阅读说明：本技术 一种基于双酚酸的多官能度阻燃环氧树脂及其制备方法 (Polyfunctional flame-retardant epoxy resin based on diphenolic acid and preparation method thereof ) 是由 敖玉辉 解瑞行 尚垒 郑勇 马金鹏 杨国瑞 张春红 李冠汐 于 2021-09-13 设计创作，主要内容包括：本发明属于有机高分子材料领域,具体涉及一种基于双酚酸的多官能度阻燃环氧树脂及其制备方法。本发明的技术方案如下：1.将DOPO和二甲苯的混合溶液缓慢滴至熔化的TGIC中,升温搅拌反应后冷却；2.熔化步骤1产物,缓慢加入二甲苯和双酚酸混合溶液,升温搅拌反应后静置,倒掉上层液体；3.将步骤2产物与环氧氯丙烷共混,加四丁基溴化铵高温反应后降温,滴加NaOH反应后冷却,加二氯甲烷稀释,过滤去沉淀,旋蒸；4.熔化步骤3所得树脂,迅速加入熔融的DDM搅拌均匀后消泡,倒入预热模具后在真空烘箱中固化。应用本发明得到的环氧树脂,原料源于可再生资源,廉价环保节能,过程简单低毒,阻燃性、热稳定性和热机械性能较好。(The invention belongs to the field of organic polymer materials, and particularly relates to a multifunctional flame-retardant epoxy resin based on diphenolic acid and a preparation method thereof. The technical scheme of the invention is as follows: 1. slowly dripping the mixed solution of DOPO and xylene into the molten TGIC, heating, stirring, reacting and cooling; 2. melting the product in the step 1, slowly adding a mixed solution of xylene and diphenolic acid, heating, stirring, reacting, standing, and pouring out the upper layer liquid; 3. blending the product obtained in the step 2 with epoxy chloropropane, adding tetrabutylammonium bromide, reacting at high temperature, cooling, dropwise adding NaOH, reacting, cooling, adding dichloromethane for dilution, filtering to remove precipitate, and performing rotary evaporation; 4. and (3) melting the resin obtained in the step (3), quickly adding the molten DDM, stirring uniformly, defoaming, pouring into a preheating mould, and curing in a vacuum oven. The epoxy resin obtained by the invention has the advantages of renewable raw material source, low price, environmental protection, energy conservation, simple process, low toxicity, good flame retardance, thermal stability and thermal mechanical property.)

1. A multifunctional flame-retardant epoxy resin based on diphenolic acid is characterized in that the structural formula is as follows:

2. the method for preparing the multifunctional flame-retardant epoxy resin based on diphenolic acid according to claim 1, comprising the following steps:

(1) sending TGIC into a 500mL four-neck glass flask, equipped with a mechanical stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, heating, stirring and melting the TGIC, then slowly dropping a mixed solution of DOPO and xylene into the flask within 1h, heating to 130 ℃ and 150 ℃, continuously stirring and reacting for 5-7h, and then gradually cooling to room temperature to obtain a light yellow solid product;

(2) stirring and melting the product in the step (1) at the temperature of 130-;

(3) under the mechanical stirring, blending the product obtained in the step (2) and epoxy chloropropane in a three-necked flask, adding tetrabutyl ammonium bromide, reacting for 4-6h at the temperature of 100-120 ℃, cooling to 55-75 ℃, dropwise adding a NaOH solution, reacting for 1-3h after dropwise adding, cooling to room temperature, adding a proper amount of dichloromethane for dilution, filtering to remove precipitates, and performing rotary evaporation to obtain the multifunctional flame-retardant epoxy resin based on diphenolic acid;

(4) melting the epoxy resin obtained in (3) at the temperature of 100 ℃ and 120 ℃, then rapidly adding the molten DDM, vigorously stirring until a uniform mixture is obtained, then carrying out vacuum defoaming at the temperature of 70-90 ℃, pouring the bubble-free mixture into a preheated stainless steel mold, and then curing in a vacuum oven to obtain the fully-cured multifunctional flame-retardant epoxy resin based on diphenolic acid.

