阅读说明：本技术 一种低介电常数形状记忆聚苯乙烯及其制备方法和应用 (Low-dielectric-constant shape memory polystyrene and preparation method and application thereof ) 是由 陶立明 郭丽和 张耀明 赵普 王廷梅 王齐华 于 2021-09-27 设计创作，主要内容包括：本发明提供了一种低介电常数形状记忆聚苯乙烯及其制备方法和应用,属于形状记忆聚合物技术领域。本发明将丙烯酸酯、乙烯基单体和自由基引发剂混合进行自由基无规共聚反应,得到所述低介电常数形状记忆聚苯乙烯,所述多乙烯基交联剂包括二乙烯基苯、三乙烯基苯或四乙烯基苯,所述乙烯基单体包括苯乙烯和4-乙烯基苯并环丁烯。本发明采用含有苯并环丁烯的4VB作为改性剂,4VB与苯乙烯结构类似,所不同的是在侧链中增加了苯并环丁烯这种具有潜在反应性的官能团,通过自由基无规共聚反应时苯并环丁烯四元环的开环加成形成扭曲空间构象(八元环结构),从而增大线性分子链共聚物(苯乙烯与丙烯酸酯形成的)之间的自由体积,显著降低介电常数。(The invention provides shape memory polystyrene with low dielectric constant and a preparation method and application thereof, belonging to the technical field of shape memory polymers. The low-dielectric-constant shape memory polystyrene is obtained by mixing acrylate, vinyl monomer and free radical initiator for free radical random copolymerization, wherein the polyvinyl crosslinking agent comprises divinyl benzene, trivinyl benzene or tetravinyl benzene, and the vinyl monomer comprises styrene and 4-vinylbenzocyclobutene. The invention adopts 4VB containing benzocyclobutene as a modifier, the structure of the 4VB is similar to that of styrene, except that a functional group with potential reactivity, namely benzocyclobutene, is added in a side chain, and the ring-opening addition of a benzocyclobutene four-membered ring forms a twisted space conformation (an eight-membered ring structure) through the free radical random copolymerization reaction, so that the free volume between linear molecular chain copolymers (formed by styrene and acrylate) is increased, and the dielectric constant is obviously reduced.)

1. A preparation method of shape memory polystyrene with low dielectric constant comprises the following steps:

and mixing acrylate, vinyl monomer and free radical initiator to perform free radical random copolymerization reaction to obtain the low dielectric constant shape memory polystyrene, wherein the polyvinyl crosslinking agent comprises divinyl benzene, trivinyl benzene or tetravinyl benzene, and the vinyl monomer comprises styrene and 4-vinylbenzocyclobutene.

2. The method according to claim 1, wherein the mass ratio of 4-vinylbenzocyclobutene to styrene is 1: 9-4: 6.

3. the method of claim 1, wherein the acrylate is methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, or isobutyl acrylate.

4. The production method according to claim 1, 2 or 3, wherein the mass ratio of the acrylate to the vinyl monomer is 4: 6-2: 8.

5. the production method according to claim 1 or 2, wherein the mass ratio of the polyvinyl crosslinking agent to styrene is 1: 100-4: 100.

6. the method according to claim 1, wherein the mass ratio of the radical initiator to the styrene is 0.5: 100-2.0: 100.

7. the production method according to claim 1 or 6, wherein the radical initiator is an azo initiator or an organic peroxide initiator.

8. The method according to claim 1, wherein the temperature of the radical random copolymerization is 70 to 200 ℃ and the time is 24 to 72 hours.

9. The low dielectric constant shape memory polystyrene prepared by the preparation method of any one of claims 1 to 8, wherein the low dielectric constant shape memory polystyrene is 10%⁶The dielectric constant at Hz is 1.818 to 2.742.

10. Use of the low dielectric constant shape memory polystyrene of claim 9 in the field of intelligent electronic devices.

Technical Field

The invention relates to the technical field of shape memory polymers, in particular to shape memory polystyrene with a low dielectric constant and a preparation method and application thereof.

Background

Shape memory polymers have been extensively studied and explored in recent years, and the application of such smart materials can improve device performance, improve device efficiency and overcome some inherent disadvantages of the conventional device mechanism, such as difficult operation due to complex assembly process and large volume and weight.

The existing shape memory polymers are various in types, including polystyrene, epoxy resin, polyurethane, polyacrylates, polyacrylamides, polyimides and the like, and the application research field of the shape memory polymers covers aerospace, intelligent medical equipment, machinery, electric power and the like. The existing modification research on shape memory polymers in China is mostly based on modification research on shape memory mechanical properties, such as improvement of shape fixation rate and shape recovery rate, acceleration of shape recovery rate and the like, for example, Chinese patent CN105416613A is proposed to solve the problems of complex motor-driven catching structure, large mass and the like of the traditional aerospace machinery, and mainly comprises an unfolding structure of a shape memory polymer composite material sheet layer, namely a three-wing unfolding beam and a dielectric elastomer, wherein the structure formed by the shape memory polymer composite material sheet layer is used for driving and controlling the catching structure to a specified position, and the structure formed by the shape memory polymer and the dielectric elastomer is used for catching space debris.

