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Preparation methods of SiO2 nano particle modified expandable graphite and flame retardant polypropylene

A flame-retardant polypropylene and expanded graphite technology, which is applied in the field of expandable graphite modification technology and the preparation of flame-retardant polypropylene, can solve the problem of poor compatibility between expandable graphite and a polymer matrix, and deterioration of the mechanical properties of the polymer matrix. , the carbon layer structure is easy to fall off, etc., to achieve the effect of inhibiting the popcorn effect, inhibiting thermal decomposition and thermal stability

Active Publication Date: 2018-08-17
SOUTHWEST JIAOTONG UNIV +1
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Polypropylene is a typical general-purpose plastic, with large output, wide application and low price; in terms of performance, it has excellent electrical insulation and chemical corrosion resistance, the highest mechanical properties and heat resistance among general-purpose plastics, and good fatigue resistance. In terms of processing and molding, its processing performance is excellent; however, polypropylene is extremely flammable, and its limiting oxygen index is only 17.4%. Applications in electrical and electronics, building materials and other fields
[0003] In order to improve the flame retardancy of polypropylene and maximize its performance during the period, there have been many studies in recent years. On the basis of halogen-free environmental protection, a relatively effective method is to add intumescent flame retardants; compared to traditional non-toxic Halogenated intumescent flame retardants, expandable graphite stands out as another class of intumescent flame retardants that, when in contact with a flame, rapidly expand into a swollen multi-voided "worm-like" structure; resulting in a polymer surface covered with a large Combustion residues, which can slow down the heat transfer properties and can interrupt the continued degradation of the polymer matrix; meanwhile, during the expansion of expandable graphite, CO 2 、H 2 O and SO 2 When the gases are released, they can dilute the concentration of combustible gases released in the flame zone; however, when expandable graphite is used as a flame retardant, the rapid reaction during the heat flow process leads to non-directional expansion, resulting in a loose carbon layer structure It is easy to fall off, that is, the "popcorn effect" is produced, resulting in low flame retardant efficiency; and the compatibility of expandable graphite with the polymer matrix is ​​not good, which seriously deteriorates the mechanical properties of the polymer matrix; in order to overcome its shortcomings, the researchers They have also adopted a variety of modification methods for expandable graphite. Although these methods have improved the flame retardant efficiency of expandable graphite and the compatibility of organic polymer materials to a certain extent, they have not yet effectively solved the problem. High loading when used as a flame retardant and low mechanical properties of flame retardant polymer composites

Method used

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  • Preparation methods of SiO2 nano particle modified expandable graphite and flame retardant polypropylene
  • Preparation methods of SiO2 nano particle modified expandable graphite and flame retardant polypropylene
  • Preparation methods of SiO2 nano particle modified expandable graphite and flame retardant polypropylene

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Embodiment 1

[0030] A SiO 2 A preparation method for nanoparticle modified expandable graphite, comprising the following steps:

[0031] Step 1: Add 100g of expandable graphite of 50 meshes to 240mL of ethanol aqueous solution with a water-alcohol volume ratio of 1:5; disperse through an ultrasonic instrument for about 10 minutes, and then add it to a 250mL container with a reflux condensing device, a thermometer and a stirrer In a three-necked flask; the three-necked flask is heated while stirring in a water bath, heated to 45°C, slowly dripping ammonia water with a rubber dropper to adjust the pH of the solution to 8-9, and an expandable graphite suspension is obtained.

[0032] Step 2: Slowly add 5mL of tetraethyl orthosilicate dropwise to the expandable graphite suspension obtained in step 1 with a rubber dropper, and stir evenly under the conditions of stirring temperature of 45°C and stirring speed of 350r / min Reaction 6h.

[0033] Step 3: After the reaction in step 2 is complete, ...

