CN110229353A - A method of improving organic powder-compound polyurethane material interface performance and mechanical property - Google Patents

Abstract

The invention discloses a method for improving the interface properties and mechanical properties of an organic powder-polyurethane composite material. The preparation process includes polyurethane composite solution preparation, coagulation bath preparation, polyurethane composite solution scraping, phase inversion molding and drying treatment; the method Under the premise of not changing the preparation process of organic powder-polyurethane composite materials, it is mixed with a poor solvent for polyurethane, N,N-dimethylformamide and a solvent with a polarity lower than N,N-dimethylformamide The ternary mixed solvent enables the unmodified organic powder to be better uniformly dispersed in the polyurethane solution, which not only retains the original characteristics of the organic powder particles, but also improves the mechanical properties of the composite material. The prepared organic powder ‑Polyurethane composite materials have good strength and strain properties, and the preparation process is simple, and have broad market demand prospects in the fields of textile bionics and clothing.

Description

A method for improving the interface properties and mechanical properties of organic powder-polyurethane composite materials method

technical field

The invention relates to the technical field of composite materials, in particular to a method for improving the interface properties and mechanical properties of organic powder-polyurethane composite materials.

Background technique

Polyurethane is a polymer material composed of flexible segments and rigid segments, and its elasticity is between rubber and plastic materials. The polyurethane structure contains a large number of polar groups such as carbamate groups, ester groups and urea groups, which endow polyurethane elastomers with excellent wear resistance, high strength, good elasticity, low temperature resistance and heat resistance And other characteristics, and polyurethane materials also have excellent biocompatibility, making polyurethane one of the new materials that has attracted wide attention. The organic powder-polyurethane composite materials prepared by it are widely used in the field of polymer films.

With the development of science and technology, polymer films are more and more widely used in the national economy, and the requirements for the performance of film materials, especially mechanical properties and hydrophilic moisture permeability comfort are also getting higher and higher. At present, the organic powder-polyurethane composite material prepared by traditional single solvent and single molding method, under the condition of high organic powder ratio, the interface between organic powder and polyurethane is poor, making the strength of polyurethane composite material and strain are poor; under the condition of low organic powder ratio, the polyurethane composite material can only reflect the performance of the polyurethane bulk material, and cannot well show the excellent surface properties of the natural organic powder. In addition, by modifying the surface of organic powder, such as plasma modification and surface graft modification, the interface bonding force between organic powder and polyurethane material can be improved, thereby improving the mechanical properties of polyurethane composite materials. However, organic The surface modification of the powder will destroy the surface characteristics of the organic powder, and the effective utilization of the powder cannot be well realized. Aiming at the poor interface properties and tensile mechanical properties of organic powder-polyurethane composite materials at present, by changing the molding process of organic powder-polyurethane composite materials, the interface properties between organic powder and polyurethane are improved, and a It is of great significance to develop an organic powder-polyurethane composite film with high filling and high mechanical properties.

The patent application with the publication number CN105111490A discloses a method for preparing a high-strength, high-modulus and high-elasticity polyurethane film. This method uses ammonium salt as a coagulation bath, so that the ammonium salt molecules in the polyurethane film after film formation and the amorphous region molecules in the polyurethane The micro-crosslinked structure formed in the form of hydrogen bonds, or the formation of nano-needle structures and nano-spherical structures in the pores of the polyurethane film, can simultaneously increase the tensile stress and strain of the polyurethane film, but its disadvantage is that this Composite membranes do not have good hydrophilic moisture permeability.

In the open magazine "Technical Textiles" in October 2006, the 8th issue titled "The Effect of Ultrafine Wool Powder on the Waterproof and Moisture Permeability of Polyurethane Membranes", the mechanical properties and waterproof permeability of polyurethane membranes with different contents of wool powder were studied. The influence of wet performance, the solvent used in this article is a single N, N-dimethylformamide, and the film-forming method used is the immersion precipitation method. The prepared polyurethane/wool powder composite film has certain moisture permeability , but its shortcoming is that the breaking strength and elongation at break of the composite film are low.

In the article titled "Silk Fibroin Powder and Medical Polyurethane Sol Blending-Preparation and Properties of Hot-pressed Blending Film" of the open magazine "Macromolecule Materials Science and Engineering" in August 2011, the 8th issue, solution blending and thermal compression were used. Polyurethane composite films with different silk fibroin powder contents were prepared by pressing method, and the prepared polyurethane composite films had a certain breaking strength, but the disadvantage was that when the silk fibroin powder content was large, the polyurethane/silk fibroin composite film The elongation at break is much lower than that of polyurethane film, which limits the application of polyurethane/silk fibroin composite film.

