A heat-resistant and degradable polyester composition and its preparation method

Abstract

The present invention belongs to the technical field of biodegradable polyesters, and specifically relates to a class of heat-resistant degradable polyester compositions and their preparation methods. The present invention uses furfural derivative furoyl chloride to prepare a series of furan dihydrazide-based degradable polyester nucleating agents. On this basis, melt blending is carried out in a mass ratio of 100 parts degradable polyester to 0.3-1 parts nucleating agent, which can significantly improve the heat resistance and transparency of degradable polyester plastic products. The nucleating agent has a wide range of raw material sources and a simple preparation process. It can effectively improve the crystallization rate of degradable polyesters including polybutylene succinate, polybutylene terephthalate-adipate-polybutylene terephthalate-succinate-polybutylene glycol, and has good industrial prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of biodegradable polyesters, and in particular relates to a heat-resistant degradable polyester composition and a preparation method thereof. Background Art

[0002] As human demand for polymer materials, primarily plastics, continues to increase year by year, the accumulation of waste plastics in nature and the resulting white pollution are also increasing. Biodegradable polymer materials, such as polybutylene succinate, can be degraded into water and carbon dioxide under composting conditions. The widespread use of these biodegradable polyesters can effectively address the current severe white pollution problem.

[0003] However, most of these biodegradable polyesters have weak crystallization capabilities or their crystallization process cannot be controlled. Adding nucleating agents is an effective means of regulating polymer crystallization behavior. Nucleating agents can provide heterogeneous nucleation sites in the polymer melt, accelerating the crystallization rate and reducing the crystal size, thereby improving the crystallinity and heat resistance of the finished product.

[0004] Patent CN111333910A discloses a class of rare earth aryl phosphates containing amino groups, which can be used as nucleating agents for degradable polyesters to increase their Vicat softening temperature. Patent CN102911400A discloses a class of dibenzoylhydrazide compounds containing an aliphatic main chain (one of which is trade-named TMC300), which can regulate the crystallization morphology of degradable polyesters, improve their crystallinity, and enhance their transparency and mechanical properties. However, these nucleating agents are mostly derived from petrochemical resources and even contain heavy metal ions, which are not in line with the current sustainable development strategy and have potential hidden dangers to the human body or the environment; or there is a poor compatibility between the nucleating agent and the matrix, which is prone to agglomeration, resulting in insignificant improvement in crystallization performance, low heat resistance, and limited application scenarios. Therefore, it is a technical problem to be solved urgently to develop a nucleating agent that improves the crystallization rate and heat resistance of degradable polyesters, has good compatibility with polymers, and is green and environmentally friendly. Summary of the Invention

[0005] To address the technical issues of existing biodegradable polyesters, such as slow crystallization, low heat resistance, poor compatibility with nucleating agents, and environmental concerns, the present invention provides a biodegradable polyester composition and preparation method. The novel nucleating agent is bio-based and exhibits excellent nucleation properties, effectively improving the crystallinity, heat resistance, and compatibility of the biodegradable polyester with polymers.

[0006] In a first aspect, the present invention provides a heat-resistant degradable polyester composition, characterized in that, calculated by mass, the composition comprises 100 parts of degradable polyester and 0.1-3 parts of nucleating agent.

[0007] The nucleating agent is a type of furan structure-containing bishydrazide degradable polyester nucleating agent, and the structural formula of the nucleating agent is:

[0008]

[0009] Where n is a natural number ranging from 2 to 6.

[0010] Furthermore, the degradable polyester used is at least one selected from polybutylene succinate, polybutylene terephthalate-adipate, and polybutylene terephthalate-succinate.

[0011] Furthermore, in the heat-resistant degradable polyester composition, the mass ratio of the nucleating agent to the degradable polyester is preferably 0.3-1:100.

[0012] In a second aspect, the present invention provides a method for preparing the above-mentioned nucleating agent, which specifically comprises the following steps:

[0013] S1. Add alkyl dicarboxylic acid dimethyl ester, hydrazine hydrate, and alcohol solvent into a reactor and reflux at 70-100° C. to generate the corresponding alkyl dihydrazide;

[0014] S2, respectively adding the alkyl dihydrazide and the acid binding agent to a high boiling point solvent, adding furoyl chloride dropwise thereto at a temperature of -10°C-25°C, then heating to 60-100°C for reaction to obtain alkyl dicarboxylic acid difuryl hydrazide, and separating and purifying to obtain the nucleating agent;

[0015] The number of carbon atoms in the dimethyl alkyl dicarboxylate is 6-12.

[0016] Furthermore, the alkyl dicarboxylic acid dimethyl ester used is at least one selected from dimethyl suberate, dimethyl adipate, and dimethyl sebacate.

