CN110079012A - Compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS and preparation method thereof - Google Patents

Abstract

The present invention provides a kind of compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS and preparation method thereof, the flame-retardant polypropylene composite material is according to parts by weight, its raw material components includes 70~85 parts of polypropylene, 15~30 parts of unimolecule expansion type flame retardant, 0.1~5 part of oligomeric silsesquioxane, 0.05~5 part of graphene；Preparation method is that polypropylene, unimolecule expansion type flame retardant, oligomeric silsesquioxane, graphene are added in pan type physico chemical reactor, mixing oxides solid method mixes 2~30 times under 50~300r/min of revolving speed, extruding pelletization is added into double screw extruder to get the material grain of the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS in gained mixture.Prepared flame-retardant polypropylene composite material flame retarding efficiency is high, and expansion type flame retardant additive amount is greatly reduced, and compares similar flame-retardant polypropylene composite material mechanical property and greatly improves.

Description

Graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material and its preparation method

technical field

The invention belongs to the field of flame-retardant polypropylene material preparation, and in particular relates to a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material and a preparation method thereof.

Background technique

In recent years, with the improvement of people's awareness of environmental protection and safety, more and more attention has been paid to halogen-free flame-retardant plastics. Halogen-free flame-retardant polypropylene (PP) materials have developed rapidly and are widely used in automobiles, electrical appliances, Electronics, building materials and other fields. Among the halogen-free flame retardants currently used in polypropylene, there are mainly intumescent flame retardants (IFR), inorganic flame retardants, nano-flame retardants, etc., among which intumescent flame retardants are the most widely used. However, when traditional intumescent flame retardants are applied to polypropylene materials, there are also some disadvantages, such as high polarity, easy water absorption, and large addition amount.

Therefore, one of the current development directions of intumescent flame retardants is to consider the preparation of monomolecular intumescent flame retardants (RA-IFR) that integrate acid sources, gas sources, and carbon sources. In recent years, some researchers have attempted to combine monomolecular intumescent flame retardants and nano-flame retardants in a synergistic combination in order to prepare flame-retardant functional polypropylene composites with excellent comprehensive properties.

Among the nano-flame retardants, graphene (GE) is a nano-material composed of carbon atoms with a two-dimensional sheet structure. The carbon atoms have a hexagonal honeycomb structure and have good barrier properties. When the graphene sheets are uniformly dispersed in the polymer material matrix, the strength and density of the carbon layer can be effectively enhanced, and a good physical barrier effect can be achieved. Graphene has been increasingly used in polymer flame retardant research due to its potential excellent flame retardant effect as a nano flame retardant. However, when graphene is used as a single flame retardant, it has problems such as difficult dispersion and single flame retardant mechanism, so when it is used alone for polymer flame retardant, the flame retardant effect is poor, and it is generally used as a synergist for polymer flame retardant research.

The inventors have found in research that when graphene is used as a flame retardant synergist in a monomolecular intumescent flame retardant/polypropylene matrix system, graphene is easy to agglomerate due to its large molecular surface energy, so it is difficult to achieve The uniform dispersion in the polypropylene matrix results in a decrease in the mechanical properties of the resulting flame retardant composite. In addition, the monomolecular intumescent flame retardant has high polarity and poor compatibility with the polypropylene matrix, so it is easy to reduce the flame retardancy and mechanical properties of the prepared flame-retardant composite material.

Therefore, how to apply graphene as a flame retardant synergist in the monomolecular intumescent flame retardant/polypropylene matrix system, and take advantage of the flame retardant properties of graphene itself, to obtain a flame retardant and mechanical properties excellent Halogen-free flame-retardant polypropylene composite material is an urgent problem to be solved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned prior art problems, to provide a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material and its preparation method, the prepared flame-retardant polypropylene composite material has high flame-retardant efficiency, Moreover, the addition amount of intumescent flame retardant is greatly reduced, and the mechanical properties of similar flame-retardant polypropylene composite materials are greatly improved.

In order to achieve the above object, the present invention is achieved by adopting the technical solution consisting of the following technical measures:

A graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material, in parts by weight, whose raw material components include:

Preferably, in parts by weight, its raw material components include:

