阅读说明：本技术 一种可回收腰果酚基光固化树脂及其制备方法 (Recoverable cardanol-based light-cured resin and preparation method thereof ) 是由 刘敬成 苏循政 周珍 陈梦佳 于 2019-10-21 设计创作，主要内容包括：本发明提供一种可回收腰果酚基光固化树脂及其制备方法,主要包括三个步骤：原料腰果酚的烯丙基化,原料2,2’-(1,4-亚苯基)-双[4-巯基-1,3,2-二氧杂硼杂环戊烷](BDB)的制备,利用上述两种产物制备腰果酚基光固化树脂。本发明以源自天然的腰果酚为起始原料制备生物基光固化树脂,腰果酚中的羟基先和3-卤代丙烯发生消去反应,引入醚键和端位碳碳不饱和双键,再通过巯基烯光点击反应将端位以及侧链碳碳不饱和双键与巯基进行交联。巯基烯光点击反应具有产率高；反应条件简单；反应时间短的优点,引入硼酸酯键使传统的光固化树脂变为更加绿色环保的可回收的热固性树脂。(The invention provides a recoverable cardanol-based light-cured resin and a preparation method thereof, which mainly comprises the following three steps: allylation of raw material cardanol, preparation of raw material 2,2' - (1, 4-phenylene) -bis [ 4-mercapto-1, 3, 2-dioxaborolane ] (BDB), preparation of cardanol-based photocurable resin using the above two products. According to the invention, natural cardanol is used as an initial raw material to prepare the bio-based light-cured resin, hydroxyl in the cardanol and 3-halopropene undergo elimination reaction, ether bonds and terminal carbon-carbon unsaturated double bonds are introduced, and then the terminal carbon-carbon unsaturated double bonds and side chain carbon-carbon unsaturated double bonds are crosslinked with sulfydryl through a sulfydryl alkene light click reaction. The mercaptoalkene light click reaction has high yield; the reaction conditions are simple; the reaction time is short, and the introduction of the boric acid ester bond changes the traditional light-cured resin into more environment-friendly recyclable thermosetting resin.)

1. The preparation method of the recyclable cardanol-based light-cured resin is characterized by comprising the following steps:

s1: allylation of cardanol: uniformly mixing cardanol and an alkaline substance, dropwise adding 3-halopropene at 20-100 ℃, heating and preserving heat for reaction for 1-60 hours, washing, extracting, adsorbing and drying to obtain allylated cardanol, wherein the reaction formula (1) is as follows:

wherein the content of the first and second substances,

s2: preparation of 2,2' - (1, 4-phenylene) -bis [ 4-mercapto-1, 3, 2-dioxaborolane ] (BDB): dissolving benzene-1, 4-diboronic acid and thioglycerol in tetrahydrofuran and water, adding anhydrous magnesium sulfate, reacting for 1-10h, filtering, concentrating, washing, and drying to obtain white powder, wherein the reaction formula (2) is as follows:

s3: preparation of the photocurable resin: dissolving allylated cardanol and BDB in an organic solvent, adding 1-10 wt% of photoinitiator, reacting for 1-10h under ultraviolet irradiation, supplementing 3 wt% of photoinitiator or thermal initiator, and concentrating to obtain the recyclable cardanol-based photocuring resin, wherein the reaction formula (3) is as follows:

2. the preparation method of the recoverable cardanol-based photocurable resin according to claim 1, wherein the basic substance in S1 is one or more of sodium carbonate, potassium carbonate, pyridine, triethylamine, sodium acetate, sodium hydroxide and potassium hydroxide; the molar ratio of the cardanol to the alkaline substances is 10 (5-20).

3. The preparation method of the recyclable cardanol-based photocurable resin according to claim 1, wherein the 3-halopropene in S1 is one or more of 3-bromopropene, 3-chloropropene, and 3-fluoropropene; the molar ratio of the 3-halopropene to cardanol is (1-10): 1.

4. The preparation method of the recyclable cardanol-based photocuring resin as claimed in claim 1, wherein the molar ratio of benzene-1, 4-diboronic acid, thioglycerol and anhydrous magnesium sulfate in S2 is 1 (2-10): (4-20); the amount of water used was 0.1 ml.

5. The method for preparing the recyclable cardanol-based photocuring resin as claimed in claim 1, wherein the molar ratio of the allylated cardanol, BDB and the organic solvent in S3 is 1 (1-10) to (1-100).

6. The method for preparing recoverable cardanol-based photocurable resin according to claim 5, wherein the organic solvent is one or more of chloroform, ethyl acetate, acetone, toluene, xylene, dimethyl sulfoxide, N-dimethylformamide, and acetonitrile.

7. The preparation method of the recyclable cardanol-based photocurable resin according to claim 1, wherein the photoinitiator is one or both of I-184 and 1173.

8. The method for preparing the recyclable cardanol-based photocuring resin according to claim 1, wherein the thermal initiator is one or two of azodiisobutyronitrile and dibenzoyl peroxide.

9. A recyclable cardanol-based photocurable resin characterized by being prepared by the method of any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of bio-based functional materials, in particular to a recyclable cardanol-based light-cured resin and a preparation method thereof.

Background

With the development of society, the problems of non-renewable, serious pollution, non-degradability and the like inherent in petroleum-based materials are increasingly prominent. The biobased material is used as a perfect green substitute of petroleum-based materials and has great market prospect. The cardanol is a plant polyene substance derived from tropical cashew nuts, is a cheap and easily-obtained green natural renewable plant phenol, and has a wide application prospect.

