CN117903340A - Phosphaphenanthrene grafted butadiene polymer and preparation method thereof - Google Patents

Abstract

The invention discloses a phosphaphenanthrene grafted butadiene polymer and a preparation method thereof. The phosphaphenanthrene grafted polybutadiene, phosphaphenanthrene grafted styrene/butadiene copolymer, phosphaphenanthrene grafted acrylonitrile/butadiene copolymer and phosphaphenanthrene grafted acrylonitrile/butadiene/styrene copolymer are prepared by grafting a phosphaphenanthrene group onto the butadiene unit of the butadiene polymer through an addition reaction between a phosphorus-hydrogen bond on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and an unsaturated carbon-carbon double bond of a butadiene unit on a butadiene polymer in the presence of a dissolution-promoting diluent and/or a catalyst. The polymer has excellent thermal stability and acid and alkali resistance stability, can be used as a high molecular flame retardant component, and can be alloyed and composited with polymer materials such as thermoplastic polyester, thermosetting unsaturated resin and epoxy resin, so that the polymer has excellent flame retardant performance and physical and mechanical properties, and provides a key raw material for the development of high-performance flame retardant structural parts materials urgently needed in the high-end manufacturing field.

Description

Phosphaphenanthrene grafted butadiene polymer and preparation method thereof

Technical Field

The invention belongs to the technical field of preparing flame retardant group grafted polymers by utilizing a common polymer material chemical functionalization method, and specifically relates to a phosphaphenanthrene grafted butadiene polymer and a preparation method thereof.

Background technique

The construction theory and structural form exploration of high-performance flame-retardant molecules have always been the research focus and hotspot in the field of modern flame-retardant science and technology. In particular, as modern manufacturing industries have put forward increasingly stringent comprehensive performance requirements for various fire-safe material products, researchers' expectations for high-performance flame-retardant molecules are no longer limited to high-efficiency flame retardancy, but also include their effective maintenance and even significant enhancement of the inherent properties of the matrix material during application. Among them, the research on high-performance flame-retardant molecules that can effectively maintain or even significantly improve the physical and mechanical properties of the matrix material has attracted the most attention.

Compared with low molecular weight flame retardant molecules, high molecular weight flame retardant molecules with excellent water resistance and acid and alkali stability usually show higher limitations in molecular motion due to their high molecular weight characteristics, which makes them have excellent migration resistance and precipitation resistance in the matrix material, thereby giving the modified matrix material more durable and stable excellent flame retardant properties; the construction of high molecular weight flame retardant macromolecules can be achieved in the following two ways: (1) using the condensation or addition reaction between small molecular monomers containing flame retardant groups to construct high molecular weight macromolecular flame retardants; (2) grafting flame retardant groups onto ordinary polymer chemical structures through grafting reactions, performing flame retardant functional modification of ordinary polymers, and preparing high molecular weight macromolecular flame retardants; therefore, in addition to optimizing the efficient organizational form of flame retardant groups, optimizing the skeleton structure of high molecular weight macromolecular flame retardants can also be an effective way to enhance their application performance and expand their functions.

Summary of the invention

The invention aims to provide a phosphaphenanthrene grafted butadiene polymer and a preparation method thereof. The invention relates to grafting a phosphaphenanthrene group onto the butadiene unit of a butadiene polymer in the presence of a dissolution-promoting diluent or/and a catalyst through an addition reaction between a phosphorus-hydrogen bond on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and a carbon-carbon double bond on a butadiene unit on a butadiene polymer, thereby preparing a phosphaphenanthrene grafted butadiene polymer having excellent thermal stability and acid-base stability; through the grafting and aggregation of the phosphaphenanthrene group, the aggregation synergism of its flame retardant behavior is achieved, and the phosphaphenanthrene grafted butadiene polymer is endowed with the characteristic of high-efficiency flame retardancy; through the rigidity and polarity of the phosphaphenanthrene group, the aggregated rigid modulus of the phosphaphenanthrene grafted butadiene polymer and its compatibility with materials such as polyester and epoxy resin are improved; and through the rubber property of the linear butadiene polymer skeleton, the phosphaphenanthrene grafted butadiene polymer is endowed with the characteristic of toughness deformation, which has not been reported in currently published literature and materials.

The phosphaphenanthrene grafted butadiene polymer provided by the present invention has the following general chemical structure formula:

The polymerization degrees x, y, u and w in the general chemical structure formula may all be 0 at the same time.

