Method for preparing room temperature self-repairing waterborne polyurethane based on castor oil and bone glue

Abstract

This invention discloses a method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue. Specifically, a D-A adduct is prepared via a Diels-Alder reaction using furanol methanol and bismaleimide as raw materials. Isophorone diamine and bone glue are used as hydrogen-bonding functional monomers, and further polymerized using castor oil, isophorone diisocyanate, and self-healing monomers as raw materials to obtain the self-healing waterborne polyurethane. Castor oil has an average hydroxyl functionality of 2.7, which can directly replace petroleum-based polyols. The amino groups of bone glue can react with isocyanate groups to form urea bonds, resulting in more hydrogen bonds in the system, thereby improving the self-healing and mechanical properties of the polyurethane. At room temperature, the tensile strength and elongation at break of the waterborne polyurethane can reach 2.978 MPa and 189.16%, respectively, with a self-healing efficiency exceeding 80%.

Description

Technical Field

[0001] This invention belongs to the field of biomass-based waterborne polyurethane preparation technology, specifically relating to a method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue. Background Technology

[0002] Waterborne polyurethane is a polymer compound with excellent properties such as high strength, wear resistance, and corrosion resistance, making it one of the most widely used engineering materials. Due to its highly tunable chemical structure and the availability of synthetic chemicals, it has wide applications in material coatings, transportation, aerospace, and other fields. However, during use, environmental or external forces can easily cause micro-cracks and damage, affecting the structure and properties of waterborne polyurethane materials and significantly reducing their service life.

[0003] The concept of "self-healing" originates from bionics research. Its essence lies in using energy and material replenishment, along with mimicking the healing mechanisms of biological damage, to partially or completely repair internal damage incurred during molding, processing, and use. This eliminates potential hazards and extends the material's lifespan to some extent. Self-healing materials are divided into two main categories: extrinsic and intrinsic. Intrinsic self-healing typically involves external factors such as light, heat, and pH to trigger the healing process, completing the repair through bond breakage and recombination. Currently, intrinsic self-healing waterborne polyurethanes primarily use non-renewable petrochemical resources as raw materials. They achieve self-healing by introducing groups or structures with reversible chemical effects (covalent bonds, non-covalent bonds, etc.), thereby extending their service life.

[0004] Renewable biomass plant oils are widely used in the preparation of biomass-based self-healing waterborne polyurethanes due to their advantages such as good solubility, low cost, high yield, and ease of modification. Natural castor oil, extracted from castor seeds, carries multiple hydroxyl functional groups and can directly react with isocyanate groups as a polyol to form urethane bonds, yielding plant oil-based self-healing waterborne polyurethanes without prior modification. However, due to the low reactivity of secondary hydroxyl groups in castor oil, the chemical cross-linking degree of castor oil-based self-healing waterborne polyurethanes is poor, making them susceptible to mechanical and thermal effects, resulting in deep cracks, deformation, or damage. Bone glue, as a biomass material, is inexpensive, biodegradable, and biocompatible. Its abundant hydroxyl and amino groups can interact with polyurethane segments to generate sacrificial bonds (covalent and hydrogen bonds) with multiple energy dissipation effects, thereby improving the mechanical properties of polyurethane films. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing room temperature self-healing waterborne polyurethane based on castor oil and bone glue, which solves the problems of low self-healing efficiency and poor mechanical properties of existing waterborne polyurethanes.

[0006] The technical solution adopted in this invention is a method for preparing room temperature self-healing waterborne polyurethane based on castor oil and bone glue, specifically implemented according to the following steps:

[0007] Step 1: Preparation of DA adduct;

[0008] Step 2: Castor oil, isophorone diisocyanate, DA adduct, dibutyltin dilaurate, dimethylolpropionic acid, triethylamine, bone glue, and isophorone diamine are mixed and subjected to polymerization reaction to obtain room temperature self-healing waterborne polyurethane based on castor oil and bone glue.

[0009] The invention is further characterized in that,

[0010] Step 1 specifically involves:

[0011] Dissolve 10-15 parts by weight of bismaleimide in 70-80 parts by weight of chloroform, add 15-25 parts by weight of furanol, and stir in a water bath at 60-70℃ for 5-6 hours to form a homogeneous product; separate and purify it by rotary evaporation at 55-65℃ for 40-45 minutes to obtain the DA adduct.

