Preparation Of Silicon-containing Arylacetylene Resin And Research On Its High Temperature Resistant Adhesiv

Organic heat-resistant adhesive plays an important role in the structural connection of aerospace vehicles.Its application environment,bonding properties,use process and thermal stability put forward strict requirements on the structure of the main resin and modified components of the adhesive.Silicon-containing arylacetylene resin has excellent heat resistance,high thermal decomposition temperature and high carbon residue rate at high temperature,low room temperature viscosity,wide processing range and low curing temperature,so it has good application potential in high temperature resistant adhesives.In this paper,several silicon-containing arylacetylene resins were synthesized,and high temperature resistant adhesives were prepared by modification of polyimide,phthalonitrile and inorganic fillers.The heat resistance,adhesion and processability of the adhesives were studied.In this paper,1,3-dibromobenzene and 2-methyl-3-butyne-2-ol were used to synthesize the intermediate product by Heck reaction,and then m-diethynylbenzene was prepared by deacetone.The structure of m-diethynylbenzene was characterized by FT-IR,¹H-NMR,differential scanning calorimetry（DSC）and high performance liquid chromatography（HPLC）.Methyl phenyl silicon-containing aromatic alkyne（MPSA）resin,phenyl vinyl silicon-containing aromatic alkyne（PVSA）resin,diphenyl silicon-containing aromatic alkyne（PPSA）resin and methyl vinyl silicon-containing aromatic alkyne（MVSA）resin were synthesized by the reaction of m-diethynylbenzene with methyl phenyl dichlorosilane,phenyl vinyl dichlorosilane,diphenyl dichlorosilane and methyl vinyl dichlorosilane,phenyltriphenylethynylsilylarylacetylene（PTPESA）resin was synthesized from phenylacetylene and phenyltrichlorosilane,and they were characterized by FT-IR,¹H-NMR,DSC curing behavior analysis,TGA and DMA heat resistance.The curing behavior of MPSA resin was studied,and its chemical rheological properties were analyzed and characterized.The results showed that the prepared silicon-containing arylacetylene resin showed excellent heat resistance and processability.The viscosity of MPSA resin was below 10 Pa·s from 40℃ to 210℃,T_d5was 583℃,and Y_r800 was 88%,which could be used as the main body or modified resin of high temperature resistant adhesive.Then,the acetylene-terminated polyimide（AtPI）was prepared and characterized by FT-IR and ^IH-NMR.The MPSA resin was modified by AtPI,thermoplastic polyimide and bisphthalonitrile（BPh）to prepare a high temperature resistant adhesive.The curing properties and heat resistance of the adhesive were studied by DSC and TGA.The room temperature and high temperature bonding shear strength and dielectric properties of the adhesive were tested.The results showed that the short-chain MPSA had good compatibility with the modified resin.The modified MPSA adhesive showed good high temperature thermal stability and high temperature bonding performance.T_d5was above 532℃ and Y_r800 was above 78%.The SEM image of the fracture surface of the modified MPSA resin shows that the failure mode is ductile failure.The shear strength of MPSA-551 adhesive at room temperature and 450℃ was 13.5 MPa and 4.8MPa,respectively.The shear strength of MPSA-5 adhesive at room temperature and450℃ was 10.7 MPa and 7.5 MPa,respectively.Finally,the MPSA adhesive doped with inorganic fillers was studied,and its curing,heat resistance and bonding shear strength were analyzed.The results showed that B₄C was helpful to improve the heat resistance and bonding shear strength of MPSA adhesive.