Contents of the invention

In view of the above problems, the present invention provides a method for improving the interface properties and mechanical properties of the organic powder-polyurethane composite material. Under the premise of not changing the preparation process of the organic powder-polyurethane composite material, a poor solvent made of polyurethane, N ,N-dimethylformamide and a ternary mixed solvent blended with a solvent less polar than N,N-dimethylformamide, so that the unmodified organic powder can be better uniformly dispersed in the polyurethane solution , not only retaining the original characteristics of the organic powder particles, but also improving the mechanical properties of the composite material, and the prepared organic powder-polyurethane composite material has good strength and strain properties.

In order to achieve the above object, the present invention provides a method for improving the interfacial performance and mechanical properties of organic powder-polyurethane composite material, comprising the steps of:

(1) Polyurethane composite solution preparation: mix the poor solvent of polyurethane, N,N-dimethylformamide and a solvent with a polarity lower than N,N-dimethylformamide into a ternary mixed solvent, and then mix the polyurethane The prepolymer and unmodified organic powder are placed in a ternary mixed solvent, and after mechanical stirring, vacuum defoaming is prepared to prepare a polyurethane composite solution;

(2) Coagulation bath preparation: mix deionized water and alcoholic organic solvents, and mix them into a coagulation bath after stirring evenly;

(3) Polyurethane composite solution scraping: the polyurethane composite solution is scraped on the mould;

(4) Phase inversion molding and drying treatment: Immediately immerse the mold containing the polyurethane composite solution in a coagulation bath, take it out and place it in a drying oven for heat treatment.

Further, the mass fraction of the polyurethane poor solvent in step (1) is 5% to 45%; the mass fraction of the N,N-dimethylformamide is 30% to 90%; the low polarity The mass fraction of the solvent in N,N-dimethylformamide is 5%-30%.

Further, the mass percentage of the polyurethane prepolymer in step (1) is 5% to 33.25%; the mass percentage of the unmodified organic powder is 0.5% to 17.5%; the ternary mixed solvent The mass percentage is 65% to 90%.

Further, the poor solvent of polyurethane described in step (1) is one or two blends in toluene or xylene; the solvent with a lower polarity than N,N-dimethylformamide is acetone, One or more mixtures of dioxane or tetrahydrofuran.

Further, the polyurethane prepolymer in step (1) is one of polyether polyurethane prepolymer, polyester polyurethane prepolymer or polyester-polyether polyurethane prepolymer.

Further, the unmodified organic powder in step (1) is one or two or more of ultrafine protein fiber powder, ultrafine wool fiber powder or leather powder.

Further, the stirring temperature of the mechanical stirring in step (1) is 20-45°C, the stirring rate is 500-3000 rpm, and the stirring time is 1.5-5h.

Further, the mass fraction ratio of the deionized water to the alcoholic organic solvent in step (2) is 99%: 1% to 80%: 20%; the conductivity of the deionized water is 16MΩ·cm; the The alcoholic organic solvent is one of ethanol, 1-propanol, 1-butanol, 2-propanol or ethylene glycol; the solution temperature of the coagulation bath is 10-50°C.

Further, the mold described in step (3) is polytetrafluoroethylene.

Further, the soaking time in the coagulation bath in step (4) is 1.5-6 hours; the temperature in the drying oven is 30-80° C.; the heat treatment time is 12-48 hours.

The beneficial effects of the present invention are:

1. Under the premise of not changing the preparation process of the organic powder-polyurethane composite material, the technical solution of the present invention adopts the poor solvent of polyurethane, N,N-dimethylformamide and the polarity lower than N,N-dimethylformamide The ternary mixed solvent mixed with the solvent of base formamide, compared with the traditional single good solvent, the organic powder can be better uniformly dispersed in the polyurethane solution, which not only retains the original characteristics of the organic powder particles, but also improves the composite The mechanical properties of the material, the prepared organic powder-polyurethane composite material has good strength and strain properties;

2. The ternary mixed solvent adopted in the present invention is in the process of preparing the organic powder-polyurethane composite material, the metastable system caused by the poor solvent of polyurethane can drive the more orderly arrangement of the polyurethane molecular chain, thereby improving the polyurethane material. Strength and strain properties; in the process of film formation, the self-adjustment process of polyurethane molecular chain is conducive to the formation of good interfacial bonding force between polyurethane and organic powder, thereby improving the mechanical properties of organic powder-polyurethane composite materials;

3. Compared with the traditional surface modification of organic powder particles to increase the interfacial properties of composite materials, the present invention does not carry out surface modification on organic powder particles, and can retain organic powder particles on the basis of maintaining good mechanical properties of composite materials The original characteristics make the polyurethane composite material have the specific functional characteristics of organic powder;

