Bio-based thermosetting elastomer as well as preparation method and degradation method thereof

Abstract

The invention relates to a preparation method of a bio-based thermosetting elastomer. The preparation method comprises the step of reacting sugar alcohol with dihydric alcohol in the presence of a catalyst. The invention also relates to a bio-based thermosetting elastomer and a degradation method thereof. The thermosetting elastomer prepared by the preparation method provided by the invention is high in yield, has good thermal stability and elasticity, and can be degraded and recycled under mild conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of synthetic plastics, and particularly relates to a bio-based thermoset elastomer and a preparation method and degradation method thereof. BACKGROUND

[0002] In the global economic and social development, oil-based plastics as raw materials of fossil resources have played an extremely important role, and they have a wide range of uses in various aspects of daily life and production. However, fossil resources are a limited and non-renewable resource, and as the demand for oil-based plastics continues to increase, the global resource reserves will eventually be exhausted, so it is particularly important to develop renewable resources to replace oil resources. Secondly, most of the widely used oil-based plastics are non-degradable, and metal catalysts are used in the production process, which complicates the treatment of waste and increases production costs and causes serious environmental problems. Among renewable resources, biomass resources not only have a wide distribution and large output, but also have the characteristics of carbon neutrality, which can reduce carbon dioxide emissions and reduce the pressure on the atmospheric environment. Therefore, in order to reduce our dependence on non-renewable resources and improve the long-term sustainability of the plastics industry, it is of great significance to develop new biodegradable bio-based plastics synthesized by "green" chemical methods.

[0003] The scientific research and industrial communities have long been engaged in the development and research of bio-based monomers and polymers. Common bio-based monomers include bio-based carboxylic acids (succinic acid, fumaric acid, itaconic acid), diols (1,3-propanediol, 1,4-butanediol, isosorbide, xylitol), furan-based (2,5-furandicarboxaldehyde, 2,5-furandicarboxylic acid) and vanillin-based (vanillin, syringaldehyde, vanillic acid) monomers, which can be used to prepare bio-based polyethers, polyesters and polyurethanes and other polymers. Currently developed bio-based plastics are mostly thermoplastic plastics, such as polylactide and polyhydroxyalkanoate, which have been widely used. However, the development of bio-based thermoset plastics is still in its infancy due to problems such as difficulty in controlling crosslinking density, poor mechanical properties, and difficulty in degradation, and it is urgent to develop bio-based thermoset plastics that can replace oil-based thermoset plastics. SUMMARY

[0004] The present application provides a bio-based thermoset elastomer and a preparation method and degradation method thereof to overcome the deficiencies of the prior art. The bio-based thermoset elastomer is prepared by reacting sugar alcohol and diol under the condition of a catalyst, the multiple hydroxyl groups of the sugar alcohol can provide crosslinking reaction sites, and the addition of diol can reduce the density of crosslinking hydroxyl groups. By changing the ratio of sugar alcohol / diol, the crosslinking density can be simply adjusted, and the prepared bio-based thermoset elastomer has high yield, good thermal stability and elasticity, and can be degraded under mild conditions.

[0005] To this end, the present application provides, in a first aspect, a method for preparing a bio-based thermoset elastomer, comprising reacting a sugar alcohol and a diol under catalyst conditions.

[0006] In some embodiments of the present application, the molar ratio of the sugar alcohol and the diol is 2:1-8:1; preferably 2:1-6:1; more preferably 2:1-4:1.

[0007] In some embodiments of the present application, the molar percentage of the catalyst, based on the total amount of the sugar alcohol, the diol and the catalyst, is 1-5%; preferably 1-4%; more preferably 2-3%.

[0008] In some embodiments of the present application, the sugar alcohol comprises one or more of xylitol, sorbitol, mannitol, erythritol, maltitol and lactitol.

[0009] In some embodiments of the present application, the diol comprises one or more of 1,4-butanediol, ethylene glycol and 1,3-propanediol.

[0010] In some embodiments of the present application, the catalyst comprises an acid-base non-eutectic mixed organic matter.

[0011] According to the present application, the catalyst is a mixture of methanesulfonic acid (MSA) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0012] In some embodiments of the present application, the molar ratio of the methanesulfonic acid and 1,5,7-triazabicyclo[4.4.0]dec-5-ene is 0.5:1-4:1; preferably 1:1-4:1; more preferably 2:1-4:1.