The most basic requirement of polymer packaging resin for intelligent electronic device systems such as artificial skin, wearable equipment micro-signal sensing systems and the like is low dielectric constant to reduce loss in the signal transmission process, but the dielectric property of the existing shape memory polymer is not effectively regulated and controlled, and the requirement of the intelligent electronic device on the low dielectric constant resin cannot be met.

Disclosure of Invention

In view of the above, the present invention is directed to a shape memory polystyrene with low dielectric constant, and a preparation method and applications thereof. The shape memory polystyrene prepared by the invention has low dielectric constant, and can meet the requirement of intelligent electronic devices on low dielectric constant packaging resin.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of shape memory polystyrene with low dielectric constant, which comprises the following steps:

and mixing acrylate, vinyl monomer and free radical initiator to perform free radical random copolymerization reaction to obtain the low dielectric constant shape memory polystyrene, wherein the polyvinyl crosslinking agent comprises divinyl benzene, trivinyl benzene or tetravinyl benzene, and the vinyl monomer comprises styrene and 4-vinylbenzocyclobutene.

Preferably, the mass ratio of the 4-vinylbenzocyclobutene to the styrene is 1: 9-4: 6.

preferably, the acrylate is methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, or isobutyl acrylate.

Preferably, the mass ratio of acrylate to vinyl monomer is 4: 6-2: 8.

preferably, the mass ratio of the polyvinyl crosslinker to styrene is 1: 100-4: 100.

preferably, the mass ratio of the radical initiator to styrene is 0.5: 100-2.0: 100.

preferably, the radical initiator is an azo-type initiator or an organic peroxide initiator.

Preferably, the temperature of the free radical random copolymerization reaction is 70-200 ℃, and the time is 24-72 h.

The invention also provides the low dielectric constant shape memory polystyrene prepared by the preparation method of the technical scheme, wherein the low dielectric constant shape memory polystyrene is 10%⁶The dielectric constant at Hz is 1.818 to 2.742.

The invention also provides the application of the low dielectric constant shape memory polystyrene in the technical scheme in the field of intelligent electronic devices.

The invention provides a preparation method of shape memory polystyrene with low dielectric constant, which comprises the following steps: and mixing acrylate, vinyl monomer and free radical initiator to perform free radical random copolymerization reaction to obtain the low dielectric constant shape memory polystyrene, wherein the polyvinyl crosslinking agent comprises divinyl benzene (DVB), trivinyl benzene or tetravinyl benzene, and the vinyl monomer comprises styrene and 4-vinylbenzocyclobutene (4 VB). The invention adopts 4VB containing benzocyclobutene as a modifier, the structure of the 4VB is similar to that of styrene, except that a functional group with potential reactivity, namely benzocyclobutene, is added in a side chain, and the ring-opening addition of a benzocyclobutene four-membered ring forms a twisted space conformation (an eight-membered ring structure) during the free radical random copolymerization reaction, so that the free volume between linear molecular chain copolymers (the linear molecular chain copolymers formed by vinyl monomers and acrylic ester) is increased, and the dielectric constant is obviously reduced. On the other hand, through the free radical random copolymerization reaction, benzocyclobutene in-situ ring-opening addition forms a twisted eight-membered ring structure, and the twisted structure enlarges the distance between linear molecular chain segments between any two originally relatively soft crosslinking points, so that the free volume between the molecular chains is increased, and the dielectric constant of the material is further remarkably reduced.

The data of the examples show that the low dielectric constant shape memory polystyrene prepared by the invention has the following performance indexes:

10⁶dielectric constant as low as 1.818 at Hz (1 MHz);

the shape fixing rate is more than or equal to 98 percent;

the shape recovery rate is more than or equal to 98 percent.

Further, in the invention, the DVB and the linear molecular chain copolymer have good compatibility, a homogeneous system can be formed in a lower concentration range, and the residue of gaps in the formed material is avoided.

The preparation method provided by the invention is simple, convenient to operate, free of special requirements on reactants and catalysts, simple in curing procedure, mild in conditions and suitable for process scale-up production.

The invention also provides the low dielectric constant shape memory polystyrene prepared by the preparation method in the technical scheme, and the low dielectric constant shape memory polystyrene prepared by the invention can effectively regulate and control the dielectric constant of the polystyrene. The preparation is simple, the molding is convenient, and the method is suitable for large-scale production.