The preparation method of the phosphaphenanthrene grafted butadiene polymer of the present invention is as follows: after DOPO is heated and melted, the temperature is raised to 120-150° C., a certain amount of dissolution-promoting diluent or/and catalyst is added, and after uniform mixing, a butadiene polymer is slowly added under stirring conditions to blend the butadiene polymer and the DOPO/dissolution-promoting diluent system into a homogeneous system with moderate viscosity, and then stirred and reacted at 130-200° C. for 2-24 hours, the reaction is terminated, and then the phosphaphenanthrene grafted butadiene polymer is obtained after washing, purification and drying.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, the butadiene polymer is a combination of one or more of polybutadiene, styrene/butadiene copolymer, acrylonitrile/butadiene copolymer, acrylonitrile/butadiene/styrene copolymer; the butadiene units in the butadiene polymer include 1,2-polymerized and 1,4-polymerized butadiene units; the chemical structure of the butadiene polymer is as follows:

For purposes of this invention, molecular weight is the apparent molecular weight measured by gel permeation chromatography (GPC) relative to a polystyrene standard; GPC molecular weight determinations are performed using tetrahydrofuran as the eluent.

Preferably, in the method for preparing the phosphaphenanthrene grafted butadiene polymer, the weight average molecular weight of the butadiene polymer is 1,000 to 200,000.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, the content of butadiene units in the butadiene polymer is not less than 10%; for polybutadiene, the content of butadiene units is 100%; for styrene/butadiene copolymer and acrylonitrile/butadiene/styrene copolymer, the liquid ¹ HNMR method can be used to determine the aromatic proton peak of the styrene unit, the carbon-carbon double bond proton peak of the "1,2-butadiene unit" and the carbon-carbon double bond proton peak of the "1,4-butadiene unit" in the copolymer to determine the butadiene unit content of the styrene/butadiene copolymer and the "1,2-butadiene unit" content in the butadiene unit; for acrylonitrile/butadiene copolymer, the liquid ¹ H The NMR method is used to determine the proton peak of the saturated alkane structure, the carbon-carbon double bond proton peak of the "1,2-butadiene unit" and the carbon-carbon double bond proton peak of the "1,4-butadiene unit" in the copolymer. Combined with the type and ratio of the proton peaks of the acrylonitrile unit and the butadiene unit, the butadiene unit content of the acrylonitrile/butadiene copolymer and the "1,2-butadiene unit" content in the butadiene unit are determined.

Since the butadiene unit of the butadiene polymer contains aliphatic unsaturated carbon-carbon double bonds, addition polymerization reactions between aliphatic carbon-carbon double bonds will occur under heating conditions, so that the butadiene polymer forms an insoluble and infusible cross-linking system, which is very unfavorable for the phosphaphenanthrene grafted butadiene polymer; the phosphorus-hydrogen bonds in DOPO can not only undergo addition reactions with aliphatic carbon-carbon double bonds, but also effectively inhibit addition polymerization reactions between unreacted aliphatic carbon-carbon double bonds; therefore, when preparing the phosphaphenanthrene grafted butadiene polymer, it is necessary to first heat and melt or dissolve DOPO, and then slowly add the butadiene polymer to ensure that DOPO can fully and effectively inhibit the cross-linking reaction of the butadiene polymer.

At the same time, since the addition reaction between the phosphorus-hydrogen bond in DOPO and the aliphatic carbon-carbon double bond is a relatively mild chemical reaction, a relatively long reaction time is usually required to achieve a sufficient addition reaction between DOPO and the aliphatic carbon-carbon double bond. In order to avoid addition polymerization between unreacted aliphatic carbon-carbon double bonds in the butadiene polymer during the grafting reaction, resulting in cross-linking of the system, it should be ensured that there is always an excess of DOPO in the system before the end of the reaction to prevent addition polymerization between aliphatic carbon-carbon double bonds in the system.

Preferably, in the method for preparing the phosphaphenanthrene grafted butadiene polymer, the amount of DOPO used is 1.05 to 3 times the amount of butadiene units participating in the phosphaphenanthrene grafting reaction in the butadiene polymer.

