CN109400880B - Methyl vinyl phenyl silicone rubber with high phenyl content and high vinyl content and preparation method thereof - Google Patents

Abstract

The invention discloses methyl vinyl phenyl silicone rubber with high phenyl content and high vinyl content and a preparation method thereof. The structural formula of the silicone rubber is as follows:

the molar ratio of x, y and z is (40-85): (10-40): (5-30). The methyl vinyl phenyl silicone rubber prepared by the invention has high phenyl content and vinyl content, the phenyl content can reach 30 percent, the vinyl content can reach 40 percent, and the molecular weight is more than 30 ten thousand. Subsequently, the vinyl group is successfully converted into the epoxy group, and the epoxy conversion rate can reach more than 90%.

Description

A kind of methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content and preparation method

technical field

The invention relates to the technical field of rubber, and more particularly, to a methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content and a preparation method.

Background technique

Phenyl silicone rubber is a main variety of silicone rubber. In addition to the weather resistance, dielectric properties and physiological inertia of general silicone rubber, it also has excellent cold resistance, radiation resistance and flame retardant properties. It is a modern technology. Indispensable elastic materials, mainly used in the manufacture of rubber products and bonding materials for shock absorption, sealing, heat insulation, electrical insulation and elastic bonding

At present, the phenyl content of phenyl silicone rubber on the market is about 15%, and the vinyl content is less than 1%. The current research basis shows that the introduction of phenyl segments can improve the rigidity of the molecular chain of silicone rubber, increase the glass transition temperature, and improve the heat resistance and radiation resistance of silicone rubber products; while the introduction of epoxidized groups can destroy silicon The low-temperature crystallization of rubber improves the polarity and rigidity of the molecular chain of silicone rubber, and improves the oil resistance and hydrophilic properties of silicone rubber, thereby improving the macromolecular chain and high surface energy nanoparticles (such as modified silica, carbon nanotubes, etc.) The interaction between them improves the dispersibility of nanoparticles.

The vinyl content of the existing phenyl silicone rubber is low, because the silicone rubber with a high vinyl content is easily cross-linked during the synthesis process, so it is difficult to prepare the phenyl silicone rubber with a high vinyl content.

SUMMARY OF THE INVENTION

In order to solve the problems in the prior art, the present invention provides a methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content and a preparation method. The methyl vinyl phenyl silicone rubber prepared by the invention has relatively high phenyl content and vinyl content, the phenyl content can reach 30%, the vinyl content can reach 40%, and the molecular weight is more than 300,000. Subsequently, vinyl groups were successfully converted into epoxy groups, and the epoxy conversion rate could reach more than 90%.

One of the objectives of the present invention is to provide a methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content.

The structural formula of the silicone rubber is:

The molar ratio of x:y:z is (40～85):(10～40):(5～30);

Preferably, the molar ratio of x:y:z is (60-80):(10-20):(10-20).

The second purpose of the present invention is to provide a preparation method of methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content.

include:

(1) Add octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane into the reaction flask, vacuumize and dehydrate, then add catalyst alkali glue and capping agent decamethyltetrasiloxane under nitrogen protection Oxane, finally adding octaphenyl cyclotetrasiloxane, vacuum dehydration; among them, octamethyl cyclotetrasiloxane, tetramethyl tetravinyl cyclotetrasiloxane, octaphenyl cyclotetrasiloxane , the molar ratio range of alkali glue and end-capping agent is (40-85): (10-40): (5-30): (0.02-0.05): (0.04-0.08);

(2) carry out the polymerization reaction under the protection of normal pressure nitrogen;

(3) Destroy the catalyst at 140℃～160℃;

(4) Remove unreacted monomers.

Among them, preferably:

In step (1), the vacuum degree of dehydration is -0.1～-0.09, the dehydration temperature is 45°C～50°C, and the total dehydration time is 1～2 hours.

In step (2), the polymerization temperature is 100-120° C., and the polymerization time is 1-3 hours.

In step (4), the degree of vacuum to be removed is -0.1 to -0.09, the temperature is 170°C to 190°C, and the time is 2 to 4 hours.