Wherein, the monomolecular intumescent flame retardant generally refers to an intumescent flame retardant integrating an acid source, a carbon source, and a gas source. In order to better illustrate the technical solution of the present invention, preferably, the monomolecular intumescent flame retardant is a monomolecular intumescent flame retardant RMAPP, a monomolecular intumescent flame retardant MPP (preparation references: Chen Y, Wang Q .Reaction ofMelamine Phosphate with Pentaerythritol and Its Product for Flame Retardation of Polypropylene.Polymers for Advanced Technologies.2007,18(8),587-600), monomolecular intumescent flame retardant pentaerythritol dihydrogen phosphate melamine salt (preparation reference : Cao Shengchun, Jin Shengming, Tan Benzhu. Synthesis and Properties of New Flame Retardant Pentaerythritol Dihydrogen Phosphate Melamine Salt. Journal of Hunan University (Natural Science Edition), 2000,27(4):22-10.), Unimolecular Swelling Type flame retardant Melabis (preparation reference: Halpern Y, Mott D M, Niswander R H. Fire retardancy of thermoplastic materials by intumescence. Industrial & Engineering Chemistry Product Research & Development, 1984, 23 (2): 233-238.), monomolecular expansion type flame retardant Flame TNGPA (preparation reference: Ou Yuxiang. Performance, synthesis and application of new phosphorus-nitrogen intumescent flame retardant. Jiangsu Chemical Industry, 1998 (3): 6-11.), single molecule intumescent flame retardant DOPOMPC ( References for preparation: Yang Shousheng. Application research of star-shaped monomolecular phosphorus nitrogen intumescent flame retardant in fireproof coatings. Coating industry. 2014, 44(11), 46-51.), Monomolecular intumescent flame retardant PMPT (Preparation reference: Zuo J-D, LiuS-M, Sheng Q. Synthesis and Application in Polypropylene of a Novel of Phosphorus-Containing Intumescent Flame Retardant. Molecules, 2010, 15(11), 7593-602) any one of them.

Wherein, the monomolecular intumescent flame retardant RMAPP can be selected with reference to the ammonium polyphosphate-based intumescent type in the applicant's prior patent "halogen-free intumescent flame-retardant polyoxymethylene composite material and its preparation method" (CN201010595733.6). The preparation method of the flame retardant is the prepared intumescent flame retardant.

Further, in order to improve the char-forming effect of the prepared flame-retardant polypropylene composite material, the monomolecular intumescent flame retardant RMAPP is obtained by the following preparation method:

Dry the ammonium polyphosphate, melamine, and pentaerythritol first, then mix them evenly according to the mass ratio of ammonium polyphosphate and melamine (1.5-6):1, and then react at a high temperature of 250-260°C for 3-4 hours. After the reaction time reaches , to obtain the reacted powder MAPP; the powder MAPP and pentaerythritol are uniformly mixed in a mass ratio of 7:(0.5-1.5), and then reacted at a high temperature of 225-235°C for 1.5-2.5 hours and then taken out to obtain a single Molecular expansion flame retardant RMAPP.

Usually, in order to facilitate the reaction preparation, the ammonium polyphosphate, melamine, and pentaerythritol are generally selected as powder formulations. Among them, the ammonium polyphosphate is preferably type II with a high degree of polymerization, and the degree of polymerization n is ≥ 1000; the melamine is preferably industrial grade, and the net content is ≥ 98%; the pentaerythritol is preferably industrial grade, and the net content is ≥ 98%.

Wherein, the drying is usually vacuum drying at 80-95° C. for 10-12 hours.

Wherein, the oligomeric silsesquioxane (POSS) is polyvinyl silsesquioxane, polymethyl silsesquioxane, polyphenyl silsesquioxane, polytrimethyl silsesquioxane Any one of siloxane, polyphenylpropylsilsesquioxane and polydimethylsiloxane-phenylsilsesquioxane copolymer or a combination thereof.

Usually, the particle size of the graphene is <10 μm.

In order to improve the flame retardant efficiency of the prepared flame retardant polypropylene composite material, the vertical burning level (UL-94 1.6mm) of the prepared flame retardant polypropylene composite material is at least V-1, and the mechanical properties of the finished product (tensile The tensile strength reaches 30MPa, and the breaking strength reaches 3.2kJ/m ² ), preferably, in parts by weight, the raw material components include:

In order to further improve the flame retardant efficiency, the vertical burning level (UL-941.6mm) of the prepared flame retardant polypropylene composite material is at least V-0, and the mechanical properties of the finished product are improved (the tensile strength reaches 33MPa, and the breaking strength reaches 3.4 kJ/m ² ), preferably, in parts by weight, the raw material components include:

It is worth noting that in actual industrial production, other processing aids such as antioxidants and stabilizers known in the prior art can also be selected to be added in the process of preparing the above-mentioned halogen-free flame-retardant polypropylene composite material. However, the premise is that these processing aids must not adversely affect the realization of the object of the present invention and the achievement of the excellent effects of the present invention.

A preparation method of a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material, comprising the following steps:

(1) In parts by weight, the raw material components for preparing materials include:

(2) Dry the monomolecular intumescent flame retardant, oligomeric silsesquioxane, and graphene first, and then add polypropylene, monomolecular intumescent flame retardant, oligomeric silsesquioxane, and graphene to the grinding disc In the shape force chemical reactor, the solid phase shearing and pulverizing is mixed 2 to 30 times at a speed of 50 to 300r/min to obtain a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene mixture, and the resulting mixture is added to the twin-screw Extrude and granulate in an extruder at a temperature of 180-195° C. to obtain granules of graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material.