3. The method for preparing multifunctional flame retardant epoxy resin based on diphenolic acid according to claim 2, wherein the molar ratio of TGIC to DOPO in step (1) is 1: 1.

4. The method of claim 2, wherein the TGIC is melted in step (1) under the following conditions: the temperature is 100-120 ℃, and the stirring speed is 140-160 r/min.

5. The method for preparing multifunctional flame-retardant epoxy resin based on diphenolic acid according to claim 2, wherein the molar ratio of the product of step (1) to diphenolic acid in step (2) is 1: 2.

6. The method for preparing polyfunctional flame-retardant epoxy resin based on diphenolic acid according to claim 2, wherein the molar ratio of the product of step (2), epichlorohydrin and tetrabutylammonium bromide in step (3) is 1: 8-12: 0.10-0.15.

7. The method for preparing multifunctional flame-retardant epoxy resin based on diphenolic acid of claim 2, wherein the NaOH solution in step (3) has a mass concentration of 20-60% and a volume of 90-110 mL.

8. The method for preparing the multifunctional flame-retardant epoxy resin based on diphenolic acid of claim 2, wherein the molar ratio of the epoxy resin to the DDM in the step (4) is 2: 1.

9. The method for preparing multifunctional flame-retardant epoxy resin based on diphenolic acid as claimed in claim 2, wherein the curing conditions in the vacuum oven of step (4) are baking at a temperature of 100-120 ℃ for 1-3 hours, and then baking at a temperature of 130-150 ℃ for 1-3 hours.

Technical Field

The invention belongs to the field of organic polymer materials, and particularly relates to a multifunctional flame-retardant epoxy resin based on diphenolic acid and a preparation method thereof.

Background

The epoxy resin has a large amount of active and polar groups, and as a thermosetting resin, the epoxy resin is widely applied to the fields of coatings, composite materials, adhesives, electronic packaging materials, engineering plastics, civil engineering and building materials and the like due to excellent comprehensive performance, good cohesiveness, excellent mechanical property, small curing shrinkage, good manufacturability, excellent electric insulation property and corrosion resistance. However, at present, most of epoxy resins are derived from petroleum resources, particularly bisphenol a epoxy resins, and petroleum resources are non-renewable resources, and the cost of polymer materials derived from petroleum resources is increased along with the gradual reduction of reserves of the petroleum resources. In addition, bisphenol a is suspected of having physiological toxicity and has been restricted in use in many countries such as europe, and therefore, under the current situation of increasingly depleted petroleum resources, there is an urgent need to use raw materials from other sources to produce epoxy resins, and reduce dependence on petroleum resources. The search for sustainable, high-quality, inexpensive, non-toxic alternatives to petroleum is a key to the existence and development of the polymer industry, and it is particularly important to develop alternatives with renewable resources and possessing comparable properties. The vigorous development of the bio-based renewable monomer has good development prospect and conforms to the green sustainable development strategy of the polymer industry.

At present, almost all epoxy resins are completely dependent on petroleum resources. The bisphenol A type epoxy resin (DGEBA) is the most widely used one with the largest yield, and accounts for more than 90 percent of the market. However, bisphenol a (bpa), the main raw material of bisphenol a type epoxy resin, is not only certified as a reproductive toxic R2-like substance, but also has a negative effect on the human immune system and reproductive system, and is an endocrine disrupter. The united states and some developed countries mandate the use of bisphenol a in the food packaging, metal surface coatings, baby bottles, and duct liners industries. In addition, the limit oxygen index of the bisphenol A type epoxy resin is 19.2 percent, the bisphenol A type epoxy resin belongs to a flammable material, and meanwhile, in consideration of the aspects of world petroleum energy exhaustion and increasingly severe environmental pollution, people are prompted to search renewable resources of biomass as raw materials to produce new flame-retardant epoxy resin with excellent comprehensive performance so as to replace the requirement on DGEBA.

Disclosure of Invention

The invention provides a multifunctional flame-retardant epoxy resin based on diphenolic acid and a preparation method thereof, aiming at solving the problems that the traditional synthetic resin is poor in flame retardance, toxic in raw materials and non-renewable.

