Preparation method and application of a dicyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization and its comb-shaped copolymer

Abstract

The present invention discloses a dicyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization and a preparation method and application of a comb-shaped copolymer thereof. The inhibitor can be used in the preparation of polycycloolefin materials using front-end ring-opening metathesis polymerization to prepare a polycycloolefin material, comprising the following raw materials: the inhibitor; a ruthenium-based catalyst; and a cycloolefin monomer. The lactic acid oligomer chain segment in the inhibitor can reduce the ring-opening activity of the cycloolefin monomer, hindering contact between the catalyst and the substrate, and can coordinate with the catalyst active center to reduce the catalytic activity, thereby reducing the polymerization rate of the cycloolefin monomer and improving the material processing performance; at the same time, the inhibitor contains copolymerization units that can participate in the polymerization reaction and increase the degree of polymerization of the polycycloolefin material; the lactic acid oligomer chain segment in the inhibitor has good compatibility with polylactic acid and can form a comb-shaped copolymer with epoxy dicyclopentadiene that has both chain extension and plasticizing effects. The copolymer can simultaneously improve the strength and toughness of the polylactic acid blend.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials and engineering technology, and in particular to a preparation method and application of a dicyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization and a comb-shaped copolymer thereof. Background Art

[0002] Front-end ring-opening metathesis polymerization is a highly efficient and energy-efficient polymerization technology. It operates through a self-propagating reaction, whereby a localized reaction zone forms a "polymerization front" under light or heat stimulation. The energy provided by the exothermic heat of the polymerization reaction sustains the polymerization reaction and propagates toward the unreacted monomers until polymerization is complete. This rapid, efficient, and low-energy method has gradually become a mainstream method for preparing polycycloolefin materials. However, due to its rapid polymerization rate, front-end ring-opening metathesis polymerization suffers from poor processing properties. Therefore, inhibitors are typically added during the polymerization process to slow the polymerization and improve the material's processing properties. Typical inhibitors are phosphate derivatives, which can significantly reduce the polymerization rate. However, these inhibitors remain within the matrix, reducing the mechanical properties of the material itself. Summary of the Invention

[0003] The main purpose of the present invention is to provide a preparation method and application of a dicyclopentadienyl functional inhibitor and a comb-shaped copolymer thereof for preparing polycycloolefin materials by front-end ring-opening metathesis polymerization and capable of ensuring the mechanical properties of the materials.

[0004] To achieve the above objectives, the present invention provides a biscyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization, which is represented by the following general formula 1:

[0005]

[0006]

[0007] In general formula 1, m=5-7, n=5-7, R1 and R2 are each independently an aliphatic substituent or an aromatic substituent having n1 (0-6) carbon atoms, and n1=0, 1, 2, 3, ...

[0008] The present invention also provides a method for preparing the above inhibitor, comprising the following steps:

[0009] (1) placing dicyclopentadiene and a catalyst in an organic solvent for epoxidation reaction at a reaction temperature of 20 to 40° C. for a reaction time of 3 to 5 hours to obtain epoxy dicyclopentadiene;

[0010] (2) placing epoxy dicyclopentadiene, lactic acid polyol and a catalyst in an organic solvent to carry out an epoxidation reaction at a reaction temperature of 50 to 70° C. for 3 to 5 hours to obtain the inhibitor containing lactic acid oligomer chain segments.

[0011] Furthermore, in step (1), the catalyst is any one of sodium hypochlorite, m-chloroperbenzoic acid, 4-phenylpyridine nitrogen oxide and N-methylmorpholine-N-oxide, or a mixture of two or more thereof in any proportion, and the molar ratio of the catalyst to dicyclopentadiene is 1:1.

[0012] Furthermore, in step (1), the organic solvent is any one of anhydrous dichloromethane, anhydrous chloroform, and anhydrous dichloropropane, or a mixture of two or more thereof in any proportion.

[0013] Furthermore, in step (2), the catalyst is any one of 1-methylimidazole, phosphoric acid, zinc chloride, and aluminum chloride, or a mixture of two or more thereof in any proportion, the molar ratio of epoxy dicyclopentadiene and lactic acid polyol is 1:1, and the ratio of the catalyst to the total mass of the monomers (the sum of the mass of epoxy dicyclopentadiene and lactic acid polyol) is 5:95.

[0014] Furthermore, in step (2), the organic solvent is any one of ethyl acetate, toluene, and tetrahydrofuran, or a mixture of two or more thereof in any proportion.

[0015] The present invention also provides application of the inhibitor in preparing polycycloolefin materials by front-end ring-opening metathesis polymerization.

[0016] The present invention also provides a polycycloolefin material comprising the following raw materials by mass percentage:

[0017] 0.50wt% to 4.00wt% of the above inhibitor;

[0018] Ruthenium-based catalyst 0.10 wt% to 0.12 wt%;

[0019] The balance of cycloolefin monomers.

[0020] Furthermore, the ring tension of the cycloolefin monomer ranges from 6.7 to 54.5 kcal·mol -1 .

[0021] Furthermore, the cycloolefin monomer is dicyclopentadiene.

[0022] The present invention also provides a method for preparing the polycycloolefin material, comprising the following steps:

[0023] (1) mixing the cycloolefin monomer and the above-mentioned inhibitor, adding a ruthenium-based catalyst, and ultrasonically dispersing the mixture in an ice-water bath for 60 to 180 seconds to obtain a uniform dispersion;

[0024] (2) The dispersion is injected into a mold, heated at 250° C. for local thermal initiation, and copolymerized to obtain the polycycloolefin material.

