Method for improving mechanical properties of silicon-containing arylenevinylene resins and composites thereof

Abstract

The present application relates to a method for improving the mechanical properties of silicon-containing aryl alkyne resin and its composite material, in particular to a method for improving the mechanical properties of silicon-containing aryl alkyne resin and its composite material by copolymerization with thermal polymerization monomer, belonging to the technical field of high-performance resin matrix composite material. The method selects common and relatively low-cost partial thermal polymerization monomer on the market as a modifier, and modifies the silicon-containing aryl alkyne by copolymerization. The present application selects styrene with large molecular rigidity and cheap and easy to obtain in industry as the modifier, so that it is mixed with the modified PSA resin monomer or prepolymer in a suitable proportion. At this time, the viscosity of the glue solution has almost no obvious change, and the forming process of the PSA resin and its composite material is not changed. During the curing process of the composite material, styrene and PSA resin copolymerize to form an integrated and uniform modified crosslinked network. The crosslinked network density is reduced, and the desired toughening effect can be achieved, and the interlaminar shear property of the composite material is also significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for improving the mechanical properties of silicon-containing arylene resin and its composite material, in particular to a method for improving the mechanical properties of silicon-containing arylene resin and its composite material by copolymerization with thermal polymerization monomers, belonging to the technical field of high-performance resin-based composite materials. TECHNICAL BACKGROUND

[0002] Silicon-containing arylene (PSA) resin refers to a kind of polymer containing arylene group and silane group in the molecular backbone. The resin has excellent heat resistance and dielectric properties, and no small molecule by-products are generated during resin curing, so the shrinkage rate is low. In addition, it has low viscosity and suitable curing temperature, and good molding process. Quartz fiber reinforced silicon-containing arylene resin composite material has the advantages of low dielectric constant and small change of dielectric loss in wide temperature and wide frequency range, and is an ideal high-temperature resistant wave-transparent composite material. However, due to the brittleness of silicon-containing arylene resin, combined with the poor interfacial adhesion between the reinforcing fibers, the mechanical properties of the composite material, especially the interlaminar shear performance, are low, which becomes the bottleneck restricting its wide application.

[0003] Toughening modification of silicon-containing arylene resin can improve the interlaminar shear strength of the composite material, but the premise of toughening modification of silicon-containing arylene resin is to maintain its good dielectric properties and not to significantly reduce its heat resistance, which undoubtedly increases the difficulty and challenge of modification.

[0004] So far, there are not many successful attempts to modify silicon-containing arylene resin and its composite material reported in the literature. Most of them are modified by copolymerization with second components or even third components containing characteristic functional groups such as alkyne group, ether bond and oxazine ring. Although better modification effect can be obtained to some extent, the compounds required for copolymerization need to be obtained through a complex, time-consuming and high-cost synthesis process, and are only suitable for small-scale experiments in the laboratory in terms of scale, and are not suitable for large-scale industrial application. SUMMARY

[0005] The purpose of the present application is to solve the problems of the prior art process, high cost and inability to industrialize, and to provide a method for improving the mechanical properties of silicon-containing arylene resin and its composite material. The method selects several common and relatively low-cost thermal polymerization monomers on the market as modifiers, and modifies them by copolymerization with silicon-containing arylene resin. The present application selects styrene with high molecular rigidity and low cost in industry as a modifier, and mixes it with the modified PSA resin monomer or prepolymer in a suitable proportion. At this time, the viscosity of the glue solution does not change significantly, so the implementation of the method will not change the molding process of the PSA resin-based composite material. During the curing process of the composite material, styrene copolymerizes with PSA resin to form an integrated and uniform modified crosslinked network. Compared with the modified one, the crosslinking density of the crosslinked network is reduced, the crosslinked structure is more uniform, the desired toughening effect can be achieved, and the interlaminar shear performance of the composite material is also significantly improved. In addition, the newly introduced styrene in the crosslinked network has low polarity, which will not deteriorate the dielectric properties of the resin and its composite material.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] A method for improving the mechanical properties of silicon-containing arylene resin, comprising the following steps:

[0008] Step one, mix the thermal polymerization monomer and the silicon-containing arylene resin glue solution uniformly to obtain a mixed glue solution. The mass ratio of the thermal polymerization monomer to the silicon-containing arylene resin is 1:(2.3-9);

[0009] Step two, dry the mixed glue solution to constant weight to obtain a mixture 1;

[0010] Step three, place the mixture 1 in a 70℃ vacuum oven until constant weight to obtain a mixture 2;

[0011] Step four, cure the mixture 2 to obtain a modified resin cast body.

[0012] The curing process of step four is the same as that of the unmodified silicon-containing arylene resin, and the curing temperature range is 100-300℃.