Preferably, in parts by weight, the raw material components of the preparations include:

Wherein, the drying is usually at an environment of 80-95°C.

Preferably, the solid phase shear pulverization and mixing are performed 10 to 20 times.

Wherein, the disc-shaped mechanochemical reactor is the mechanochemical reactor disclosed in the applicant's prior patent ZL 95111258.9.

It is worth noting that in actual industrial production, other processing aids such as antioxidants and stabilizers known in the prior art can also be selected to be added in the process of preparing the above-mentioned halogen-free flame-retardant polypropylene composite material. However, the premise is that these processing aids must not adversely affect the realization of the object of the present invention and the achievement of the excellent effects of the present invention. Typically, these processing aids are optionally added with the polypropylene during manufacture.

The oligomeric silsesquioxane selected in the present invention has both compatibilizing and synergistic effects on the monomolecular intumescent flame retardant. Among them, the reason for the compatibilization effect of oligomeric silsesquioxane (POSS) particles is that the cage-shaped skeleton of oligomeric silsesquioxane (POSS) particles is connected with organic groups, so that it has a better phase with polypropylene molecular chains. Capacitance.

In the preferred technical solution, the combination of oligomeric silsesquioxane and monomolecular intumescent flame retardant RMAPP is used for synergistic flame retardancy, which has a good flame retardant effect, mainly because: (1) POSS particles are nanometer-sized, It has a large specific surface area and has electrostatic adsorption with the monomolecular intumescent flame retardant RMAPP particles; (2) Between the oxygen atom of the Si-O-Si bond in POSS and the hydrogen atom of the _-NH2 group in RMAPP There are hydrogen bonding interactions. Therefore, POSS particles can coat RMAPP particles, make RMAPP better dispersed in the PP matrix, and improve system compatibility. This is also the use of POSS as a synergist to make the flame retardancy and mechanical properties of the finished product better than similar flame retardancy. system reasons.

In addition, the synergistic flame retardant mechanism of oligomeric silsesquioxane is as follows: On the one hand, POSS has a rigid cage skeleton with Si-O-Si structure, which can improve the high-temperature thermal stability of polypropylene materials, and POSS is decomposed by heat Due to the large surface energy, the generated SiO ₂ particles can migrate to the surface of the expanded carbon layer, and form a composite carbon layer with higher strength, which enhances the flame retardancy of the condensed phase; on the other hand, some POSS particles participate in the combustion process of the polymer. Through the carbonization process of polypropylene macromolecular chains, the quality of residual charcoal is improved, thereby improving the flame retardancy of the material. The introduction of graphene as a synergistic flame retardant mainly plays the role of condensed phase flame retardancy. The addition of a small amount of graphene can significantly improve the strength and density of the carbon layer, making the expanded carbon layer not easy to collapse, and effectively preventing heat and oxygen from entering the material. The transfer between the degradation zone and the combustion zone, thereby improving the flame retardancy of the material and reducing the addition of monomolecular intumescent flame retardants.

In summary, the polypropylene matrix flame retardant composite material with oligomeric silsesquioxane and graphene as the compound synergist combined with the monomolecular intumescent flame retardant has excellent flame retardant performance and is significantly higher than that of the same kind. Mechanical properties of flame retardant composites. In the preferred technical solution of the present invention, the limiting oxygen index of the prepared flame-retardant polypropylene composite material reaches 34.5%, the flame-retardant grade reaches 1.6mm UL-94V-0 level, the tensile strength reaches 34.6Mpa, and the impact strength reaches 3.82kJ/ m ² , and the added amount of intumescent flame retardant is reduced to less than 20%.

The technical solution of the present invention has the following beneficial effects:

(1) The present invention selects graphene and oligomeric silsesquioxane as a composite synergist, and there is a good synergistic flame retardant effect between the monomolecular intumescent flame retardant (RA-IFR), graphene, POSS Mainly by improving the quality of the condensed phase intumescent carbon layer, enhancing the flame retardant effect of the condensed phase carbon layer, effectively preventing the transfer of heat and oxygen between the material degradation zone and the combustion zone, thereby improving the flame retardant performance of the material and reducing the loss of flame retardants. The addition amount improves the mechanical properties of the composite material. Under the condition of the same vertical combustion UL-94V-0 level, in the preferred version of the present invention, the amount of raw material intumescent flame retardant is compared with the amount of intumescent flame retardant of similar products without adding oligomeric silsesquioxane Up to 35% reduction and up to 45% increase in tensile strength.

(2) The flame-retardant composite material obtained in the present invention has excellent flame-retardant performance. In the preferred solution, the prepared flame-retardant composite material can pass the vertical combustion test 1.6mm UL-94V-0 level, and the limiting oxygen index reaches 34.5%. The peak heat release rate and the total heat release were reduced by 72.8% and 30.1% respectively compared with pure polypropylene material.