[0025] The present invention also provides a dicyclopentadienyl comb copolymer, which is represented by the following general formula 2:

[0026]

[0027] In general formula 2, m=5-7, n=5-7, R1 and R2 are each independently an aliphatic substituent or an aromatic substituent having n1 (0-6) carbon atoms, and n1=0, 1, 2, 3, ...

[0028] The present invention also provides a method for preparing the above-mentioned dicyclopentadienyl comb copolymer, comprising the following steps:

[0029] The inhibitor, epoxy dicyclopentadiene and catalyst are mixed to carry out ring-opening metathesis polymerization reaction at a reaction temperature of 80-100° C. and a reaction time of 1-2 hours to obtain the dicyclopentadiene comb copolymer containing lactic acid oligomer chain segments and epoxy group structures.

[0030] Furthermore, in the preparation method of the dicyclopentadienyl comb copolymer, the catalyst is a ruthenium-based catalyst, the mass ratio of the inhibitor to epoxy dicyclopentadiene is 2:1, and the amount of the catalyst is such that the molar concentration reaches 400 ppm.

[0031] Furthermore, the ruthenium-based catalyst of the present invention is a Grubbs catalyst.

[0032] The present invention also provides the use of the dicyclopentadienyl comb copolymer in preparing a polylactic acid blend.

[0033] The present invention also provides a polylactic acid blend, comprising the following raw materials by mass percentage:

[0034] 1.00 wt% to 5.00 wt% of the above-mentioned dicyclopentadienyl comb copolymer;

[0035] Polybutylene terephthalate-butylene adipate 19.00wt% ~ 20.00wt%;

[0036] Polylactic acid balance.

[0037] The present invention also provides a method for preparing the above-mentioned polylactic acid blend, comprising the following steps: uniformly mixing polylactic acid, polybutylene terephthalate-adipate and the above-mentioned dicyclopentadienyl comb copolymer, adding the mixture to a torque rheometer, and melt-blending the mixture at a temperature of 180° C. and a rotation speed of 50 rpm for 5 to 6 minutes to obtain the polylactic acid blend.

[0038] The dicyclopentadienyl comb-shaped copolymer prepared by the invention can simultaneously play the role of chain extension and plasticization in the polylactic acid blend.

[0039] The beneficial effects of the present invention are embodied in:

[0040] (1) The dicyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization of the present invention is a type of dicyclopentadienyl functional inhibitor containing lactic acid oligomer chain segments, wherein the larger lactic acid oligomer chain segments can reduce the ring-opening activity of cycloolefin monomers, hinder the contact between the catalyst and the substrate, and at the same time can coordinate with the active center of the catalyst to reduce the catalytic activity, thereby reducing the polymerization rate of the cycloolefin monomers and improving the processing performance of the material; and since it contains a dicyclopentadiene structure, it can also participate in the polymerization process of the material, increase the polymerization degree of the polycycloolefin material, thereby improving the comprehensive performance of the material and broadening its application field.

[0041] (2) The bio-based lactic acid oligomer segment in the dicyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization of the present invention has good compatibility with polylactic acid. Based on this, the present invention prepares and synthesizes a dicyclopentadienyl comb-shaped copolymer containing a lactic acid oligomer segment and an epoxy group structure, and introduces the polylactic acid blend by melt blending. The epoxy group can improve the compatibility of the polylactic acid blend through an epoxidation reaction, and the lactic acid oligomer segment can play a plasticizing role, improve the mobility of the molecular segment, and enhance the crystallization ability of the polylactic acid blend. Under the combined action of the two, the strength and toughness of the polylactic acid blend are simultaneously improved, so that the material has an excellent rigidity and toughness balance to meet production application requirements.

[0042] (3) The intermediate of the present invention, epoxy dicyclopentadiene monomer, has a flexible and controllable structure and a simple synthesis process. It can simultaneously improve the comprehensive properties of polydicyclopentadiene materials and polylactic acid blends, and has a high utilization rate, which fully reflects the flexible and multi-faceted application of epoxy dicyclopentadiene.

[0043] (4) The front-end polymerization temperature and polymerization rate of the polycycloolefin material prepared by the present invention are as low as 140°C and 0.06 cm·s -1 The gelation time is as high as 689.00s, and the storage stability of the material is significantly improved. The molecular weight and swelling ratio between cross-linking points of the material are as low as 127.79g·mol -1 , 253.00%, the degree of polymerization is improved, the tensile strength and elongation at break of the material are 55.21MPa and 15.43% respectively, with good rigidity and toughness balance. In addition, the heat deformation temperature of the polydicyclopentadiene material reaches 183.00℃, and the initial thermal decomposition temperature is as high as 350.75℃. At the same time, the bio-based lactic acid oligomer chain segment in the functional monomer has good compatibility with polylactic acid. Therefore, it is copolymerized with epoxy dicyclopentadiene to prepare a dicyclopentadiene-based comb copolymer with both chain extension and plasticizing effects. It is introduced into the polylactic acid blending system by melt blending to prepare a polylactic acid blend. The gel content of the obtained material is as high as 27.65%, the tensile strength is 36.05MPa, the elongation at break is as high as 355.81%, and the impact strength is 53kJ / m2 , the material has excellent balance of rigidity and toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Biscyclopentadienyl functional inhibitor A for front-end ring-opening metathesis polymerization 1 H NMR spectrum;

