Full-bio-based epoxy resin with bio-based curing agent participating in construction and preparation method of full-bio-based epoxy resin

Abstract

The invention discloses a preparation method of novel environment-friendly full bio-based epoxy resin, a bio-based epoxy resin curing agent (AEESN) is derived from eugenol and cysteamine, and a bio-based epoxy monomer is derived from a magnolol-based epoxy monomer (EP1) of magnolol and a furfural-based aniline epoxy resin (EP2) of furfural. The full-bio-based epoxy resin is wide in source, low in price, green, environmentally friendly, low in polymerization temperature and high in biomass content, and a new thought and method are provided for development and application of bio-based materials.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and specifically relates to a preparation method of a fully bio-based epoxy resin constructed with a bio-based curing agent Background Art

[0002] Epoxy resins have outstanding mechanical strength and good chemical stability, and are widely used in fields such as aerospace, coatings, electronic components, construction industry, and medical materials. Currently, more than 90% of the epoxy resin market share is dominated by bisphenol A diglycidyl ether (DGEBA) in petroleum-based bisphenol A (BPA), but BPA is considered an endocrine disruptor similar to estrogen, and the potential health risks associated with long-term BPA exposure are related to adverse effects on fetal growth. Given the low stability and possible physiological toxicity of BPA and DGEBA, people's concerns about fossil fuel depletion and the environment have gradually increased, thus ultimately making the demand for developing new bio-based materials more urgent

[0003] Bio-based curing agents are a class of compounds derived from natural organic substances, with characteristics such as environmental protection, renewability, and low toxicity, and have broad application prospects. The molecular structure of materials can be changed through chemical reaction processes to achieve optimization in physical properties and engineering applications, thereby improving the heat resistance, impact resistance, hardness, etc. of the materials. Such curing agents make it much easier to enhance the performance of epoxy resins, while also enhancing the environmental protection performance and sustainability of the materials

[0004] The main objective of the present invention is to explore a fully bio-based epoxy resin constructed with a bio-based eugenol curing agent, and to characterize the structural and performance characteristics of the materials through Fourier transform infrared spectroscopy and thermal properties, etc., so as to provide new ideas and methods for the development and application of bio-based materials Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is to provide a fully bio-based epoxy resin constructed with a class of bio-based curing agents in view of the deficiencies of the prior art

[0006] The technical problem to be solved by the present invention is to provide a preparation method of the above bio-based curing agent participating in the construction of a fully bio-based epoxy resin polymer

[0007] To solve the above first technical problem, the present invention discloses a fully bio-based epoxy resin polymer constructed with a bio-based curing agent, and the polymerization of structural unit A with B or C constitutes a bio-based binary polymer. Among them, structural units A, B, and C are respectively

[0008]

[0009] Among them, the binary polymer composed of A and C has a repeating structural unit shown in Formula I, and the binary polymer composed of B and C has a repeating structural unit shown in Formula II.

[0010]

[0011] To solve the above-mentioned second technical problem, the present invention discloses a preparation method of a fully bio-based epoxy resin constructed by the above-mentioned bio-based curing agent. Specifically, a bio-based epoxy resin monomer EP1 or EP2 is mixed with a bio-based curing agent AEESN, stirred and heated until uniform, then injection-molded and heated for curing to obtain a fully bio-based epoxy resin.

[0012] The bio-based epoxy monomers include magnolol-based epoxy monomers (EP1) and furfural-based aniline epoxy resins (EP2).

[0013]

[0014] The molar ratio of the epoxy group of the bio-based epoxy monomer to the amino group of the bio-based diamine curing agent is 0.8 - 1.5:1, preferably 0.8 - 1.2:1.

[0015] The mixing temperature is 20 - 40°C, preferably 30°C; the curing temperature is 40 - 100°C, preferably 60 - 80°C.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0017] (1) Both the epoxy monomer and the curing agent provided by the present invention are of biomass origin and are liquids with low viscosity at room temperature, which are easy to operate.

[0018] (2) The bio-based diamine curing agent provided by the present invention has high activity and a wider application range.

[0019] (3) The fully bio-based epoxy resin provided by the present invention has a high degree of greenness, high biological added value, high biological safety, and the corresponding preparation process is simple and the conditions are mild.

[0020] (4) The preparation process temperature of the fully bio-based epoxy resin provided by the present invention is low, and the curing process is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following further specific description of the present invention is made in conjunction with the drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0022] Figure 1 IR analysis diagrams of polymers AEESN / EP1 and AEESN / EP2

[0023] Figure 2 Thermogravimetric analysis diagrams of polymers AEESN / EP1 and AEESN / EP2

[0024] Figure 3 DSC analysis diagrams of polymers AEESN / EP1 and AEESN / EP2 Detailed implementation manners

[0025] In the following examples, unless otherwise specified, the experimental methods are all conventional methods; unless otherwise specified, the reagents and materials can all be obtained from commercial channels.

