Polybutylene succinate / polylactic acid polymer as well as preparation method and application thereof
By introducing the Diels-Alder reaction of furan/maleimide into the PBS/PLA system to form thermally reversible bonds, the problems of poor compatibility and processability between PLA and PBS are solved, and the reprocessability and degradability of high-performance composite materials are realized.
Patent Information
- Application Number
- CN202411048870.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-01
- Publication Date
- 2026-02-03
AI Technical Summary
The poor interfacial compatibility between PLA and PBS results in limited improvement in the mechanical properties of the blend, and the cross-linking structure caused by traditional coupling agents worsens the processability of the material.
The introduction of the Diels-Alder reaction between furan and maleimide forms a thermally reversible bond, improving the compatibility of the PBS/PLA system and enabling good processability through dissociation at high temperature.
It improves the elongation at break and impact strength of PBS/PLA composite materials while maintaining good processability, avoiding the processing difficulties caused by traditional coupling agents.
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Figure CN121449905A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a kind of polybutylene succinate / polylactic acid polymer and its preparation method, application, especially the preparation method of a kind of polybutylene succinate / polylactic acid polymer with heat reversible crosslinking structure and its application. BACKGROUND
[0002] Polylactic acid (PLA) is an important biodegradable plastic, with the advantage of high rigidity, but its toughness is poor, elongation at break is small, impact strength is low, and needs to be modified to meet its many application requirements. The physical modification of PLA mainly includes blending modification, plasticizing modification, copolymerization modification and fiber composite modification. As a biodegradable polymer, polybutylene succinate (PBS) has good toughness, high elongation at break and excellent impact strength, and can complement the performance of PLA, so PBS is a good modification material for PLA. However, a large number of studies have shown that the interfacial compatibility of PLA and PBS is very poor, which seriously restricts the improvement degree of the mechanical properties of the blend. At present, people usually add block or grafted polymer compatibilizers to improve the compatibility of PLA and PBS and improve the toughness of the composite material, but the compatibilization effect of physical toughening agent is very limited. In addition, researchers have also improved the compatibility of the two polymers by chain extension, that is, adding a multifunctional coupling agent to establish a covalent bond between the two polymers, thereby linking the two components and increasing the compatibility of the two phases. However, this also leads to the formation of crosslinked structures in the material, resulting in increased viscosity and difficult processing. SUMMARY
[0003] To solve the problems of PLA and PBS modification in the prior art, the present application provides a kind of polybutylene succinate / polylactic acid polymer, which utilizes the thermal reversibility of Diels-Alder reaction between furan and maleimide, introduces it into PBS / PLA system, and improves the compatibility between the two polymers by thermal reversible Diels-Alder bonding. It is expected to effectively improve the performance of the material, and also benefit from the reverse dissociation reaction of Diels-Alder bond at high temperature to make the polymer have good processability, thereby solving the problem of material processability caused by permanent crosslinking of traditional coupling agent, and obtaining a functional new material.
[0004] To achieve the above technical purpose, the technical scheme of the present application is as follows:
[0005] The first aspect of the present application is to provide a kind of polybutylene succinate / polylactic acid polymer, which has the structure shown in formula I:
[0006]
[0007] wherein, R1 a hydrocarbon group containing 1-3 benzene rings or a hydrocarbon group containing at least one ester bond;
[0008] R 2 and R 3 are each independently selected from C1-C8 alkyl.
[0009] x, m, n are integers not less than 1, m / (m+n)=0.0001-0.1, preferably 0.0005-0.05.
[0010] Further, R 1 is * represents the connection of one end of furan; R 2 and R 3 are each independently selected from C2-C6 linear alkyl.
[0011] Further, x is any integer from 10 to 5000, preferably any integer from 50 to 1000, more preferably any integer from 100 to 500.
[0012] Further, m+n is an integer from 30 to 3000, preferably an integer from 100 to 1000.
[0013] The technical purpose of the second aspect of the present application is to provide a preparation method of a polybutylene succinate / polylactic acid polymer, comprising the following steps:
[0014] (1) Preparation of polybutylene succinate with furan substituent in side groups:
[0015] Polybutylene succinate, furan-containing small molecule monomer After mixing the free radical initiator and the free radical stabilizer, melt extrusion is performed.
