CN112079988A - Preparation method of photocuring polyurethane/ZnO nanocomposite - Google Patents

Abstract

The invention discloses a preparation method of a photocuring polyurethane/ZnO nano composite material. The invention takes isophorone diisocyanate (IPDI), polytetrahydrofuran glycol (PTMG), dimethylol propionic acid (DMPA), 2-hydroxyethyl methacrylate (HEMA), n-butyl alcohol and pentaerythritol triacrylate (PETA) as raw materials to synthesize photosensitive amphiphilic polyurethane with different functionalities by a step-by-step polymerization method; the amphiphilic polyurethane is used as a stabilizer and an emulsifier, and the light-cured APU-ZnO nano composite material is prepared by adopting an inverse miniemulsion method through the strong interaction between the hydroxyl on the surface of ZnO and the carboxyl of the amphiphilic polyurethane. The photocuring PUA/ZnO nano composite material prepared by the invention has good optical property and mechanical property, which are the results of the double functions of uniform dispersion of ZnO nano particles and crosslinking between photosensitive groups on the surface of the ZnO nano particles and PUA resin.

Description

Preparation method of photocuring polyurethane/ZnO nanocomposite

Technical Field

The invention relates to the field of polyurethane nanocomposites, in particular to a preparation method of a photocuring polyurethane/ZnO nanocomposite.

Background

Polyurethane is a novel synthetic material between plastic and rubber, and is widely used in practical application, namely Polyurethane (PU) in English. It is a compound containing repeated urethane bonds (-NH-COO-) in a high molecular main chain, and is generally prepared by the gradual addition polymerization reaction of polyisocyanate (mainly diisocyanate), polyol (mainly polyester polyol and polyether polyol) and a micromolecular chain extender. Since the first synthesis of polyurethanes by professor Bayer in germany in 1937, the development of polyurethanes has been on the verge of diversification. In addition, the polyurethane also has the outstanding advantages of wide adjustment range of hardness, good flexibility, strong adhesive force and the like, and can be widely applied to the fields of coatings, adhesives, elastomers, printing and dyeing auxiliaries, leather finishing agents, foams, fibers, building materials and the like. The light solidified polyurethane belongs to one kind of polyurethane, and the difference is that the chain segment contains functional groups (such as carbon-carbon double bonds) which can be initiated by photosensitive free radicals and can further react with the prepolymer for crosslinking under the action of ultraviolet light. The photocuring polyurethane has the characteristics of high curing speed, high efficiency, low cost, energy conservation and the like, and the coating film has the advantages of excellent performance, high impact strength, good low-temperature flexibility, wear resistance, controllable hardness and transparency, and wide application range of base materials. In addition, the use of organic solvents can be effectively reduced by adopting a green and environment-friendly photocuring technology, and the pollution of organic solvent VOC to the environment is reduced.

Polyurethane with adjustable hardness, high elasticity, abrasion resistance and strong adhesion capability is gradually replacing old polymers and becoming a polymer material with wide application. Polyurethanes can also be tailored to the highly diverse needs of modern technology development aspects, such as coatings, adhesives, reaction injection molding, fibers, foams, rubbers, thermoplastic elastomers, and composites, among others. Meanwhile, the application of high and new technical fields such as military equipment, aerospace, electronics and optical devices and the like continuously requires that the polyurethane has additional properties and functions such as high mechanical property, chemical resistance, flame retardance, water resistance, ultraviolet resistance, electrical conductivity, magnetic field resistance, radar absorbability and the like. By combining with the large background of continuous development in the fields of nano science and nano science, the introduction of nano materials into polyurethane or photo-cured polyurethane enhances the optical, mechanical, magnetic and photoelectric properties of the composite material and endows the composite material with functionality, which has become a great focus of the research and development of polyurethane at present. The research is expected to further widen the application range of the polyurethane in the high and new technical field.

