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

Methyl vinyl phenyl silicone rubber with high phenyl content and high vinyl content and preparation method thereof

Technical Field

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

Background

Phenyl silicone rubber is a main variety of silicone rubber, has weather aging resistance, dielectric property and physiological inertia of common silicone rubber, has excellent cold resistance, radiation resistance, flame retardance and the like, is an indispensable elastic material in modern technology, and is mainly used for manufacturing rubber products and bonding materials for shock absorption, sealing, heat insulation, electrical insulation and elastic bonding

The phenyl content of the phenyl silicone rubber on the current market is about 15 percent at most, and the vinyl content is lower than 1 percent. The current research base shows that the introduction of the phenyl chain segment can improve the rigidity of a silicon rubber molecular chain, improve the glass transition temperature and improve the heat resistance and radiation resistance of a silicon rubber product; and the introduction of the epoxy group can destroy the low-temperature crystallization of the silicone rubber, improve the polarity and rigidity of a molecular chain of the silicone rubber, and improve the oil resistance and the hydrophilic performance of the silicone rubber, thereby improving the interaction between the molecular chain and high-surface-energy nano particles (such as modified white carbon black, carbon nano tubes and the like) and improving the dispersibility of the nano particles.

The existing phenyl silicone rubber has low vinyl content, and the preparation of the phenyl silicone rubber with high vinyl content is difficult because the silicone rubber with high vinyl content is easy to crosslink in the synthesis process.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides methyl vinyl phenyl silicone rubber with high phenyl content and high vinyl content and a preparation method thereof. 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%.

One of the purposes of the invention is to provide methylvinyl phenyl silicone rubber with high phenyl content and high vinyl content.

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);

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

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

The method comprises the following steps:

(1) adding octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing and dehydrating, then adding catalyst alkali gel and end-capping agent decamethyltetrasiloxane under the protection of nitrogen, finally adding octaphenylcyclotetrasiloxane, and vacuumizing and dehydrating; wherein the molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, alkali gum and end-capping reagent is (40-85): (10-40): (5-30): (0.02-0.05): (0.04-0.08);

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

(3) destroying the catalyst at 140-160 deg.c;

(4) unreacted monomers are removed.

Among them, preferred are:

in the step (1), the vacuum degree of dehydration is-0.1 to-0.09, the dehydration temperature is 45 to 50 ℃, and the total dehydration time is 1 to 2 hours.

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

In the step (4), the removal vacuum degree is-0.1 to-0.09, the temperature is 170 to 190 ℃, and the time is 2 to 4 hours.

The following steps can be specifically adopted:

(1) adding octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 45-50 ℃ to remove water for 1 hour, then adding catalyst alkali gel and end-capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding octaphenylcyclotetrasiloxane; vacuumizing at 45-50 ℃ to remove water for 1 hour;

(2) reacting for 2.5 hours at 110-120 ℃ under the protection of normal pressure nitrogen;

(3) then the catalyst is destroyed at 160 ℃;

(4) finally, unreacted monomers were removed at 180 ℃ for 3 hours.

The invention also aims to provide the epoxidized methylvinyl phenyl silicone rubber with high phenyl content and high vinyl content.

The structural formula is as follows:

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

The preparation method of the epoxidized high-phenyl high-vinyl methyl vinyl phenyl silicone rubber comprises the following steps:

the methyl vinyl phenyl silicone rubber is prepared into the epoxidized silicone rubber through an epoxidation reaction.

The method specifically comprises the following steps:

(1) adding trichloromethane and methyl vinyl phenyl silicone rubber with high phenyl content and high vinyl content into a round-bottom flask (1L or 2L) or a 10L glass reaction kettle with a magneton stirrer, controlling the temperature of the system to be 25 ℃ through water bath, and controlling the stirring speed of the system;

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

(3) and (3) separating out the mixture by using methanol after a period of time, washing the mixture for 2-3 times, putting the mixture into a vacuum oven, drying the mixture for 12 hours, and taking the dried mixture out for later use.

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%.

The vinyl content is high, the epoxy modified silica gel can be used for epoxidation modification research, and the introduction of the epoxy functional group can also endow ESiR and fumed silica with better interface interaction, so that the physical and mechanical properties of the fumed silica are improved. Most importantly, with the increase of the epoxidation degree, the Tg of the ESiR is shifted to a high temperature direction, so that the damping performance of the silicone rubber can be effectively improved.

The content of the phenyl is high, and the introduction of the phenyl chain segment can improve the rigidity of a silicon rubber molecular chain, improve the glass transition temperature and improve the heat resistance and the radiation resistance of a silicon rubber product.