[0013] In some embodiments of the present application, the method for preparing comprises the following specific steps:

[0014] S1, heating and mixing the sugar alcohol, the diol and the catalyst into a mixed liquid;

[0015] S2, heating and reacting the mixed liquid, and cooling to obtain the bio-based thermoset elastomer after the reaction is completed.

[0016] In some embodiments of the present application, the heating temperature of step S1 is 40-60℃; preferably 40-50℃.

[0017] In some embodiments of the present application, the reaction temperature of step S2 is 120-180℃; preferably 120-160℃; more preferably 140-160℃, and the reaction time is 12-48h.

[0018] In some embodiments of the present application, the method for preparing comprises the following specific steps:

[0019] The sugar alcohol, dihydric alcohol and catalyst are weighed into a beaker, mixed into a mixed liquid under rapid stirring at 40-60℃; after the hot stage is warmed to a temperature of 120-180℃, the mixed liquid is placed on a polytetrafluoroethylene plate on the hot stage to react for 12-48h; after the reaction is completed, a bio-based thermoset elastomer solid product is obtained.

[0020] The second aspect of the present application provides a bio-based thermoset elastomer prepared by the method.

[0021] According to the present application, the bio-based thermoset elastomer is degradable.

[0022] According to the present application, the bio-based thermoset elastomer is a polyether type bio-based thermoset elastomer.

[0023] The third aspect of the present application provides a degradation method of a bio-based thermoset elastomer, which degrades the bio-based thermoset elastomer by immersing it in water.

[0024] In some embodiments of the present application, the temperature of the water is 20-100℃.

[0025] In some embodiments of the present application, the degradation time is 1-24h.

[0026] Advantages:

[0027] 1. The raw materials used in the present application are sugar alcohol and dihydric alcohol synthesized by biological method, which are pollution-free to the environment and meet the requirements of green chemistry.

[0028] 2. The method provided in the present application has high yield of thermoset elastomer, good thermal stability and elasticity, and can be degraded and recovered under mild conditions.

[0029] 3. The catalyst used in the present application is an acid-base non-eutectic mixed organic matter, which does not need to be separated from the product and is pollution-free to the environment. DETAILED DESCRIPTION

[0030] In order to make the present application easier to understand, the present application will be described in detail below in combination with embodiments, which are only illustrative and do not limit the scope of application of the present application.

[0031] The reagents and materials used in the present application are shown in Table 1:

[0032] Table 1 Reagents and materials

[0033]

[0034]

[0035] Example 1

[0036] In a beaker, 150 g (0.99 mol) of xylitol, 44 g (0.49 mol) of 1,4-butanediol, 1 mol% of catalyst [1.10 g (0.011 mol) of MSA, 0.44 g (0.0032 mol) of TBD] were mixed at 50 °C under rapid stirring; the mixture was left to react on a Teflon® flat plate at 140 °C for 12 h, obtaining a solid product of biobased thermoset elastomer with a yield of 98.7%. A small amount of product was taken for analysis, the remaining product was immersed in water, heated to 80 °C and hydrolyzed for 2 h, after which the solid product completely disappeared.

[0037] Example 2

[0038] In a beaker, 150 g of xylitol, 15 g (0.17 mol) of 1,4-butanediol, 3 mol% of catalyst [2.40 g (0.025 mol) of MSA, 1.18 g (0.0085 mol) of TBD] were mixed at 50 °C under rapid stirring; the mixture was left to react on a Teflon® flat plate at 160 °C for 16 h, obtaining a solid product of biobased thermoset elastomer with a yield of 99.2%. A small amount of product was taken for analysis, the remaining product was immersed in water, heated to 60 °C and hydrolyzed for 2 h, after which the solid product completely disappeared.

[0039] Example 3

[0040] In a beaker, 150 g of xylitol, 22 g (0.24 mol) of 1,4-butanediol, 2 mol% of catalyst [1.51 g (0.0157 mol) of MSA, 1.13 g (0.0081 mol) of TBD] were mixed at 50 °C under rapid stirring; the mixture was left to react on a Teflon® flat plate at 120 °C for 24 h, obtaining a solid product of biobased thermoset elastomer with a yield of 98.9%. A small amount of product was taken for analysis, the remaining product was immersed in water, heated to 100 °C and hydrolyzed for 1 h, after which the solid product completely disappeared.