According to the present invention, when preparing a phosphaphenanthrene grafted butadiene polymer with a low grafting rate, the reaction conditions such as the ratio of DOPO/aliphatic carbon-carbon double bonds, reaction temperature and reaction time can be comprehensively controlled under the premise of ensuring a moderate excess of DOPO. When there are still aliphatic carbon-carbon double bonds remaining, the grafting reaction is stopped to obtain a phosphaphenanthrene grafted butadiene polymer with a low grafting rate. It is worth noting that the phosphaphenanthrene grafted butadiene polymer with a low grafting rate still contains polymerizable aliphatic carbon-carbon double bonds. Therefore, after washing and purification and removing excess DOPO, an appropriate amount of inhibitor can be added to prevent it from cross-linking during the desolventizing process.

In addition, when there is a sufficient amount of DOPO, when butadiene polymer is added to the DOPO melt, it is difficult for the two to form a homogeneous system, and the butadiene polymer will be distributed in the DOPO melt in the form of dispersed phase droplets; the grafting reaction and inhibition effect of DOPO are only effective for the butadiene polymer on the surface of the dispersed phase droplets. Since the butadiene polymer inside the dispersed phase droplets is not in direct contact with DOPO, the aliphatic carbon-carbon double bonds in its structure will be addition polymerized under the heating conditions during the reaction process, so that the butadiene polymers are cross-linked with each other to form discrete cross-linked particles with the dispersed phase droplets as the basic units.

Therefore, how to effectively improve the compatibility between DOPO and butadiene polymer in the melt state, achieve efficient addition reaction between DOPO molecules and the carbon-carbon double bonds of butadiene units on butadiene polymers by ensuring effective contact between DOPO molecules and butadiene polymers, and inhibit the polymerization of carbon-carbon double bonds of butadiene units on butadiene polymers, is a key issue that needs to be solved in the preparation of phosphaphenanthrene grafted butadiene polymers with high grafting rates.

According to the present invention, an appropriate amount of halogenated hydrocarbons can be added to the DOPO melt as a dissolving diluent to improve the compatibility of the butadiene polymer in the DOPO melt, so that the components in the grafting reaction system form a homogeneous system and reduce the viscosity of the system. This is beneficial to promoting material transfer during the grafting reaction and improving the efficiency of the grafting reaction, and is also beneficial for DOPO to fully inhibit the addition polymerization reaction between aliphatic carbon-carbon double bonds in the system, so that the carbon-carbon double bonds of the butadiene units on the butadiene polymer can be grafted with DOPO as much as possible, thereby obtaining a phosphaphenanthrene grafted butadiene polymer with a high grafting rate.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, the dissolution-promoting diluent is a combination of one or more halogenated hydrocarbons; the halogenated hydrocarbons include chlorobenzene, dichlorobenzene, bromobenzene, dibromobenzene, etc.; the dissolution-promoting diluent is used in an amount sufficient to promote the melt blending of DOPO and butadiene polymer into a homogeneous system and the viscosity of the system allows stable stirring at the reaction temperature, and the amount used is 0.5 to 3 mL of dissolution-promoting diluent/1 g of butadiene polymer.

According to the present invention, when preparing the phosphaphenanthrene grafted butadiene polymer, a catalyst is further introduced on the basis of the presence of a dissolution-promoting diluent, which is beneficial to promote the addition reaction between the phosphorus-hydrogen bond on DOPO and the aliphatic carbon-carbon double bond on the butadiene unit, thereby improving the grafting reaction efficiency between DOPO and the butadiene polymer, and is particularly suitable for preparing a phosphaphenanthrene grafted butadiene polymer with a high grafting rate.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, the catalyst is a combination of one or more bicyclic imide compounds, specifically including 1,8-diazabicyclo[5.4.0]undec-7-ene, etc.; the amount of the catalyst used is 0 to 0.1 mol/1 mol of butadiene monomer.