The phenyl silicone rubber in the prior art has low vinyl content which is lower than 1 percent, is difficult to perform epoxidation modification, has low vinyl content originally, can not introduce much epoxy groups during epoxidation modification, and can not play a role even if the vinyl content is very low. The synthesized phenyl silicone rubber has high vinyl content, and the epoxy group content which can be introduced through epoxidation modification is also higher.

Drawings

FIG. 1 is a comparison of the thermogravimetric curves of prior and present synthetic phenyl silicone rubbers.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

Adding 85mol of octamethylcyclotetrasiloxane and 10mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 45 ℃ for dewatering for 1 hour, then adding 0.02mol of catalyst alkali gel and 0.04mol of end capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 5mol of octaphenylcyclotetrasiloxane, vacuumizing at 46 ℃ for dewatering for 1 hour, and controlling the vacuum degree to be-0.09; reacting for 3 hours at 100 ℃ under the protection of normal pressure nitrogen; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 170 ℃ for 2 hours, the vacuum being controlled at-0.1.

Adding 175ml of trichloromethane and 5.25g of synthesized methyl vinyl phenyl silicone rubber into a round-bottom flask (250ml) with a magnetic stirrer, controlling the temperature of the system to be 25 ℃ through a water bath, controlling the stirring rate of the system, adding 2.35g of m-chloroperoxybenzoic acid (m-CPBA) after the silicone rubber is completely dissolved, starting reaction, separating out the mixture by using methanol after 96 hours, washing for 2-3 times, putting the mixture into a vacuum oven, drying for 12 hours, and taking out the dried mixture for later use.

Example 2

Adding 75mol of octamethylcyclotetrasiloxane and 15mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 48 ℃ for dewatering for half an hour, then adding 0.03mol of catalyst alkali gel and 0.05mol of end-capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 10mol of octaphenylcyclotetrasiloxane, vacuumizing at 47 ℃ for dewatering for 1 hour, and controlling the vacuum degree to be-0.09; reacting for 1 hour at 120 ℃ under the protection of normal pressure nitrogen; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 170 ℃ for 3 hours, the vacuum being controlled at-0.09.

Adding 175ml of trichloromethane and 5.25g of synthesized methyl vinyl phenyl silicone rubber into a round-bottom flask (250ml) with a magnetic stirrer, controlling the temperature of a system to be 25 ℃ through a water bath, controlling the stirring rate of the system, adding 3.14g of m-chloroperoxybenzoic acid (m-CPBA) after the silicone rubber is completely dissolved, starting reaction, separating out the mixture by using methanol after 96 hours, washing for 2-3 times, putting the mixture into a vacuum oven, drying for 12 hours, and taking out the dried mixture for later use.

Example 3

Adding 65mol of octamethylcyclotetrasiloxane and 20mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing and dehydrating for half an hour at 50 ℃, then adding 0.035mol of catalyst alkali glue and 0.07mol of end-capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 15mol of octaphenylcyclotetrasiloxane, vacuumizing and dehydrating for half an hour at 50 ℃, and controlling the vacuum degree to be-0.092; reacting for 2.5 hours at 110 ℃ under the protection of nitrogen at normal pressure; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 180 ℃ for 2.5 hours with the vacuum degree controlled at-0.096.

Adding 525ml of trichloromethane and 15.75g of synthesized methyl vinyl phenyl silicone rubber into a round-bottom flask (100ml) with a magnetic stirrer, controlling the temperature of a system to be 25 ℃ through a water bath, controlling the stirring rate of the system, adding 11.79g of m-chloroperoxybenzoic acid (m-CPBA) after the silicone rubber is completely dissolved, starting reaction, separating out the mixture by using methanol for 96 hours, washing for 2-3 times, drying for 12 hours in a vacuum oven, and taking out for later use.

Example 4

Adding 40mol of octamethylcyclotetrasiloxane and 40mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 49 ℃ for dewatering for 1 hour, then adding 0.035mol of catalyst alkali gel and 0.055mol of end-capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 20mol of octaphenylcyclotetrasiloxane, vacuumizing at 49 ℃ for dewatering for half an hour, and controlling the vacuum degree to be-0.096; reacting for 1.5 hours at 120 ℃ under the protection of nitrogen under normal pressure; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 190 ℃ for 3.5 hours with the vacuum degree controlled at-0.1.