[0016] (2) Preparation of polylactic acid with maleimide substituent at both ends:
[0017] First step: sequentially add organic solvent, polylactic acid organic diacid and catalyst into the reaction container to perform esterification reaction, to obtain polylactic acid with carboxyl at both ends
[0018]
[0019] Second step: sequentially add organic solvent, polylactic acid with carboxyl at both ends prepared in the first step, hydroxyl-substituted maleimide catalyst into the reaction container to perform esterification reaction, to obtain polylactic acid with maleimide substituent at both ends;
[0020] (3) Preparation of polybutylene succinate / polylactic acid polymer:
[0021] The side group furan-substituted polybutylene succinate obtained in step (1) and the both end maleimide-substituted polylactic acid obtained in step (2) are mixed and melt-extruded to obtain the polybutylene succinate / polylactic acid polymer.
[0022] In the above method, R 1 , R 2 and R 3 are selected as in the first aspect, which will not be repeated.
[0023] Further, the amount of the furan-containing small molecule monomer added in step (1) is 0.01% to 20% by mass of the polybutylene succinate, preferably 0.05% to 10% by mass.
[0024] Further, the free radical initiator in step (1) is an organic peroxide initiator or an azo initiator, and the amount of the free radical initiator added is 0.01% to 1% by weight of the polybutylene succinate. More specifically, the free radical initiator is selected from at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, and dibenzoyl peroxide.
[0025] Further, the free radical stabilizer in step (1) is selected from at least one of a hindered phenol antioxidant, a phosphite antioxidant, and an alkyl ester antioxidant, and the amount of the free radical stabilizer added is 0.05% to 1% by weight of the polybutylene succinate. More specifically, the free radical stabilizer is selected from at least one of antioxidant 1010, antioxidant 168, phenol, and trimethylphenol.
[0026] Further, the melt-extrusion in step (1) is performed using a screw extruder, the temperature of the screw extruder is 150°C to 250°C, preferably 150°C to 200°C, and the residence time of the mixed components in the extruder is 30 seconds to 300 seconds, preferably 90 to 180 seconds.
[0027] Further, the reaction molar ratio of the polylactic acid to the organic diacid in step (2) is 0.01 to 0.5:1, preferably 0.1 to 0.5:1.
[0028] Further, the reaction molar ratio of the both end carboxyl-containing polylactic acid to the hydroxyl-substituted maleimide in step (2) is 0.01 to 0.5:1, preferably 0.1 to 0.5:1.
[0029] Further, the organic solvent in the two-step reaction in step (2) is selected from at least one of C1-C5 chloroalkane, dimethylformamide, tetrahydrofuran, acetonitrile and dimethyl sulfoxide; the catalyst for the two-step esterification reaction is selected from at least one of inorganic acid, organic acid and carbodiimide compound; the reaction temperature of the esterification reaction is 0-60°C, preferably 20-60°C, and the reaction time is 1-72 hours, preferably 2-10 hours.
[0030] Further, the molar ratio of the furan group of the polybutylene succinate side group to the maleimide group at both ends of the polylactic acid in step (3) is 0.5-2:1, preferably 1-2:1.
[0031] Further, the melt extrusion in step (3) is realized by using a screw extruder, the temperature of the screw extruder is 180-250°C, preferably 180-230°C; the residence time of the mixed components in the extruder is 30-300 seconds, preferably 90-180 seconds.
[0032] The technical purpose of the second aspect of the present application is to provide an application of the polybutylene succinate / polylactic acid polymer, due to the thermal reversibility, the reverse dissociation reaction of the Diels-Alder bond occurs at high temperature, so that the polymer has good processability, and can be used as a repeatable processing and degradable resin, or as a raw material to prepare a repeatable processing and degradable resin.
[0033] Compared with the prior art, the present application has the following advantages:
[0034] (1) The polybutylene succinate / polylactic acid polymer of the present application has a Diels-Alder bond, and the reverse dissociation reaction of the Diels-Alder bond occurs at high temperature, so that the polymer has good repeatable processing and degradability, and avoids the problem that the material cannot be repeatedly processed due to permanent crosslinking of the traditional coupling agent.