(3) In the preparation method of the present invention, the disc-shaped mechanochemical reactor is selected to utilize the solid phase shearing milling technology to significantly improve the dispersibility and interfacial compatibility of the flame retardant in the polypropylene matrix, so that the flame retardant performance of the material and The mechanical properties and the like are better than those of the comparative examples.

(4) The preparation method of the graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material provided by the present invention has a simple process, a short flow process, and no three-waste pollution in the production process, and can be prepared as a high-performance flame-retardant polypropylene material New processing method.

Instructions attached

Fig. 1 is a comparison photo of carbon residue electron microscopy after the vertical combustion test of the halogen-free flame-retardant polypropylene composite material obtained in Comparative Example 7, Example 3, Example 5, and Example 4 of the present invention. Wherein, (a), (b), (c), (d) correspond to comparative example 7, embodiment 3, embodiment 5, embodiment 4 respectively, it can be clearly seen that in (b) (c) (d) The density of the carbon layer is significantly higher than that of the carbon layer in (a).

Fig. 2 is a comparison curve of carbon residue EDS of the halogen-free flame-retardant polypropylene composite material prepared in Example 3 and Example 5 of the present invention. Among them, (a) and (b) respectively correspond to Example 3 and Example 5. It can be seen from the figure that the content of C element on the surface of residual carbon in the composite material obtained in Example 3 is 77.5wt%, and the content of Si element is 15.5wt%. %, compared to the C and Si content on the surface of the carbon residue in Example 5, all increased.

Fig. 3 is a comparison electron microscope photograph of the quenched section of the sample of the halogen-free flame-retardant polypropylene composite material prepared in Comparative Example 4 and Example 3 of the present invention. Wherein, (a) and (b) respectively correspond to Comparative Example 4 and Example 3.

Detailed ways

The present invention will be further described below by way of embodiments and in conjunction with the accompanying drawings. It is worth noting that the given embodiments cannot be construed as limiting the protection scope of the present invention, and some non-essential improvements and adjustments made by those skilled in the art according to the content of the present invention should still belong to the protection scope of the present invention.

Among them, the ammonium polyphosphate is selected from high polymerization degree type II, the degree of polymerization n is ≥ 1000, and is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; the melamine is selected from industrial grade, with a net content of ≥ 98%, and is purchased from Chengdu Yulong Chemical Co., Ltd. Purchased; pentaerythritol selected industrial grade, net content ≥ 98%, purchased from Chengdu Kelong Reagent Co., Ltd.; graphene purchased from Changzhou Sixth Element Materials Technology Co., Ltd., brand SE1233; the polyvinyl silsesquioxane The alkane is octavinyl cage silsesquioxane, and its average particle size is 1-10nm.

Wherein, the monomolecular intumescent flame retardant RMAPP is obtained by the following preparation method:

Ammonium polyphosphate, melamine, and pentaerythritol were vacuum-dried at 90°C for 12 hours, then mixed evenly according to the mass ratio of ammonium polyphosphate and melamine at a ratio of 6:1, and then reacted at a high temperature of 260°C for 4 hours. After the reaction time was up, the reaction The final powder MAPP: Mix the powder MAPP and pentaerythritol at a mass ratio of 6:1, and then react at a high temperature of 230°C for 2 hours and then take it out to obtain the monomolecular intumescent flame retardant RMAPP.

The test conditions are as follows:

Oxygen index performance is tested according to GB/T 2406.2-2009 standard;

Vertical combustion performance is tested according to GB/T 2408-2008 standard;

Tensile performance is tested according to GB/T 1040.2-2006 standard.

Embodiment 1～6

Embodiments 1 to 6 of the present invention prepare materials according to the ratio of raw materials in the following table:

The raw material ratio of table 1 embodiment 1～6

After preparing the materials, Embodiments 1 to 6 were prepared according to the following steps:

Put the monomolecular intumescent flame retardant RMAPP, octavinyl cage silsesquioxane, and graphene in an oven at 90°C for half an hour, and take the dried RMAPP, octavinyl cage silsesquioxane, Graphene and polypropylene are added to the disc-shaped solid-phase force chemical reactor according to the ratio of the materials prepared in each embodiment, and solid-phase shearing and pulverizing are mixed 15 times at a speed of 220r/min to obtain a graphene/POSS composite synergistic halogen-free flame retardant Polypropylene mixture; put the obtained mixture into a twin-screw extruder, melt and extrude it at a rotation speed of 100r/min and an extrusion temperature of 190°C to obtain graphene/POSS composite synergistic halogen-free flame-retardant polypropylene The pellets of the composite material; the pellets of the obtained flame-retardant polypropylene composite material are injection-molded into standard test specimens by an injection molding machine, and the injection molding temperature is 195°C.