[0017] Furthermore, in step S1, the molar ratio of dimethyl alkyl dicarboxylate to hydrazine hydrate is 1:8-12.

[0018] Furthermore, the molar ratio of the alkyl dihydrazide to furoyl chloride in step S2 is 1:2-2.5.

[0019] Furthermore, the molar ratio of the acid binding agent to furoyl chloride in step S2 is 1-1.5:1.

[0020] Furthermore, the alcohol solvent used is at least one of methanol, ethanol, isopropanol, and n-butanol.

[0021] Furthermore, the high boiling point solvent used is at least one of toluene, xylene, acetonitrile, dimethyl sulfoxide, N,N'-dimethylformamide, and N,N'-dimethylacetamide.

[0022] Furthermore, the acid binding agent used is triethylamine or pyridine.

[0023] In a third aspect, the present invention provides a method for preparing a heat-resistant and degradable polyester composition, comprising the following steps:

[0024] R1, drying the degradable polyester and the nucleating agent in a vacuum oven at 50-80°C for 12-24 hours, and pre-mixing them after drying;

[0025] R2. The mixed materials are placed in an internal mixer at a mixing temperature of 165-200° C. for not less than 10 minutes and a rotor speed of 15-30 rpm to obtain the heat-resistant and degradable polyester composition.

[0026] Furthermore, the input ratio of the degradable polyester and the nucleating agent is 0.1-3:100 by mass.

[0027] Furthermore, the input ratio of the degradable polyester and the nucleating agent is 0.3-1:100 by mass.

[0028] Beneficial effects:

[0029] The novel nucleating agent provided by the present invention belongs to the hydrazide class of compounds and can be dissolved in a degradable polyester matrix. It promotes polymer crystallization through unique self-assembly behavior, resulting in a significant nucleating effect and greatly increasing the crystallization rate of the degradable polyester. It also has good compatibility with the degradable polyester and is evenly dispersed in the matrix. Even a small amount of addition can promote polymer crystallization. Compared with inorganic minerals, it can better prevent the degradation of the mechanical properties of polymer products. The heat-resistant degradable polyester composition products of the present invention have good transparency, are simple to prepare, and are easily adaptable to large-scale industrial production, showing good practical value and market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the synthetic route of sebacic acid hydrazide in Example 1;

[0031] Figure 2 The synthetic route of sebacoyl difurylcarboxylic acid hydrazide in Example 1 is as follows;

[0032] Figure 3 is the sebacoyl difuryl carboxylic acid hydrazide in Example 1 1 H-NMR spectrum;

[0033] Figure 4 The DSC curves of the samples in Example 3 and Example 4 were obtained by cooling at 10°C / min.

[0034] Figure 5 The DSC curves of the samples in Examples 5 and 6 were obtained by cooling at 10°C / min.

[0035] Figure 6 The DSC curves of the samples in Examples 7 and 8 were obtained by cooling at 10°C / min. DETAILED DESCRIPTION

[0036] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] The preferred embodiments of the present invention will be described in detail below with reference to the examples. It should be understood that the following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0039] Test instrument model: The nuclear magnetic resonance spectrometer used was Vaian DLG400 (Varian, USA), and the differential scanning calorimeter used was DSC25 (TA, USA).

[0040] Example 1 (Preparation of nucleating agent, sebacoyl difurylcarboxylic acid hydrazide, n=6)

[0041] (1) Preparation of Sebacic Acid Hydrazide: 23.04 g of dimethyl sebacate, 25.04 g of hydrazine hydrate (80%) and 50 mL of anhydrous ethanol were added to a reaction flask and refluxed at 90°C for 7 h. During this period, a large amount of white solid precipitated. After the reaction was completed, the mixture was cooled to room temperature, filtered and washed with anhydrous ethanol. After drying, 21.24 g of a white solid with a metallic luster was obtained. The yield was 92%. The synthetic route is shown in FIG. Figure 1 .

[0042] (2) Preparation of Sebacyldifuroylhydrazide: 13.83 g of sebacylhydrazide, 13.35 g of triethylamine and 120 mL of anhydrous acetonitrile were placed in a reaction flask. 17.22 g of furoyl chloride was added dropwise to the reaction system at 0°C. After the addition was completed, the temperature was raised to 80°C for 10 h. After the reaction was completed, the temperature was cooled to room temperature. The filter cake was washed once with water and once with anhydrous ethanol, and dried to obtain 16.86 g of white powder, which is a degradable polyester nucleating agent. The yield was 67%. The synthetic route is shown in FIG. Figure 2 .

[0043] The product was characterized by H NMR spectroscopy. Figure 3 .

