CN-121718173-B - Functionalized linear polycarbosilane modified vinyl silicone rubber composite material and preparation method and application thereof

Abstract

The invention provides a functionalized linear polycarbosilane modified vinyl silicone rubber composite material, and a preparation method and application thereof, and belongs to the field of ablation heat protection. The composite material comprises, by weight, 3-15 parts of ethoxy modified polycarbosilane, 100 parts of vinyl silicone rubber, 5-80 parts of functional filler and 0.5-10 parts of cross-linking agent. The invention adopts functionalized linear polycarbosilane to modify solid vinyl silicone rubber, and establishes chemical bond connection between filler and silicone rubber matrix through condensation reaction of hydroxyl structure between ethoxy and hydrophilic silicon dioxide. The introduction of the ethoxy modified polycarbosilane improves the crosslinking density and rigidity of the composite material, remarkably improves the overall heat protection performance of the composite material, particularly greatly improves the ablation resistance of the composite material in a high heat flow environment, ensures that the composite material has excellent mechanical property and ablation resistance at the same time, and has good application prospect in the field of ablation heat protection.

Inventors

• ZOU HUAWEI
• TIAN YUE
• YAN LIWEI
• SHI RONGJIE
• ZHOU SHENGTAI
• LONG LU
• CHEN YANG
• LIANG MEI

Assignees

• 四川大学

Dates

Publication Date

20260508

Application Date

20260213

Claims (9)

1. 1. The functionalized linear polycarbosilane modified vinyl silicone rubber composite material is characterized by comprising, by weight, 3-15 parts of ethoxy modified polycarbosilane, 100 parts of vinyl silicone rubber, 5-80 parts of functional filler and 0.5-10 parts of cross-linking agent, wherein the vinyl silicone rubber is solid silicone rubber, the vinyl silicone rubber is at least one of methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber and methyl vinyl trifluoropropyl silicone rubber, the functional filler is silicon dioxide, carbon fiber T700 SC or a mixture of silicon dioxide and carbon fiber T700 SC, and the ethoxy modified polycarbosilane has ethoxy and olefinic bonds.
2. 2. The functionalized linear polycarbosilane modified vinyl silicone rubber composite material according to claim 1 is characterized by comprising, by weight, 7-11 parts of ethoxy modified polycarbosilane, 100 parts of vinyl silicone rubber, 10-45 parts of functional filler and 0.5-2 parts of cross-linking agent.
3. 3. The functionalized linear polycarbosilane modified vinylsilicone rubber composite according to any one of claims 1-2, wherein the crosslinking agent is a peroxide crosslinking agent.
4. 4. The functionalized linear polycarbosilane modified vinylsilicone rubber composite according to claim 3, comprising the following raw materials, by weight, 9 parts of ethoxyl modified polycarbosilane, 100 parts of vinylsilicone rubber, 30 parts of silicon dioxide, and 1 part of a crosslinking agent.
5. 5. The functionalized linear polycarbosilane modified vinylsilicone rubber composite according to claim 3, comprising the following raw materials, by weight, 9 parts of ethoxyl modified polycarbosilane, 100 parts of vinylsilicone rubber, 30 parts of silicon dioxide, 15 parts of carbon fiber T700 SC, and 1 part of a crosslinking agent.
6. 6. The functionalized linear polycarbosilane modified vinyl silicone rubber composite material according to any one of claims 1-2, wherein the ethoxy modified polycarbosilane is prepared by uniformly mixing triethoxysilane and a catalyst, adding polycarbosilane, uniformly stirring, and reacting to obtain ethoxy modified polycarbosilane.
7. 7. The functionalized linear polycarbosilane modified vinyl silicone rubber composite according to claim 6, wherein the mass ratio of triethoxysilane, catalyst and polycarbosilane is 3-6..0.4-0.6..18-22.
8. 8. The method for preparing the functionalized linear polycarbosilane modified vinyl silicone rubber composite material according to any one of claims 1 to 7, which is characterized in that the method for preparing the functionalized linear polycarbosilane modified vinyl silicone rubber composite material comprises the following steps: (1) Mixing ethoxy modified polycarbosilane, vinyl silicone rubber, functional filler and cross-linking agent together according to parts by weight to obtain a mixed material; (2) And then placing the mixed material into a mould, and heating and curing according to a set program to obtain the functionalized linear polycarbosilane modified vinyl silicone rubber composite material.
9. 9. Use of the functionalized linear polycarbosilane modified vinylsilicone rubber composite of any one of claims 1-7 in the field of ablative heat protection.