In recent years, the reports on the research on the light curing of cardanol are increasing, and mainly include the research on direct ultraviolet light curing of cardanol, acrylation, epoxy acrylation, vinylation, phenolic resination, isocyanate grafting modification, blending compounding, nano-compounding modification and the like. The cardanol photocuring materials mainly use a cardanol monomer phenolic hydroxyl group and a side chain unsaturated double bond as reactive active sites, and methacryloxy or acryloxy is introduced into a molecular structure through etherification or esterification reaction to prepare photocuring monomers and oligomers, but the cardanol photocuring materials are often limited in further utilization of cardanol-based photocuring due to high ultraviolet light power and long curing time during curing.

The Chinese invention patent with application number 201710148516.4 discloses an ultraviolet-cured polyurethane acrylate photosensitive resin and a preparation method and application thereof, the photosensitive resin is prepared by modifying cardanol to prepare cardanol etherified dihydric alcohol, then reacting with diisocyanate, using cardanol for sealing end to prepare polyurethane, then epoxidizing unsaturated double bond groups in polyurethane molecules, and then reacting the epoxy groups with (methyl) acrylic acid to obtain the ultraviolet-cured polyurethane acrylate photosensitive resin. The urethane acrylate photosensitive resin obtained by the method has low yield, and the product cannot be recycled. Therefore, under the global environment advocating green environmental protection, it is necessary to find a preparation method of recyclable photocurable resin with high efficiency, simple reaction conditions and short reaction time.

Disclosure of Invention

Aiming at the problems and the defects in the prior art, the invention provides the recoverable cardanol-based light-cured resin and the preparation method thereof, and the environment-friendly recoverable light-cured resin is obtained through mercaptoalkene click reaction.

In order to achieve the purpose, the invention provides a specific technical scheme that:

a preparation method of a recyclable cardanol-based light-cured resin specifically comprises the following steps:

s1: allylation of cardanol: uniformly mixing cardanol and an alkaline substance, dropwise adding 3-halopropene at 20-100 ℃, heating and preserving heat for reaction for 1-60 hours, washing, extracting, adsorbing and drying to obtain allylated cardanol, wherein the reaction formula (1) is as follows:

wherein the content of the first and second substances,

s2: preparation of 2,2' - (1, 4-phenylene) -bis [ 4-mercapto-1, 3, 2-dioxaborolane ] (BDB): dissolving benzene-1, 4-diboronic acid and thioglycerol in tetrahydrofuran and water, adding anhydrous magnesium sulfate, reacting for 1-10h, filtering, concentrating, washing, and drying to obtain white powder, wherein the reaction formula (2) is as follows:

s3: preparation of the photocurable resin: dissolving allylated cardanol and BDB in an organic solvent, adding 1-10 wt% of photoinitiator, reacting for 1-10h under ultraviolet irradiation, supplementing 3 wt% of photoinitiator or thermal initiator, and concentrating to obtain the recyclable cardanol-based photocuring resin, wherein the reaction formula (3) is as follows:

further, the alkaline substance in S1 is one or more of sodium carbonate, potassium carbonate, pyridine, triethylamine, sodium acetate, sodium hydroxide, and potassium hydroxide; the mol ratio of the cardanol to the alkaline substances is 10 (5-20);

further, the 3-halopropene in S1 is one or more of 3-bromopropene, 3-chloropropene and 3-fluoropropene; the molar ratio of the 3-halopropene to cardanol is (1-10): 1.

Further, the molar ratio of the benzene-1, 4-diboronic acid, the thioglycerol and the anhydrous magnesium sulfate in the S2 is 1 (2-10): (4-20); the amount of water used was 0.1 ml.

Furthermore, the mol ratio of the allylated cardanol, BDB and the organic solvent in the S3 is 1 (1-10) to (1-100).

Further, the organic solvent is one or more of chloroform, ethyl acetate, acetone, toluene, xylene, dimethyl sulfoxide, N-dimethylformamide and acetonitrile.

Further, the photoinitiator is one or two of I-184 and 1173.

Further, the thermal initiator is one or two of azodiisobutyronitrile and dibenzoyl peroxide.

The second purpose of the invention is to provide a recyclable cardanol-based light-cured resin prepared by any one of the methods.

The beneficial effects produced by the invention are as follows:

1. according to the invention, natural cardanol is used as an initial raw material to prepare the bio-based light-cured resin, hydroxyl in the cardanol and 3-halopropene undergo elimination reaction, ether bonds and terminal carbon-carbon unsaturated double bonds are introduced, and then the terminal carbon-carbon unsaturated double bonds and side chain carbon-carbon unsaturated double bonds are crosslinked with sulfydryl through a sulfydryl alkene light click reaction.

2. The mercaptoalkene light click reaction has the advantages of high yield, simple reaction condition, short reaction time, safety, controllability and the like, and the mercaptoalkene light click reaction is used as a preparation method of the light-cured resin, provides a new method for preparing the light-cured resin and has wide application space.

3. The introduction of the borate bond is a dynamic reversible covalent bond, so that the light-cured resin has good physical and mechanical properties, and the traditional light-cured resin is changed into more environment-friendly recyclable thermosetting resin.

Drawings

FIG. 1 is a nuclear magnetic spectrum of allylated cardanol prepared in example 1 of the present invention;

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of 2,2' - (1, 4-phenylene) -bis [ 4-mercapto-1, 3, 2-dioxaborolane ] (BDB) obtained in example 1 of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all embodiments, and do not limit the claims of the present invention at all.