The standard test strips of the graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material obtained in Examples 1 to 6 were tested for performance, and the results were as follows:

The performance test result of the composite material of table 2 embodiment 1～6 gained

It can be clearly seen from the above table that the introduction of a small amount of graphene and POSS can significantly improve the flame retardancy of the composite flame-retardant polypropylene material. The results show that when the addition of graphene is 0.8wt%, the addition of POSS is 1%, RMAPP is At 18.5wt%, the limiting oxygen index of the prepared flame-retardant polypropylene material is 34.5%, and the 1.6mm vertical burning level is UL-94V0 level; in comparison, when the content of graphene and POSS continues to increase, the flame-retardant polypropylene material The flame retardant performance of the flame retardant material did not increase significantly, but decreased slightly, indicating that there is a synergistic flame retardant effect between RMAPP, POSS and graphene; at the same time, as the POSS and graphene content continued to increase, the mechanical properties of the flame retardant material decreased significantly. , indicating that there is an optimal synergistic range between POSS and graphene, and the flame-retardant polypropylene material prepared in this range can have excellent flame-retardant and mechanical properties at the same time. .

Example 7

The monomolecular intumescent flame retardant MPP used in this embodiment is the reference "Chen Y, WangQ.Reaction of Melamine Phosphate with Pentaerythritol and Its Product for Flame Retardation of Polypropylene.Polymers for Advanced Technologies.2007,18(8),587 -600" in the preparation method obtained.

(1) In parts by weight, the raw material components for preparing materials include:

(2) Dry the monomolecular intumescent flame retardant MPP, polyphenylsilsesquioxane, and graphene in an oven at 90°C for half an hour, and then dry the polypropylene, monomolecular intumescent flame retardant MPP, polyphenylene Base silsesquioxane and graphene were added into a disc-shaped mechanochemical reactor, solid-phase shearing pulverized and mixed 20 times at a rotational speed of 220r/min to obtain a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene mixture, The resulting mixture was added to a twin-screw extruder at a temperature of 190° C. to extrude and pelletize to obtain pellets of graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material.

The above-mentioned pellets were injection-molded into standard test specimens through an injection molding machine, and the injection molding temperature was 195°C. After testing, the vertical combustion performance of the sample reached 1.6mm UL94V-0 level, the limiting oxygen index (LOI) was 32.2%, the mechanical property tensile strength reached 25.7MPa, and the Charpy notched impact strength reached 2.16kJ/m ² .

Example 8

The monomolecular intumescent flame retardant DOPOMPC used in the present embodiment is reference " star-shaped monomolecular phosphorus nitrogen intumescent flame retardant application research in fireproof coating (Yang Shousheng. Coating Industry. 2014; 44 (11): 46-51.)" in the preparation method obtained.

(1) In parts by weight, the raw material components for preparing materials include:

(2) Dry the monomolecular intumescent flame retardant DOPOMPC, polytrimethylsilyl silsesquioxane and graphene in an oven at 90°C for half an hour, then dry polypropylene, monomolecular intumescent flame retardant DOPOMPC , polytrimethylsilyl silsesquioxane, and graphene were added to a disc-shaped mechanochemical reactor, and solid-phase shearing and pulverization were mixed 25 times at a speed of 300r/min to obtain a graphene/POSS composite synergistic halogen-free resistor. Combustible polypropylene mixture, adding the resulting mixture into a twin-screw extruder at a temperature of 180°C to extrude and pelletize to obtain pellets of graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material.

The above-mentioned pellets were injection-molded into standard test specimens through an injection molding machine, and the injection molding temperature was 195°C. After testing, the vertical combustion performance of the sample reached 1.6mm UL94V-0 level, the limiting oxygen index (LOI) was 33.9%, the mechanical property tensile strength reached 33.7MPa, and the Charpy notched impact strength reached 3.41kJ/m ² .

Example 9

The monomolecular intumescent flame retardant pentaerythritol dihydrogen phosphate melamine salt used in this example is the reference "Cao Shengchun, Jin Shengming, Tan Benzhu. Synthesis and performance research of new flame retardant pentaerythritol dihydrogen phosphate melamine salt. Hunan University Journal (Natural Science Edition), 2000,27(4):22-10." obtained by the preparation method.

(1) In parts by weight, the raw material components for preparing materials include:

(2) Put the monomolecular intumescent flame retardant pentaerythritol dihydrogen phosphate melamine salt, polyvinylsilsesquioxane, polymethylsilsesquioxane and graphene in an oven at 90°C for half an hour, Then polypropylene, monomolecular intumescent flame retardant pentaerythritol dihydrogen phosphate melamine salt, polyvinyl silsesquioxane, polymethyl silsesquioxane and graphene are added into the disc-shaped mechanochemical reactor, Solid-phase shear pulverization and mixing twice at a rotational speed of 60r/min to obtain a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene compound, which was added to a twin-screw extruder and extruded at a temperature of 195°C to produce Granules, that is, graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material pellets.