The application of nano materials in polyurethane is more and more extensive, and the development of nano materials in the fields of polyurethane and waterborne polyurethane is promoted by the high performance requirement in the high and new technical field. The nano zinc oxide is concerned due to the fact that the nano zinc oxide is non-toxic, high in chemical stability, good in heat conductivity and excellent in ultraviolet resistance, and researches show that the nano zinc oxide has the advantages of trace quantity, high efficiency and good ultraviolet absorption performance and is a good choice for preparing ultraviolet-resistant polyurethane/zinc oxide nano composite coatings and composite films. But the characteristics of extremely high specific surface area and surface energy and single surface group enable the polyurethane to be easily agglomerated, thus influencing the improvement of the performance of the composite material and limiting the application thereof.

Disclosure of Invention

Aiming at the defects generated by adding the nano zinc oxide into the polyurethane, the invention provides a photocuring polyurethane/ZnO nano composite material.

When the nano zinc oxide (ZnO) is applied to the polymer composite material, the performance improvement effect of the composite material depends on the dispersion condition of the ZnO and the interface interaction between the ZnO and the polymer matrix. The polymer can be adsorbed onto the surface of ZnO particles by a solution method, an inverse emulsion method, and a fine emulsion method, and physically adsorbed onto the surface of the particles as a surfactant during the reaction, thereby inhibiting the growth of crystal particles and rendering the surface of the particles hydrophobic. The amphiphilic copolymer is easy to obtain, and has better control on the hydrophilicity and hydrophobicity of the particle surface, so that the amphiphilic copolymer not only plays a role in stabilizing particles, but also improves the compatibility between the nanoparticles and the polymer matrix. Amphiphilic Polyurethanes (APUs) are interesting and readily available surfactants, dispersants, and can react with a variety of hydrophilic and hydrophobic segments. The amphiphilic polyurethane contains carbonyl, carboxyl, carbamate and reactive vinyl groups, which make it suitable for stabilizing organic or inorganic nanoparticles in aqueous or organic media, thus improving the chemical or physical interaction between the nanoparticles and the polymer matrix. The specific technical scheme of the invention is as follows:

a preparation method of a photocuring polyurethane/ZnO nano composite material comprises the following specific steps:

(1) synthesis of Amphiphilic Polyurethane (APU): firstly, respectively adding 8.70g of isophorone diisocyanate (IPDI), 28.55g of polytetrahydrofuran glycol (PTMG) and a catalyst dibutyltin dilaurate (DBTDL) into three 250mL four-neck flasks, keeping the system temperature at 50 ℃, and uniformly stirring for reacting for 1.5 h; adding dimethylol propionic acid (DMPA) in three batches, wherein the total amount is 1.88g, stirring the mixture at the temperature of 60 ℃ for reaction for 5 hours, adding a polymerization inhibitor 2, 6-di-tert-butyl-p-cresol (BHT) and n-butyl alcohol 1.62g or methacrylic acid-2-Hydroxyethyl (HEMA)2.84g or pentaerythritol triacrylate (PETA)6.51g, stirring the mixture at the temperature of 70 ℃ for reaction for 5 hours, and adding a proper amount of acetone in the reaction process to adjust the viscosity of the system to obtain amphiphilic polyurethane with different functionalities;

(2) preparing APU-ZnO by an inverse miniemulsion method: dissolving 0.80g of Zn (Ac)2 & 2H2O and 0.30g of NaOH in 2.20g of distilled water and 2.70g of distilled water respectively according to the mixture ratio, dripping the aqueous solution into 23.4g of toluene solution containing 0.7g of the amphiphilic polyurethane prepared in the step (1), quickly stirring for coarse emulsification for 1H to form inverse fine emulsion, and then respectively carrying out ultrasonic fine emulsification for 30 min; mixing the two emulsions, continuously performing ultrasonic fine emulsification for 30min, performing rotary evaporation, vacuum drying and water washing on the obtained product, dispersing the product in toluene again, and removing water by condensation reflux to obtain ZnO toluene dispersion liquid with amphiphilic polyurethane as surface modification;