Specifically, the following steps can be taken:

(1) Add octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane into the reaction flask, vacuumize and remove water at 45-50°C for 1 hour, and then add catalyst alkali glue under nitrogen protection and end-capping agent decamethyltetrasiloxane, finally adding octaphenylcyclotetrasiloxane; vacuuming and removing water at 45-50°C for 1 hour;

(2) Under normal pressure nitrogen protection, react at 110～120 ℃ for 2.5 hours;

(3) then destroy the catalyst at 160°C;

(4) Finally, unreacted monomers were removed at 180°C for 3 hours.

The third object of the present invention is to provide an epoxidized methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content.

The structural formula is:

The molar ratio of x:y:z is (40-85):(10-40):(5-30).

The preparation method of epoxidized methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content includes:

The epoxidized silicone rubber is prepared from methyl vinyl phenyl silicone rubber through an epoxidation reaction.

Specifically include the following steps:

(1) Add chloroform and methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content to a round-bottomed flask (1L or 2L) or a 10L glass reactor equipped with magnetic stirring, and control the system through a water bath. The temperature is 25°C, and the stirring rate of the system is controlled;

(2) after the silicone rubber is completely dissolved, add m-chloroperoxybenzoic acid (m-CPBA) to start the reaction;

(3) Precipitate with methanol after a period of time, wash 2 to 3 times, put it in a vacuum oven to dry for 12 hours, and take it out for use.

The methyl vinyl phenyl silicone rubber prepared by the invention has relatively high phenyl content and vinyl content, the phenyl content can reach 30%, the vinyl content can reach 40%, and the molecular weight is more than 300,000. Subsequently, vinyl groups were successfully converted into epoxy groups, and the epoxy conversion rate could reach more than 90%.

The high vinyl content can be used for epoxidation modification research. The introduction of epoxidized functional groups can also give ESiR a better interface interaction with fumed silica and improve its physical and mechanical properties. Most importantly, with the increase of the degree of epoxidation, the Tg of ESiR moves to the high temperature direction, which can effectively improve the damping performance of silicone rubber.

The phenyl content is high, and the introduction of phenyl segments can improve the rigidity of the silicone rubber molecular chain, increase the glass transition temperature, and improve the heat resistance and radiation resistance of silicone rubber products.

The vinyl content of phenyl silicone rubber in the prior art is low, less than 1%, and it is difficult to carry out epoxidation modification. Oxygen groups, even if introduced, are ineffective at very low levels. However, the synthesized phenyl silicone rubber has a high vinyl content, and the epoxy group content that can be introduced by epoxidation modification is also relatively high.

Description of drawings

Fig. 1 Comparison of the thermogravimetric curves of the existing and the present synthetic phenyl silicone rubber.

Detailed ways

Below in conjunction with embodiment, the present invention is further described.

Example 1

85mol of octamethylcyclotetrasiloxane and 10mol of tetramethyltetravinylcyclotetrasiloxane were added to the reaction flask, and the water was removed by vacuum at 45 ° C for 1 hour, and then 0.02mol of catalyst alkali glue and 0.04mol of decamethyltetrasiloxane as the end-capping agent, finally added 5mol of octaphenylcyclotetrasiloxane, vacuumed to remove water at 46°C for 1 hour, and the vacuum degree was controlled to -0.09; The reaction was carried out at °C for 3 hours; then the catalyst was destroyed at 160 °C; finally, the unreacted monomer was removed by vacuuming at 170 °C for 2 hours, and the vacuum degree was controlled to -0.1.