[0045] Figure 2 Biscyclopentadienyl functional inhibitor B for front-end ring-opening metathesis polymerization 1 H NMR spectrum;

[0046] Figure 3 is the FTIR spectrum of dicyclopentadienyl comb copolymer A;

[0047] Figure 4 is the FTIR spectrum of dicyclopentadienyl comb copolymer B;

[0048] Figure 5 Epoxy dicyclopentadiene 1 H NMR spectrum;

[0049] Figure 6 The figure is a synthetic flow chart of a biscyclopentadienyl functional inhibitor A for front-end ring-opening metathesis polymerization;

[0050] Figure 7 The figure is a synthetic flow chart of a biscyclopentadienyl functional inhibitor B for front-end ring-opening metathesis polymerization;

[0051] Figure 8 1 is a synthetic flow chart of dicyclopentadienyl comb copolymer A;

[0052] Figure 9 This is a synthetic flow chart of dicyclopentadienyl comb copolymer B. DETAILED DESCRIPTION

[0053] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0054] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0055] Dicyclopentadiene, purchased from Sigma-Aldrich;

[0056] Polylactic acid (4032D) was purchased from Nature Works, USA;

[0057] Polybutylene terephthalate-adipate (C1200) was purchased from BASF, Germany;

[0058] Lactic acid polyol-1000(M w =1000), lactic acid polyol-2000 (M w =2000), purchased from Anhui Fengyuan Group;

[0059] The catalysts 3-chloroperbenzoic acid and 1-methylimidazole were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0060] Plasticizer PEG was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0061] Chain extender SG-20 was purchased from Jiangsu Jiayirong Compatibilizer Co., Ltd.;

[0062] Grubbs catalyst was purchased from Sigma-Aldrich.

[0063] Example 1

[0064] Preparation of biscyclopentadienyl functional inhibitor A (hereinafter referred to as inhibitor A) for front-end ring-opening metathesis polymerization

[0065] The structural formula of inhibitor A is shown in Formula 1:

[0066]

[0067] The synthetic route of inhibitor A is as follows Figure 6 As shown, the preparation method is:

[0068] (1) Dicyclopentadiene (6.78 g, 51.3 mmol) and anhydrous dichloromethane (100 mL) were mixed evenly at 25 ° C and poured into a 500 mL flask. Then, the catalyst 3-chloroperoxybenzoic acid (8.80 g, 51 mmol) was dissolved in anhydrous dichloromethane (100 mL) and slowly added to the flask three times. After reacting for 4 hours at 25 ° C under nitrogen conditions, a white precipitate appeared. The reaction liquid was then filtered, and the filtrate was repeatedly washed and extracted with a 10% mass fraction of sodium bicarbonate aqueous solution. The filtrate was then dried with anhydrous sodium sulfate and then vacuum concentrated to obtain white crystals. Finally, the white crystals were vacuum dried at 45 ° C for 48 hours to obtain the intermediate epoxy dicyclopentadiene containing epoxy groups, whose structural formula is shown in Formula 2. Formula 2 1 H NMR spectrum Figure 5 shown.

[0069]

[0070] (2) Lactic acid polyol-1000 (10 g) and the intermediate epoxy dicyclopentadiene (2 g) obtained in step (1) were placed in a flask containing ethyl acetate (150 mL), and then a catalyst, 1-methylimidazole (0.12 g), was added. The mixture was heated in a water bath at 60° C. for 4 h to obtain a light yellow solution. The reaction liquid was then filtered, and the filtrate was finally concentrated in vacuo at 50° C. to obtain inhibitor A containing lactic acid polyol oligomer segments.

[0071] The initial thermal decomposition temperature of inhibitor A was tested according to ISO11358-1:2014 standard. The initial thermal decomposition temperature of inhibitor A was 220℃. As the molecular chain grew, the initial thermal decomposition temperature increased. The molecular weight of the dicyclopentadienyl functional inhibitor A was about 1150 by gel permeation chromatography, which proved the successful synthesis of inhibitor A. Figure 1 The H NMR spectrum also demonstrates the successful synthesis of inhibitor A.

[0072] Example 2

[0073] Preparation of biscyclopentadienyl functional inhibitor B (hereinafter referred to as inhibitor B) for front-end ring-opening metathesis polymerization

[0074] The structural formula of inhibitor B is shown in Formula 3:

[0075]

[0076] The synthetic route of inhibitor B is as follows Figure 7 As shown, the preparation method is:

[0077] (1) Dicyclopentadiene (6.78 g, 51.3 mmol) and anhydrous dichloromethane (100 mL) were mixed evenly at 25°C and poured into a 500 mL flask. Then, the catalyst 3-chloroperoxybenzoic acid (8.80 g, 51 mmol) was dissolved in anhydrous dichloromethane (100 mL) and slowly added to the flask three times. After reacting for 4 hours at 25°C under nitrogen, a white precipitate appeared. The reaction liquid was then filtered, and the filtrate was repeatedly washed and extracted with a 10% mass fraction sodium bicarbonate aqueous solution. The filtrate was then dried with anhydrous sodium sulfate and then vacuum concentrated to obtain white crystals. Finally, the white crystals were vacuum dried at 45°C for 48 hours to obtain the intermediate epoxy dicyclopentadiene containing epoxy groups;

[0078] (2) Lactic acid polyol-2000 (10 g) and the intermediate epoxydicyclopentadiene (2 g) obtained in step (1) were placed in a flask containing ethyl acetate (150 mL), and 1-methylimidazole catalyst (0.12 g) was added. The mixture was heated in a water bath at 60° C. for 4 h to obtain a light yellow solution. The reaction liquid was then filtered, and the filtrate was finally concentrated in vacuo at 50° C. to obtain inhibitor B containing lactic acid polyol oligomer segments.