[0041] Example 4

[0042] In a beaker, 150 g of xylitol, 15 g (0.17 mol) of 1,4-butanediol, 4 mol% of catalyst [2.06 g (0.0215 mol) of MSA, 3.09 g (0.0222 mol) of TBD] were mixed at 50 °C under rapid stirring; the mixture was left to react on a Teflon® flat plate at 120 °C for 18 h, obtaining a solid product of biobased thermoset elastomer with a yield of 99.5%. A small amount of product was taken for analysis, the remaining product was immersed in water, heated to 50 °C and hydrolyzed for 6 h, after which the solid product completely disappeared.

[0043] Example 5

[0044] In a beaker, 150 g of xylitol, 22 g of 1,4-butanediol, 5 mol% of catalyst [1.97 g (0.0205 mol) of MSA, 5.71 g (0.0411 mol) of TBD] were added, the mixture was stirred rapidly at 50°C; after 4 h of reaction at 180°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 99.0%. A small amount of product was taken for analysis, the rest of the product was immersed in water, after 24 h of hydrolysis at room temperature, the solid product completely disappeared.

[0045] Example 6

[0046] In a beaker, 150 g of xylitol, 44 g of 1,4-butanediol, 1 mol% of catalyst [0.47 g (0.0049 mol) of MSA, 1.36 g (0.0098 mol) of TBD] were added, the mixture was stirred rapidly at 50°C; after 6 h of reaction at 160°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 98.6%. A small amount of product was taken for analysis, the rest of the product was immersed in water, after 6 h of hydrolysis at 60°C, the solid product completely disappeared.

[0047] Example 7

[0048] In a beaker, 150 g of xylitol, 15 g of 1,4-butanediol, 2 mol% of catalyst [1.71 g (0.0178 mol) of MSA, 0.64 g (0.0046 mol) of TBD] were added, the mixture was stirred rapidly at 50°C; after 12 h of reaction at 140°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 99.6%. A small amount of product was taken for analysis, the rest of the product was immersed in water, after 4 h of hydrolysis at 80°C, the solid product completely disappeared.

[0049] Example 8

[0050] In a beaker, 150 g of xylitol, 11 g of 1,4-butanediol, 3 mol% of catalyst [2.06 g of MSA, 1.54 g (0.0111 mol) of TBD] were added, the mixture was stirred rapidly at 50°C; after 6 h of reaction at 180°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 98.7%. A small amount of product was taken for analysis, the rest of the product was immersed in water, after 2 h of hydrolysis at 100°C, the solid product completely disappeared.

[0051] Example 9

[0052] In a beaker, 150 g of xylitol, 44 g of 1,4-butanediol, 5 mol% of catalyst [3.44 g (0.0358 mol) of MSA, 5.15 g (0.0371 mol) of TBD] were added, the mixture was stirred rapidly at 50°C; after 12 h of reaction at 140°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 98.5%. A small amount of product was taken for analysis, the remaining product was immersed in water, after 48 h of hydrolysis at room temperature, the solid product completely disappeared.

[0053] Example 10

[0054] In a beaker, 150 g of xylitol, 22 g of 1,4-butanediol, 4 mol% of catalyst [3.44 g of MSA, 1.37 g (0.0099 mol) of TBD] were added, the mixture was stirred rapidly at 50°C; after 18 h of reaction at 160°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 99.1%. A small amount of product was taken for analysis, the remaining product was immersed in water, heated to 40°C, after 24 h of hydrolysis, the solid product completely disappeared.

[0055] Example 11

[0056] In a beaker, 150 g of xylitol, 178 g (1.98 mol) of 1,4-butanediol, 1 mol% of catalyst (1.10 g of MSA, 0.44 g of TBD) were added, the mixture was stirred rapidly at 50°C; after 12 h of reaction at 140°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 93.5%. A small amount of product was taken for analysis, the remaining product was placed in water, after 2 h of hydrolysis at room temperature, the solid completely disappeared.