The above-mentioned pellets were injection-molded into standard test specimens through an injection molding machine, and the injection molding temperature was 195°C. After testing, the vertical combustion performance of the sample reached 1.6mm UL94V-0 level, the limiting oxygen index (LOI) was 32.8%, the mechanical property tensile strength reached 29.3MPa, and the Charpy notched impact strength reached 3.08kJ/m ² .

Example 10

The monomolecular intumescent flame retardant Melabis used in this embodiment is reference "Halpern Y, Mott DM, Niswander R H.Fire retardancy of thermoplastic materials by intumescence.Industrial&Engineering Chemistry Product Research&Development, 1984,23(2):233-238 Obtained by the preparation method in .”.

(1) In parts by weight, the raw material components for preparing materials include:

(2) Put the monomolecular intumescent flame retardant Melabis, polyphenylpropyl silsesquioxane, polydimethylsiloxane-phenyl silsesquioxane copolymer and graphene in an oven at 90°C After drying for half an hour, polypropylene, monomolecular intumescent flame retardant Melabis, polyphenylpropylsilsesquioxane, polydimethylsiloxane-phenylsilsesquioxane copolymer and graphene were added In a disc-shaped mechanochemical reactor, solid-phase shear pulverization and mixing 30 times at a rotational speed of 120r/min to obtain a graphene/POSS composite synergistic halogen-free flame-retardant polypropylene compound, and the resulting mixture was added to a twin-screw extruder Extrude and granulate at a temperature of 190°C to obtain pellets of graphene/POSS composite synergistic halogen-free flame-retardant polypropylene composite material.

The above-mentioned pellets were injection-molded into standard test specimens through an injection molding machine, and the injection molding temperature was 195°C. After testing, the vertical combustion performance of the sample reached 1.6mm UL94V-0 level, the limiting oxygen index (LOI) was 36.1%, the mechanical property tensile strength reached 33.9MPa, and the Charpy notched impact strength reached 3.44kJ/m ² .

Example 11

The monomolecular intumescent flame retardant TNGPA used in this example is the reference "Ou Yuxiang. The performance, synthesis and application of new phosphorus-nitrogen intumescent flame retardants. Jiangsu Chemical Industry, 1998 (3): 6-11." Obtained by the preparation method in.

(1) In parts by weight, the raw material components for preparing materials include:

(2) Dry the monomolecular intumescent flame retardant TNGPA, polyvinyl silsesquioxane, polyphenyl silsesquioxane and graphene in an oven at 90°C for half an hour, then dry the polypropylene, monomolecular The intumescent flame retardant TNGPA, polyvinyl silsesquioxane, polyphenyl silsesquioxane and graphene were added into a disc-shaped mechanochemical reactor, and solid-phase shearing pulverized and mixed 10 times at a speed of 200r/min , to obtain graphene/POSS composite synergistic halogen-free flame-retardant polypropylene mixture, and the obtained mixture was added to a twin-screw extruder at a temperature of 190°C to extrude and pelletize to obtain graphene/POSS composite synergistic halogen-free flame-retardant Combustion of pellets of polypropylene composites.

The above-mentioned pellets were injection-molded into standard test specimens through an injection molding machine, and the injection molding temperature was 195°C. After testing, the vertical combustion performance of the sample reached 1.6mm UL94V-0 level, the limiting oxygen index (LOI) was 35.6%, the mechanical property tensile strength reached 33.4MPa, and the Charpy notched impact strength reached 3.38kJ/m ² .

Comparative example 1-6

Comparative examples 1～6 of the present invention carry out raw material preparation according to the raw material proportioning in the following table:

Raw material proportioning of table 3 comparative examples 1～6

After preparing the materials, comparative examples 1 to 6 were prepared according to the following steps:

The monomolecular intumescent flame retardant RMAPP, octavinyl cage silsesquioxane and graphene were dried in an oven at 90°C for half an hour, and then polypropylene, monomolecular intumescent Flame retardant RMAPP, octavinyl cage silsesquioxane, and graphene are fully mixed in a high-speed mixer and then added to a twin-screw extruder, melted and extruded at a speed of 100r/min and an extrusion temperature of 190°C Pelletizing to obtain pellets of the flame-retardant polypropylene composite material; injecting the obtained pellets of the flame-retardant polypropylene composite material into a standard test sample by an injection molding machine, and the injection molding temperature is 195°C.