[0035] (2) Compared with the general PBS / PLA polymer, the polymer of the present application has good elongation at break and impact strength.
[0036] (3) The preparation method of the present application is simple and easy to operate, and the Diels-Alder reaction between furan / maleimide has thermal reversibility, which is introduced into the PBS / PLA system to obtain a PBS / PLA polymer with high compatibility, and a functional new material is obtained.
[0037] Other features and advantages of the present application will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS
[0038] Figure 1NMR spectra of raw material polybutylene succinate and product polymer D used in Example 2.
[0039] Figure 2 NMR spectra of raw material polylactic acid and product polylactic acid with maleimide substituent at both ends used in Example 4.
[0040] Figure 3 Infrared spectra of products of Example 2, Example 5 and Example 7. DETAILED DESCRIPTION
[0041] The following non-limiting examples can make those of ordinary skill in the art more fully understand the present application, but in no way limit the present application.
[0042] In the following examples, the amount of monomer A or B incorporated was determined by nuclear magnetic resonance hydrogen spectrum, with deuterated tetrachloroethane as the solvent, a test temperature of 120°C, and the corresponding relationship between the amount of incorporation and m, n values being: amount of incorporation % = [m / (m+n)]%.
[0043] Elongation at break: determined according to GB / T1040.1-2006 method.
[0044] Tensile strength: determined according to GB / T1040.1-2006 method.
[0045] Impact strength: determined according to GB / T1043.1-2008 method.
[0046] Small molecule monomer containing furan:
[0047] For the synthesis of small molecule monomers containing furan, a conventional synthesis method is provided, which is not a limitation on small molecule monomers containing furan.
[0048] (1) Small molecule monomer A containing furan:
[0049] Into a flask containing 100 mL of dichloromethane, 9.81 g of furfuryl alcohol and 15.2 g of triethylamine were poured and stirred in an ice water bath for 10 min; then 15.6 g of acryloyl chloride was injected into a dropping funnel through a syringe after three times of gas replacement by nitrogen, and after sealing, it was slowly dropped into the flask (about 30 min for dropping), and after continuous stirring in the ice water bath for 6 h, the product was filtered, saturated aqueous sodium chloride solution was added to the filtrate, and the liquid was allowed to separate into two layers using a separatory funnel for 5-10 min, the lower layer was taken out, and saturated aqueous sodium chloride solution was repeatedly added for washing three times, and then anhydrous sodium sulfate was used for drying, and the small molecule monomer A containing furan had the following structural formula:
[0050]
[0051] (2) Small molecule monomer B containing furan:
[0052]
[0053] Ref. Synth. Macromolecules, 1998, 31(2): 314-321.
[0054] Preparation of polybutylene succinate with pendant furan substituent:
[0055] Example 1
[0056] 100 parts of polybutylene succinate, 0.1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (radical initiator), 0.1 part of 1010 (radical stabilizer), 0.2 part of 168 (radical stabilizer), 2 parts of monomer A were mixed in mass parts, and then the mixture was added into a twin-screw extruder for melt extrusion at 150°C, with a residence time of 150 s. The extruded product was cooled by a circulating water bath and pelletized to obtain polybutylene succinate with pendant furan substituent, which was denoted as polymer C. The content of monomer A was calculated to be 1.5 mol% by nuclear magnetic hydrogen spectrum.
[0057] Example 2
[0058] 100 parts of polybutylene succinate, 0.1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (radical initiator), 0.1 part of 1010 (radical stabilizer), 0.2 part of 168 (radical stabilizer), 2 parts of monomer B were mixed in mass parts, and then the mixture was added into a twin-screw extruder for melt extrusion at 150°C, with a residence time of 150 s. The extruded product was cooled by a circulating water bath and pelletized to obtain polybutylene succinate with pendant furan substituent. The nuclear magnetic hydrogen spectrum of the raw material polybutylene succinate and the product is shown in Figure 1 , and the infrared spectrum of the product is shown in Figure 3 . Figure 1 It can be seen from the nuclear magnetic hydrogen spectrum that the characteristic peaks of furan (a, b) and ether bond (c, d) on monomer B appeared in the product, indicating that monomer B was successfully grafted onto the molecular chain of polybutylene succinate. The content of monomer B was calculated to be 1.8 mol% by nuclear magnetic hydrogen spectrum.