To the round-bottomed flask (250ml) equipped with magnetic stirring, add 175ml of chloroform and 5.25g of synthesized methylvinylphenyl silicone rubber, control the temperature of the system to be 25°C by a water bath, control the stirring rate of the system, and wait until After the silicone rubber was completely dissolved, 2.35 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction. After 96 hours, it was precipitated with methanol, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

Example 2

Add 75mol octamethylcyclotetrasiloxane and 15mol tetramethyltetravinylcyclotetrasiloxane into the reaction flask, vacuumize and remove water at 48°C for half an hour, then add 0.03mol catalyst alkali glue under nitrogen protection and 0.05mol of decamethyltetrasiloxane, finally adding 10mol of octaphenylcyclotetrasiloxane, and vacuuming to remove water at 47°C for 1 hour, and controlling the vacuum degree to be -0.09; The reaction was carried out at 120 °C for 1 hour; then the catalyst was destroyed at 160 °C; finally, the unreacted monomer was evacuated at 170 °C for 3 hours, and the vacuum degree was controlled to be -0.09.

To the round-bottomed flask (250ml) equipped with magnetic stirring, add 175ml of chloroform and 5.25g of synthesized methylvinylphenyl silicone rubber, control the temperature of the system to be 25°C by a water bath, control the stirring rate of the system, and wait until After the silicone rubber was completely dissolved, 3.14 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction. After 96 hours, it was precipitated with methanol, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

Example 3

Add 65mol octamethylcyclotetrasiloxane and 20mol tetramethyltetravinylcyclotetrasiloxane into the reaction flask, vacuumize and remove water at 50°C for half an hour, and then add 0.035 catalyst alkali glue and 0.07% nitrogen under nitrogen protection. mol end capping agent decamethyltetrasiloxane, finally add 15mol octaphenylcyclotetrasiloxane, vacuumize and remove water at 50℃ for half an hour, control the vacuum degree to -0.092; Then, the catalyst was destroyed at 160 °C for 2.5 hours; finally, the unreacted monomer was removed by vacuuming at 180 °C for 2.5 hours, and the vacuum degree was controlled to be -0.096.

Add 525ml of chloroform and 15.75g of synthetically obtained methylvinylphenyl silicone rubber to a round-bottomed flask (100ml) equipped with magnetic stirring, control the temperature of the system to be 25°C by a water bath, and control the stirring rate of the system. After the silicone rubber was completely dissolved, 11.79 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction, precipitated with methanol for 96 hours, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

Example 4

40mol of octamethylcyclotetrasiloxane and 40mol of tetramethyltetravinylcyclotetrasiloxane were added to the reaction flask, vacuumed to remove water at 49 ° C for 1 hour, and then 0.035mol of catalyst alkali glue and 0.055mol of decamethyltetrasiloxane, the end-capping agent, and finally 20mol of octaphenylcyclotetrasiloxane were added, and the water was removed by vacuuming at 49°C for half an hour, and the vacuum degree was controlled to -0.096; The reaction was carried out at °C for 1.5 hours; then the catalyst was destroyed at 160 °C; finally, the unreacted monomer was removed by vacuuming at 190 °C for 3.5 hours, and the vacuum degree was controlled to -0.1.

To the round-bottomed flask (2000ml) equipped with magnetic stirring, add 1400ml of chloroform and 42g of the synthesized methylvinylphenyl silicone rubber, control the temperature of the system to be 25°C through a water bath, control the stirring rate of the system, and wait until the silicon After the rubber was completely dissolved, 18.84 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction. After 96 hours, it was precipitated with methanol, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

Example 5

70mol octamethylcyclotetrasiloxane and 10mol tetramethyltetravinylcyclotetrasiloxane were added to the reaction flask, and the water was removed by vacuum at 46 ° C for 1 hour, and then 0.05mol catalyst alkali glue and 0.08mol of decamethyltetrasiloxane as the end-capping agent, finally added 20mol of octaphenylcyclotetrasiloxane, vacuumed to remove water at 46°C for 1 hour, and the vacuum degree was controlled to -0.098; The reaction was carried out at °C for 2 hours; then the catalyst was destroyed at 160 °C; finally, the unreacted monomer was removed by vacuuming at 190 °C for 4 hours, and the vacuum degree was controlled to be -0.09.