Performance tests were performed on the flame-retardant polypropylene composites obtained in Comparative Examples 1 to 6, and the results are shown in the following table:

The performance test results of the composite material obtained in Table 4 Comparative Examples 1 to 6

Comparing Table 2 and Table 4, it can be clearly seen that, under the premise of the same proportioning components, the resistance of the composite material samples obtained in Examples 1 to 4 of the technical solution of the present invention is adopted in Examples 1 to 4 and Comparative Examples 2 to 5. The combustion performance and mechanical strength are significantly higher than those of Comparative Examples 2-5, and the reasons are as follows:

Comparing the flame retardant polypropylene composite material prepared by solid phase shear milling technology with the above comparative example (flame retardant polypropylene composite material prepared by simple melt blending method), it is found that the former has significantly improved flame retardant properties and mechanical properties , due to the strong shear force of the disc-shaped solid-phase mechanochemical reactor, it can significantly improve the dispersion of the flame retardant in the matrix and improve the interfacial compatibility between the two. As in the accompanying drawing 3 of the description, (a) corresponding to the comparative example 4, the composite material obtained obviously shows agglomerated large-sized flame retardant mixture particles, and the interfacial compatibility is poor. This is because the shear force of the twin-screw extruder is relatively high Weak, the mixing effect is poor, and it is difficult to achieve a uniform dispersion of a flame retardant mixture with a certain polarity and containing nano-sized particles in the PP matrix resin. In comparison, the quenched surface of the composite material obtained in Example 3 corresponding to (b) is smoother, the size of the flame retardant particles is significantly reduced, and there is no agglomerated flame retardant particles, and most of them are covered by the matrix resin. Coated, flame retardant dispersion and interfacial compatibility are significantly improved. This is because under the action of strong extrusion and three-dimensional shear force field generated during the milling process of the disc-shaped mechanochemical reactor, both polypropylene and flame retardant are crushed strongly, and some flame retardant particles are even embedded in the polypropylene matrix. In the process, the polypropylene and the flame retardant and the components of the flame retardant mixture are fully mixed with each other, so the particles of the flame retardant mixture can be uniformly dispersed in the polypropylene matrix. This is also the fundamental reason why the flame retardant performance of milled polypropylene material is significantly higher than that of unmilled flame retardant polypropylene material.

Comparative Example 7

(1) In parts by weight, the raw material components for preparing materials include:

Polypropylene 80 parts,

Monomolecular intumescent flame retardant RMAPP 19.3 parts,

1 part of octavinyl cage silsesquioxane;

(2) Dry the monomolecular intumescent flame retardant RMAPP and octavinyl cage silsesquioxane in an oven at 90°C for half an hour, then dry polypropylene, monomolecular intumescent flame retardant RMAPP, octavinyl Cage-type silsesquioxane was added to a disc-shaped mechanochemical reactor, solid-phase shear pulverized and mixed 15 times at a rotational speed of 220r/min to obtain a flame-retardant polypropylene compound, and the resulting mixture was added to a twin-screw extruder Extrude and granulate at a temperature of 190°C to obtain pellets of the flame-retardant polypropylene composite material; inject the obtained pellets of the flame-retardant polypropylene composite material into standard test specimens by an injection molding machine at an injection molding temperature of 195°C.

The standard test sample of the flame-retardant polypropylene composite material obtained in this comparative example is subjected to a performance test, and the results are respectively that the limiting oxygen index is 28.9%, the vertical burning performance is 1.6mm UL94V-2 level, there is a droplet, and the tensile strength is 32.11 MPa, the impact strength is 3.34kJ/m ² .

Comparative Example 8

(1) In parts by weight, the raw material components for preparing materials include:

Polypropylene 80 parts,

Monomolecular intumescent flame retardant RMAPP 19.5 parts,

0.8 parts of graphene;

(2) Place the monomolecular intumescent flame retardant RMAPP and graphene in an oven at 90°C to dry for half an hour, then add polypropylene, monomolecular intumescent flame retardant RMAPP, and graphene into the disc-shaped mechanochemical reactor, Solid-phase shear pulverization and mixing 15 times at a rotational speed of 220r/min to obtain a flame-retardant polypropylene compound, which was added to a twin-screw extruder at a temperature of 190°C to extrude and granulate to obtain a flame-retardant polypropylene compound The pellets of the material; the pellets of the obtained flame-retardant polypropylene composite material are injection-molded into standard test specimens by an injection molding machine, and the injection molding temperature is 195°C.

The standard test sample of the flame-retardant polypropylene composite material obtained in this comparative example is subjected to a performance test, and the results are that the limiting oxygen index is 29.1%, the vertical burning performance is 1.6mm UL94V-2 level, there is a droplet, and the tensile strength is 29.67 MPa, the impact strength is 3.08kJ/m ² .

Comparative example 7, comparative example 8 gained test result are compared with embodiment 3, it can be clearly seen that the joint addition of POSS and graphene makes the flame retardant effect of the obtained composite material obviously improve, POSS and graphene both lack Either will make the flame retardant performance significantly reduced, on the one hand because of the lack of POSS/graphene composite synergistic effect, on the other hand because comparative example 7 and comparative example 8 have adopted low-expansion flame retardant the same as embodiment 3 The amount of agent added.