[0013] A method for improving the mechanical properties of silicon-containing arylene resin composite material, comprising the following steps:

[0014] Step one, mix the thermal polymerization monomer and the silicon-containing arylene resin glue solution uniformly to obtain a mixed glue solution. The mass ratio of the thermal polymerization monomer to the silicon-containing arylene resin is 1:(2.3-9);

[0015] Step two, the mixed glue solution and quartz fiber are impregnated by brushing or other methods to obtain a composite material prepreg. After drying, cutting, layering, compaction and hot pressing, a quartz fiber reinforced modified silicic silicic acetylene resin composite material is obtained.

[0016] The process conditions of the hot pressing in step two are the same as those of the unmodified silicic acetylene resin or its composite material, and the curing temperature is 100-300℃.

[0017] The thermal polymerization monomer includes styrene, methyl (butyl) methacrylate;

[0018] The solvent used in the silicic acetylene resin glue solution is one or a mixture of several of acetone, tetrahydrofuran, dichloromethane, toluene and xylene;

[0019] Beneficial effects

[0020] 1. The modifier used in the present application is a commercially available, industrialized and batch-produced chemical reagent, which has low cost;

[0021] 2. During initial batching, only the modifier and the silicic acetylene resin need to be simply stirred and mixed, which is simple in operation and convenient for industrial promotion;

[0022] 3. The addition of the thermal polymerization monomer does not increase the viscosity of the silicic acetylene resin glue solution, and the good process property of the original resin can be retained;

[0023] 4. During the curing process of the PSA resin and its composite material, the thermal polymerization monomer as the modifier participates in the curing reaction of the resin in a copolymerization manner, so as to improve the mechanical properties of the modified PSA resin and its composite material;

[0024] 5. The present application can improve the mechanical properties of the PSA resin and its composite material under the premise of maintaining the good heat resistance and dielectric properties of the PSA resin. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 DSC curve for the co-heating process of styrene and silicic acetylene resin mixture in Example 1 of the present application.

[0026] Figure 2 DSC curve for the co-heating process of styrene and silicic acetylene resin mixture in Example 2 of the present application.

[0027] Figure 3 Flow chart for preparing a quartz fiber reinforced modified silicic acetylene resin composite material. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose and advantages of the present application, the content of the application will be further described below in combination with the drawings and examples.

[0029] Example 1

[0030] A preparation method of a styrene modified silicon-containing aryl alkyne resin casting body, the specific steps are as follows:

[0031] (1) uniformly mix styrene and silicon-containing aryl alkyne acetone glue solution to obtain a mixed glue solution, wherein the mass ratio of styrene to silicon-containing aryl alkyne is 1:9;

[0032] (2) dry the mixed glue solution to constant weight to obtain a mixture 1;

[0033] (3) place the mixture 1 in a 70℃ vacuum oven and treat to constant weight to obtain a mixture 2;

[0034] (4) place the mixture 2 in a high-temperature oven to complete curing between 100-300℃ to obtain a modified resin casting body.

[0035] Table 1 thermal gravimetric (TG) data of silicon-containing aryl alkyne resin casting body before and after modification

[0036]

[0037] Figure 1 is the DSC curve of the mixture when the mass ratio of styrene to silicon-containing aryl alkyne resin is 1:9. It can be seen from Figure 1 that the DSC curve after adding styrene is similar to the DSC curve without adding styrene, and there is only one exothermic peak, which indicates that styrene and silicon-containing aryl alkyne resin have copolymerization reaction during the curing process, forming a uniform cured crosslinked system.

[0038] Example 2

[0039] A preparation method of a styrene modified silicon-containing aryl alkyne resin casting body, the specific steps are as follows:

[0040] (1) uniformly mix styrene and silicon-containing aryl alkyne acetone glue solution to obtain a mixed glue solution, wherein the mass ratio of styrene to silicon-containing aryl alkyne is 1:9;

[0041] (2) dry the mixed glue solution to constant weight to obtain a mixture 1;

[0042] (3) place the mixture 1 in a 70℃ vacuum oven and treat to constant weight to obtain a mixture 2;

[0043] (4) place the mixture 2 in a high-temperature oven to complete curing between 100-300℃ to obtain a modified resin casting body.

[0044] Table 2 thermal gravimetric (TG) data of silicon-containing aryl alkyne resin casting body before and after modification

[0045]

[0046] Figure 2 is the DSC curve of the mixture when the mass ratio of styrene to silicium-containing aryl alkyne resin is 1:4. It can be seen from Figure 2 that the styrene and silicium-containing aryl alkyne blended resin only has one curing exothermic peak in the DSC curve. It can be seen from Table 2 that the mass residual rate of the modified silicium-containing aryl alkyne resin cast body at 350℃ is 99.6%. In addition, the T d5 of the cast body is reduced by 23.3℃ compared with before modification, but is much higher than the limit use temperature of 350℃. In general, the addition of a certain amount of styrene does not significantly affect the heat resistance of the resin.