According to the present invention, after the grafting reaction between DOPO and butadiene polymer is completed, the crude product of phosphaphenanthrene grafted butadiene polymer still contains excessive DOPO and dissolution-promoting diluent and other components, which can be added to halogenated hydrocarbons, dissolved and diluted, and then washed with water; since DOPO hydrolysis is acidic, adding alkali can promote DOPO hydrolysis, so the pH value of the water washing system can be adjusted with an alkaline solution, so that the pH value of the aqueous phase during the first water washing is stabilized at 8 to 10, ensuring that the residual DOPO in the product is fully hydrolyzed; after standing and separating the liquid, repeatedly washing with water until neutrality, deeply removing the residual impurities in the product solution, and then desolventizing to obtain the purified phosphaphenanthrene grafted butadiene polymer.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, in the washing and purification step, the halogenated hydrocarbon used to dissolve the crude product of the phosphaphenanthrene grafted butadiene polymer includes a combination of one or more of dichloromethane, chloroform, ethyl chloride, dichloroethane, chlorobenzene and dichlorobenzene, and the amount used is 0.5 to 5 mL of the halogenated hydrocarbon/1 g of the crude product of the phosphaphenanthrene grafted butadiene polymer.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, in the washing and purification step, the alkaline solution used to adjust the pH value of the water washing system is an aqueous solution of one or more of alkali metal hydroxides, alkali metal carbonates and alkali metal bicarbonates, the mass fraction of the solute in the alkaline solution is 0.5% to 20%, and the amount of the alkaline solution is used in an amount such that the pH value of the aqueous phase in the washing system reaches 8 to 10 and is stable for 0.25 to 2 hours.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, in the washing and purification step, the volume ratio of water to halogenated hydrocarbon is preferably 1:1 to 3:1, the washing temperature is preferably 10 to 100° C., and the washing time is preferably 0.5 to 2 hours.

Preferably, in the preparation method of the phosphaphenanthrene grafted butadiene polymer, in the washing and purification step, the alkali washing is repeated 1 to 3 times, and the neutral water washing after the alkali washing is repeated 3 to 10 times.

According to the present invention, the phosphaphenanthrene grafting rate of the phosphaphenanthrene grafted butadiene polymer is a key factor affecting its flame retardant efficiency, rigidity modulus and glass transition temperature; when the butadiene polymer skeleton is the same, the higher the phosphaphenanthrene grafting rate, the higher the flame retardant efficiency, the greater the rigidity modulus and the higher the glass transition temperature of the phosphaphenanthrene grafted butadiene polymer.

Preferably, in the method for preparing the phosphaphenanthrene grafted butadiene polymer, the grafting rate of the phosphaphenanthrene of the butadiene units on the butadiene polymer is not less than 20%.

According to the present invention, during the addition grafting of DOPO and butadiene polymer, chain scission may occur in the butadiene polymer, resulting in the weight average molecular weight of the actually prepared phosphaphenanthrene grafted butadiene polymer being lower than the theoretical value.

Preferably, in the method for preparing the phosphaphenanthrene grafted butadiene polymer, the weight average molecular weight of the phosphaphenanthrene grafted butadiene polymer is 2,000 to 250,000.

The phosphaphenanthrene grafted butadiene polymer of the present invention has excellent thermal stability and acid and alkali resistance stability. The 1% weight loss temperature in a nitrogen atmosphere reaches above 400°C. When the temperature is further increased, it will rapidly and concentratedly crack and release flame retardant components, resulting in concentrated release and enhancement of flame retardant effect, and exerting a high-efficiency flame retardant effect. The phosphaphenanthrene grafted butadiene polymer chemical structure can also be optimized and adjusted to give it a specific rigid modulus and plastic deformable properties. The phosphaphenanthrene grafted butadiene polymer is used as a high molecular weight flame retardant component and alloyed with thermoplastic polyesters such as polycarbonate, butylene terephthalate, and ethylene terephthalate, and thermosetting resins such as unsaturated polyesters and epoxy resins. During compounding, the phosphaphenanthrene grafted butadiene polymer will be evenly distributed in the resin matrix in the form of dispersed phase particles with specific rigid modulus and plastic deformable properties, while exerting a high-efficiency flame retardant effect, it will produce different degrees of reinforcement and/or toughening effects on the resin matrix, while improving the flame retardant properties and physical and mechanical properties of the resin matrix, and preparing a high-performance flame retardant polymer composite material with excellent flame retardant properties and physical and mechanical properties; in particular, when the phosphaphenanthrene grafted styrene/butadiene copolymer is alloyed and compounded with polycarbonate, it can significantly improve the anti-ignition performance and self-extinguishing performance of the polycarbonate material, greatly reduce the combustion heat release rate, and at the same time give the polycarbonate material higher tensile properties, bending properties, impact properties and other comprehensive mechanical properties.