4. The preparation process of the organic powder-polyurethane composite material provided by the present invention is simple, and the prepared organic powder-polyurethane composite material has good mechanical properties, and has broad market demand prospects in the fields of textile bionics and clothing.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with the following examples; it should be understood that the specific examples described here are only used to explain the present invention and are not intended to limit the present invention ; Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

Example 1

This embodiment provides a method for improving the interface properties and mechanical properties of organic powder-polyurethane composite materials, including the following steps:

(1) Polyurethane composite solution preparation: the mass fraction ratio is 5%: 90%: 5% toluene, N, N-dimethylformamide and dioxane are blended into a ternary mixed solvent, and then the mass fraction Ratio is 15%: 15%: 70% polyester polyurethane prepolymer, unmodified superfine wool fiber powder and ternary mixed solvent are mixed, vacuum defoaming after mechanical stirring 2.5h is mixed with polyurethane composite solution; Wherein , the stirring temperature is 25°C, and the stirring rate is 700 rpm;

(2) coagulation bath preparation: the mass fraction ratio is 95%: 5% deionized water and ethylene glycol are compounded, after stirring evenly, be prepared into coagulation bath; Wherein, the temperature of coagulation bath solution is 40 ℃, deionized water The conductivity is 16MΩ·cm;

(3) Polyurethane composite solution scraping coating: the configured polyurethane composite solution is scraped on the polytetrafluoroethylene mold with a glass rod;

(4) Phase inversion molding and drying treatment: Immediately immerse the mold containing the polyurethane composite solution in a coagulation bath for 1.5 hours, take it out, and then place it in a 30°C drying oven for heat treatment for 48 hours.

comparative example

This comparative example provides a method for improving the interfacial properties and mechanical properties of organic powder-polyurethane composite materials. Compared with Example 1, the difference is that the solvent used is a single N, N-dimethylformamide solvent, and other Example 1 is the same.

Embodiment 2～7

Embodiments 2 to 7 provide a method for improving the interfacial properties and mechanical properties of organic powder-polyurethane composite materials. Compared with Example 1, the difference is that toluene, N, N-di The mass fraction ratio of methylformamide and dioxane, the specific mass fraction ratio of each solvent corresponding to Examples 1 to 7 and comparative examples and the mechanical properties of the obtained organic powder-polyurethane composite material are shown in Table 1 .

Table 1 Mechanical properties of composites obtained under different ratios of toluene, N, N-dimethylformamide and dioxane

It can be seen from Table 1 that with the increase of the poor solvent toluene in the ternary solvent system, the tensile strength, elongation at break and toughness of the polyurethane composite material showed an upward trend. When toluene, N, N-di When the mass fraction ratio of methylformamide and dioxane is 45%:45%:10%, the mechanical properties of the prepared organic powder-polyurethane composite material are the best. And the mechanical properties of the polyurethane composite material prepared in Examples 1 to 7 are significantly better than the composite material prepared in the comparative example, showing that the mechanical properties of the organic powder-polyurethane composite material prepared by the ternary solvent system in the present invention are obvious It is superior to composite materials prepared by traditional single solvent immersion precipitation method.

Embodiment 8～11

Embodiments 8 to 11 provide a method for improving the interface properties and mechanical properties of organic powder-polyurethane composite materials. Compared with Embodiment 7, the difference is that the solvent type in the ternary mixed solvent is changed, and the difference between each solvent The mass fraction ratio is still 45%:45%:10%. The specific solvent composition corresponding to each embodiment and the mechanical properties of the organic powder-polyurethane composite material are shown in Table 2.

The mechanical properties of the composites obtained under different solvent compositions in table 2

As can be seen from Table 2, the type of solvent in the ternary mixed solvent has a greater influence on the mechanical properties of the composite material, and the addition of a solvent with a weaker polarity is conducive to improving the mechanical properties of the polyurethane composite material. Therefore, Example 9 corresponds to The mechanical properties of the organic powder-polyurethane composite material prepared by the ternary mixed solvent of toluene, N,N-dimethylformamide and tetrahydrofuran are relatively better.

Examples 12-13

Embodiments 12 to 13 provide a method for improving the interface properties and mechanical properties of organic powder-polyurethane composite materials. Compared with Embodiment 9, the difference is that toluene, N, N-di The mass fraction ratio of methylformamide and tetrahydrofuran, the specific mass fraction ratios corresponding to Examples 12 and 13 and the mechanical properties of the prepared organic powder-polyurethane composite material are shown in Table 3.

Table 3 Mechanical properties of composites obtained under different ratios of toluene, N,N-dimethylformamide and tetrahydrofuran

It can be seen from Table 3 that the mass fraction of solvents with a polarity lower than that of N, N-dimethylformamide in the ternary mixed solvent has a great influence on the mechanical properties of polyurethane composites, and with the increase of the solvent mass fraction , the tensile strength, elongation at break and toughness of the polyurethane composite show an upward trend, when the mass fraction ratio of toluene, N, N-dimethylformamide and tetrahydrofuran is 40%: 30%: 30% The obtained organic powder-polyurethane composite material has better mechanical properties.