[0057] Example 12

[0058] In a beaker, 150 g of xylitol, 9 g (0.1 mol) of 1,4-butanediol, 1 mol% of catalyst (1.10 g of MSA, 0.44 g of TBD) were added, the mixture was stirred rapidly at 50°C; after 12 h of reaction at 140°C on a Teflon plate, a solid product of biobased thermoset elastomer was obtained with a yield of 99.0%. A small amount of product was taken for analysis, the remaining product was placed in water, heated to 100°C, after 24 h of hydrolysis, the solid swelled, did not completely disappear.

[0059] Example 13

[0060] In a beaker, 150 g of xylitol, 44 g of 1,4-butanediol, 1 mol% of catalyst [1.20 g (0.0125 mol) of MSA, 0.22 g (0.0016 mol) of TBD] were mixed at 50°C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a polytetrafluoroethylene flat plate at 140°C to react for 12 h, and an elastomer solid product was obtained with a yield of 82.0%. A small amount of the product was taken for analysis, and the remaining product was immersed in water and heated to 80°C, and hydrolyzed for 2 h, and the solid product completely disappeared.

[0061] Example 14

[0062] In a beaker, 150 g of xylitol, 44 g of 1,4-butanediol, 0.3 mol% of catalyst [0.33 g (0.0034 mol) of MSA, 0.13 g (0.0009 mol) of TBD] were mixed at 50°C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a polytetrafluoroethylene flat plate at 140°C to react for 12 h, and a viscous liquid was obtained without forming an elastomer.

[0063] Comparative Example 1

[0064] In a three-necked flask, 30 g of polyethylene glycol, 25 mL of tetrahydrofuran, 5.7 g of furanoyl chloride, and 4 g of triethylamine were stirred to react for 2 days, and after the reaction, the reaction liquid was concentrated and dried to obtain furan-modified polyethylene glycol; 25 g of the furan-modified polyethylene glycol and 4 g of tris(2-maleimidoethyl)amine crosslinking agent were uniformly mixed and placed on a polytetrafluoroethylene flat plate at 80°C to react for 12 h, and a light yellow gel was obtained with a yield of 96.2%. A small amount of the product was taken for analysis, and the remaining product was placed in water and heated to 100°C, and hydrolyzed for 24 h, and the solid swelled without completely disappearing.

[0065] Comparative Example 2

[0066] In a beaker, 136 g (0.9989 mol) of pentaerythritol, 44 g of 1,4-butanediol, 1 mol% of catalyst (1.10 g of MSA, 0.44 g of TBD) were mixed at 50°C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a polytetrafluoroethylene flat plate at 140°C to react for 12 h, and an elastomer solid product was obtained with a yield of 97.0%. A small amount of the product was taken for analysis, and the remaining product was immersed in water and heated to 80°C, and hydrolyzed for 2 h, and the solid product completely disappeared.

[0067] Comparative Example 3

[0068] In a beaker, 150 g of xylitol, 30 g of ethylene glycol, 1 mol% of catalyst (1.10 g of MSA, 0.44 g of TBD) were mixed at 50 °C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a Teflon flat plate at 140 °C for 12 h of reaction, after which an elastomeric solid product was obtained with a yield of 98.0%. A small amount of product was taken for analysis, and the remaining product was immersed in water, heated to 80 °C, and hydrolyzed for 2 h, after which the solid product completely disappeared.

[0069] Comparative Example 4

[0070] In a beaker, 136 g of pentaerythritol, 30 g of ethylene glycol, 1 mol% of catalyst (1.10 g of MSA, 0.44 g of TBD) were mixed at 50 °C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a Teflon flat plate at 140 °C for 12 h of reaction, after which an elastomeric solid product was obtained with a yield of 97.6%. A small amount of product was taken for analysis, and the remaining product was immersed in water, heated to 80 °C, and hydrolyzed for 2 h, after which a small amount of solid remained unhydrolyzed.

[0071] Comparative Example 5

[0072] In a beaker, 150 g of xylitol, 44 g of 1,4-butanediol, 1 mol% of double metal cyanide catalyst were mixed at 50 °C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a Teflon flat plate at 140 °C for 12 h of reaction, after which an elastomeric solid product was obtained with a yield of 95.2%. A small amount of product was taken for analysis, and the remaining product was immersed in water, heated to 80 °C, and hydrolyzed for 2 h, after which the solid product disappeared and a small amount of catalyst remained in the water.