[0044] Example 2 (Preparation of nucleating agent: adipoyldifurylcarboxylic acid hydrazide, n=2)

[0045] (1) Preparation of adipic acid hydrazide: 17.42 g of dimethyl adipate, 31.29 g of hydrazine hydrate (80%) and 50 mL of anhydrous ethanol were added to a reaction flask and refluxed at 90°C for 8 h. During this period, a large amount of white solid precipitated. After the reaction was completed, the mixture was cooled to room temperature, filtered and washed with anhydrous ethanol. After drying, 15.68 g of a white solid with a metallic luster was obtained. The yield was 95%. The synthetic route is shown in FIG. Figure 1 .

[0046] (2) Preparation of adipic acid difuroyl hydrazide: 17.42 g of adipic acid dihydrazide, 20.24 g of triethylamine and 100 mL of anhydrous acetonitrile were placed in a reaction flask, and 26.11 g of furoyl chloride was added dropwise to the reaction system at 0°C. After the addition was completed, the temperature was raised to 80°C and the reaction was continued for 10 h. After the reaction was completed, the mixture was cooled to room temperature, and the filter cake was washed once with water and once with anhydrous ethanol by suction filtration. After drying, 21.38 g of white powder was obtained, which was a degradable polyester nucleating agent with a yield of 59%.

[0047] Example 3 (Blending)

[0048] The nucleating agent and polybutylene succinate prepared in Example 1 were dried in a vacuum oven at 60°C for 12 hours. 60g of polybutylene succinate and 0.18g of the nucleating agent were mixed in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer melt temperature and the three temperature control zone temperatures were set to 170°C, 169°C, 168°C, and 165°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization by DSC revealed a crystallization temperature of 86°C.

[0049] Example 4 (Comparative Example)

[0050] Pure polybutylene succinate was dried in a vacuum oven at 60°C for 12 hours. 60g of polybutylene succinate was melt-mixed in a SU-70B micro-internal mixer. The melt temperature and the three temperature control zones of the mixer were set at 170°C, 169°C, 168°C, and 165°C, respectively, and the rotor speed was set at 15 rpm. Non-isothermal DSC crystallization tests revealed a crystallization temperature of 69°C.

[0051] Example 5 (Blending)

[0052] The nucleating agent and polybutylene terephthalate-adipate prepared in Example 1 were dried in a vacuum oven at 60°C for 12 hours. 60g of polybutylene terephthalate-adipate and 0.18g of the nucleating agent were mixed in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The melt temperature and the three temperature control zone temperatures of the internal mixer were set to 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization testing by DSC revealed a crystallization temperature of 79°C.

[0053] Example 6 (Comparative Example)

[0054] Pure poly(butylene terephthalate-adipate) was dried in a vacuum oven at 60°C for 12 hours. 60g of poly(butylene terephthalate-adipate) was melt-mixed in a SU-70B micro-internal mixer. The melt temperature and the three temperature control zones of the mixer were set at 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set at 15 rpm. Non-isothermal DSC crystallization tests revealed a crystallization temperature of 62°C.

[0055] Example 7 (Blending)

[0056] The nucleating agent and poly(butylene terephthalate-succinate-co-ol) prepared in Example 1 were dried in a vacuum oven at 60°C for 12 hours. 60g of poly(butylene terephthalate-adipate-co-ol) were mixed with 0.18g of the nucleating agent in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer melt temperature and the three temperature control zone temperatures were set to 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization testing by DSC revealed a crystallization temperature of 89.6°C.

[0057] Example 8 (Comparative Example)

[0058] Pure poly(butylene terephthalate-succinate-butylene terephthalate) was dried in a vacuum oven at 60°C for 12 hours. 60g of poly(butylene terephthalate-adipate-butylene terephthalate) was melt-mixed in a SU-70B micro-internal mixer. The melt temperature and the three temperature control zones of the mixer were set at 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set at 15 rpm. Non-isothermal DSC crystallization tests revealed a crystallization temperature of 47.9°C.

[0059] Example 9 (Blending)

[0060] The nucleating agent and polybutylene succinate prepared in Example 2 were dried in a vacuum oven at 60°C for 12 hours. 60g of polybutylene succinate and 0.18g of the nucleating agent were mixed in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer melt temperature and the three temperature control zone temperatures were set to 170°C, 169°C, 168°C, and 165°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization by DSC revealed a crystallization temperature of 83°C.

[0061] Example 10 (Blending)

[0062] The nucleating agent and polybutylene terephthalate-adipate prepared in Example 2 were dried in a vacuum oven at 60°C for 12 hours. 60g of polybutylene terephthalate-adipate and 0.18g of the nucleating agent were premixed in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer melt temperature and the three temperature control zone temperatures were set to 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization testing by DSC revealed a crystallization temperature of 76°C.

