anhydride containing the norbornene group and an aromatic diamine, and its general reaction formula is:
[0013]
[0014] Where R is C or O.
[0015] The specific synthesis process is as follows:
[0016] Step (1): Take 0.050-0.055 mol of anhydride containing norbornene groups, add 150 mL of dichloromethane solution, and stir at room temperature until completely dissolved; then add 0.025 mol of aromatic diamine monomer and 0.020-0.050 mol of triethylamine, and react overnight;
[0017] Step (2): Remove the solvent from the solution obtained in step (1) by vacuum distillation, then dehydrate and condense it in an oil bath at 110-130°C. After naturally cooling to room temperature, add dichloromethane until the solid is completely dissolved. Then pass it through a 200-300 mesh neutral alumina column and remove the solvent by vacuum distillation. Dry the product under vacuum to obtain a white solid, which is an imide monomer containing norbornene groups.
[0018] Furthermore, the aromatic diamine monomer mentioned in step (1) may be one of the following, but not limited to, diamine compounds:
[0019]
[0020] The beneficial effects of this invention are:
[0021] By adjusting the structure and amount of imide monomers containing norbornene groups, the tensile modulus, tensile strength, flexural modulus, flexural strength, and thermal properties of the prepared composite material are improved to varying degrees. Compared with pure polydicyclopentadiene, the composite material prepared by this invention has better thermal stability, with the glass transition temperature increased by up to 109°C and the thermal decomposition temperature greater than 400°C. The rigidity of the composite material is enhanced, with the tensile strength increased by up to 38%, the tensile modulus increased by up to 41%, the flexural strength increased by up to 61%, and the flexural modulus increased by up to 47%.
[0022] The imide monomer used in this invention is soluble in dicyclopentadiene and is end-capped with norbornene. This method involves fewer raw material synthesis steps, simplifies the composite material molding process, and is suitable for large-scale industrial production. Furthermore, it can copolymerize with dicyclopentadiene, avoiding a decrease in crosslinking degree. By introducing polyimide, a special engineering material, this method effectively improves the rigidity and heat resistance of polydicyclopentadiene, meeting the diverse application needs of polydicyclopentadiene in the electronics, automotive, and construction industries. This opens a new path for the high-performance modification of polydicyclopentadiene materials. Attached Figure Description
[0023] Figure 1 : NMR spectrum of PI-1 in Example 1. (Figure) 1 ¹H NMR (400MHz, CDCl₃) δ 7.22 (d, J = 8.4 Hz, 4H), 7.05 (d, J = 8.4, 4H), 6.24 (t, J = 1.8, 4H), 3.98 (s, 2H), 3.49 (m, 4H), 3.41 (dd, J = 1.5 Hz, J = 2.9 Hz, 4H), 1.75 (dt, J = 1.6 Hz, J = 8.8 Hz, 2H), 1.58 (dt, J = 1.6 Hz, J = 8.8 Hz, 2H), indicating the successful synthesis of the target compound.
[0024] Figure 2 Example 2: Effect of PI-1 addition on the glass transition temperature of the material. As the amount of PI-1 added increases, the glass transition temperature gradually increases.
[0025] Figure 3 Example 2: Effect of PI-1 addition on the mechanical properties of the material. With increasing PI-1 addition, the mechanical properties all increased, with a significant improvement observed when the addition reached 15 wt%.
[0026] Figure 4 Thermogravimetric curves of PI-1 to PI-6 in Example 3 at an addition amount of 15wt% are shown. The curves indicate that the decomposition temperatures of all materials are greater than 400℃, with PI-5, the sulfone-containing modified material, exhibiting the best mechanical and thermal properties. Detailed Implementation
[0027] The present invention will be described below through specific embodiments, but is not limited thereto.
[0028] Example 1
[0029] Table 1: Amounts of each raw material used in the synthesis of norbornene-containing imide monomers in Example 1
[0030]
[0031] For the synthesis of imide monomers containing norbornene groups, the raw materials are weighed according to the reactants and molar ratios corresponding to monomers PI-1 to PI-6 in the table.
[0032] Taking the synthesis of the imide PI-1 monomer containing norbornene groups as an example:
[0033] Step (1): Take 0.0525 mol of norborneol olefinic anhydride, add 150 mL of dichloromethane solution, stir at room temperature until completely dissolved, then add 0.025 mol of 4,4'-diaminodiphenylmethane and 0.035 mol of triethylamine, and react overnight.
[0034] Step (2): The solution obtained in step (1) is subjected to vacuum distillation to remove the solvent and then placed in an oil bath at 120°C for dehydration condensation. After natural cooling, dichloromethane is added until the solid is completely dissolved. Then, the solution is passed through a 200-300 mesh neutral alumina column and the solvent is removed by vacuum distillation. The product is then placed in a vacuum oven to dry, yielding white solid PI-1 with a yield of 91.8%.