[0079] The initial thermal decomposition temperature of inhibitor B was tested according to ISO11358-1:2014 standard, and the initial thermal decomposition temperature of inhibitor B was 230 ° C. The molecular weight of inhibitor B was tested by gel permeation chromatography and was about 2150, which proved that inhibitor B was successfully synthesized. Figure 2 The H NMR spectrum also demonstrates the successful synthesis of inhibitor B.

[0080] Example 3

[0081] Preparation of polydicyclopentadiene materials

[0082] (1) Grubbs catalyst (0.12 wt%) and inhibitor A (0.50 wt%) were added to dicyclopentadiene (99.38 wt%) to obtain a mixed solution, and the vial containing the mixed solution was ultrasonically dispersed in an ice-water bath for 60 s to obtain a uniform dispersion.

[0083] (2) Finally, the dispersion is injected into a prefabricated mold and locally thermally initiated at 250°C to polymerize by self-propagation driven by its own heat to obtain polydicyclopentadiene material.

[0084] Example 4

[0085] Preparation of polydicyclopentadiene materials

[0086] The preparation method of the polydicyclopentadiene material in this embodiment is the same as that in Example 3, except that the raw material amounts are adjusted to: dicyclopentadiene (98.88 wt %), inhibitor A (1.00 wt %), and Grubbs catalyst (0.12 wt %).

[0087] Example 5

[0088] Preparation of polydicyclopentadiene materials

[0089] The preparation method of the polydicyclopentadiene material in this embodiment is the same as that in Example 3, except that the raw material amounts are adjusted to: dicyclopentadiene (97.88 wt %), inhibitor A (2.00 wt %), and Grubbs catalyst (0.12 wt %).

[0090] Example 6

[0091] Preparation of polydicyclopentadiene materials

[0092] The preparation method of the polydicyclopentadiene material in this embodiment is the same as that in Example 3, except that the raw material amounts are adjusted to: dicyclopentadiene (96.88 wt %), inhibitor A (3.00 wt %), and Grubbs catalyst (0.12 wt %).

[0093] Example 7

[0094] Preparation of polydicyclopentadiene materials

[0095] The preparation method of the polydicyclopentadiene material in this embodiment is the same as that in Example 3, except that the raw material amounts are adjusted to: dicyclopentadiene (95.88 wt %), inhibitor A (4.00 wt %), and Grubbs catalyst (0.12 wt %).

[0096] Example 8

[0097] Preparation of polydicyclopentadiene materials

[0098] The preparation method of the polydicyclopentadiene material in this embodiment is the same as that in Example 3, except that inhibitor A is replaced by inhibitor B, and the raw material amounts are adjusted to: dicyclopentadiene (96.89 wt%), inhibitor B (3.00 wt%), and Grubbs catalyst (0.11 wt%).

[0099] Example 9

[0100] Preparation of polydicyclopentadiene materials

[0101] The preparation method of the polydicyclopentadiene material in this embodiment is the same as that in Example 6, except that the inhibitor A is replaced by a mixture of inhibitor A and inhibitor B in a mass ratio of 1:1.

[0102] Example 10

[0103] Preparation of dicyclopentadienyl comb copolymer A (hereinafter referred to as copolymer A)

[0104] The structural formula of copolymer A is shown in Formula 4:

[0105]

[0106] The synthetic route of copolymer A is as follows Figure 8 As shown, the preparation method is:

[0107] Inhibitor A (6 g) prepared in Example 1, epoxy dicyclopentadiene (an intermediate obtained in the synthesis process of the inhibitor shown in Formula 2, 3 g), and Grubbs catalyst (14.3 mg) were mixed in a beaker and thoroughly mixed by ultrasonic dispersion. The mixture was then placed in a forced air oven and reacted at 80° C. for 1 h. Dicyclopentadienyl comb copolymer A was obtained by ring-opening metathesis polymerization.

[0108] like Figure 3 As shown in the infrared spectrum of the dicyclopentadienyl comb copolymer A, 3500 cm -1 The characteristic peak of -OH appeared at 3042 cm -1 The area of ​​the C-H stretching vibration peak of the C=C double bond at 1744 cm -1 The stretching vibration peak of C=O at 831 cm -1 The characteristic peak of the epoxy group appears at , indicating the successful synthesis of the biscyclopentadienyl comb copolymer A. The initial thermal decomposition temperature of the biscyclopentadienyl comb copolymer A was tested according to the ISO11358-1:2014 standard and was found to be 280°C. Furthermore, the molecular weight of the biscyclopentadienyl comb copolymer A was determined to be between 55,000 and 60,000 using gel permeation chromatography, both demonstrating the successful preparation of the biscyclopentadienyl comb copolymer A.

[0109] Example 11

[0110] Preparation of dicyclopentadienyl comb copolymer B (hereinafter referred to as copolymer B)

[0111] The structural formula of copolymer B is shown in Formula 5:

[0112]

[0113] The synthetic route of copolymer B is as follows Figure 9 As shown, the preparation method is:

[0114] Inhibitor B (6 g) prepared in Example 2, epoxy dicyclopentadiene (an intermediate obtained in the synthesis process of the inhibitor shown in Formula 2, 3 g), and Grubbs catalyst (7.6 mg) were mixed in a beaker and thoroughly mixed by ultrasonic dispersion. The mixture was then placed in a forced air oven and reacted at 80° C. for 1 h. Dicyclopentadienyl comb copolymer B was obtained by ring-opening metathesis polymerization.