[0073] Comparative Example 6

[0074] In a beaker, 150 g of xylitol, 44 g of 1,4-butanediol, 1.10 g of MSA (1 mol%) were mixed at 50 °C under rapid stirring to form a mixed liquid; the mixed liquid was placed on a Teflon flat plate at 140 °C for 12 h of reaction, after which a viscous liquid was obtained, which did not form an elastomer.

[0075] Test Example

[0076] The elastomeric products prepared in Examples 1-10 and Comparative Examples 1-7, Comparative Example 9 were subjected to dynamic mechanical analysis, tensile testing, and thermogravimetric analysis, and the mechanical and thermal performance parameters of the elastomeric products prepared in Examples 1-10 and Comparative Examples 1-7, Comparative Example 9 are shown in Table 2.

[0077] Table 2 Mechanical and thermal performance parameters of bio-based thermoset elastomers

[0078]

[0079] a Resilience after stretching 1 / 2 / 3 times, respectively, b Temperature at 5% mass loss.

[0080] As shown in Table 2, the elastomer products prepared in Examples 1-10 all exhibit elastic behavior, with elongation at break higher than 40%. The resilience after stretching 20% is between 70% and 80%, showing excellent elasticity. As shown by thermal analysis, the glass transition temperature is below -30℃, indicating that the lower limit of the temperature for using these elastomer materials as elastomers is low; the thermal decomposition temperature of all the elastomers is about 400℃, showing good thermal stability.

[0081] The method of the present application has high yield of elastomer products, reaching 98.5%-99.6%, and the elastomer products prepared can be completely degraded and recycled under mild conditions.

[0082] It should be noted that the above examples are only used to explain the present application and do not constitute any limitation on the present application. The present application is described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present application can be modified as specified within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications with the same function.

Claims

1. A method of making a bio-based thermoset elastomer, characterized in that, It comprises reacting a sugar alcohol and a diol under catalyst conditions.

2. The method of claim 1, wherein, The molar ratio of the sugar alcohol and the diol is 2:1-8:1; preferably 2:1-6:1; more preferably 2:1-4:1; the molar percentage of the catalyst is 1-5% based on the total amount of the sugar alcohol, diol and catalyst; preferably 1-4%; more preferably 2-3%.

3. The method according to claim 1 or 2, characterized in that, The sugar alcohol comprises one or more of xylitol, sorbitol, mannitol, erythritol, maltitol and lactitol.

4. The method according to any one of claims 1 to 3, characterized in that, The diol comprises one or more of 1,4-butanediol, ethylene glycol and 1,3-propanediol.

5. The method according to any one of claims 1 to 4, characterized in that, The catalyst comprises a mixture of acid and base non-eutectic organic matter; preferably a mixture of methanesulfonic acid and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

6. The method of claim 5, wherein, The molar ratio of the methanesulfonic acid and 1,5,7-triazabicyclo[4.4.0]dec-5-ene is 0.5:1-4:1; preferably 1:1-4:1; more preferably 2:1-4:

1.

7. The method according to any one of claims 1 to 6, characterized in that, It comprises the following specific steps: S1, heating and mixing the sugar alcohol, diol and catalyst into a mixed liquid; S2, heating and reacting the mixed liquid, and cooling to obtain a bio-based thermoset elastomer after the reaction is completed.

8. The method of claim 7, wherein, The heating temperature of step S1 is 40-60℃; preferably 40-50℃; and / or the reaction temperature of step S2 is 120-180℃; preferably 120-160℃; more preferably 140-160℃, and the reaction time is 12-48h.

9. A bio-based thermoset elastomer prepared by the method of any one of claims 1-8; preferably, the bio-based thermoset elastomer is degradable.

10. A method of degrading a bio-based thermoset elastomer, characterized in that, The bio-based thermoset elastomer is immersed in water for degradation; preferably, the temperature of the water is 20-100℃. The bio-based thermoset elastomer is immersed in water for degradation; preferably, the temperature of the water is 20-100℃.

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