Drawings

FIG. 1 is a graph showing the change of dielectric constant with frequency of shape memory polystyrene materials prepared in example 1 and comparative example;

FIG. 2 is a graph showing the change of dielectric constant with frequency of the shape memory polystyrene materials prepared in example 2 and comparative example;

FIG. 3 is a graph showing the change of dielectric constant with frequency of the shape memory polystyrene materials prepared in example 3 and comparative example;

FIG. 4 is a graph showing the change of dielectric constant with frequency of the shape memory polystyrene materials prepared in example 4 and comparative example.

Detailed Description

The invention provides a preparation method of shape memory polystyrene with low dielectric constant, which comprises the following steps;

and mixing acrylate, vinyl monomer and free radical initiator to perform free radical random copolymerization reaction to obtain the low dielectric constant shape memory polystyrene, wherein the polyvinyl crosslinking agent comprises divinyl benzene, trivinyl benzene or tetravinyl benzene, and the vinyl monomer comprises styrene and 4-vinylbenzocyclobutene.

In the present invention, the mass ratio of the acrylate to the vinyl monomer is preferably 4: 6-2: 8, more preferably 85.714: 200-133.33: 200.

in the present invention, the acrylic ester is preferably methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate or isobutyl acrylate.

In the present invention, the mass ratio of 4VB to styrene is preferably 1: 9-4: 6, more preferably 1: 4. 2: 3 or 3: 2.

in the present invention, the ratio of the total molar amount of vinyl groups to the molar amount of styrene in the polyvinyl crosslinking agent is preferably 1: 100-4: 100, more preferably 4: 180. 1: 20. 1: 15 or 1: 40.

in the present invention, the mass ratio of the radical initiator to styrene is preferably 0.5: 100-2.0: 100, more preferably 1: 100.

in the present invention, the radical initiator is preferably an azo-type initiator or an organic peroxide initiator, and more preferably Azobisisobutyronitrile (AIBN) or Benzoyl Peroxide (BPO).

In the invention, the temperature of the free radical random copolymerization reaction is preferably 70-200 ℃, more preferably 120-160 ℃, and the time is preferably 35-50 h.

In the present invention, the radical random copolymerization is preferably carried out under nitrogen protection. In the examples of the present invention, the radical random copolymerization reaction is preferably carried out in a forced air drying oven.

In the present invention, in the process of the radical random copolymerization, the linear molecular chain copolymer having the structure shown in formula I, which is formed by styrene and vinyl monomer, is crosslinked with divinylbenzene to obtain a compound having the structure shown in formula II (low dielectric constant shape memory polystyrene), wherein the compound having the structure shown in formula II contains an eight-membered ring structure, which exists in a distorted spatial structure from the chemical thermodynamic perspective, the energy is the lowest, and the distorted spatial structure further causes the dielectric constant to be reduced.

In the formulas I-II, m, n, o and p are respectively a positive integer.

The specific mixing method is not particularly limited, and a method known to those skilled in the art may be adopted, such as mechanical stirring, and in the specific embodiment of the present invention, the time of the mechanical stirring is preferably 10 to 60 min.

In the present invention, the radical random copolymerization preferably further comprises, before the radical random copolymerization: and standing the mixed solution system, wherein the standing time is preferably 20-60 min, and the standing function is to enable bubbles generated in the mixing process to disappear automatically so as to avoid pores generated in the free radical random copolymerization reaction and avoid the reduction of the material strength.

After the radical random copolymerization reaction is completed, the low dielectric constant shape memory polystyrene is preferably obtained directly without post-treatment.

After the low dielectric constant shape memory polystyrene is obtained, the low dielectric constant shape memory polystyrene is preferably cut into a wafer with the diameter of 9mm, and the wafer is tested on an Agilent dielectric spectrometer from 10⁴Hz～10⁸Dielectric constant in the frequency range of Hz.

The invention also provides the low dielectric constant shape memory polystyrene prepared by the preparation method in the technical scheme.

The invention also provides application of the low dielectric constant shape memory polystyrene in the technical scheme in the field of intelligent electronic devices, and the polystyrene is preferably used as packaging resin. The invention is not particularly limited to the specific manner of use described, as such may be readily adapted by those skilled in the art.

In order to further illustrate the present invention, the low dielectric constant shape memory polystyrene provided by the present invention, the preparation method and application thereof are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Comparative example

At normal temperature and normal pressure, in a 250mL three-necked bottle with electromagnetic stirring, adding 20.84g (200mmol) of styrene, 6.409g (50mmol) of butyl acrylate, 0.52g (8 mmol) of vinyl DVB and 0.484g (2mmol) of BPO, stirring for 60min at room temperature to completely dissolve the materials to obtain a homogeneous solution, standing for 60min at room temperature to eliminate bubbles generated by stirring, pouring into a clean culture dish, and preserving heat for 72h in a forced air drying box at 70 ℃ to complete solidification to obtain the shape memory polystyrene material. It was cut into a disk having a diameter of 9mm for evaluation of dielectric properties.