[0115] like Figure 4 As shown in the infrared spectrum, in the infrared curve of dicyclopentadienyl comb copolymer B, 3500 cm -1 The characteristic peak of -OH appeared at 3042 cm -1The area of ​​the C-H stretching vibration peak of the C=C double bond at 1744 cm -1 The stretching vibration peak of C=O at 831 cm -1 The characteristic peak of the epoxy group appears at , indicating the successful synthesis of biscyclopentadienyl comb copolymer B. The initial thermal decomposition temperature of biscyclopentadienyl comb copolymer B was tested according to ISO11358-1:2014 standard and was found to be 300°C. Furthermore, the molecular weight of biscyclopentadienyl comb copolymer B was determined to be between 80,000 and 95,000 by gel permeation chromatography, both demonstrating the successful preparation of biscyclopentadienyl comb copolymer B.

[0116] Example 12

[0117] Preparation of polylactic acid blends

[0118] Polylactic acid (79.20 wt%), polybutylene terephthalate-adipate (19.80 wt%) and copolymer A (1.00 wt%) were mixed uniformly, placed in a torque rheometer and melt-blended at 180° C. and 50 rpm for 5 to 6 minutes to obtain a polylactic acid blend.

[0119] Example 13

[0120] Preparation of polylactic acid blends

[0121] The preparation method of the polylactic acid blend in this embodiment is the same as that in Example 12, except that the amounts of raw materials are adjusted to: polylactic acid (78.40 wt %), polybutylene terephthalate-adipate (19.60 wt %), and copolymer A (2.00 wt %).

[0122] Example 14

[0123] Preparation of polylactic acid blends

[0124] The preparation method of the polylactic acid blend in this embodiment is the same as that in Example 12, except that the raw material amounts are adjusted to: polylactic acid (77.60 wt%), polybutylene terephthalate-adipate (19.40 wt%), copolymer A (3.00 wt%).

[0125] Example 15

[0126] Preparation of polylactic acid blends

[0127] The preparation method of the polylactic acid blend in this embodiment is the same as that in Example 12, except that the amounts of raw materials are adjusted to: polylactic acid (76.80 wt %), polybutylene terephthalate-adipate (19.20 wt %), and copolymer A (4.00 wt %).

[0128] Example 16

[0129] Preparation of polylactic acid blends

[0130] The preparation method of the polylactic acid blend in this embodiment is the same as that in Example 12, except that the amounts of raw materials are adjusted to: polylactic acid (76.00 wt%), polybutylene terephthalate-adipate (19.00 wt%), and copolymer A (5.00 wt%).

[0131] Example 17

[0132] Preparation of polylactic acid blends

[0133] The preparation method of the polylactic acid blend in this embodiment is the same as that in Example 14, except that copolymer A is replaced by copolymer B.

[0134] Example 18

[0135] Preparation of polylactic acid blends

[0136] The preparation method of the polylactic acid blend in this example is the same as that in Example 14, except that copolymer A is replaced by a mixture of copolymer A and copolymer B in a mass ratio of 1:1.

[0137] Comparative Example 1

[0138] Preparation of polydicyclopentadiene materials

[0139] The preparation method of the polydicyclopentadiene material in this comparative example is the same as that in Example 3, except that the inhibitor A is omitted and the raw material amounts are adjusted to: dicyclopentadiene (99.88 wt %) and Grubbs catalyst (0.12 wt %).

[0140] Comparative Example 2

[0141] Preparation of polydicyclopentadiene materials

[0142] The preparation method of the polydicyclopentadiene material in this comparative example is the same as that in Example 3, except that inhibitor A is replaced with lactic acid polyol-1000, and the raw material amounts are adjusted to: dicyclopentadiene (96.88 wt %), lactic acid polyol-1000 (3.00 wt %), and Grubbs catalyst (0.12 wt %).

[0143] Comparative Example 3

[0144] Preparation of polydicyclopentadiene materials

[0145] The preparation method of the polydicyclopentadiene material in this comparative example is the same as that in Example 3, except that inhibitor A is replaced with lactic acid polyol-2000, and the raw material amounts are adjusted to: dicyclopentadiene (96.90 wt %), lactic acid polyol-2000 (3.00 wt %), and Grubbs catalyst (0.10 wt %).

[0146] Comparative Example 4

[0147] Preparation of polydicyclopentadiene materials

[0148] The preparation method of the polydicyclopentadiene material in this comparative example is the same as that in Example 3, except that inhibitor A is replaced by a mixed inhibitor. The mixed inhibitor is prepared by mixing lactic acid polyol-1000 and lactic acid polyol-2000 in a mass ratio of 1:1, and the amount of raw materials is adjusted to: dicyclopentadiene (96.89 wt %), mixed inhibitor (3.00 wt %), and Grubbs catalyst (0.11 wt %).

[0149] Comparative Example 5

[0150] Preparation of polylactic acid blends

[0151] The preparation method of the polylactic acid blend in this comparative example is the same as that in Example 12, except that copolymer A is omitted and the amount of raw materials is adjusted to: polylactic acid (80.00 wt %) and polybutylene terephthalate-adipate (20.00 wt %).