[0035] Example 2
[0036] Table 2: Amounts of each raw material in the polyimide-reinforced polydicyclopentadiene composite material in Example 2
[0037]
[0038] Weigh the pharmaceuticals according to the amount of each raw material in Table 2. Melt the dicyclopentadiene and pour it into the reactor. Then, under the condition of heating and stirring at 70°C, add 0g, 0.45g, 1.11g, 2.60g and 6.31g of PI-1 monomer in Example 1 in small batches (divided into 3 batches, each batch being one-third of the monomer feed amount). After fully dissolving, add 0.1mol% of Grubbs 2nd generation catalyst and 0.2mol% of tributyl phosphite inhibitor (i.e., the amount of catalyst is 0.1mol% of the sum of the amounts of "dicyclopentadiene and PI-1", and the molar ratio of inhibitor to catalyst is 2:1). After mixing, degas for 10min. Slowly pour the mixture into the mold for curing treatment (curing is carried out using an oven, and the curing conditions are: 1.5h at 40°C, 3h at 60°C, and 5h at 80°C). After complete curing, take it out to obtain polyimide in-situ reinforced polydicyclopentadiene composite material (1) to (5).
[0039] Example 3
[0040] 14.73g of dicyclopentadiene was melted and poured into the reactor. Then, under the condition of heating and stirring at 70°C, 2.60g of PI-1 monomer prepared in Example 1 was added in small batches (divided into 3 batches, each batch being one-third of the monomer feed amount). After being fully dissolved, 0.1mol% of Grubbs 2nd generation catalyst and 0.2mol% of tributyl phosphite inhibitor were added (i.e., the amount of catalyst was 0.1mol% of the sum of the amounts of dicyclopentadiene and PI-1, and the molar ratio of inhibitor to catalyst was 2:1). After mixing, the mixture was degassed for 10 minutes. The mixture was then slowly poured into a mold for curing (curing was carried out in an oven under the following conditions: 1.5h at 40°C, 3h at 60°C, and 5h at 80°C). After complete curing, the polyimide in-situ reinforced polydicyclopentadiene composite material (6) was obtained.
[0041] Under the experimental conditions described above, 2.60g of PI-2 to PI-6 monomers prepared in Example 1 were taken and the above steps were repeated. After complete curing, the polyimide in-situ reinforced polydicyclopentadiene composite material (7) to (11) was obtained.
[0042] Table 3: Amounts of raw materials and related properties of the polyimide-reinforced polydicyclopentadiene composite material in Example 3
[0043]
[0044]
[0045] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art can make corresponding changes and substitutions based on the technical solutions and inventive concepts of the present invention, and any modifications or substitutions resulting in the same performance or application should be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a composite material of polyimide in situ reinforced polydicyclopentadiene, characterized in that: The process involves melting dicyclopentadiene, then adding a small amount of imide monomer containing norbornene groups in batches under heating and stirring at 60-80 °C. After the monomer is fully dissolved, a catalyst and an inhibitor are added, and the mixture is mixed and degassed. The resulting mixture is then cured, and the cured mixture is removed to obtain the polyimide in-situ reinforced polydicyclopentadiene composite material. The imide monomer containing the norbornene group is synthesized from an acid anhydride containing the norbornene group and an aromatic diamine, and the steps are as follows. Step (1): Take 0.050~0.055 mol of anhydride containing norbornene group, add 150 mL of dichloromethane solution, and stir at room temperature until completely dissolved; then add 0.025 mol of aromatic diamine monomer and 0.020~0.050 mol of triethylamine, and react overnight; Step (2): Remove the solvent from the solution obtained in step (1) by vacuum distillation, then carry out dehydration condensation in an oil bath at 110~130 ℃, and add dichloromethane after natural cooling to room temperature until the solid is completely dissolved. Then pass it through a 200~300 mesh neutral alumina column, remove the solvent by vacuum distillation, and dry the product under vacuum to obtain a white solid, which is an imide monomer containing norbornene groups. The aromatic diamine monomer mentioned in step (1) is one of the following diamine compounds, ； The structural formula of the anhydride containing norbornene groups mentioned in step (1) is shown below. 。 2. The method for preparing a polyimide-reinforced polydicyclopentadiene composite material as described in claim 1, characterized in that: The catalyst is a ruthenium-based catalyst, and the amount of catalyst used is 0.05~0.2 mol of the sum of the amounts of dicyclopentadiene and the imide monomer containing norbornene groups.
3. The method for preparing a polyimide-reinforced polydicyclopentadiene composite material as described in claim 1, characterized in that: The inhibitor is a phosphite compound, and the molar ratio of inhibitor to catalyst is 0.1~10:
1.
4. The method for preparing a polyimide-reinforced polydicyclopentadiene composite material as described in claim 1, characterized in that: The curing process is performed using an oven, heating table, or heating blanket. The curing conditions are 35-45 ℃ for 1-2 h, 55-65 ℃ for 2-4 h, and 75-85 ℃ for 2-10 h.
5. The method for preparing a polyimide-reinforced polydicyclopentadiene composite material as described in claim 1, characterized in that: The mass of dicyclopentadiene and the imide monomer containing norbornene group is calculated as 100%, with the imide monomer containing norbornene group accounting for 1~30% of the mass, and the remainder being dicyclopentadiene.
6. A composite material of polyimide in situ reinforced polydicyclopentadiene, characterized in that: It is prepared by the method described in any one of claims 1 to 5.