The technical scheme of the invention is as follows:

a multifunctional flame-retardant epoxy resin based on diphenolic acid has a structural formula shown in the specification.

The preparation method of the multifunctional flame-retardant epoxy resin based on diphenolic acid comprises the following steps:

(1) TGIC (triglycidyl isocyanurate) is fed into a 500mL four-neck glass flask, a mechanical stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel are arranged, the TGIC is heated, stirred and melted, then a mixed solution of DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide) and xylene is slowly dropped into the flask within 1h, the temperature is increased to 130-150 ℃, the reaction is continuously stirred for 5-7h, then the reaction is gradually cooled to room temperature, and the product is observed to be light yellow solid.

The specific reaction route is as follows:

(2) and (3) stirring and melting the product in the step (1) at the temperature of 130-.

The specific reaction route is as follows:

(3) and (3) blending the product obtained in the step (2) and epoxy chloropropane in a three-necked flask under mechanical stirring, adding tetrabutylammonium bromide, reacting for 4-6h at the temperature of 100-120 ℃, cooling to 55-75 ℃, dropwise adding a NaOH solution, reacting for 1-3h after dropwise adding, cooling to room temperature, adding a proper amount of dichloromethane for dilution, filtering to remove precipitates, and performing rotary evaporation to obtain the multifunctional flame-retardant epoxy resin based on diphenolic acid.

The specific reaction route is as follows:

(4) melting the epoxy resin obtained in (3) at the temperature of 100 ℃ and 120 ℃, then rapidly adding the molten DDM, vigorously stirring until a uniform mixture is obtained, then carrying out vacuum defoaming at the temperature of 70-90 ℃, pouring the bubble-free mixture into a preheated stainless steel mold, and then curing in a vacuum oven to obtain the fully-cured multifunctional flame-retardant epoxy resin based on diphenolic acid.

Preferably, the molar ratio of TGIC to DOPO described in step (1) is 1: 1.

Preferably, the conditions for TGIC melting in step (1) are: the temperature is 100-120 ℃, and the stirring speed is 140-160 r/min.

Preferably, the molar ratio of the product to the diphenolic acid in step (1) described in step (2) is 1: 2.

Preferably, the molar ratio of the product of step (2) described in step (3), epichlorohydrin and tetrabutylammonium bromide is 1: 8-12: 0.10-0.15.

Preferably, the NaOH solution in the step (3) has a mass concentration of 20-60% and a volume of 90-110 mL.

Preferably, the molar ratio of the epoxy resin to the DDM in step (4) is 2: 1.

Preferably, the curing conditions in the vacuum oven in the step (4) are that the baking is performed at the temperature of 100-120 ℃ for 1-3 hours, and then the baking is performed at the temperature of 130-150 ℃ for 1-3 hours.

Compared with the prior art, the invention has the following beneficial effects:

1. the main raw materials of the epoxy resin prepared by the invention are derived from renewable resources, and the epoxy resin is cheap, environment-friendly and energy-saving;

2. the whole reaction process is simple, low in toxicity and simple, and does not need too harsh reaction conditions;

3. the diphenolic acid and TGIC are used as raw materials for preparing the epoxy monomer, the aromatic structure of the diphenolic acid and TGIC is favorable for improving the thermal stability of the materials, the four functional groups are also favorable for introducing epoxy groups, and the crosslinking density of the resin is improved, so that the thermal mechanical property of the resin is improved.

Drawings

FIG. 1 is a chart of infrared spectra of products obtained at each step in example 1;

FIG. 2 shows the NMR spectrum of the product obtained in step (1) in example 1;

FIG. 3 is a NMR spectrum of the product obtained in step (2) in example 1;

FIG. 4 is a NMR chart of a product obtained in step (3) of example 1;

FIG. 5 is a cone calorimetry graph of the resulting multifunctional flame retardant epoxy resin and bisphenol A epoxy resin;

FIG. 6 is a differential thermogravimetric analysis graph of the prepared multifunctional flame-retardant epoxy resin and bisphenol A epoxy resin;

FIG. 7 is a dynamic mechanical analysis graph of the prepared multifunctional flame-retardant epoxy resin and bisphenol A epoxy resin.