[0059] Example 3
[0060] By weight, 100 parts of polybutylene succinate, 0.1 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (free radical initiator), 0.1 parts of 1010 (free radical stabilizer), 0.2 parts of 168 (free radical stabilizer), and 5 parts of monomer B were mixed. The mixture was then fed into a twin-screw extruder and melt-extruded at 150°C for 150 s. The extruded product was cooled in a circulating water bath and pelletized to obtain polybutylene succinate with furan-substituted side groups, denoted as polymer E. The content of monomer B, as determined by 1H NMR spectroscopy, was 4.5 mol%.
[0061] Preparation of polylactic acid with maleimide substituents at both ends:
[0062] Example 4
[0063] 5g of polylactic acid (degree of polymerization x = 200), containing one hydroxyl group and one carboxyl group at each end, was dissolved in 100mL of dichloromethane. 1.25g of oxalic acid and 0.1g of p-toluenesulfonic acid were added, and the mixture was heated under reflux for 2 hours, continuously removing the water generated during the reaction. The reaction solution was washed with saturated NaHCO3 solution until neutral, and extracted to obtain polylactic acid with carboxyl groups at both ends. It has the structure shown in Formula III.
[0064]
[0065] 4g of the polylactic acid (PLA) with carboxyl groups at both ends prepared above was dissolved in 100mL of dichloromethane. 1.5g of maleimide ethanol and 0.1g of p-toluenesulfonic acid were added, and the mixture was heated under reflux for 2 hours, continuously removing the generated water during the reaction. The reaction solution was washed with saturated NaHCO3 solution until neutral, and extracted to obtain PLA with maleimide substituents at both ends. It has the structure shown in Formula IV:
[0066]
[0067] The 1H NMR spectra of the raw material polylactic acid and the product are shown below. Figure 2 As can be seen in the figure, the product shows the characteristic peak of maleimide (at d) and the characteristic peak formed by the esterification reaction (at a, b, and c), indicating that maleimide groups were successfully attached to both ends of the polylactic acid molecule.
[0068] Example 5
[0069] 10g of polylactic acid (degree of polymerization x = 400), containing one hydroxyl group and one carboxyl group at each end, was dissolved in 100mL of dichloromethane. 2.35g of oxalic acid and 0.15g of p-toluenesulfonic acid were added, and the mixture was heated under reflux for 2 hours, continuously removing the water generated during the reaction. The reaction solution was washed with saturated NaHCO3 solution until neutral, and extracted to obtain polylactic acid with carboxyl groups at both ends. It has the structure shown in Formula V:
[0070]
[0071] The product was dissolved in 150 mL of dichloromethane, 2.4 g of maleimide butanol and 0.15 g of p-toluene sulfonic acid were added, and the mixture was heated to reflux for 2 hours. The reaction was continuously removed water during the reaction. The reaction solution was washed with saturated NaHCO3solution until neutral, and extracted to obtain the polylactic acid with maleimide substituent at both ends. The product has the structure shown in formula VI:
[0072]
[0073] The infrared spectrum of the product is shown in Figure 3 .
[0074] Preparation of polybutylene succinate / polylactic acid polymer:
[0075] Example 6
[0076] The product of example 1 (100 g) and the product of example 4 (100 g) were mixed, and then the mixture was added to a twin-screw extruder for melt extrusion at 180°C with a residence time of 150 s. The extruded product was cooled by a circulating water bath and pelletized to obtain the final product. The composition and properties of the product are shown in Table 1.