Embodiment 2

[0037] A SiO 2 A preparation method for nanoparticle modified expandable graphite, comprising the following steps:

[0038] Step 1: Add 150g of expandable graphite of 50 meshes to 300mL of ethanol aqueous solution formed with a water-alcohol volume ratio of 1:5; disperse through an ultrasonic instrument for about 20 minutes, and then add it to a 250mL container with a reflux condensing device, a thermometer and a stirrer In a three-necked flask; the three-necked flask is heated while stirring in a water bath, heated to 40°C, slowly dripping ammonia water with a rubber dropper to adjust the pH of the solution to 7-8, and an expandable graphite suspension is obtained.

[0039] Step 2: Slowly add 8mL of tetraethyl orthosilicate dropwise to the expandable graphite suspension obtained in step 1 with a rubber dropper, and stir evenly under the condition of stirring temperature of 40°C and stirring speed of 350r / min Reaction 8h.

[0040] Step 3: After the reaction in step 2 is comp...

Embodiment 3

[0044] A SiO 2 A preparation method for nanoparticle modified expandable graphite, comprising the following steps:

[0045] Step 1: Add 150g of expandable graphite of 50 meshes to 300mL of ethanol aqueous solution with a water-alcohol volume ratio of 1:5; disperse through an ultrasonic instrument for about 30 minutes, and then add it to a 250mL container with a reflux condensing device, a thermometer and a stirrer In a three-necked flask; the three-necked flask is heated while stirring in a water bath, heated to 45°C, slowly dripping ammonia water with a rubber dropper to adjust the pH of the solution to 8-9, and an expandable graphite suspension is obtained.

[0046] Step 2: Divide 8mL of tetraethyl orthosilicate into four parts, and slowly add one part of tetraethyl orthosilicate to the expandable graphite suspension obtained in step 1 at regular intervals; Before the second dropwise addition, adjust the pH to 8-9 until the addition is complete. Under the condition of stirr...

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Abstract

The invention discloses preparation methods of SiO2 nano particle modified expandable graphite and flame retardant polypropylene. The preparation method of the SiO2 nano particle modified expandable graphite comprises the following steps of step 1, adding expandable graphite into an ethanol aqueous solution, performing dispersion to form a suspension, regulating the pH value of the suspension to be 7-9 to obtain an expandable graphite suspension; step 2, slowly dropwise adding tetraethyl orthosilicate into the expandable graphite suspension obtained in the step 1 for reaction; and step 3, performing pumping filtration after reaction is complete, performing washing until a filtrate is neutral, and performing drying to obtain the SiO2 nano particle modified expandable graphite. The preparation method of the flame retardant polypropylene comprises the following steps of adopting polypropylene particles and an SiO2 nano particle modified expandable graphite flame retardant with the mass ratio of 8 to 2, performing melt blending, extruding pelletizing and injection moulding to obtain a halogen-free flame retardant polypropylene composite. The prepared flame retardant polypropylene composite is remarkably improved in flame retardant property, heat stability, carbon formation ability, impact property, tensile strength and the like and has the advantages of no halogen, low smoke, nontoxicity, corrosion resistance and the like.

Description

technical field [0001] The invention relates to an expandable graphite modification technology and a preparation method of flame-retardant polypropylene, in particular to a SiO 2 The invention discloses a preparation method of nano particle modified expandable graphite and flame retardant polypropylene. Background technique [0002] Polypropylene is a typical general-purpose plastic, with large output, wide application and low price; in terms of performance, it has excellent electrical insulation and chemical corrosion resistance, the highest mechanical properties and heat resistance among general-purpose plastics, and good fatigue resistance. In terms of processing and molding, its processing performance is excellent; however, polypropylene is extremely flammable, and its limiting oxygen index is only 17.4%. Applications in electrical and electronics, building materials and other fields. [0003] In order to improve the flame retardancy of polypropylene and maximize its p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L23/12C08K9/02C08K3/36C08K7/24
CPCC08K3/36C08K7/24C08K9/02C08K2201/011C08L2201/02C08L2201/08C08L2201/22C08L2205/24C08L23/12
Inventor 陈晓浪王娜李灵通刘念吴一帆张鲲
Owner SOUTHWEST JIAOTONG UNIV
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