[0026] Example 1 Preparation of AEESN / EP1

[0027] Weigh EP1 (0.38 g, 1 mmol) and curing agent AEESN (0.18 g, 0.5 mmol) in a reaction flask. After fully mixing at room temperature until it becomes clear and transparent, slowly heat it at a rate of 1.5 °C / min, and keep it at 60 °C for 2 h, 70 °C for 1 h, and 10 °C for 1 h. Then, let it cool naturally to room temperature to obtain polymer AEESN / EP1.

[0028] Example 2 Preparation of AEESN / EP2

[0029] Weigh EP2 (0.29 g, 1 mmol) and curing agent AEESN (0.18 g, 0.5 mmol) in a reaction flask. After fully mixing at room temperature until it becomes clear and transparent, slowly heat it at a rate of 1.5 °C / min, and keep it at 60 °C for 2 h, 70 °C for 1 h, and 10 °C for 1 h. Then, let it cool naturally to room temperature to obtain polymer AEESN / EP2.

[0030] Judged by infrared data, as Figure 1 shown, the stretching vibration infrared absorption peaks of ethylene oxide in the original epoxy monomer (860 and 910 cm -1 ), and at the same time, the bending vibration at 1594 cm -1 in AEESN disappears. In the AEESN / EP1 system, such characteristic peaks all disappear, indicating that the epoxy groups of the epoxy resin and the amino groups have been completely polymerized. The same is true for the AEESN / EP2 system, thus proving that the system is completely polymerized.

[0031] The nitrogen flow rate for thermogravimetric analysis was 40 mL / min, the heating rate was 20 °C / min, and the temperature range was from 30 °C to 800 °C to analyze the thermal stability of the samples. For the AEESN / EP1 system, the initial decomposition temperature was 278.9 °C, the decomposition temperature corresponding to 30 wt% decomposition was 397.9 °C, the corresponding maximum decomposition temperatures were 299.1 °C / 349.4 °C, and the carbon residue at 800 °C was 25.8%. For the AEESN / EP2 system, the initial decomposition temperature was 307.7 °C, the decomposition temperature corresponding to 30 wt% decomposition was 346.5 °C, the maximum decomposition temperature was 344.7 °C, and the carbon residue at 800 °C was 24.3%.

[0032] The glass transition temperatures of the two polymers were measured by differential scanning calorimetry. For the AEESN / EP1 system, it was 66.3 °C, and for the AEESN / EP2 system, it was 64.7 °C.

[0033] Table 1 Thermal data analysis of double bio-based epoxy resins

[0034]

[0035] The present invention provides a bio-based curing agent for constructing a fully bio-based epoxy resin and its preparation method. There are many methods and ways to specifically implement this technical solution. The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by existing technologies.

Claims

1. A bio-based epoxy resin constructed with the participation of a bio-curing agent, wherein the curing agent structure is shown in the following figure:

2. A fully bio-based epoxy resin constructed with the participation of a bio-curing agent, wherein the structure of the bio-based epoxy monomer is shown in the figure below:

3. A fully bio-based epoxy resin constructed with the participation of a bio-curing agent, characterized in that its structural unit is a new type of binary polymer formed by the link between A and B or C. The structural units A, B, and C are respectively: in, The binary polymer composed of A and C has a repeating structural unit shown in Formula I, and the binary polymer composed of B and C has a repeating structural unit shown in Formula II: Among them, m≥2, n≥2, m=2n.

4. The method for preparing a fully bio-based epoxy resin constructed with the participation of a bio-curing agent according to claim 3, characterized in that The bio-based curing agent AEESN is mixed with the bio-based epoxy monomer EP1 or EP2, and then degassing and mold curing are performed to obtain a fully bio-based epoxy resin.

5. The preparation method according to claim 4, characterized in that The molar ratio of the bio-based epoxy monomer EP1 or EP2 to the bio-based curing agent AEESN is 0.8-1.5:1; the mixing temperature is 20-40°C; and the curing temperature is 40-100°C.

6. The all-biobased epoxy resin according to claim 3, characterized in that The initial decomposition temperature of the all-bio-based epoxy resin in a nitrogen atmosphere is between 275°C and 310°C, and the residual carbon rate at 800°C is between 20% and 30%; the glass transition temperature of the all-bio-based epoxy resin is between 60°C and 70°C.

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