To the round bottom flask (1000ml) equipped with magnetic stirring, add 700ml of chloroform and 21g of synthesized methylvinylphenyl silicone rubber, control the temperature of the system to be 25°C through a water bath, control the stirring rate of the system, wait for the silicon After the rubber was completely dissolved, 18.84 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction. After 96 hours, it was precipitated with methanol, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

Example 6

60mol of octamethylcyclotetrasiloxane and 10mol of tetramethyltetravinylcyclotetrasiloxane were added to the reaction flask, vacuumed to remove water for 1 hour at 47°C, and then 0.035mol of catalyst alkali glue and 0.06mol decamethyltetrasiloxane, the end capping agent, finally added 30mol octaphenylcyclotetrasiloxane, vacuumed to remove water at 47°C for 1 hour, and the vacuum degree was controlled to -0.1; The reaction was carried out at °C for 3 hours; then the catalyst was destroyed at 160 °C; finally, the unreacted monomer was removed by vacuuming at 180 °C for 3.5 hours, and the vacuum degree was controlled to be -0.092.

To the round-bottomed flask (2000ml) equipped with magnetic stirring, add 1400ml of chloroform and 42g of the synthesized methylvinylphenyl silicone rubber, control the temperature of the system to be 25°C through a water bath, control the stirring rate of the system, and wait until the silicon After the rubber was completely dissolved, 22.21 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction. After 96 hours, it was precipitated with methanol, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

Example 7

60mol of octamethylcyclotetrasiloxane and 30mol of tetramethyltetravinylcyclotetrasiloxane were added to the reaction flask, vacuumed to remove water for 1 hour at 45°C, and then 0.03mol of catalyst alkali glue and 0.05mol of decamethyltetrasiloxane, the end-capping agent, and finally 10mol of octaphenylcyclotetrasiloxane were added, and the water was removed by vacuuming at 45°C for 1 hour, and the vacuum degree was controlled to -0.092; The reaction was carried out at °C for 2.5 hours; then the catalyst was destroyed at 160 °C; finally, the unreacted monomer was removed by vacuuming at 180 °C for 3 hours, and the vacuum degree was controlled to -0.1.

To the round bottom flask (1000ml) equipped with magnetic stirring, add 700ml of chloroform and 21g of synthesized methylvinylphenyl silicone rubber, control the temperature of the system to be 25°C through a water bath, control the stirring rate of the system, wait for the silicon After the rubber was completely dissolved, 14.64 g of m-chloroperoxybenzoic acid (m-CPBA) was added to start the reaction. After 96 hours, it was precipitated with methanol, washed 2 to 3 times, dried in a vacuum oven for 12 hours, and taken out for use.

The values of xyz for each embodiment are shown in Table 1.

Table 1

x y z Example 1 85 10 5 Example 2 75 15 10 Example 3 65 20 15 Example 4 40 40 20 Example 5 70 10 20 Example 6 60 10 30 Example 7 60 30 10

The product structural formula that each embodiment makes is:

Product performance test

1. Molecular weight determination of methyl vinyl phenyl silicone rubber

The molecular weight of silicone rubber was determined by gel permeation chromatography (GPC). GPC test sample preparation: Dissolve 0.003-0.005g of silicone rubber in 1ml of tetrahydrofuran solution, the concentration of the prepared solution is about 2-4mg/ml, remove the cross-linked molecular chain through a sieve and test to obtain the number average molecular weight of silicone rubber with different structures (Mn), weight average molecular weight (Mw) and molecular weight distribution index (PDI).

2. H NMR characterization of methyl vinyl phenyl silicone rubber

The ¹ H-NMR measurement of the polymer was carried out by using an AV300 nuclear magnetic resonance spectrometer (300 MHz) from Bruker. The vinyl content and phenyl content of the silicone rubber were calculated by NMR spectroscopy.

3. Thermogravimetric Analysis (TGA)

Thermogravimetric properties of silicone rubber were tested by a TGA/DSC synchronous thermal analyzer (model STARe system). During the test, the temperature was increased from 30°C to 800°C at 10°C/min under N2 atmosphere, and the TGA curve was obtained.