[0063] Example 11 (Blending)

[0064] The nucleating agent and polybutylene terephthalate (PTTE) prepared in Example 2 were dried in a vacuum oven at 60°C for 12 hours. 60g of PTTE and 0.18g of nucleating agent were mixed in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer melt temperature and the three temperature control zone temperatures were set to 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization by DSC revealed a crystallization temperature of 85.4°C.

[0065] Example 12 (Comparative Example)

[0066] A commercial nucleating agent, sebacyl dibenzohydrazide (trade name TMC300), and polybutylene succinate were dried in a vacuum oven at 60°C for 12 hours. 60g of polybutylene succinate was premixed with 0.18g of the nucleating agent in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer's melt temperature and the three controlled temperature zones were set at 170°C, 169°C, 168°C, and 165°C, respectively, and the rotor speed was set at 15 rpm. Non-isothermal DSC crystallization tests revealed a crystallization temperature of 82°C.

[0067] Example 13 (Comparative Example)

[0068] A commercial nucleating agent, sebacyl dibenzohydrazide (trade name TMC300), and poly(butylene terephthalate-adipate) were dried in a vacuum oven at 60°C for 12 hours. 60g of poly(butylene terephthalate-adipate) was mixed with 0.18g of the nucleating agent in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer's melt temperature and the three temperature control zone temperatures were set at 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set at 15 rpm. Non-isothermal crystallization testing by DSC revealed a crystallization temperature of 74°C.

[0069] Example 14 (Comparative Example)

[0070] The commercial nucleating agent sebacyl dibenzohydrazide (trade name TMC300) and poly(butylene terephthalate-succinate-butylene terephthalate) were dried in a vacuum oven at 60°C for 12 hours. 60g of poly(butylene terephthalate-succinate-butylene terephthalate) was mixed with 0.18g of the nucleating agent in a ziplock bag and then melt-mixed in a SU-70B micro-internal mixer. The mixer melt temperature and the three temperature control zone temperatures were set to 180°C, 180°C, 180°C, and 180°C, respectively, and the rotor speed was set to 15 rpm. Non-isothermal crystallization testing by DSC revealed a crystallization temperature of 81.2°C.

[0071] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A heat-resistant and degradable polyester composition, characterized in that: Based on mass components, 100 parts of degradable polyester and 0.1-3 parts of nucleating agent; The structural formula of the nucleating agent is: Where n is a natural number, ranging from 2 to 6; The degradable polyester is selected from at least one of polybutylene succinate, polybutylene terephthalate-adipate, and polybutylene terephthalate-succinate.

2. The heat-resistant and degradable polyester composition according to claim 1, characterized in that The nucleating agent is prepared by the following method, which specifically includes the following steps: S1. Add alkyl dicarboxylic acid dimethyl ester, hydrazine hydrate, and alcohol solvent into a reactor and reflux at 70-100° C. to generate the corresponding alkyl dihydrazide; S2. Add the alkyl dihydrazide and the acid binding agent to a high-boiling-point solvent, add furoyl chloride dropwise thereto at a temperature of -10°C-25°C, then raise the temperature to 60-100°C for reaction to obtain bisfuran dihydrazide, and obtain the nucleating agent after separation and purification; The molar ratio of the alkyl dihydrazide to furoyl chloride is 1:2-2.5; The high boiling point solvent is at least one of toluene, xylene, acetonitrile, dimethyl sulfoxide, N,N'-dimethylformamide, and N,N'-dimethylacetamide; and the acid binding agent is triethylamine or pyridine.

3. The heat-resistant and degradable polyester composition according to claim 2, characterized in that: The alkyl dicarboxylic acid dimethyl ester is at least one selected from dimethyl suberate, dimethyl adipate, and dimethyl sebacate.

4. The heat-resistant and degradable polyester composition according to claim 2, characterized in that: The molar ratio of dimethyl alkyl dicarboxylate to hydrazine hydrate in step S1 is 1:8-12.

5. The heat-resistant and degradable polyester composition according to claim 2, characterized in that: The molar ratio of the acid binding agent to furoyl chloride in step S2 is 1-1.5:

1.

6. The heat-resistant and degradable polyester composition according to claim 2, characterized in that: The alcohol solvent is at least one of methanol, ethanol, isopropanol and n-butanol.

7. A method for preparing the heat-resistant and degradable polyester composition according to claim 1, characterized in that: The following steps are involved: R1, drying the degradable polyester and the nucleating agent in a vacuum oven at 50-80°C for 12-24 hours, and pre-mixing them after drying; R2. The mixed materials are placed in an internal mixer at a mixing temperature of 165-200° C., a mixing time of not less than 10 minutes, and a rotor speed of 15-30 rpm to obtain the heat-resistant and degradable polyester composition.

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