Detailed Description

Example 1:

(1) 23.9g of TGIC was charged into a 500mL four-necked glass flask equipped with a mechanical stirrer, a thermometer, a reflux condenser and a dropping funnel at a constant pressure, heated and stirred at a temperature of 110 ℃ and a stirring speed of 150r/min to melt, and then a mixed solution of 17.6g of DOPO and 100mL of xylene was slowly dropped into the flask over 1 hour, heated to 130 ℃, continuously stirred to react for 5 hours, and then gradually cooled to room temperature, and it was observed that the product was a pale yellow solid.

The infrared spectra of the raw DOPO and the product are shown in FIG. 1, and it can be seen that 2383cm is included in the DOPO raw material curve^-1The P-H bond disappeared in the product curve at the same time as 3412cm^-1The appearance of the O-H absorption peak represents that the synthesized product is DOTG; the nmr hydrogen spectrum is shown in fig. 2, and it is observed that the chemical shifts of all peaks and the protons in the chemical structure of the integrated area DOTG are well matched, further proving that DOTG was successfully synthesized.

(2) Stirring and melting the product in the step (1) at 150 ℃, then slowly adding a mixed solution of 100mL of dimethylbenzene and 45.82g of diphenolic acid, heating to 170 ℃, continuously stirring and reacting for 5 hours, standing, pouring off upper dimethylbenzene, and observing that the product is a reddish brown solid

The infrared spectrum of the product is shown in FIG. 1, 1043cm in the curve^-1The appearance of ether group represents the product TDBA for further synthesis; the nuclear magnetic resonance hydrogen spectrogram is shown in fig. 3, and chemical shifts and integral areas of all peaks are observed to be well matched with protons in the chemical structure of TDBA, so that the successful synthesis of TDBA is further proved.

(3) Under the mechanical stirring, blending the product obtained in the step (2) and 74.02g of epoxy chloropropane in a three-neck flask, adding 2.42g of tetrabutylammonium bromide, reacting for 4-6h at 100 ℃, cooling to 65 ℃, dropwise adding 90mL of NaOH solution with the mass concentration of 20%, and reacting for 1h after dropwise adding. Cooling to room temperature, adding a proper amount of dichloromethane for dilution, filtering to remove precipitates, and performing rotary evaporation.

The infrared spectrum of the product is shown in FIG. 1, 916cm in the curve^-1The appearance of the epoxy group represents the successful synthesis of TDBE; the NMR spectrum is shown in FIG. 4, and the chemical shifts and integral areas of all peaks and the chemical structure of TDBE are observedThe proton coincidence is good, further proving that the TDBE is successfully synthesized.

(4) Melting the TDBE prepared in the step (3) at 110 ℃, then rapidly adding 7.9g of molten DDM, vigorously stirring until a uniform mixture is obtained, then carrying out vacuum defoaming at 80 ℃, pouring the bubble-free mixture into a preheated stainless steel mold, then baking for 1-3 hours at the temperature of 100-120 ℃ in a vacuum oven, and then baking for 1-3 hours at the temperature of 130-150 ℃ to obtain the fully cured multifunctional flame-retardant epoxy resin TDBE-DDM based on diphenolic acid.

The TDBE-DDM and DGEBA-DDM thermosetting resins are respectively subjected to cone calorimetric tests, and the curves are shown in figure 5, so that the peak of the heat release rate of the TDBE-DDM is obviously lower than that of the DGEBA-DDM thermosetting resins, and the excellent flame retardant property is embodied.

In nitrogen atmosphere, TDBE-DDM and DGEBA-DDM were subjected to differential thermogravimetric analysis respectively, and as shown in FIG. 6, it can be seen that TDBE-DDM has a lower initial decomposition temperature than DGEBA-DDM, mainly because the O-P-O bond is less stable than the C-C bond, but the carbon residue rate of TDBE-DDM is much higher than that of DGEBA-DDM, and excellent thermal stability is exhibited.