The phosphaphenanthrene grafted butadiene polymer disclosed in the present invention will provide a key raw material for the manufacture of high-performance flame-retardant polymer composite materials with excellent flame retardant properties and physical and mechanical properties, and has excellent application prospects in high-performance flame-retardant structural materials in the field of high-end manufacturing.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a typical hydrogen NMR spectrum of phosphaphenanthrene grafted butadiene polymer;

Figure 2 is a typical thermogravimetric curve of phosphaphenanthrene grafted butadiene polymer;

Figure 3 Infrared spectrum of a typical phosphaphenanthrene grafted butadiene polymer.

Detailed ways

The present invention is further described below in conjunction with examples; these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention; the experimental methods in the following examples without specifying specific conditions are generally based on conventional conditions in the art; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets; any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention are within the scope of protection claimed by the present invention.

Example 1

DOPO (133 g, 0.615 mol) was heated to melt in an oil bath at 130°C. After the system temperature was raised to 130°C, 1,2-dichlorobenzene (60 mL) was added as a dissolution-promoting diluent. After being fully stirred and mixed, styrene/butadiene copolymer (SBS, weight-average molecular weight 160,000, 40 g, 0.555 mol butadiene unit) was slowly added. After stirring until SBS was completely dissolved in the DOPO/dissolution-promoting diluent system, the system temperature was raised to 160°C. After stirring and reacting for 15 hours, the result was beam reaction; firstly dissolve the obtained crude product of phosphaphenanthrene grafted styrene/butadiene copolymer in dichloroethane (200 mL), add 300 mL of deionized water, and then adjust the pH value of the aqueous phase to 8-9 with a 5% NaOH aqueous solution and maintain it for 1 hour, then stir and wash it with deionized water for 9 times, desolventize and dry to obtain the purified phosphaphenanthrene grafted styrene/butadiene copolymer with a weight average molecular weight of 16800, a glass transition temperature of 160°C, and a 1% weight loss temperature of 406°C under a nitrogen atmosphere.

Example 2

DOPO (165 g, 0.763 mol) was heated to melt in an oil bath at 135°C. After the system temperature was raised to 140°C, 1,2-dichlorobenzene (90 mL) was added as a dissolution-promoting diluent. After being fully stirred and mixed, polybutadiene (PB, weight-average molecular weight 20,000, 40 g, 0.740 mol butadiene unit) was slowly added. After stirring until PB was completely dissolved in the DOPO/dissolution-promoting diluent system, the system temperature was raised to 150°C. After stirring for 20 hours, the reaction was terminated. The obtained crude product of phosphaphenanthrene grafted polybutadiene was first dissolved in ethylene dichloride (200 mL), 200 mL of deionized water was added, and the pH value of the aqueous phase was adjusted to 9-10 with a 10% NaOH aqueous solution and maintained for 0.5 hours, and then washed with deionized water for 5 times with stirring, desolventized and dried to obtain a purified low molecular weight phosphaphenanthrene grafted polybutadiene with a weight average molecular weight of 6385, a glass transition temperature of 159°C, and a 1% weight loss temperature of 429°C under a nitrogen atmosphere.

Example 3

DOPO (136 g, 0.629 mol) was heated to melt in an oil bath at 135°C. After the system temperature was raised to 150°C, bromobenzene (100 mL) was added as a dissolution-promoting diluent. After being fully stirred and mixed, polybutadiene (PB, weight-average molecular weight 100,000, 40 g, 0.740 mol butadiene unit) was slowly added. After stirring until PB was completely dissolved in the DOPO/dissolution-promoting diluent system, the system temperature was raised to 170°C and stirred for 10 hours. After that, the reaction is terminated; the obtained crude product of phosphaphenanthrene grafted polybutadiene is first dissolved in dichloroethane (250 mL), 300 mL of deionized water is added, and the pH value of the aqueous phase is adjusted to 8-9 with a 5% NaOH aqueous solution and maintained for 0.5 hour, and then washed with deionized water for 7 times with stirring, desolventized and dried to obtain the purified medium molecular weight phosphaphenanthrene grafted polybutadiene, with a glass transition temperature of 154°C and a 1% weight loss temperature of 414°C under a nitrogen atmosphere.