Example 1

18.747g (180mmol) of styrene, 2.604g (20mmol) of 4VB, 11.478g (133.33mmol) of methyl acrylate, 0.26g (4mmol) of DVB and 0.657g (4mmol) of AIBN are added into a 250mL three-necked bottle with electromagnetic stirring at normal temperature and normal pressure in a nitrogen protective atmosphere, the materials are stirred for 10min at room temperature to completely dissolve the materials to obtain a homogeneous solution, then the homogeneous solution is stood at room temperature for 20min to eliminate bubbles generated by stirring, the homogeneous solution is poured into a clean culture dish, and the homogeneous solution is kept warm in a forced air drying oven at 120 ℃ for 50h to complete solidification to obtain the shape memory polystyrene material. It was cut into a disk having a diameter of 9mm for evaluation of dielectric properties.

FIG. 1 is a plot of the dielectric constant versus test frequency for comparative example and example 1, showing that the dielectric constant of the material prepared in example 1 is significantly lower than that of the comparative example, at 10⁶The dielectric constant at Hz (1MHz) was 2.803 and 1.844, respectively, a 34.2% reduction.

Example 2

16.664g (160mmol) of styrene, 5.208g (40mmol) of 4VB, 8.582g (85.714mmol) of ethyl acrylate, 0.52g (8 mmol) of DVB and 0.242g (1mmol) of BPO are added into a 250mL three-necked bottle with electromagnetic stirring at normal temperature and normal pressure in a nitrogen protective atmosphere, the materials are stirred for 60min at room temperature to completely dissolve the materials to obtain a homogeneous solution, then the homogeneous solution is stood at room temperature for 60min to eliminate bubbles generated by stirring, the homogeneous solution is poured into a clean culture dish, and the homogeneous solution is kept warm in a forced air drying oven at 160 ℃ for 35h to complete solidification to obtain the shape memory polystyrene material. It was cut into a disk having a diameter of 9mm for evaluation of dielectric properties.

FIG. 2 is a plot of the dielectric constant versus test frequency for comparative and example 2, showing that the dielectric constant of the material prepared in example 2 is significantly lower than that of the comparative example, at 10⁶The dielectric constants at Hz (1MHz) were 2.803 and 2.224, respectively, which are a 20.6% reduction.

Example 3

12.498g (120mmol) of styrene, 10.415g (80mmol) of 4VB, 6.409g (50mmol) of butyl acrylate, 0.52g (8 mmol) of DVB and 0.484g (2mmol) of BPO are added into a 250mL three-necked bottle with electromagnetic stirring at normal temperature and normal pressure in a nitrogen protective atmosphere, the materials are stirred for 20min at room temperature to be completely dissolved to obtain a homogeneous solution, then the homogeneous solution is stood at room temperature for 40min to eliminate bubbles generated by stirring, the homogeneous solution is poured into a clean culture dish, and the homogeneous solution is kept warm in a forced air drying oven at 200 ℃ for 24h to complete solidification to obtain the shape memory polystyrene material. It was cut into a disk having a diameter of 9mm for evaluation of dielectric properties.

FIG. 3 is a plot of the dielectric constant versus test frequency for comparative example and example 3, showing that the dielectric constant of the material prepared in example 3 is significantly lower than that of the comparative example, at 10⁶The dielectric constants at Hz (1MHz) were 2.803 and 1.818, respectively, a 35.1% reduction.

Example 4

8.332g (80mmol) of styrene, 15.623g (120mmol) of 4VB, 5.707g (50mmol) of propyl acrylate, 0.13g (2mmol) of DVB and 0.328g (2mmol) of AIBN are added into a 250mL three-necked bottle with electromagnetic stirring at normal temperature and normal pressure in a nitrogen protective atmosphere, the materials are stirred for 40min at room temperature to completely dissolve the materials to obtain a homogeneous solution, then the homogeneous solution is stood at room temperature for 40min to eliminate bubbles generated by stirring, the homogeneous solution is poured into a clean culture dish, and the homogeneous solution is kept warm in a forced air drying oven at 200 ℃ for 24h to complete solidification to obtain the shape memory polystyrene material. It was cut into a disk having a diameter of 9mm for evaluation of dielectric properties.

FIG. 4 is a plot of the dielectric constant versus test frequency for comparative and example 4. it can be seen that the dielectric constant of the material prepared in example 4 is lower than that of the comparative example, with a dielectric constant of 2.803 and 2.742 at 106Hz (1MHz), respectively, which is about a 2.2% reduction.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.