By comparing the thermodynamic properties of TDBE-DDM and DGEBA-DDM by Dynamic Mechanical Analysis (DMA), as shown in the storage modulus and glass transition temperature curve in FIG. 7, it can be seen that the storage modulus of TDBA-DDM is obviously higher than that of DGEBA-DDM, and excellent thermo-mechanical properties are represented.

Example 2:

(1) 23.9g of TGIC was charged into a 500mL four-necked glass flask equipped with a mechanical stirrer, a thermometer, a reflux condenser and a dropping funnel at a constant pressure, heated and stirred at a temperature of 110 ℃ and a stirring speed of 150r/min to melt, and then a mixed solution of 17.6g of DOPO and 100mL of xylene was slowly dropped into the flask over 1 hour, heated to 140 ℃ and continuously stirred to react for 6 hours, and then gradually cooled to room temperature, and it was observed that the product was a pale yellow solid.

(2) And (3) melting the product in the step (1) by stirring at 150 ℃, slowly adding a mixed solution of 100mL of xylene and 45.82g of diphenolic acid, heating to 180 ℃, continuously stirring for reacting for 6 hours, standing, pouring off xylene at the upper layer, and observing that the product is a reddish brown solid.

(3) Under the mechanical stirring, blending the product obtained in the step (2) and 74.02g of epoxy chloropropane in a three-neck flask, adding 2.42g of tetrabutylammonium bromide, reacting for 4-6h at 100 ℃, cooling to 65 ℃, dropwise adding 100mL of NaOH solution with the mass concentration of 40%, and reacting for 2h after dropwise addition. Cooling to room temperature, adding a proper amount of dichloromethane for dilution, filtering to remove precipitates, and performing rotary evaporation to obtain a final product.

(4) Melting the TDBE prepared in the step (3) at 110 ℃, then rapidly adding 7.9g of molten DDM, vigorously stirring until a uniform mixture is obtained, then carrying out vacuum defoaming at 80 ℃, pouring the bubble-free mixture into a preheated stainless steel mold, then baking for 1-3 hours at the temperature of 100-120 ℃ in a vacuum oven, and then baking for 1-3 hours at the temperature of 130-150 ℃ to obtain the fully cured multifunctional flame-retardant epoxy resin TDBE-DDM based on diphenolic acid.

Example 3:

(1) 23.9g of TGIC was charged into a 500mL four-necked glass flask equipped with a mechanical stirrer, a thermometer, a reflux condenser and a dropping funnel at a constant pressure, heated and stirred at a temperature of 110 ℃ and a stirring speed of 150r/min to melt, and then a mixed solution of 17.6g of DOPO and 100mL of xylene was slowly dropped into the flask over 1 hour, heated to 150 ℃ and continuously stirred to react for 7 hours, and then gradually cooled to room temperature, and it was observed that the product was a pale yellow solid.

(2) And (3) melting the product in the step (1) by stirring at 150 ℃, slowly adding a mixed solution of 100mL of xylene and 45.82g of diphenolic acid, heating to 190 ℃, continuously stirring for reaction for 7 hours, standing, pouring off xylene at the upper layer, and observing that the product is a reddish brown solid.

(3) Under the mechanical stirring, blending the product obtained in the step (2) and 74.02g of epoxy chloropropane in a three-neck flask, adding 2.42g of tetrabutylammonium bromide, reacting for 4-6h at 100 ℃, cooling to 65 ℃, dropwise adding 110mL of NaOH solution with the mass concentration of 60%, and reacting for 3h after dropwise adding. Cooling to room temperature, adding a proper amount of dichloromethane for dilution, filtering to remove precipitates, and performing rotary evaporation to obtain a final product.

(4) Melting the TDBE prepared in the step (3) at 110 ℃, then rapidly adding 7.9g of molten DDM, vigorously stirring until a uniform mixture is obtained, then carrying out vacuum defoaming at 80 ℃, pouring the bubble-free mixture into a preheated stainless steel mold, then baking for 1-3 hours at the temperature of 100-120 ℃ in a vacuum oven, and then baking for 1-3 hours at the temperature of 130-150 ℃ to obtain the fully cured multifunctional flame-retardant epoxy resin TDBE-DDM based on diphenolic acid.