Examples 14-17

Embodiments 14 to 17 provide a method for improving the interface properties and mechanical properties of organic powder-polyurethane composite materials. Compared with embodiment 13, the difference is that the polyester polyurethane prepolymer, unmodified super The mass fraction ratio of the fine wool fiber powder to the ternary mixed solvent, the specific mass fraction ratios corresponding to Examples 14-17 and the mechanical properties of the prepared organic powder-polyurethane composite material are shown in Table 4.

Table 4 Mechanical properties of composites obtained under different ratios of polyester polyurethane prepolymer, unmodified ultrafine wool fiber powder and ternary mixed solvent

It can be seen from Table 4 that the proportion of polyurethane prepolymer, unmodified ultrafine wool fiber powder and ternary mixed solvent has a great influence on the mechanical properties of polyurethane composite materials, and the higher content of polyester polyurethane prepolymer And the lower content of unmodified superfine wool fiber powder is more conducive to improving the mechanical properties of the obtained polyurethane composites. Mechanical properties of organic powder-polyurethane composites prepared when the mass fraction ratio of polyester polyurethane prepolymer, unmodified superfine wool fiber powder and ternary mixed solvent is 33.25%:0.5%:66.25% The performance is better.

The above is only an illustrative embodiment of the present invention, and is not intended to limit the present invention in any form and in essence. Several improvements and supplements should also be regarded as the protection scope of the present invention; at the same time, all changes, modifications and evolutions made to the above-mentioned embodiments according to the substantive technology of the present invention still belong to the protection scope of the present invention.

Claims (10)

1. a kind of method for improving organic powder-compound polyurethane material interface performance and mechanical property, which is characterized in that including Following steps:

(1) polyurethane composite solution is prepared: the poor solvent, N,N-dimethylformamide and polarity of polyurethane are lower than N, N- bis- The solvent compounding of methylformamide is ternary mixed solvent, then base polyurethane prepolymer for use as and unmodified organic powder are placed in ternary In the mixed solvent, generating polyurethane composite solution is prepared in vacuum defoamation after mechanical stirring is uniform；

(2) coagulating bath is prepared: deionized water being mixed with alcohol organic solvent, is configured to coagulating bath after mixing evenly；

(3) polyurethane composite solution scratches: by polyurethane composite solution blade coating on mold；

(4) inversion of phases molding and drying process: the mold containing polyurethane composite solution is immersed in coagulating bath immediately and is impregnated, is taken It puts in a drying box and is heat-treated again after out.

2. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: the mass fraction of the poor solvent of polyurethane described in step (1) is 5%~45%；The N, N- bis- The mass fraction of methylformamide is 30%~90%；Mass fraction of the polarity lower than the solvent of N,N-dimethylformamide It is 5%~30%.

3. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: the mass percent of base polyurethane prepolymer for use as described in step (1) is 5%~33.25%；It is described not change Property organic powder mass percent be 0.5%~17.5%；The mass percent of the ternary mixed solvent be 65%~ 90%.

4. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: the poor solvent of polyurethane described in step (1) is the blending of one or both of toluene or dimethylbenzene Object；The solvent that the polarity is lower than N,N-dimethylformamide is one of acetone, dioxane or tetrahydrofuran or a variety of Mixture.

5. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: base polyurethane prepolymer for use as described in step (1) is that Polyether-Polyol Polyurethane Prepolymer or polyester polyurethane are pre- One of aggressiveness or polyester-polyether Type Polyurethane Prepolymer.

6. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: unmodified organic powder described in step (1) is the protein fibre powder or fine of fine One or both of wool fiber powder or leather powder are a variety of.

7. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: churned mechanically whipping temp described in step (1) is 20~45 DEG C, and stirring rate is 500~3000 Rev/min, mixing time is 1.5~5h.

8. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: the mass fraction ratio of deionized water described in step (2) and alcohol organic solvent be 99%:1%~ 80%:20%；The conductivity of the deionized water is 16M Ω cm；The alcohol organic solvent is ethyl alcohol or 1- propyl alcohol or 1- Butanol or one of 2- propyl alcohol or ethylene glycol；The solution temperature of the coagulating bath is 10~50 DEG C.

9. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: mold described in step (3) is polytetrafluoroethylene (PTFE).

10. a kind of organic powder-compound polyurethane material interface performance and mechanical property of improving according to claim 1 Method, it is characterised in that: the time impregnated in coagulating bath described in step (4) is 1.5~6h；Temperature in the drying box is 30~80 DEG C；The time of the heat treatment is 12~48h.