In addition, the flame retardant mechanism research shows that graphene and POSS can effectively prevent the transfer of heat and oxygen between the material degradation zone and the combustion zone by improving the quality of the condensed phase expanded carbon layer and enhancing the flame retardant effect of the condensed phase carbon layer. Improve the flame retardant performance of the material. As shown in Figure 1 of the description, (a) corresponds to the residual carbon electron microscope photo of the composite material made in Comparative Example 7 after the vertical combustion test. There are many cracks on the surface of the carbon layer, and the strength is low, so it cannot effectively prevent the matrix from agglomerating. Further degradation and combustion of propylene resin; (b) corresponding to the composite material obtained in Example 3, when the graphene addition was 0.8wt%, the density of the corresponding carbon layer was significantly improved. It can be seen that the addition of graphene effectively improves the quality of the condensed phase carbon layer of flame-retardant PP materials. The carbon layer is denser and the strength of the carbon layer is enhanced. flammability.

In order to further study the synergistic effect between RMAPP/POSS/GE, EDS analysis was carried out to the carbon residue of flame retardant material, the result is as shown in accompanying drawing 2 of description: It is obvious that after adding 0.8wt% graphene (GE) , the C element content of the carbon residue surface of the composite material obtained in Example 3 is 77.5wt%, and the Si element content is 15.5wt%. The C and Si contents on the carbon surface both decreased, indicating that the contents of amorphous carbon and SiO ₂ on the surface of the condensed phase carbon layer of the flame-retardant polypropylene composite sample decreased after further increasing the graphene content. The main reason involves two aspects. One is that the high content of GE is easy to agglomerate, which affects the uniform dispersion of the flame retardant mixture in the matrix resin. The condensed phase expansion carbon layer has many defects, and large pores are formed on the surface of the carbon layer. It is difficult to prevent the interpenetration between the flammable gas generated by the thermal decomposition of the matrix resin and the external oxygen, which reduces the flame retardant performance.

In summary, when the amount of POSS added is about 1wt%, and the amount of graphene (GE) added is about 0.8wt%, the flame retardancy and mechanical properties of the prepared flame retardant polypropylene composite material are optimal.

Claims (10)

1. a kind of compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS, it is characterised in that according to parts by weight, Raw material components include:

2. the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 1, it is characterised in that: The unimolecule expansion type flame retardant is unimolecule expansion type flame retardant RMAPP, unimolecule expansion type flame retardant MPP, unimolecule Two hydrogen ester melamine salt of expansion type flame retardant pentaerythrite diphosphate, unimolecule expansion type flame retardant Melabis, unimolecule are swollen Swollen type fire retardant TNGPA, unimolecule expansion type flame retardant DOPOMPC and unimolecule expansion type flame retardant PMPT are wherein any one Kind.

3. the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 2, it is characterised in that institute Stating unimolecule expansion type flame retardant RMAPP is to be obtained by following preparation methods:

Ammonium polyphosphate, melamine, pentaerythrite are first dried, are then (1.5 according to ammonium polyphosphate, melamine mass ratio ~6): 1 ratio is reacted 3~4 hours under 250~260 DEG C of high temperature after mixing, after the reaction time reaches, is reacted Powder MAPP afterwards；With mass ratio be 7:(0.5~1.5 by powder MAPP and pentaerythrite) ratio be uniformly mixed, then in It takes out after being reacted 1.5~2.5 hours under 225~235 DEG C of high temperature to get unimolecule expansion type flame retardant RMAPP.

4. the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 1, it is characterised in that: The oligomeric silsesquioxane is polyvinyl silsesquioxane, poly methyl silsesquioxane, polyphenylsilsesquioxane, poly- three Methyl-monosilane base silsesquioxane, polyphenylene propylsilsesquioxane and dimethyl silicone polymer-phenyl silsesquioxane copolymerization Any or combinations thereof object in object.

5. the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 1, it is characterised in that press Parts by weight meter, the raw material components include:

Or are as follows:

6. the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 1, it is characterised in that press Parts by weight meter, the raw material components include:

7. a kind of preparation method of the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS, it is characterised in that including Following steps:

(1) according to parts by weight, the raw material components of stock include:

(2) unimolecule expansion type flame retardant, oligomeric silsesquioxane and graphene are first dried, then by polypropylene, unimolecule Expansion type flame retardant, oligomeric silsesquioxane, graphene are added in pan type physico chemical reactor, in 50~300r/min of revolving speed Lower mixing oxides solid method mixes 2~30 times, the compound synergistic halogen-free polypropylene flame redardant mixture of graphene/POSS is obtained, by gained Mixture be added into double screw extruder in 180~195 DEG C of extruding pelletizations of temperature to get the compound synergistic of graphene/POSS without The material grain of halogen flame-retardant polypropylene composite material.

8. the preparation method of the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 7, Be characterized in that: the mixing oxides solid method mixes 10~20 times.

9. the preparation method of the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 7, It is characterized in that according to parts by weight, the raw material components of the stock include:

Or are as follows:

10. the preparation method of the compound synergistic halogen-free flame retardant polypropylene composite material of graphene/POSS according to claim 7, It is characterized in that according to parts by weight, the raw material components of the stock include: