CN104592717B - One inter-species acetylenylbenzene azo biphenyl type phenol formaldehyde foam and preparation method thereof - Google Patents

Abstract

The invention discloses a m-ethynylphenylazobiphenyl type phenolic foam and a preparation method thereof; the phenolic foam is composed of m-ethynylphenylazobiphenyl type phenolic resin, a solvent, a foaming agent and a fluorine-containing surfactant. Foaming and solidification; the preparation method is simple to operate, the reaction conditions are mild, and easy to control, which meets the requirements of industrial production; the obtained m-ethynylphenylazobiphenyl type phenolic foam has uniform cells, and has high heat resistance and resistance Combustibility, high carbon residual rate, low thermal conductivity and high compressive strength, etc., can be widely used in many fields such as aviation and aerospace.

Description

A kind of m-ethynyl phenylazobiphenyl type phenolic foam and its preparation method

technical field

The invention relates to a novel m-ethynylphenylazobiphenyl type phenolic foam and a preparation method thereof, belonging to the field of polymer foam materials.

Background technique

Since its inception, foam plastics have been widely used in industry, agriculture, construction, transportation, aerospace and other fields due to their excellent properties such as low density, high specific strength, heat insulation and sound insulation. Many foam plastics can only be used in the range of 0-150 °C, which cannot meet the performance requirements used in military fields such as aviation and aerospace, while high-temperature-resistant foam plastics can work continuously for a long time at high temperatures above 200 °C, and some instantaneous Heat resistance up to 540°C. Due to its outstanding heat resistance and low thermal conductivity, high temperature resistant foam plastics have become one of the research directions for high performance foam plastics.

Phenolic foam is obtained by foaming and curing with phenolic resin as the matrix, and is known as the "king of heat preservation". Among many foam plastics, phenolic foam has been widely valued for its advantages of heat resistance, low thermal conductivity, flame retardant and self-extinguishing, low smoke, resistance to flame penetration, no spillage in case of fire, and low price. In recent years, with the continuous improvement of thermal stability and flame resistance requirements for synthetic foam plastics in high-rise buildings, transportation, ships, aerospace and other fields, the development of phenolic foam has become more rapid.

However, due to its inherent defects, such as brittleness, poor thermal stability, low temperature for long-term use, and the need for catalysts during foaming and curing, traditional phenolic foams are difficult to meet higher performance requirements. Therefore, the design and preparation of new high-performance special phenolic foams, especially phenolic foams with high temperature resistance, ablation resistance, low thermal conductivity, high flame retardancy and certain mechanical strength, has become one of the important research directions for high performance phenolic foams.

Contents of the invention

The present invention aims at the defects of the traditional phenolic foam in the prior art, and aims to provide a foam with uniform cells, high heat resistance and flame retardancy, high carbon residual rate, low thermal conductivity and strong compression High-strength m-ethynyl phenylazobiphenyl type phenolic foam, which can be widely used in many fields such as aviation and aerospace.

Another object of the present invention is to provide a method for preparing the m-ethynylphenylazobiphenyl type phenolic foam with simple process, mild reaction conditions and easy control.

The invention provides a m-ethynylphenylazobiphenyl type phenolic foam, which is obtained by foaming and curing the following components in parts by mass: m-ethynylphenylazobiphenyl 100 parts of type phenolic resin, 10 to 59 parts of solvent, 1 to 28 parts of foaming agent, and 2 to 18 parts of surfactant. The m-ethynylphenylazobiphenyl type phenolic resin has the structure of formula 1:

Among them, the molecular weight is between 495 and 10,000.

The m-ethynyl phenylazobiphenyl type phenolic foam of the present invention also includes the following preferred options:

The preferred m-ethynyl phenylazobiphenyl type phenolic foam is passed through by 100 parts of m-ethynyl phenylazobiphenyl type phenolic resin, 18-52 parts of solvent, 5-24 parts of blowing agent, and 4-16 parts of surfactant Foaming and curing are obtained.

In a preferred solution, the foaming agent is at least one of 4,4'-oxobisbenzenesulfonyl hydrazide, azodicarbonamide, and N,N-dinitrosopentamethylenetetramine.

In a preferred solution, the solvent is at least one of acetone, butanone, N,N-dimethylformamide, and tetrahydrofuran.

The fluorine-containing surfactant of the present invention is branched-chain perfluoroalkyl polyoxyethylene ether nonionic surfactant FY-F501 or H30. It can be purchased from manufacturers such as Guangzhou Fluorine Silicon Technology Co., Ltd. or Zichuan Huahai Chemical Factory in Zibo City.

The present invention also provides a preparation method of the m-ethynyl phenylazobiphenyl type phenolic foam, which comprises the following steps: m-ethynyl phenylazobiphenyl type phenolic resin, surfactant, solvent and foaming After the agent is mixed evenly, put it into a mold, and foam and solidify at a temperature of 100-250°C.

The preparation method of the m-ethynylphenylazobiphenyl type phenolic foam of the present invention also includes the following preferred schemes:

In a preferred solution, the initial foaming temperature is 100-160°C; most preferably 120-150°C.

In a preferred solution, the initial foaming temperature is maintained for 10 to 60 minutes; most preferably 15 to 50 minutes.

In the preferred solution, the mold is an open or capped and sealed type.

The m-ethynyl phenylazobiphenyl type phenolic resin of the present invention is prepared by the following method:

Step 1: Slowly add m-aminophenylacetylene dropwise into 12-18wt% hydrochloric acid solution, cool down to -5-0°C, then slowly add 30-40wt% sodium nitrite solution dropwise into the hydrochloric acid solution, After the dropwise addition, react at 0-2°C for 1.0-2.5 hours to obtain m-ethynylphenyldiazonium salt solution;

Step 2: Under the catalysis of Friedel-Crafts catalyst, phenol and 4,4'-dichloromethylbiphenyl are subjected to Friedel-Crafts reaction at 80-110°C to obtain biphenyl-type phenolic resin; the obtained biphenyl-type phenolic resin is mixed with The m-alkynyl phenyl diazonium salt is subjected to a coupling reaction in an alkaline solution at a temperature not higher than 0° C. to obtain a m-ethynyl phenylazobiphenyl type phenolic resin.

Wherein, the molar ratio of the intermediate aminophenylacetylene to sodium nitrite in step 1 is 1:0.9-1.3. The molar ratio of m-aminophenylacetylene to hydrochloric acid is 1:2~5. The Friedel-Crafts reaction in step 2 takes 2 to 7 hours. The coupling reaction takes 4 to 7 hours. The molar ratio of phenol to 4,4'-dichloromethylbiphenyl is 2-11:1. The mass ratio of m-aminophenylacetylene to biphenyl phenolic resin is 0.9-1.7:1.

Beneficial effects of the present invention: In the present invention, a m-ethynyl phenylazobiphenyl type phenolic resin with a novel structure is used for the foaming formula for the first time, and the m-ethynyl phenylazobiphenyl type phenolic resin is used at a relatively low temperature It can self-cure, and has good heat resistance and high carbon residue rate. The m-ethynyl phenylazobiphenyl type phenolic resin is combined with a suitable proportion of fluorine-containing surfactant, solvent and blowing agent to prepare a foam with a density of 100-450Kg/ ^m3 under appropriate conditions, and the foam foam The pores are relatively uniform, and the particle size is between 100 and 900 μm. At the same time, the foam has the characteristics of high heat resistance, high flame retardancy, high carbon residue rate, low thermal conductivity and high compressive strength, and can be widely used in Aviation, aerospace, launch vehicle and many other fields. The m-ethynylphenylazobiphenyl type phenolic resin foam preparation method of the present invention has simple process, easy controllable reaction conditions, and is suitable for large-scale popularization and application.

Description of drawings

[Fig. 1] is the FT-IR spectrogram of the biphenyl type phenolic resin BN prepared in Example 1 and the m-ethynyl phenylazo biphenyl type phenolic resin EPABN.

[Fig. 2] is the GPC figure of the m-ethynylphenylazobiphenyl type phenolic resin EPABN prepared in Example 1.

[Fig. 3] is the SEM figure of the m-ethynyl phenylazobiphenyl type phenolic resin foam obtained in Example 1.

[Fig. 4] is the TGA figure of the m-ethynylphenylazobiphenyl type phenolic resin foam that embodiment 1 makes.

detailed description

The following examples are intended to further illustrate the content of the present invention, but not to limit the protection scope of the present invention.

The measurement methods used to measure the physical and chemical properties of m-ethynylphenylazobiphenyl type phenolic foams in the examples.

Determination of apparent density: Measured according to standard ASTMD1662.

Compressive strength: Tested according to GJB1585A-2004, the shape of the sample is a cylinder, and the size is Φ25mm×30mm.

Thermal conductivity test: test according to GB 3399-82, the shape of the sample is a cylinder, and the size is Φ28mm×9mm.

Critical oxygen index test: test according to GB/T2406.2-2009.

Example 1

Step (1): Weigh 20.20g of 4,4'-dichloromethylbiphenyl, 2.24g of methanol, 38.77g of phenol, and 2.25g of concentrated hydrochloric acid, and put them into a 250mL four- In the flask, stir and raise the temperature to 90°C, and reflux at this temperature for 5h. After the reaction, the temperature was raised to 180°C for distillation under reduced pressure, and then the light yellow biphenyl phenolic resin was obtained after cooling. The FT-IR diagram of the biphenyl phenolic resin structure is shown in Figure 1.

Step (2): Measure 99.30g of 15% hydrochloric acid solution, put it into a 250mL four-necked flask with a mechanical stirring device, a condenser and a thermometer, weigh 18.75g of 3-aminophenylacetylene, and drop into the acid solution drop by drop In the process, a milky slurry was formed, and after the dropwise addition was completed, the system was cooled to -5°C. Weigh 11.39g of sodium nitrite, dissolve it in 21.15g of distilled water, and make it into a 35% NaNO ₂ aqueous solution, then add dropwise into the above milky slurry, stir well, and react at 0°C for 1.5h after the dropwise addition, and add an appropriate amount of Urea, and then filtered to obtain brown-red transparent diazonium salt solution. The product is stored at low temperature and can be used as it is made.

Step (3): Measure 135mL of absolute ethanol, put it into a 250mL four-necked flask with a mechanical stirring device, a condenser tube and a thermometer, add 15g of biphenyl phenolic novolac synthesized, 14.03g of sodium hydroxide, mechanically stir, wait After the biphenyl phenolic resin is dissolved, cool down to 0°C, add the synthesized diazonium salt solution drop by drop, and react at 0°C for 5 hours. After the reaction is complete, acid solution is added to adjust the pH to 7, the product is precipitated, filtered with suction, washed, and dried in a vacuum oven at 60° C. for 10 h to obtain a brown-red powder. The number average molecular weight of the prepared m-ethynylphenylazobiphenyl type phenolic resin (EPABN) is 1656.

Step (4): Weigh 8g of m-ethynylphenylazobiphenyl phenolic resin, 0.64g of FY-F501, 3mL of N,N-dimethylformamide and 1.44g of azodicarbonamide, mix them evenly, and put them into the opening Seal the mold, foam and solidify at 125°C/0.7h+150°C/1h+170°C/1h+190°C/4h+210°C/1h+225°C/4h°C to obtain m-ethynylphenylazobiphenyl novolac Resin foam.

The foam density of the obtained m-ethynyl phenylazobiphenyl type phenolic resin is 115Kg/m ³ , the carbon residue rate can reach 62% in a nitrogen atmosphere at 1000°C, the decomposition temperature of 5% thermal weight loss is 457°C, and the compressive strength is 0.553Mpa. The oxygen index is 42, and the thermal conductivity is 0.059W·m ^-1 ·K ^-1 .

Example 2

Prepare foam with the m-ethynyl phenyl azo biphenyl type phenolic resin that embodiment 1 makes:

Weigh 3g of m-ethynylphenylazobiphenyl type phenolic resin, 0.24g of H30, 1.1mL of N,N-dimethylformamide and 0.54g of azodicarbonamide, mix them evenly, put them into a closed and sealed mold, and ℃/0.5h+150℃/1h+170℃/1h+190℃/4h+210℃/1h+225℃/4h under foaming and curing molding to obtain m-ethynyl phenyl azobiphenyl type phenolic resin foam.

The obtained m-ethynyl phenylazo biphenyl type phenolic resin foam has a density of 190Kg/m ³ , a carbon residue rate of 62% in a nitrogen atmosphere at 1000°C, a 5% thermal weight loss decomposition temperature of 457°C, and a compressive strength of 1.537Mpa. The oxygen index is 45, and the thermal conductivity is 0.065W·m ^-1 ·K ^-1 .

Example 3

Step (1): Weigh 20.20g of 4,4'-dichloromethylbiphenyl, 2.18g of methanol, 15.14g of phenol, and 2.52g of concentrated hydrochloric acid, and put them into a 250mL four- In a flask with nitrogen protection, stir and raise the temperature to 100°C, and reflux at this temperature for 6h. After the reaction is over, quickly heat up to 180°C for distillation under reduced pressure, remove while hot, and cool to obtain light yellow biphenyl phenolic resin.

Step (2): Measure 119.16g of 15% hydrochloric acid solution, put it into a 250mL four-neck flask with a mechanical stirring device, a condenser and a thermometer, weigh 22.5g of 3-aminophenylacetylene, and drop into the acid solution drop by drop In the process, a milky slurry was formed, and after the dropwise addition was completed, the system was cooled to -5°C. Weigh 13.52g of sodium nitrite, dissolve it in 31.55g of distilled water, then dropwise dropwise into the above milky slurry, stir thoroughly, and react at 0°C for 2.0h after the dropwise addition is completed, add an appropriate amount of urea after the reaction is complete, and then filter to obtain a brownish red color Transparent diazonium salt solution. The product is stored at low temperature and can be used as it is made.

Step (3): Measure 135mL of absolute ethanol, put it into a 250mL four-necked flask with a mechanical stirring device, a condenser tube and a thermometer, add 15g of synthesized biphenyl phenolic novolac, 16.02g of sodium hydroxide, mechanically stir, wait After the biphenyl phenolic resin is dissolved, cool down to 0°C, add the synthesized diazonium salt solution drop by drop, and react at 0°C for 6 hours. After the reaction is complete, acid solution is added to adjust the pH to 7, the product is precipitated, filtered with suction, washed, and dried in a vacuum oven at 60° C. for 10 h to obtain a brown-red powder. The number average molecular weight of the prepared m-ethynylphenylazobiphenyl type phenolic resin (EPABN) is 7035.

Step (4): Weigh 4g of m-ethynylphenylazobiphenyl phenolic resin, 0.40g of H30, 1.5mL of N,N-dimethylformamide and 0.64g of azodicarbonamide, mix them evenly, and put them into a closed seal Mold, foaming and curing at 125°C/0.5h+150°C/1h+170°C/1h+190°C/4h+210°C/1h+225°C/4h to obtain m-ethynylphenylazobiphenyl type phenolic resin Foam.

The foam density of the obtained m-ethynyl phenylazobiphenyl type phenolic resin is 280Kg/m ³ , the carbon residue rate can reach 63% in a nitrogen atmosphere of 1000°C, the decomposition temperature of 5% thermal weight loss is 457°C, and the compressive strength is 5.152Mpa. The oxygen index is 49, and the thermal conductivity is 0.073W·m ^-1 ·K ^-1 .

Example 4

Prepare foam with the m-ethynyl phenyl azo biphenyl type phenolic resin that embodiment 3 makes:

Weigh 5.5g of m-ethynylphenylazobiphenyl type phenolic resin, 0.66g of FY-F501, 2mL of N,N-dimethylformamide and 0.77g of azodicarbonamide, mix them evenly, put them into a closed mold, and Foaming and curing at 120°C/0.6h+150°C/1h+170°C/1h+190°C/4h+210°C/1h+225°C/4h to obtain m-ethynylphenylazobiphenyl type phenolic resin foam.

The foam density of the obtained m-ethynyl phenylazobiphenyl type phenolic resin is 353Kg/m ³ , the carbon residue rate can reach 63% in a nitrogen atmosphere at 1000°C, the decomposition temperature of 5% thermal weight loss is 457°C, and the compressive strength is 8.099Mpa. The oxygen index is 51, and the thermal conductivity is 0.084W·m ^-1 ·K ^-1 .

Claims (7)

1. a m-ethynyl phenylazo biphenyl type phenolic foam, is characterized in that, obtains by foaming solidification by following mass parts component: 100 parts of m-ethynyl phenylazobiphenyl type phenolic resin, 10-59 parts of solvent, Foaming agent 1～28 parts, 2 to 18 parts of fluorine-containing surfactants, The m-ethynyl phenylazobiphenyl type phenolic resin has a structure of formula 1: Among them, the molecular weight is between 495 and 10,000. 2. m-ethynyl phenylazobiphenyl type phenolic foam as claimed in claim 1, is characterized in that, by 100 parts of m-ethynyl phenylazobiphenyl type phenolic resins, 18～52 parts of solvents, foaming agent 5 ～24 parts and 4～16 parts of surfactant are obtained by foaming and curing. 3. m-ethynyl phenylazobiphenyl type phenolic foam as claimed in claim 2, is characterized in that, described foaming agent is 4,4 '-oxobisbenzenesulfonyl hydrazide, azodicarbonamide, At least one of N,N'-dinitrosopentamethylenetetramines. 4. m-ethynyl phenylazobiphenyl type phenolic foam as claimed in claim 2, is characterized in that, described solvent is at least in acetone, butanone, N, N'-dimethylformamide, tetrahydrofuran A sort of. 5. prepare the method for the described m-ethynyl phenylazobiphenyl type phenolic foam of any one of claim 1～4, it is characterized in that, m-ethynyl phenylazobiphenyl type phenolic resin, tensio-active agent, solvent After mixing evenly with the foaming agent, put it into a mold, foam and solidify at a temperature of 100-250°C. 6. The method according to claim 5, characterized in that the initial foaming temperature is 100-160°C. 7. The method according to claim 6, characterized in that the initial foaming temperature is maintained for 10 to 60 minutes.