[0077] Example 7
[0078] The product of example 2 (100 g) and the product of example 5 (100 g) were mixed, and then the mixture was added to a twin-screw extruder for melt extrusion at 180°C with a residence time of 150 s. The extruded product was cooled by a circulating water bath and pelletized to obtain the final product. The composition and properties of the product are shown in Table 1, and the infrared spectrum of the product is shown in Figure 3 As can be seen from the figure, the furan groups of the polybutylene succinate side groups reacted with the maleimide groups at both ends of the polylactic acid, and characteristic peaks of the furan-maleimide reaction to form a six-membered ring appeared at 1190 cm -1 and 1375 cm -1 .
[0079] Example 8
[0080] The product of example 3 (100 g) and the product of example 5 (100 g) were mixed, and then the mixture was added to a twin-screw extruder for melt extrusion at 180°C with a residence time of 150 s. The extruded product was cooled by a circulating water bath and pelletized to obtain the final product. The composition and properties of the product are shown in Table 1.
[0081] Example 9
[0082] The product 150 g of Example 2 and the product 50 g of Example 5 were mixed, and then the mixture was fed into a twin-screw extruder to be melt-extruded at 180°C with a residence time of 150 s, and the extruded product was cooled by a circulating water bath and pelletized to obtain a final product. The product composition and properties are shown in Table 1.
[0083] Example 10
[0084] The product 50 g of Example 2 and the product 150 g of Example 5 were mixed, and then the mixture was fed into a twin-screw extruder to be melt-extruded at 180°C with a residence time of 150 s, and the extruded product was cooled by a circulating water bath and pelletized to obtain a final product. The product composition and properties are shown in Table 1.
[0085] Comparative Example 1
[0086] Polybutylene succinate 50 g and polylactic acid (polymerization degree x is 400) 150 g were mixed, and then the mixture was fed into a twin-screw extruder to be melt-extruded at 180°C with a residence time of 150 s, and the extruded product was cooled by a circulating water bath and pelletized to obtain a final product. The product composition and properties are shown in Table 1.
[0087] Comparative Example 2
[0088] Polybutylene succinate 100 g and polylactic acid (polymerization degree x is 400) 100 g were mixed, and then the mixture was fed into a twin-screw extruder to be melt-extruded at 180°C with a residence time of 150 s, and the extruded product was cooled by a circulating water bath and pelletized to obtain a final product. The product composition and properties are shown in Table 1.
[0089] Table 1
[0090] Example Elongation at break (%) Tensile strength (Mpa) impact strength / (kJ / m 2 ) Example 1 310.2 36.65 12.98 Example 2 290.3 37.61 13.60 Example 3 281.3 37.93 13.65 Example 4 11.85 55.75 1.82 Example 5 12.50 56.31 2.73 Example 6 213.46 22.40 3.55 Example 7 470.81 35.57 4.11 Example 8 578.37 40.59 7.36 Example 9 320.66 35.48 10.31 Example 10 393.12 45.94 5.12 Comparative Example 1 29.98 48.10 3.01 Comparative Example 2 64.12 40.05 3.77
[0091] From the mechanical property test results in Table 1, it can be seen that polybutylene succinate (Examples 1-3) has a high elongation at break and impact strength, but the tensile strength is low, indicating that the material has good toughness and weak rigidity; and polylactic acid (Examples 4-5) is typically rigid, with high tensile strength, but very low elongation at break and weak impact strength. Physical blending of the two (Comparative Examples 1-2) can improve the toughness of the material to a certain extent, but the degree is limited. In the present application, the furan side group of polybutylene succinate and the maleimide at both ends of polylactic acid undergo Diels-Alder reaction, thereby establishing a chemical bond between the two, significantly improving the interaction force between the two polymers, and greatly improving the elongation at break and impact strength of the composite (Examples 6-10). The furan-maleimide bonding structure can be confirmed from the infrared spectrum in Figure 3 .
Claims
1. A polybutylene succinate / polylactic acid polymer, characterized in that, It has the structure shown in Equation I: Among them, R 1 It is a hydrocarbon group containing 1-3 benzene rings or a hydrocarbon group containing at least one ester bond; R 2 and R 3 Alkyl groups selected independently from C1-C8; x, m, and n are integers not less than 1, and m / (m+n) = 0.0001-0.
1.