[0012] Step 2 specifically involves:

[0013] Mix 8.5-9.5 parts by weight of castor oil, 8-9 parts by weight of isophorone diisocyanate, 2-3 parts by weight of DA adduct, and 0.1-0.2 parts by weight of dibutyltin dilaurate, and react at 70-80°C for 4-5 hours. Then, dissolve 1-1.5 parts by weight of dimethylolpropionic acid in N-methylpyrrolidone and stir in an oil bath at 70-75°C for 2-2.5 hours. Cool to 40-50°C and add acetone and 1-1.2 parts by weight of [unspecified ingredient] in a water bath. The triethylamine reaction was carried out for 20-30 minutes. After cooling to room temperature, 50-60 parts by weight of water were added for high-speed shear emulsification. During emulsification, 0.6-1.2 parts by weight of bone glue and 0.5-1 parts by weight of isophorone diamine were added sequentially. The temperature was raised to 35-40℃ for post-chain extension to obtain a room-temperature self-healing waterborne polyurethane emulsion based on castor oil and bone glue. The emulsion was poured into a polytetrafluoroethylene plate and allowed to stand at room temperature to obtain a room-temperature self-healing waterborne polyurethane based on castor oil and bone glue.

[0014] The high-speed shear emulsification time is 10-15 min, and bone glue and isophorone diamine are added during the 5th-10th minute of emulsification.

[0015] The settling time is 8-10 days.

[0016] The beneficial effects of this invention are as follows: A room-temperature self-healing biomass-based waterborne polyurethane is prepared using castor oil and bone glue as raw materials. Castor oil has an average hydroxyl functionality of 2.7, which can directly replace petroleum-based polyols. The amino groups in bone glue can react with isocyanate groups to form urea bonds, resulting in more hydrogen bonds in the system, thereby improving the self-healing and mechanical properties of the polyurethane. Simultaneously, the synergistic introduction of DA adducts and isophorone diamine gives it extremely high self-healing efficiency and strong mechanical properties. At room temperature, the tensile strength and elongation at break of the film can reach 2.978 MPa and 189.16%, respectively, with a self-healing efficiency exceeding 80%. Attached Figure Description

[0017] Figure 1 This is a graph showing the effect of repair time on the self-healing efficiency of the waterborne polyurethane film of this invention. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0019] This invention relates to a method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue, specifically implemented according to the following steps:

[0020] Step 1: Preparation of DA adduct; specifically:

[0021] Dissolve 10-15 parts by weight of bismaleimide in 70-80 parts by weight of chloroform, and continuously add 15-25 parts by weight of furanol. Stir the mixture in a water bath at 60-70°C for 5-6 hours to form a homogeneous product. Separate and purify the product by rotary evaporation at 55-65°C for 40-45 minutes to remove the solvent chloroform and obtain the DA adduct.

[0022] Step 2: Preparation of room temperature self-healing waterborne polyurethane based on castor oil and bone glue; specifically:

[0023] 8.5-9.5 parts by weight of dried castor oil, 8-9 parts by weight of isophorone diisocyanate, 2-3 parts by weight of DA adduct, and 0.1-0.2 parts by weight of dibutyltin dilaurate were mixed and reacted at 70-80°C for 4-5 hours. Then, 1-1.5 parts by weight of dimethylolpropionic acid were dissolved in N-methylpyrrolidone and stirred continuously in an oil bath at 70-75°C for 2-2.5 hours. The temperature was further lowered to 40-50°C, and acetone and 1-1.2 parts by weight of triethylamine were added in a water bath and reacted for 20-30 minutes. The mixture was then cooled to [temperature missing]. After reaching room temperature, 50-60 parts by weight of water were added and emulsified under high-speed shear for 10-15 minutes. During the 5th-10th minute of emulsification, 0.6-1.2 parts by weight of bone glue and 0.5-1 parts by weight of isophorone diamine were added sequentially. The mixture was then heated to 35-40℃ for post-chain extension to obtain a room-temperature self-healing waterborne polyurethane emulsion based on castor oil and bone glue. The emulsion was poured into a polytetrafluoroethylene plate and allowed to stand at room temperature for 8-10 days to obtain a biomass-based waterborne polyurethane film with a dual healing mechanism. This is the room-temperature self-healing waterborne polyurethane prepared based on castor oil and bone glue.

[0024] In this invention, a structural design is implemented for waterborne polyurethane, using castor oil and bone glue as raw materials to prepare room-temperature self-healing biomass-based waterborne polyurethane. Castor oil is rich in hydroxyl groups, has a high yield, and is inedible, allowing it to directly replace petroleum-based polyols in the preparation of castor oil-based waterborne polyurethane without any pre-modification. Bone glue, as a biomass material, is inexpensive, biodegradable, and highly reactive, rich in hydroxyl, amino, and carboxyl groups. The bone glue molecular chains can form covalent and hydrogen bonds with polyurethane segments, acting as sacrificial bonds for multiple energy dissipations, thereby improving the self-healing and mechanical properties of the polyurethane. Simultaneously, the synergistic introduction of DA adducts and isophorone diamine gives it extremely high self-healing efficiency and strong mechanical properties.