[0152] Comparative Example 6

[0153] Preparation of polylactic acid blends

[0154] The preparation method of the polylactic acid blend in this comparative example is the same as that in Example 12, except that copolymer A is replaced by epoxy dicyclopentadiene shown in Formula 2, and the amount of raw materials is adjusted to: polylactic acid (77.60wt%), polybutylene terephthalate-adipate (19.40wt%), and epoxy dicyclopentadiene (3.00wt%).

[0155] Comparative Example 7

[0156] Preparation of polylactic acid blends

[0157] The preparation method of the polylactic acid blend in this comparative example is the same as that in Example 12, except that copolymer A is replaced by lactic acid polyol-1000, and the amount of raw materials is adjusted to: polylactic acid (77.60wt%), polybutylene terephthalate-adipate (19.40wt%), and lactic acid polyol-1000 (3.00wt%).

[0158] Comparative Example 8

[0159] Preparation of polylactic acid blends

[0160] The preparation method of the polylactic acid blend in this comparative example is the same as that in Example 12, except that copolymer A is replaced by lactic acid polyol-2000, and the amount of raw materials is adjusted to: polylactic acid (77.60wt%), polybutylene terephthalate-adipate (19.40wt%), and lactic acid polyol-2000 (3.00wt%).

[0161] Comparative Example 9

[0162] Preparation of polylactic acid blends

[0163] The preparation method of the polylactic acid blend in this comparative example is the same as that in Example 12, except that copolymer A is replaced by plasticizer PEG, and the amount of raw materials is adjusted to: polylactic acid (77.60wt%), polybutylene terephthalate-adipate (19.40wt%), and plasticizer PEG (3.00wt%).

[0164] Comparative Example 10

[0165] Preparation of polylactic acid blends

[0166] The preparation method of the polylactic acid blend in this comparative example is the same as that in Example 12, except that copolymer A is replaced by chain extender SG-20, and the amount of raw materials is adjusted to: polylactic acid (77.60wt%), polybutylene terephthalate-adipate (19.40wt%), and chain extender SG-20 (3.00wt%).

[0167] Tests and results

[0168] The materials prepared in the above examples and comparative examples were cut to prepare test specimens, and the test method was as follows:

[0169] Front-end polymerization rate: Using a glass tube with a scale and a stopwatch, thermal initiation was performed at 250°C in a dry and closed environment using an electric soldering iron. After initiation of polymerization, the time was recorded with a stopwatch at every 1 cm interval, and the front-end polymerization rate was then calculated by fitting.

[0170] Front-end polymerization temperature: Use a glass tube and a digital thermometer to perform thermal initiation at 250°C in a dry and closed environment using an electric soldering iron. After initiating polymerization, record the highest temperature using the digital thermometer, which is the front-end polymerization temperature.

[0171] Gelation behavior: The sample solution was evenly placed in the test plate of the rotational rheometer. A temperature sweep was performed at a fixed strain of 1%, a frequency of 10 Hz and a constant temperature of 50°C, and the gelation time was recorded.

[0172] Swelling ratio test: Soak the sample in chloroform and place it at room temperature for 7 days. Then take it out, wipe off the surface solvent, weigh the mass of the expanded sample, and finally place it in a vacuum dry state to constant weight. The swelling ratio is calculated as follows:

[0173]

[0174] Where m1 is the mass of the expanded sample and m2 is the mass of the dried sample.

[0175] Polymerization enthalpy and degree of cure: The polymerization enthalpy and degree of cure of the material were measured using a differential scanning calorimeter in a N2 atmosphere. For the polymerization enthalpy test, the sample was first cooled to -10°C, kept warm for 5 minutes, and then heated to 200°C. The heating and cooling rates for the entire process were 5°C / min. For the reaction residual heat test, the sample was first heated to 250°C, kept warm for 5 minutes, then cooled to -20°C, and finally heated from -20°C to 250°C. The heating and cooling rates for the entire process were 10°C / min. The polymerization enthalpy of the reaction (H r ) and reaction waste heat (H res ), calculate the curing degree α of the sample according to the following formula:

[0176]

[0177] Molecular weight between cross-linking points M c The results were obtained by dynamic thermomechanical analysis. c Calculated using the following formula:

[0178]

[0179] Where, the value of ρ is 1g·cm -3 , R is the ideal gas constant, which is 8.314 J·mol -1 ·K -1 , T is the characteristic temperature, T = T g +50K, T g is the glass transition temperature, E′ Tg+50K The temperature is T g Storage modulus of the sample at +50K.

[0180] Gel content test: Using the Soxhlet extraction method, the mixed sample slices were placed in a Soxhlet extractor and refluxed with chloroform at 80°C for at least 15 hours to completely dissolve all non-crosslinked components. Then, the collected insoluble residue was vacuum dried at 80°C until a constant weight was obtained. f The calculation formula is as follows:

[0181]

[0182] Where W1 is the mass of the sample, and W2 is the mass of the remaining solid after extraction;

[0183] Tensile strength: tested according to ISO527-2:1993 standard, speed is 5mm / min.

[0184] Elongation at break: Tested according to ISO527-2:1993 standard, speed is 5mm / min.

[0185] Impact strength: tested according to ISO 179 standard.

[0186] Initial thermal decomposition temperature: tested according to ISO11358-1:2014 standard.

[0187] Heat distortion temperature: tested according to ISO75-2:2004 standard.