2. The polybutylene succinate / polylactic acid polymer according to claim 1, characterized in that, R 1 for * Represents the end connected to the furan; R 2 and R 3 Each is independently selected from straight-chain alkyl groups of C2-C6.
3. The polybutylene succinate / polylactic acid polymer according to claim 1, characterized in that, x is any integer between 10 and 5000, and m+n is an integer between 30 and 3000.
4. The method for preparing the polybutylene succinate / polylactic acid polymer according to claim 1, comprising the following steps: (1) Preparation of polybutylene succinate with furan-substituents in the side group: Polybutylene succinate, furan-containing small molecule monomers The free radical initiator and free radical stabilizer are mixed and then melt-extruded. (2) Preparation of polylactic acid with maleimide substituents at both ends: Step 1: Add organic solvent and polylactic acid sequentially to the reaction vessel. Organic dicarboxylic acids With a catalyst, an esterification reaction is carried out to obtain polylactic acid containing carboxyl groups at both ends. Step 2: Add the organic solvent, the polylactic acid with carboxyl groups at both ends prepared in Step 1, and the hydroxylated maleimide sequentially to the reaction vessel. A catalyst is used to carry out an esterification reaction to obtain polylactic acid with maleimide substituents at both ends; (3) Preparation of polybutylene succinate / polylactic acid polymer: The polybutylene succinate with furan-substituted side groups obtained in step (1) and the polylactic acid with maleimide-substituted ends obtained in step (2) are mixed and melt-extruded to obtain the polybutylene succinate / polylactic acid polymer.
5. According to the preparation method of claim 4, the amount of furan-containing small molecule monomer added in step (1) is 0.01%-20% of the mass of polybutylene succinate.
6. The preparation method according to claim 4, characterized in that: The free radical initiator mentioned in step (1) is an organic peroxide initiator or an azo initiator, and the amount of free radical initiator added is 0.01%-1% of the weight of polybutylene succinate.
7. The preparation method according to claim 5, characterized in that, The free radical initiator is selected from at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, and dibenzoyl peroxide.
8. The preparation method according to claim 4, characterized in that: The free radical stabilizer mentioned in step (1) is selected from at least one of hindered phenolic antioxidants, phosphorous antioxidants and alkyl ester antioxidants, and the amount of free radical stabilizer added is 0.05%-1% of the weight of polybutylene succinate.
9. The preparation method according to claim 8, characterized in that: The free radical stabilizer is selected from at least one of antioxidant 1010, antioxidant 168, phenol, and trimethylphenol.
10. The preparation method according to claim 4, characterized in that: The melt extrusion described in step (1) is achieved using a screw extruder with a temperature of 150℃-250℃ and a residence time of the mixed components in the extruder of 30-300 seconds.
11. The preparation method according to claim 4, characterized in that: The molar ratio of polylactic acid to organic dicarboxylic acid in step (2) is 0.01-0.5:
1.
12. The preparation method according to claim 4, characterized in that: The molar ratio of polylactic acid with carboxyl groups at both ends to hydroxylated maleimide in step (2) is 0.01-0.5:
1.
13. The preparation method according to claim 4, characterized in that: In step (2), the organic solvents used in both reactions are selected from at least one of C1-C5 chloroalkanes, dimethylformamide, tetrahydrofuran, acetonitrile, and dimethyl sulfoxide; the catalysts used in both esterification reactions are selected from at least one of inorganic acids, organic acids, and carbodiimide compounds; the reaction temperature of the esterification reaction is 0℃-60℃, and the reaction time is 1-72 hours.
14. The preparation method according to claim 4, characterized in that: In step (3), the feed is prepared according to a molar ratio of furan groups on the side of polybutylene succinate to maleimide groups at both ends of polylactic acid of 0.5-2:
1.
15. The preparation method according to claim 4, characterized in that: The melt extrusion in step (3) is achieved using a screw extruder with a temperature of 180℃-250℃ and a residence time of the mixed components in the extruder of 30-300 seconds.
16. The application of the polybutylene succinate / polylactic acid polymer of claim 1 as a reprocessable and biodegradable resin and as a raw material for preparing reprocessable and biodegradable resins.