[0025] Example 1

[0026] This invention relates to a method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue, specifically as follows:

[0027] Step 1: Preparation of DA adduct;

[0028] 11 parts by weight of bismaleimide were dissolved in 72 parts by weight of chloroform, and 18 parts by weight of furanol were continuously added. The mixture was placed in a dry 250 mL three-necked flask and stirred in a water bath at 63 °C for 5.5 hours to form a homogeneous product. The product was then separated and purified by rotary evaporation at 58 °C for 42 min to remove the solvent chloroform and obtain the DA adduct.

[0029] Step 2: Preparation of room temperature self-healing waterborne polyurethane based on castor oil and bone glue;

[0030] 8.8 parts by weight of dried castor oil, 8.2 parts by weight of isophorone diisocyanate, 2.3 parts by weight of DA adduct, and 0.14 parts by weight of dibutyltin dilaurate were weighed and added to a 250 mL three-necked flask and reacted at 75 °C for 4.5 hours. Then, 1.2 parts by weight of dimethylolpropionic acid were dissolved in 6.5 mL of N-methylpyrrolidone and stirred continuously in an oil bath at 72 °C for 2 hours. The temperature was further lowered to 43 °C, and acetone and 1.13 parts by weight of triethylamine were added in a water bath and reacted for 22 min. After cooling to room temperature, 53 parts by weight of water were added and emulsified by high-speed shearing for 12 min. At the 6th minute of emulsification, 0.75 parts by weight of bone glue and 0.65 parts by weight of isophorone diamine were added sequentially, and the temperature was raised to 37 °C for post-chain extension to obtain a room temperature self-healing waterborne polyurethane emulsion based on castor oil and bone glue. The emulsion was poured into a polytetrafluoroethylene plate and left to stand at room temperature for 9 days to obtain a biomass-based waterborne polyurethane film with a dual healing mechanism.

[0031] Example 2

[0032] This invention relates to a method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue, specifically as follows:

[0033] Step 1: Preparation of DA adduct;

[0034] Dissolve 12 parts by weight of bismaleimide in 75 parts by weight of chloroform, and continuously add 20 parts by weight of furanol. Mix in a dry 250 mL three-necked flask and stir for 6 hours in a water bath at 65 °C to form a homogeneous product. Separate and purify the product by rotary evaporation at 60 °C for 43 min to remove the solvent chloroform and obtain the DA adduct.

[0035] Step 2: Preparation of room temperature self-healing waterborne polyurethane based on castor oil and bone glue:

[0036] 9.1 parts by weight of dried castor oil, 8.5 parts by weight of isophorone diisocyanate, 2.5 parts by weight of DA adduct, and 0.17 parts by weight of dibutyltin dilaurate were weighed and added to a 250 mL three-necked flask and reacted at 78 °C for 5 hours. Then, 1.3 parts by weight of dimethylolpropionic acid was dissolved in 7.2 mL of N-methylpyrrolidone and stirred continuously in an oil bath at 73 °C for 2.5 hours. The temperature was further lowered to 45 °C, and acetone and 1.15 parts by weight of triethylamine were added in a water bath and reacted for 25 min. After cooling to room temperature, 57 parts by weight of water were added and emulsified by high-speed shearing for 14 min. At the 8th minute of emulsification, 0.95 parts by weight of bone glue and 0.85 parts by weight of isophorone diamine were added sequentially, and the temperature was raised to 39 °C for post-chain extension to obtain a room temperature self-healing waterborne polyurethane emulsion based on castor oil and bone glue. The emulsion was poured into a polytetrafluoroethylene plate and left to stand at room temperature for 10 days to obtain a biomass-based waterborne polyurethane film with a dual healing mechanism.

[0037] Example 3

[0038] This invention relates to a method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue, specifically as follows:

[0039] Step 1: Preparation of DA adduct;

[0040] 14 parts by weight of bismaleimide were dissolved in 78 parts by weight of chloroform, and 24 parts by weight of furanol were continuously added. The mixture was placed in a dry 250 mL three-necked flask and stirred in a water bath at 68 °C for 6 hours to form a homogeneous product. The product was then separated and purified by rotary evaporation at 62 °C for 44 min to remove the solvent chloroform and obtain the DA adduct.