Example 4

DOPO (96 g, 0.444 mol) was heated to melt in an oil bath at 135°C. After the system temperature was raised to 140°C, 1,2-dichlorobenzene (120 mL) was added as a dissolution-promoting diluent. After being fully stirred and mixed, polybutadiene (PB, weight-average molecular weight 200,000, 40 g, 0.740 mol butadiene unit) was slowly added. After stirring until PB was completely dissolved in the DOPO/dissolution-promoting diluent system, the system temperature was raised to 165°C and the reaction was stirred for 12 hours. After hours, the reaction was terminated; the obtained crude phosphaphenanthrene grafted polybutadiene product was first dissolved in dichloroethane (250 mL), 400 mL of deionized water was added, and the pH value of the aqueous phase was adjusted to 8-9 with a 10% NaOH aqueous solution and maintained for 1 hour, and then washed with deionized water for 9 times with stirring, desolventized and dried to obtain a purified high molecular weight phosphaphenanthrene grafted polybutadiene with a glass transition temperature of 151°C and a 1% weight loss temperature of 403°C under a nitrogen atmosphere.

Example 5

DOPO (54.4 g, 0.252 mol) was heated to melt in an oil bath at 130°C. After the system temperature was raised to 130°C, 1,2-dichlorobenzene (40 mL) was added as a dissolution-promoting diluent. After being fully stirred and mixed, acrylonitrile/butadiene copolymer (NBR, weight-average molecular weight 20,000, 20 g, 0.240 mol butadiene unit) was slowly added. After stirring until NBR was completely dissolved in the DOPO/dissolution-promoting diluent system, the system temperature was raised to 165°C and the reaction was stirred for 1 minute. After 6 hours, the reaction was terminated; the obtained crude product of phosphaphenanthrene grafted acrylonitrile/butadiene copolymer was first dissolved in dichloroethane (150 mL), 300 mL of deionized water was added, and the pH value of the aqueous phase was adjusted to 8-9 with a 5% NaOH aqueous solution and maintained for 1 hour, and then washed with deionized water for 6 times with stirring, desolventized and dried to obtain the purified phosphaphenanthrene grafted acrylonitrile/butadiene copolymer, with a glass transition temperature of 166°C and a 1% weight loss temperature of 417°C under a nitrogen atmosphere.

Example 6

DOPO (64 g, 0.296 mol) was heated to melt in an oil bath at 130°C. After the system temperature was raised to 140°C, 1,2-dichlorobenzene (50 mL) was added as a dissolution-promoting diluent. After being fully stirred and mixed, polybutadiene (PB, weight-average molecular weight 20,000, 40 g, 0.740 mol butadiene unit) was slowly added. After stirring until PB was completely dissolved in the DOPO/dissolution-promoting diluent system, the system temperature was raised to 155°C and stirred for 6 hours. After that, the reaction is terminated; the obtained crude product of phosphaphenanthrene grafted polybutadiene is first dissolved in dichloroethane (100 mL), 150 mL of deionized water is added, and the pH value of the aqueous phase is adjusted to 8-9 with a 5% NaOH aqueous solution and maintained for 0.5 hour, and then washed with deionized water for 4 times with stirring, desolventized and dried to obtain a purified phosphaphenanthrene grafted polybutadiene with a low grafting rate, with a glass transition temperature of 136°C and a 1% weight loss temperature of 407°C under a nitrogen atmosphere.

Example 7

DOPO (136 g, 0.629 mol) was heated to melt in an oil bath at 130°C. After the system temperature was raised to 130°C, chlorobenzene (50 mL) was added as a dissolution-promoting diluent, and 1,8-diazabicyclo[5.4.0]undec-7-ene (4.26 g, 0.028 mol) was added as a catalyst. After being stirred and mixed thoroughly, styrene/butadiene copolymer (SBS, weight-average molecular weight 120,000, 40 g, 0.560 mol butadiene unit) was slowly added. After stirring until SBS was completely dissolved in the DOPO/dissolution-promoting diluent system, the system was stirred. The temperature was raised to 150°C, and the reaction was stirred for 10 hours before the reaction was terminated. The crude product of the phosphaphenanthrene grafted styrene/butadiene copolymer was first dissolved in ethylene dichloride (250 mL), and 350 mL of deionized water was added. The pH value of the aqueous phase was adjusted to 8-9 with a 5% NaOH aqueous solution and maintained for 1 hour. The mixture was then stirred and washed with deionized water for 9 times, and then desolventized and dried to obtain a purified phosphaphenanthrene grafted styrene/butadiene copolymer with a weight-average molecular weight of 46800, a glass transition temperature of 165°C, and a 1% weight loss temperature of 410°C under a nitrogen atmosphere.