(3) preparing a photocuring Polyurethane (PUA)/ZnO nano composite film: adding 17.4g of isophorone diisocyanate (IPDI) into a 250mL four-neck flask, dropwise adding 57.1g of polycarbonate diol (PCD) and a catalyst of dibutyltin dilaurate (DBTDL), reacting for 1h at 50 ℃ with uniform stirring after the dropwise adding is finished, and sampling to determine the-NCO content; then adding 3.75g of dimethylolpropionic acid (DMPA) for three times, stirring for reacting for 6 hours, heating to 70 ℃, adding 5.68g of 2-hydroxyethyl methacrylate (HEMA) and 2, 6-di-tert-butyl-p-cresol (BHT) for reacting until an-NCO group disappears, and obtaining the light-cured polyurethane matrix resin (PUA); and (3) adding the amphiphilic polyurethane modified nano ZnO dispersion liquid prepared in the step (2), performing ultrasonic dispersion for 3min, adding toluene to maintain the solid content of the system at about 20wt%, adding 0.04g of 1-hydroxycyclohexyl phenyl ketone, and performing ultrasonic dispersion for 5min to obtain the photocuring polyurethane/ZnO nano composite emulsion.

The invention adopts PTMG-HEMA-ZnO as functional nano filler to be added into the light-cured PUA to prepare the light-cured PUA/ZnO nano composite material, the light-cured PUA/ZnO nano composite material prepared by the invention has good optical property and mechanical property, which are the results of the double functions of the uniform dispersion of ZnO nano particles and the cross linking between the surface photosensitive groups and PUA resin.

Detailed Description

The present invention will be further described with reference to the following examples.

The invention relates to a preparation method of a photocuring polyurethane/ZnO nano composite material, which comprises the following specific steps:

(1) synthesis of Amphiphilic Polyurethane (APU): firstly, respectively adding 8.70g of isophorone diisocyanate (IPDI), 28.55g of polytetrahydrofuran glycol (PTMG) and a catalyst dibutyltin dilaurate (DBTDL) into three 250mL four-neck flasks, keeping the system temperature at 50 ℃, and uniformly stirring for reacting for 1.5 h; adding dimethylol propionic acid (DMPA) in three batches, wherein the total amount is 1.88g, stirring the mixture at the temperature of 60 ℃ for reaction for 5 hours, adding a polymerization inhibitor 2, 6-di-tert-butyl-p-cresol (BHT) and n-butyl alcohol 1.62g or methacrylic acid-2-Hydroxyethyl (HEMA)2.84g or pentaerythritol triacrylate (PETA)6.51g, stirring the mixture at the temperature of 70 ℃ for reaction for 5 hours, and adding a proper amount of acetone in the reaction process to adjust the viscosity of the system to obtain amphiphilic polyurethane with different functionalities;

(2) preparing APU-ZnO by an inverse miniemulsion method: dissolving 0.80g of Zn (Ac)2 & 2H2O and 0.30g of NaOH in 2.20g of distilled water and 2.70g of distilled water respectively according to the mixture ratio, dripping the aqueous solution into 23.4g of toluene solution containing 0.7g of the amphiphilic polyurethane prepared in the step (1), quickly stirring for coarse emulsification for 1H to form inverse fine emulsion, and then respectively carrying out ultrasonic fine emulsification for 30 min; mixing the two emulsions, continuously performing ultrasonic fine emulsification for 30min, performing rotary evaporation, vacuum drying and water washing on the obtained product, dispersing the product in toluene again, and removing water by condensation reflux to obtain ZnO toluene dispersion liquid with amphiphilic polyurethane as surface modification;