Example results are shown in Table 2:

Table 2

As can be seen from Table 2, the phenyl content and vinyl content of the methyl vinyl phenyl silicone rubber of the present invention are relatively high, the phenyl content can reach up to 30%, the vinyl content can reach 40%, and the molecular weight is also 30%. more than 10,000. The vinyl group is successfully converted into epoxy group by the direct method, and the epoxidation conversion can reach more than 90%.

table 3

Table 4

As can be seen from Table 3 and Table 4, the methyl vinyl phenyl silicone rubber synthesized by the present invention is compared with the phenyl silicone rubber sold in the market, when the phenyl content is the same, the introduction of vinyl makes methyl vinyl benzene The low-temperature crystallization performance of the base silicone rubber is limited, and its low-temperature use performance is improved, and the glass transition temperature (Tg) is slightly increased with the introduction of vinyl.

As can be seen from Table 4, the epoxidized methyl vinyl phenyl silicone rubber of the present invention is compared with the phenyl silicone rubber sold on the market, when the content of phenyl is the same, the glass transition temperature (Tg) varies with the epoxy group. The introduction has been significantly improved, from -105.88 °C to -89.55 °C, from below -100 °C to above -100 °C, and the use conditions move to high temperature.

Figure 1 is a comparison of the thermal weight loss curves of the existing phenyl silicone rubber and the methyl vinyl phenyl silicone rubber prepared in Example 2. It can be seen from the figure that epoxy groups are introduced into the silicone rubber structure. After that, its heat resistance has been greatly improved, and the thermal decomposition temperature in a nitrogen atmosphere has increased from 310 °C to 450 °C. This is because the silicone rubber is highly flexible and undergoes cyclic bite degradation under high temperature conditions. The introduction of epoxy groups can improve the rigidity of the main chain, so that the main chain of the silicone rubber is not easily twisted into rings, and the difficulty of cyclic degradation increases. Therefore, after epoxidizing the phenyl silicone rubber, the thermal stability is improved, that is, the heat resistance is further improved.

Claims (6)

1. a high phenyl high vinyl content methyl vinyl phenyl silicone rubber, is characterized in that: The structural formula of the silicone rubber is:

The molar ratio of x:y:z is (40-85):(10-40):(5-30). 2. the methyl vinyl phenyl silicone rubber of high phenyl high vinyl content as claimed in claim 1 is characterized in that: The molar ratio of x:y:z is (60-80):(10-20):(10-20). 3. a preparation method of the methyl vinyl phenyl silicone rubber of high phenyl high vinyl content as claimed in claim 1 or 2, is characterized in that described method comprises: (1) Add octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane into the reaction flask, vacuumize and dehydrate, then add catalyst alkali glue and capping agent decamethyltetrasiloxane under nitrogen protection Oxane, finally adding octaphenyl cyclotetrasiloxane, vacuum dehydration; among them, octamethyl cyclotetrasiloxane, tetramethyl tetravinyl cyclotetrasiloxane, octaphenyl cyclotetrasiloxane , the molar ratio range of alkali glue and end-capping agent is (40-85): (10-40): (5-30): (0.02-0.05): (0.04-0.08); In step (1), the vacuum degree of dehydration is -0.1～-0.09, the dehydration temperature is 45°C～50°C, and the total dehydration time is 1～2 hours; (2) carry out the polymerization reaction under the protection of normal pressure nitrogen; (3) Destroy the catalyst at 140℃～160℃; (4) remove unreacted monomer; In step (4), the degree of vacuum to be removed is -0.1 to -0.09, the temperature is 170°C to 190°C, and the time is 2 to 4 hours. 4. methyl vinyl phenyl silicone rubber preparation method as claimed in claim 3 is characterized in that: In step (2), the polymerization temperature is 100-120° C., and the polymerization time is 1-3 hours. 5. the epoxidized silicon rubber that the methyl vinyl phenyl silicone rubber of high phenyl high vinyl content as claimed in claim 1 or 2 makes, it is characterized in that the structural formula of described epoxidized silicon rubber for:

Molar ratio: x:y:z=(40-85):(10-40):(5-30). 6. the preparation method of epoxidized silicone rubber as claimed in claim 5 is characterized in that described method comprises: The epoxidized silicone rubber is prepared from methyl vinyl phenyl silicone rubber through an epoxidation reaction.

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