[0188] The test results are shown in Tables 1 to 4 below:

[0189] Table 1 Polymerization kinetics, mechanical properties, heat resistance and thermal stability performance indicators of the polydicyclopentadiene materials prepared in Examples 3-9

[0190]

[0191]

[0192] Table 2 Polymerization kinetics, mechanical properties, heat resistance and thermal stability performance indicators of the polydicyclopentadiene materials prepared in Comparative Examples 1-4

[0193] Test items unit Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Front end polymerization temperature ℃ 265.00 195.00 186.00 183.00 Front-end aggregation rate <![CDATA[cm·s -1 ]]> 0.34 0.26 0.22 0.24 Gel time s 230.00 320.00 330.00 339.00 <![CDATA[Enthalpy of polymerization H r > <![CDATA[J·g -1 ]]> 37.80 30.57 29.88 30.26 Curing degree ％ 99.50 95.60 93.20 94.70 <![CDATA[T g ]]> ℃ 172.28 140.55 135.74 139.78 <![CDATA[Molecular weight between crosslinks M c > <![CDATA[g·mol -1 ]]> 200.32 267.89 313.56 298.40 Swelling ratio ％ 307.40 356.80 398.70 384.50 tensile strength MPa 49.68 38.45 35.65 36.87 Elongation at break ％ 2.30 7.85 8.76 7.76 Heat deformation temperature ℃ 145.00 132.00 129.00 130.00 Initial thermal decomposition temperature ℃ 225.78 214.56 201.34 209.87

[0194] Table 3 Processing properties, mechanical properties, thermal properties and gel content of the polylactic acid blends prepared in Examples 12-18

[0195]

[0196]

[0197] Table 4 Processing properties, mechanical properties, thermal properties and gel content of the polylactic acid blends prepared in Comparative Examples 5-10

[0198] Test items unit Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Balanced torque N·m 7.20 6.70 6.20 6.10 6.50 7.80 Melting enthalpy <![CDATA[J·g -1 ]]> 29.10 26.81 25.14 25.34 27.86 23.34 Cold crystallization enthalpy <![CDATA[J·g -1 ]]> 24.76 26.15 23.43 23.65 23.45 22.74 Cold crystallization temperature ℃ 103.00 102.92 101.23 100.98 101.34 115.34 Melting point ℃ 169.98 169.44 163.20 164.51 168.75 162.54 crystallinity ％ 5.79 0.56 2.25 2.24 5.88 0.80 <![CDATA[T g ]]> ℃ 63.45 62.29 60.34 60.98 61.23 66.78 Gel content ％ 0 2.34 0.78 0.94 0.98 3.12 tensile strength MPa 34.87 32.19 30.23 30.76 31.45 33.23 Elongation at break ％ 88.37 149.93 110.23 107.65 176.22 193.60 Impact strength <![CDATA[kJ / m 2 ]]> 35.00 34.62 29.76 30.01 37.56 40.45

[0199] Tables 1 and 2 show the polymerization kinetics, mechanical properties, heat resistance, and thermal stability of the polydicyclopentadiene materials prepared in Examples 3-9 and Comparative Examples 1-4. Tables 3 and 4 show the processing properties, mechanical properties, and thermal performance of the polylactic acid blends prepared in Examples 12-18 and Comparative Examples 5-10.

[0200] The polymerization kinetic data of Examples 3-9 in Table 1 show that the introduction of the dicyclopentadienyl functional inhibitor significantly reduces the polymerization rate of dicyclopentadiene, making the front polymerization temperature and polymerization rate of dicyclopentadiene as low as 140°C and 0.06 cm·s -1 , the gelation time is also greatly improved, reaching 689.00s, and its storage stability is significantly improved. At the same time, the prepared polydicyclopentadiene material has a high degree of solidification, reaching a maximum of 98.80%, which can meet the needs of production applications. After mechanical properties testing of the above polydicyclopentadiene material, it was found that the introduction of dicyclopentadiene functional inhibitors increased the degree of polymerization of polydicyclopentadiene, and the molecular weight and swelling ratio between the cross-linking points of the material were reduced, reaching a minimum of 127.79g·mol -1 , 253.00%, and the tensile strength and elongation at break of the material are simultaneously improved, reaching a maximum of 55.21MPa and 15.43% respectively, showing a good balance between rigidity and toughness. At the same time, the thermal performance of the polydicyclopentadiene material is also improved, with the heat deformation temperature reaching 183.00°C and the initial thermal decomposition temperature as high as 350.75°C. This is because the dicyclopentadienyl functional inhibitor contains a large lactic acid oligomer chain segment, which can reduce the ring-opening activity of dicyclopentadiene and hinder the contact between the catalyst and the matrix. At the same time, it can coordinate with the active center of the catalyst to reduce the catalytic activity, thereby reducing the polymerization rate, improving the processing performance, and enhancing the storage stability of the material. It can also participate in the polymerization process through its own copolymerization unit, thereby increasing the degree of polymerization of the material, thereby achieving controllable polymerization process while further improving the overall performance of the material.

[0201] Table 2 shows the relevant data results of Comparative Examples 1-4. In Comparative Examples 2-4, only lactic acid polyol was introduced into polydicyclopentadiene. The results show that the addition of lactic acid polyol can reduce the polymerization rate of dicyclopentadiene, increase the gelation time, and improve the storage stability of the material. However, since it does not contain copolymerization units, it cannot participate in the polymerization process of dicyclopentadiene, which reduces the degree of polymerization of the material, resulting in a decrease in the tensile strength, heat deformation temperature, and initial thermal decomposition temperature of the material, resulting in a decrease in the overall performance of the polydicyclopentadiene material.