[0047] Example 3

[0048] A preparation method of a styrene modified silicium-containing aryl alkyne resin composite material, as shown in Figure 3 , the specific steps are as follows:

[0049] (1) uniformly stir styrene and silicium-containing aryl alkyne resin 1 glue solution to obtain a mixed glue solution, wherein the mass ratio of styrene to silicium-containing aryl alkyne is 1:5.7;

[0050] (2) using the impregnation method to make the quartz fiber fully impregnated with the glue solution to obtain a prepreg, after drying, cutting, layering, compaction, and then hot pressing at 100-300℃ to obtain a quartz fiber reinforced modified silicium-containing aryl alkyne composite material, wherein the mass percentage of quartz fiber is 50%.

[0051] In the process of preparing the mixed glue solution, it is found that the viscosity of the silicium-containing aryl alkyne resin mixed glue solution with added styrene does not change significantly compared with before adding, so it will not affect the process of impregnating the glue solution with quartz fiber later, that is, using styrene as a modifier can still maintain the good processability of the original resin, which is convenient for subsequent industrial production.

[0052] Table 3 Mechanical properties and dielectric properties of quartz fiber / silicium-containing aryl alkyne resin composite material before and after modification

[0053]

[0054] It can be seen from Table 3 that after the copolymerization modification of the silicium-containing aryl alkyne resin and styrene, the bending strength and modulus of the composite material at room temperature and 350℃ not only do not decrease but also slightly increase; the interlaminar shear strength at 350℃ increases from 12.01MPa before modification to 13.90Mpa, with an increase of 15.8%; the dielectric properties of the composite material are not affected.

[0055] Example 4

[0056] A preparation method of a styrene modified silicium-containing aryl alkyne resin composite material, the specific steps are as follows:

[0057] (1) stirring styrene and silicon-containing aryl alkyne resin 2 glue solution uniformly to obtain a mixed glue solution; wherein the mass ratio of styrene to silicon-containing aryl alkyne is 1:4;

[0058] (2) using the impregnation method to make the quartz fiber fully impregnated with the glue solution to obtain a prepreg, which is dried, cut, layered, compacted, and then hot-pressed at 100-300℃ to obtain a quartz fiber reinforced modified silicon-containing aryl alkyne composite material, wherein the mass percentage of quartz fiber is 50%.

[0059] Table 4 Mechanical properties of quartz fiber / silicon-containing aryl alkyne resin composite material before and after modification

[0060]

[0061] As can be seen from Table 4, after styrene copolymerization modification, the bending performance and interlaminar shear strength are greatly improved, especially at 350℃, the interlaminar shear strength of the modified composite material is increased by 98.3% compared with that before modification.

[0062] The above specific description further describes the purpose, technical scheme and beneficial effects of the application. It should be understood that the above description is only a specific embodiment of the application and is not used to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A method for improving the mechanical properties of silicone-containing aromatic resins, characterized in that: Includes the following steps: Step 1: Mix styrene and silanine resin solution evenly to obtain a mixed solution, wherein the mass ratio of styrene to silanine resin solution is 1:(2.3~9). Step 2: Dry the mixed adhesive solution to constant weight to obtain mixture 1; Step 3: Place mixture 1 in a vacuum oven at 70℃ until constant weight to obtain mixture 2; Step 4: Cure mixture 2 to obtain the modified resin casting. The curing process is the same as that for unmodified silyl aryl resin.

2. A method for improving the mechanical properties of siliceous aromatic yne resin composites, characterized in that: Includes the following steps: Step 1: Stir styrene and silanyl acetyne resin solution evenly to obtain a mixed solution; wherein the mass ratio of styrene to silanyl acetyne resin is 1:(2.3~9); Step 2: Impregnate the mixed adhesive solution with quartz fiber by brushing or other methods to obtain a composite material prepreg; after drying, cutting, laying, compacting and hot pressing, the composite material prepreg is used to obtain a quartz fiber reinforced modified siliceous aromatic yne resin composite material.

3. The method as described in claim 1 or 2, characterized in that: The solvent used in the silanol resin solution is one or a mixture of several of the following: acetone, tetrahydrofuran, dichloromethane, toluene, and xylene.

4. The method for improving the mechanical properties of silicone-containing aromatic resin as described in claim 1, characterized in that: The curing temperature range is 100–300℃.

5. The method as described in claim 2, characterized in that: The hot pressing process conditions are the same as those for the unmodified silyl aryl resin-based composite material.

6. The method as described in claim 5, characterized in that: The curing temperature for hot pressing is 100–300℃.

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