Table 1 Flame retardant effect of phosphaphenanthrene grafted butadiene in polycarbonate (by weight)

Claims (10)

1. A phosphaphenanthrene grafted butadiene polymer, characterized in that the chemical structure of the phosphaphenanthrene grafted butadiene polymer is as follows: The polymerization degrees x, y, u and w in the general chemical structure formula may all be 0 at the same time. 2 . The phosphaphenanthrene grafted butadiene polymer according to claim 1 , wherein the weight average molecular weight of the phosphaphenanthrene grafted butadiene polymer is 2,000 to 250,000. 3. The phosphaphenanthrene grafted butadiene polymer according to claim 1, characterized in that the content of butadiene units in the phosphaphenanthrene grafted butadiene polymer is not less than 10%, and the phosphaphenanthrene grafting rate of butadiene units is not less than 20%. 4. A method for preparing a phosphaphenanthrene grafted butadiene polymer, characterized in that the phosphaphenanthrene grafted butadiene polymer is grafted onto the butadiene unit of the butadiene polymer in the presence of a dissolution-promoting diluent or/and a catalyst by an addition reaction between the phosphorus-hydrogen bond on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and the aliphatic unsaturated carbon-carbon double bond on the butadiene polymer, specifically comprising: heating and melting DOPO, heating to 120-150° C., adding a certain amount of dissolution-promoting diluent or/and a catalyst, mixing evenly, and then slowly adding the butadiene polymer under stirring conditions to blend the butadiene polymer and the DOPO/dissolution-promoting diluent system into a homogeneous system with moderate viscosity, stirring and reacting at 130-200° C. for 2-24 hours, terminating the reaction, and then washing, purifying, and drying to obtain the phosphaphenanthrene grafted butadiene polymer. 5. The method for preparing a phosphaphenanthrene grafted butadiene polymer according to claim 4, characterized in that the butadiene polymer is a combination of one or more of polybutadiene, styrene/butadiene copolymer, acrylonitrile/butadiene copolymer, and acrylonitrile/butadiene/styrene copolymer; the chemical structure of the butadiene polymer is as follows: 6 . The method for preparing a phosphaphenanthrene grafted butadiene polymer according to claim 4 , wherein the amount of DOPO used is 1.05 to 3 times the amount of butadiene units participating in the phosphaphenanthrene grafting reaction in the butadiene polymer. 7. The method for preparing a phosphaphenanthrene grafted butadiene polymer according to claim 4, characterized in that the dissolution-promoting diluent is a combination of one or more halogenated hydrocarbons, specifically including chlorobenzene, dichlorobenzene, bromobenzene, dibromobenzene, etc.; the dissolution-promoting diluent is used in an amount sufficient to promote the melt blending of DOPO and butadiene polymer into a homogeneous system and the system viscosity allows the system to be stably stirred at the reaction temperature, and the amount used is 0.5 to 3 mL of dissolution-promoting diluent/1 g of butadiene polymer. 8. The method for preparing a phosphaphenanthrene grafted butadiene polymer according to claim 4, characterized in that the catalyst is a combination of one or more bicyclic imidazole compounds, specifically including 1,8-diazabicyclo[5.4.0]undec-7-ene, etc.; the amount of the catalyst is 0 to 0.1 mol/1 mol of butadiene monomer. 9. The method for preparing a phosphaphenanthrene grafted butadiene polymer according to claim 4, characterized in that in the washing and purification step, the halogenated hydrocarbon used to dissolve the crude product of the phosphaphenanthrene grafted butadiene polymer comprises a combination of one or more of dichloromethane, chloroform, ethyl chloride, dichloroethane, chlorobenzene and dichlorobenzene, and the amount used is 0.5-5 mL of the halogenated hydrocarbon/1 g of the crude product of the phosphaphenanthrene grafted butadiene polymer. 10. The method for preparing a phosphaphenanthrene grafted butadiene polymer according to claim 4, characterized in that in the washing and purification step, the alkaline solution used to adjust the pH value of the water washing system is an aqueous solution of one or more of alkali metal hydroxides, alkali metal carbonates and alkali metal bicarbonates, the mass fraction of the solute in the alkaline solution is 0.5% to 20%, and the amount of the alkaline solution is such that the pH value of the aqueous phase in the washing system reaches 8 to 10 and is stable for 0.25 to 2 hours.