[0202] Table 3 shows the equilibrium torque data of Examples 12-18. It shows that with the introduction of the dicyclopentadienyl comb copolymer, the equilibrium torque of the material continues to decrease, and the processing performance of the blend is significantly improved. At the same time, the crystallization data of the material show that the introduction of the dicyclopentadienyl comb copolymer reduces the T g, while improving the crystallinity of the material, with the highest crystallinity reaching 12.42%. At the same time, the gel content of the material is as high as 27.65%. The mechanical properties of the above-mentioned polylactic acid blend were tested, and the results showed that the introduction of dicyclopentadiene comb copolymer improved the strength and toughness of the polylactic acid blend at the same time, with a tensile strength of 43.76MPa, an elongation at break of up to 355.81%, and an impact strength of 53.00kJ / m 2 The material has an excellent balance of rigidity and toughness. This is because the dicyclopentadienyl comb copolymer contains epoxy groups that react with the end groups of the polylactic acid blend, improving the interfacial compatibility between the two phases. At the same time, the lactic acid oligomers in the copolymer have good compatibility with polylactic acid and can act as a plasticizer in the blend, promoting the movement of molecular segments and improving the material's crystallization ability. This significantly improves the overall performance of polylactic acid.

[0203] Table 4 is the relevant data result of comparative examples 5-10. Among comparative examples 6 and 10, epoxy dicyclopentadiene and chain extender SG-20 are introduced in the polylactic acid blend, although it can react with the end group of the polylactic acid blend, improve the two-phase interface compatibility, improve the toughness of material, but can reduce the tensile strength and the impact strength of the polylactic acid blend. Among comparative examples 7-9, the introducing of lactic acid polyol and plasticizer PEG, although can improve the crystallization ability of material, it does not improve the interfacial compatibility of the two-phase of blend, makes the mechanical property of material not significantly improved.

[0204] In summary, the introduction of a dicyclopentadienyl functional inhibitor into a lactic acid polyol oligomer not only regulates the polymerization process of dicyclopentadiene and improves storage stability, but also enhances the mechanical and thermal properties of polydipentadiene, ultimately improving its overall performance. Furthermore, the introduction of a dicyclopentadienyl comb copolymer synthesized using this inhibitor into a polylactic acid blend not only improves the blend's processing performance but also significantly enhances the mechanical properties of the polylactic acid blend, resulting in an excellent balance between rigidity and toughness. This demonstrates the flexible and versatile application of dicyclopentadienyl functional monomers.

[0205] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A biscyclopentadienyl functional inhibitor for front-end ring-opening metathesis polymerization, characterized in that It is represented by the following formula 1 or formula 3: Formula 1; Formula 3.

2. The method for preparing the inhibitor according to claim 1, wherein: The following steps are involved: (1) placing dicyclopentadiene and a catalyst in an organic solvent for epoxidation reaction at a temperature of 20 to 40°C for 3 to 5 hours to obtain epoxy dicyclopentadiene; (2) placing epoxy dicyclopentadiene, lactic acid polyol and a catalyst in an organic solvent to undergo an epoxidation reaction at a temperature of 50 to 70° C. for 3 to 5 hours to obtain the inhibitor containing lactic acid oligomer chain segments.

3. Use of the inhibitor according to claim 1 in preparing polycycloolefin materials by front-end ring-opening metathesis polymerization.

4. A polycycloolefin material, characterized in that In terms of mass percentage, it includes the following raw materials: 0.50wt% to 4.00wt% of the inhibitor according to claim 1; Ruthenium-based catalyst 0.10wt% to 0.12wt%; The balance of cycloolefin monomers.

5. The method for preparing a polycycloolefin material according to claim 4, wherein: The following steps are involved: (1) Mixing a cycloolefin monomer and the inhibitor as claimed in claim 1, adding a ruthenium-based catalyst, and ultrasonically dispersing the mixture in an ice-water bath for 60 to 180 seconds to obtain a uniform dispersion; (2) The dispersion is injected into a mold, heated at 250° C. for local thermal initiation, and copolymerized to obtain the polycycloolefin material.

6. A dicyclopentadienyl comb copolymer, characterized in that It is represented by the following formula 4 or formula 5: Formula 4; Formula 5.

7. The method for preparing a biscyclopentadienyl comb copolymer according to claim 6, wherein: The following steps are involved: The inhibitor according to claim 1, epoxy dicyclopentadiene and a catalyst are mixed to carry out a ring-opening metathesis polymerization reaction at a reaction temperature of 80 to 100° C. and a reaction time of 1 to 2 hours to obtain the dicyclopentadiene comb copolymer containing lactic acid oligomer chain segments and epoxy group structures.

8. Use of the biscyclopentadienyl comb copolymer as claimed in claim 6 in preparing polylactic acid blends.

9. A polylactic acid blend, characterized in that: In terms of mass percentage, it includes the following raw materials: 1.00 wt% to 5.00 wt% of the biscyclopentadienyl comb copolymer according to claim 6; Polybutylene terephthalate-butylene adipate 19.00wt% ~ 20.00wt%; Polylactic acid balance.

10. The method for preparing the polylactic acid blend according to claim 9, wherein: The method comprises the following steps: uniformly mixing polylactic acid, polybutylene terephthalate-adipate and the dicyclopentadienyl comb copolymer according to claim 6, adding the mixture into a torque rheometer, and melt-blending the mixture for 5 to 6 minutes at a temperature of 180° C. and a rotation speed of 50 rpm to obtain the polylactic acid blend.

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