[0041] Step 2: Preparation of room temperature self-healing waterborne polyurethane based on castor oil and bone glue:

[0042] 9.4 parts by weight of dried castor oil, 8.8 parts by weight of isophorone diisocyanate, 2.8 parts by weight of DA adduct, and 0.19 parts by weight of dibutyltin dilaurate were weighed and added to a 250 mL three-necked flask and reacted at 80 °C for 5 hours. Then, 1.4 parts by weight of dimethylolpropionic acid was dissolved in 7.8 mL of N-methylpyrrolidone and stirred continuously in an oil bath at 74 °C for 2.5 hours. The temperature was further lowered to 48 °C, and acetone and 1.18 parts by weight of triethylamine were added in a water bath and reacted for 28 min. After cooling to room temperature, 59 parts by weight of water were added and emulsified by high-speed shearing for 15 min. At the 9th minute of emulsification, 1.15 parts by weight of bone glue and 0.98 parts by weight of isophorone diamine were added sequentially, and the temperature was raised to 40 °C for post-chain extension to obtain a room temperature self-healing waterborne polyurethane emulsion based on castor oil and bone glue. The emulsion was poured into a polytetrafluoroethylene plate and left to stand at room temperature for 10 days to obtain a biomass-based waterborne polyurethane film with a dual healing mechanism.

[0043] After the waterborne polyurethane film of the present invention is formed, a cross-shaped scratch is made on the surface of the film using a blade, such as... Figure 1 As shown, the film can achieve a repair efficiency of over 80% after 32 hours of repair at room temperature; its tensile strength and elongation at break are 2.978 MPa and 189.16%, respectively. Furthermore, the film exhibits excellent fatigue resistance, puncture resistance, and recyclability. This method can alleviate the energy crisis, reduce environmental pollution, and aligns with the current trend of sustainable development, gradually becoming one of the important directions for the development of waterborne polyurethane, while also promoting the resource utilization of castor oil and bone glue.

Claims

1. A method for preparing room-temperature self-healing waterborne polyurethane based on castor oil and bone glue, characterized in that, The specific steps are as follows: Step 1: Preparation of DA adduct; Step 2: Castor oil, isophorone diisocyanate, DA adduct, dibutyltin dilaurate, dimethylolpropionic acid, triethylamine, bone glue, and isophorone diamine are mixed and subjected to a polymerization reaction to obtain a room-temperature self-healing waterborne polyurethane based on castor oil and bone glue; specifically: Mix 8.5-9.5 parts by weight of castor oil, 8-9 parts by weight of isophorone diisocyanate, 2-3 parts by weight of DA adduct, and 0.1-0.2 parts by weight of dibutyltin dilaurate, and react at 70-80°C for 4-5 hours. Then, dissolve 1-1.5 parts by weight of dimethylolpropionic acid in N-methylpyrrolidone and stir in an oil bath at 70-75°C for 2-2.5 hours. Cool to 40-50°C, and add acetone and 1-1.2 parts by weight of triethylamine in a water bath for 20-30 minutes. min; after cooling to room temperature, add 50-60 parts by weight of water for high-speed shear emulsification, and add 0.6-1.2 parts by weight of bone glue and 0.5-1 parts by weight of isophorone diamine sequentially during emulsification. Heat to 35-40℃ for post-chain extension to obtain a room temperature self-healing waterborne polyurethane emulsion based on castor oil and bone glue; pour the emulsion into a polytetrafluoroethylene plate and let it stand at room temperature to obtain a room temperature self-healing waterborne polyurethane based on castor oil and bone glue.

2. The method for preparing room temperature self-healing waterborne polyurethane based on castor oil and bone glue as described in claim 1, characterized in that, In step 1, specifically: Dissolve 10-15 parts by weight of bismaleimide in 70-80 parts by weight of chloroform, add 15-25 parts by weight of furanol, and stir for 5-6 hours in a water bath at 60-70°C to form a homogeneous product. The product was separated and purified by rotary evaporation at 55-65℃ for 40-45 min to obtain the DA adduct.

3. The method for preparing room temperature self-healing waterborne polyurethane based on castor oil and bone glue as described in claim 1, characterized in that, The high-speed shear emulsification time is 10-15 min, and bone glue and isophorone diamine are added during the 5th-10th minute of emulsification.

4. The method for preparing room temperature self-healing waterborne polyurethane based on castor oil and bone glue as described in claim 1, characterized in that, The settling time is 8-10 days.

5. The room-temperature self-healing waterborne polyurethane prepared by the method according to any one of claims 1-4.

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