Description

Functionalized linear polycarbosilane modified vinyl silicone rubber composite material and preparation method and application thereof Technical Field The invention relates to the field of advanced materials, in particular to a functionalized linear polycarbosilane modified vinyl silicone rubber composite material, and a preparation method and application thereof. Background With the rapid development of hypersonic aircraft, reusable vehicles and interstar reentry detection techniques, the aerodynamic thermal environment faced by the aircraft is becoming extremely complex. Intense pneumatic heating, intense thermal coupling effects, and complex structural deformations place unprecedented stringent demands on Thermal Protection Systems (TPS). Although the traditional rigid ablation heat-resistant material such as a carbon-phenolic resin matrix composite material is developed for many years, the inherent brittleness of the material leads to poor shock resistance and easy generation of microcracks, and the material is difficult to coordinate deformation with a flexible load-bearing structure under the action of thermal stress, so that the material becomes a key technical bottleneck for restricting the performance and reliability of a novel aircraft. Therefore, the development of a novel flexible ablation heat-proof material with high-efficiency heat insulation ablation performance and macroscopic flexibility has great strategic significance for the development of the aerospace technology in China. The material can effectively adapt to structural deformation and release thermal stress through self deformation, keeps the integrity and stability of a thermal protection layer, and plays a vital role in guaranteeing the structural safety of an aircraft under extreme thermal load and prolonging the service life. Under the background, the organic silicon rubber is an ideal matrix choice for developing a new generation of flexible ablation heat-proof materials by virtue of the unique material properties. The molecular main chain of the material has the high bond energy characteristic of inorganic-S-O-bond and the flexibility of the organic side group, so that the material has excellent thermal stability and high elasticity in a wide temperature range, and can maintain structural integrity without brittle fracture under extreme thermal shock. In the high-temperature ablation process, the silicon rubber is not simply decomposed, but a silicon dioxide-based ceramic residual layer with a porous structure is generated in situ through a series of complex physical and chemical changes, and the ceramic layer is firmly attached to an undegraded matrix, so that heat can be effectively prevented from being transferred to the inside, scouring of high-speed air flow can be resisted, high-efficiency cooperation between active consumption and passive heat insulation is realized, meanwhile, the inherent molecular flexibility of the prepared composite material enables the prepared composite material to have excellent flexibility and fatigue resistance on a macroscopic scale, and the composite material can perfectly adapt to deformation caused by complex structures and pneumatic loads of an aircraft, releases thermal stress, thereby overcoming the fundamental defect that the traditional rigid heat-proof material is easy to crack and fall. Therefore, the development of high-performance flexible ablative materials by taking silicone rubber as a matrix is one of the most promising technical approaches for coping with the severe requirements of the thermal protection system of the future aerospace vehicle. However, the ceramic layer formed by pure silicon rubber under the action of extreme heat flow for a long time has limited strength and insufficient anti-scouring capability, and in order to remarkably improve the ablation performance of the pure silicon rubber, a ceramic precursor such as Polycarbosilane (PCS) is introduced to form an effective modification path （Ding W, Yan L, Huang M, et al. Polymer, 2023, 285: 126319. Long L, Cai Y, Chi X, et al. PolymDegrad Stab, 2024, 225: 110775）., and the precursor can be converted into high-performance ceramic phases such as SiC, siOC and the like at high temperature, so that a compact, firm and anti-erosion complex-phase ceramic barrier layer can be constructed together with silicon dioxide generated by matrix pyrolysis, and the capability of resisting extreme aerodynamic heat-force coupling ablation of the material is greatly enhanced, thereby realizing long-acting heat insulation protection. However, in the polycarbosilane modified silicone rubber system, the compatibility between the polycarbosilane and other functional fillers and between the polycarbosilane and the solid silicone rubber matrix is poor, the interface bonding acting force is weak, and the ablation resistance of the obtained silicone rubber composite material cannot meet the use requirement under the extreme heat flow environ