(3) preparing a photocuring Polyurethane (PUA)/ZnO nano composite film: adding 17.4g of isophorone diisocyanate (IPDI) into a 250mL four-neck flask, dropwise adding 57.1g of polycarbonate diol (PCD) and a catalyst of dibutyltin dilaurate (DBTDL), reacting for 1h at 50 ℃ with uniform stirring after the dropwise adding is finished, and sampling to determine the-NCO content; then adding 3.75g of dimethylolpropionic acid (DMPA) for three times, stirring for reacting for 6 hours, heating to 70 ℃, adding 5.68g of 2-hydroxyethyl methacrylate (HEMA) and 2, 6-di-tert-butyl-p-cresol (BHT) for reacting until an-NCO group disappears, and obtaining the light-cured polyurethane matrix resin (PUA); and (3) adding the amphiphilic polyurethane modified nano ZnO dispersion liquid prepared in the step (2), performing ultrasonic dispersion for 3min, adding toluene to maintain the solid content of the system at about 20wt%, adding 0.04g of 1-hydroxycyclohexyl phenyl ketone, and performing ultrasonic dispersion for 5min to obtain the photocuring polyurethane/ZnO nano composite emulsion.

Claims (1)

1. A preparation method of a photocuring polyurethane/ZnO nano composite material is characterized by comprising the following specific steps:

(1) synthesis of Amphiphilic Polyurethane (APU): firstly, respectively adding 8.70g of isophorone diisocyanate (IPDI), 28.55g of polytetrahydrofuran glycol (PTMG) and a catalyst dibutyltin dilaurate (DBTDL) into three 250mL four-neck flasks, keeping the system temperature at 50 ℃, and uniformly stirring for reacting for 1.5 h; adding dimethylol propionic acid (DMPA) in three batches, wherein the total amount is 1.88g, stirring the mixture at the temperature of 60 ℃ for reaction for 5 hours, adding a polymerization inhibitor 2, 6-di-tert-butyl-p-cresol (BHT) and n-butyl alcohol 1.62g or methacrylic acid-2-Hydroxyethyl (HEMA)2.84g or pentaerythritol triacrylate (PETA)6.51g, stirring the mixture at the temperature of 70 ℃ for reaction for 5 hours, and adding a proper amount of acetone in the reaction process to adjust the viscosity of the system to obtain amphiphilic polyurethane with different functionalities;

(2) preparing APU-ZnO by an inverse miniemulsion method: dissolving 0.80g of Zn (Ac)2 & 2H2O and 0.30g of NaOH in 2.20g of distilled water and 2.70g of distilled water respectively according to the mixture ratio, dripping the aqueous solution into 23.4g of toluene solution containing 0.7g of the amphiphilic polyurethane prepared in the step (1), quickly stirring for coarse emulsification for 1H to form inverse fine emulsion, and then respectively carrying out ultrasonic fine emulsification for 30 min; mixing the two emulsions, continuously performing ultrasonic fine emulsification for 30min, performing rotary evaporation, vacuum drying and water washing on the obtained product, dispersing the product in toluene again, and removing water by condensation reflux to obtain ZnO toluene dispersion liquid with amphiphilic polyurethane as surface modification;

(3) preparing a photocuring Polyurethane (PUA)/ZnO nano composite film: adding 17.4g of isophorone diisocyanate (IPDI) into a 250mL four-neck flask, dropwise adding 57.1g of polycarbonate diol (PCD) and a catalyst of dibutyltin dilaurate (DBTDL), reacting for 1h at 50 ℃ with uniform stirring after the dropwise adding is finished, and sampling to determine the-NCO content; then adding 3.75g of dimethylolpropionic acid (DMPA) for three times, stirring for reacting for 6 hours, heating to 70 ℃, adding 5.68g of 2-hydroxyethyl methacrylate (HEMA) and 2, 6-di-tert-butyl-p-cresol (BHT) for reacting until an-NCO group disappears, and obtaining the light-cured polyurethane matrix resin (PUA); and (3) adding the amphiphilic polyurethane modified nano ZnO dispersion liquid prepared in the step (2), performing ultrasonic dispersion for 3min, adding toluene to maintain the solid content of the system at about 20wt%, adding 0.04g of 1-hydroxycyclohexyl phenyl ketone, and performing ultrasonic dispersion for 5min to obtain the photocuring polyurethane/ZnO nano composite emulsion.