1400ml of trichloromethane and 42g of methyl vinyl phenyl silicone rubber obtained by synthesis are added into a round bottom flask (2000ml) with a magnetic stirring device, the temperature of the system is controlled to be 25 ℃ through a water bath, the stirring speed of the system is controlled, 18.84g of m-chloroperoxybenzoic acid (m-CPBA) is added after the silicone rubber is completely dissolved to start reaction, methanol is used for precipitation after 96 hours, washing is carried out for 2-3 times, the mixture is placed into a vacuum oven to be dried for 12 hours, and the mixture is taken out for standby.

Example 5

Adding 70mol of octamethylcyclotetrasiloxane and 10mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 46 ℃ for dewatering for 1 hour, then adding 0.05mol of catalyst alkali gel and 0.08mol of end capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 20mol of octaphenylcyclotetrasiloxane, vacuumizing at 46 ℃ for dewatering for 1 hour, and controlling the vacuum degree to be-0.098; reacting for 2 hours at 110 ℃ under the protection of nitrogen at normal pressure; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 190 ℃ for 4 hours, with the vacuum degree being controlled at-0.09.

Adding 700ml of trichloromethane and 21g of synthesized methyl vinyl phenyl silicone rubber into a round-bottom flask (1000ml) with a magnetic stirrer, controlling the temperature of a system to be 25 ℃ through a water bath, controlling the stirring rate of the system, adding 18.84g of m-chloroperoxybenzoic acid (m-CPBA) after the silicone rubber is completely dissolved, starting reaction, separating out with methanol after 96 hours, washing for 2-3 times, drying in a vacuum oven for 12 hours, and taking out for later use.

Example 6

Adding 60mol of octamethylcyclotetrasiloxane and 10mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 47 ℃ for dewatering for 1 hour, then adding 0.035mol of catalyst alkali gel and 0.06mol of end-capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 30mol of octaphenylcyclotetrasiloxane, vacuumizing at 47 ℃ for dewatering for 1 hour, and controlling the vacuum degree to be-0.1; reacting for 3 hours at 110 ℃ under the protection of nitrogen at normal pressure; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 180 ℃ for 3.5 hours with the vacuum degree controlled at-0.092.

1400ml of trichloromethane and 42g of methyl vinyl phenyl silicone rubber obtained by synthesis are added into a round bottom flask (2000ml) with a magnetic stirring device, the temperature of the system is controlled to be 25 ℃ through a water bath, the stirring speed of the system is controlled, 22.21g of m-chloroperoxybenzoic acid (m-CPBA) is added after the silicone rubber is completely dissolved to start reaction, methanol is used for precipitation after 96 hours, washing is carried out for 2-3 times, the mixture is placed into a vacuum oven to be dried for 12 hours, and the mixture is taken out for later use.

Example 7

Adding 60mol of octamethylcyclotetrasiloxane and 30mol of tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing at 45 ℃ for dewatering for 1 hour, then adding 0.03mol of catalyst alkali gel and 0.05mol of end-capping agent decamethyltetrasiloxane under the protection of nitrogen, and finally adding 10mol of octaphenylcyclotetrasiloxane, vacuumizing at 45 ℃ for dewatering for 1 hour, and controlling the vacuum degree to be-0.092; reacting for 2.5 hours at 110 ℃ under the protection of nitrogen at normal pressure; then the catalyst is destroyed at 160 ℃; finally, the unreacted monomers were removed by vacuum-pumping at 180 ℃ for 3 hours with the vacuum degree controlled at-0.1.

Adding 700ml of trichloromethane and 21g of synthesized methyl vinyl phenyl silicone rubber into a round-bottom flask (1000ml) with a magnetic stirrer, controlling the temperature of a system to be 25 ℃ through a water bath, controlling the stirring rate of the system, adding 14.64g of m-chloroperoxybenzoic acid (m-CPBA) after the silicone rubber is completely dissolved, starting reaction, separating out the mixture by using methanol after 96 hours, washing for 2-3 times, drying for 12 hours in a vacuum oven, and taking out for later use.

The values of xyz for each example 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 obtained in each example was of the formula:

product performance testing

1. Molecular weight determination of methyl vinyl phenyl silicone rubber

The molecular weight of the silicone rubber was determined by Gel Permeation Chromatography (GPC). GPC test sample preparation: dissolving 0.003-0.005 g of silicon rubber in 1ml of tetrahydrofuran solution, preparing the solution with the concentration of about 2-4 mg/ml, and removing cross-linked molecular chains through a filter sieve for testing to obtain the number average molecular weight (Mn), the weight average molecular weight (Mw) and the molecular weight distribution index (PDI) of the silicon rubber with different structures.

2. Nuclear magnetic hydrogen spectrum characterization of methyl vinyl phenyl silicone rubber

The polymer was subjected to an AV300 nuclear magnetic resonance spectrometer (300MHz) from Bruker, USA¹H-NMR measurement. And calculating the vinyl content and the phenyl content of the silicone rubber through a nuclear magnetic spectrum.

3. Thermogravimetric analysis (TGA)

Thermogravimetric performance tests were carried out on the silicone rubber using a TGA/DSC synchronous thermal analyzer (model STARe system). The TGA curve was obtained by warming from 30 ℃ to 800 ℃ at 10 ℃/min under an atmosphere of N2.

The results of the examples are shown in Table 2:

TABLE 2

As can be seen from Table 2, the methylvinylphenyl silicone rubber of the present invention has a high phenyl content and a high vinyl content, a phenyl content of up to 30%, a vinyl content of up to 40%, and a molecular weight of over 30 ten thousand. The direct method is adopted to successfully convert the vinyl into the epoxy group, and the epoxidation conversion can reach more than 90 percent.

TABLE 3

TABLE 4

As can be seen from tables 3 and 4, compared with the commercially available phenyl silicone rubber, the methyl vinyl phenyl silicone rubber synthesized by the invention has the advantages that the low-temperature crystallization performance of the methyl vinyl phenyl silicone rubber is limited due to the introduction of the vinyl group, the low-temperature service performance of the methyl vinyl phenyl silicone rubber is improved due to the introduction of the vinyl group, and the glass transition temperature (Tg) is slightly improved along with the introduction of the vinyl group.

As can be seen from Table 4, compared with the commercially available phenyl silicone rubber, the epoxidized methyl vinyl phenyl silicone rubber of the present invention has the same phenyl content, the glass transition temperature (Tg) is significantly increased with the introduction of epoxy groups, from-105.88 ℃ to-89.55 ℃, from below-100 ℃ to above-100 ℃, and the use conditions are shifted to high temperatures.

Fig. 1 is a comparison of the thermogravimetric curves of the prior art phenyl silicone rubber and the methyl vinyl phenyl silicone rubber prepared in example 2, and it can be seen from the graph that the heat resistance is greatly improved after the epoxy group is introduced into the silicone rubber structure, and the thermal decomposition temperature in the nitrogen atmosphere is increased from 310 ℃ to 450 ℃. The silicon rubber has high flexibility, and generates loop back biting degradation under the high temperature condition, the introduction of the epoxy group can improve the rigidity of the main chain, so that the main chain of the silicon rubber is not easy to distort and form a ring, and the difficulty of ring formation degradation is increased, therefore, the thermal stability after epoxidizing the phenyl silicon rubber is improved, namely, the heat resistance is further improved.

Claims (6)

1. A methyl vinyl phenyl silicone rubber with high phenyl and high vinyl content is characterized in that:

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).

2. The high phenyl high vinyl methyl vinyl phenyl silicone rubber of claim 1, wherein:

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

3. A method for preparing a high phenyl high vinyl content methylvinylphenyl silicone rubber according to claim 1 or 2, characterized in that it comprises:

(1) adding octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane into a reaction flask, vacuumizing and dehydrating, then adding catalyst alkali gel and end-capping agent decamethyltetrasiloxane under the protection of nitrogen, finally adding octaphenylcyclotetrasiloxane, and vacuumizing and dehydrating; wherein the molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, alkali gum and end-capping reagent is (40-85): (10-40): (5-30): (0.02-0.05): (0.04-0.08);

in the step (1), the vacuum degree of dehydration is-0.1 to-0.09, the dehydration temperature is 45 to 50 ℃, and the total dehydration time is 1 to 2 hours;

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

(3) destroying the catalyst at 140-160 deg.c;

(4) removing unreacted monomers;

in the step (4), the removal vacuum degree is-0.1 to-0.09, the temperature is 170 to 190 ℃, and the time is 2 to 4 hours.

4. The process for preparing methylvinylphenyl silicone rubber according to claim 3, wherein:

in the step (2), the polymerization temperature is 100-120 ℃, and the polymerization time is 1-3 hours.

5. An epoxidized silicone rubber obtained from the high phenyl high vinyl content methylvinylphenyl silicone rubber according to claim 1 or 2, characterized in that the epoxidized silicone rubber has the structural formula:

the molar ratio is as follows: x, y, z (40-85): (10-40): (5-30).

6. The method for producing an epoxidized silicone rubber according to claim 5, characterized by comprising:

the methyl vinyl phenyl silicone rubber is prepared into the epoxidized silicone rubber through an epoxidation reaction.

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