Synthesis And Modification Of Bismaleimide Resin With Adamantane Structure

Bismaleimide,which is one of the most promising resins to replace epoxy resin in the future,is often used in aerospace,precision electronics and other fields because of the good heat resistance,corrosion resistance and radiation resistance.However,the short chain structure,high symmetry and easy crystallizability of diphenylmethane bismaleimide has some processability problems such as poor solubility and narrow processing window,and the brittleness of the cured material is large,which leads to the limited application range.The conventional chain-expanding modificationamine and allyl compounds can not solve all the above problems.Therefore,the design and synthesis of bismaleimide from the structure is one of the main ideas to solve the above process problems.Because of special large-volume cage structure and physical and chemical properties,adamantane was introduced into polymer chain structure to improve its propertiesIn this paper,we design the introduction of large-volume adamantane into bismaleimide,one hand,the larger volume hinders the close accumulation of molecular chains,improves the solubility and improves the processing performance.On the other hand,the heat resistance of adamantane structure is good,which can maintain the heat resistance of bismaleimide.In this paper,the synthesis and copolymerization modification of bismaleimide resin with adamantane structure were carried out as follows:A novel bismaleimide with adamantane structure was designed and synthesized by adamantane diamine and maleic anhydride in consideration of insoluble and thermal property.The chemical structure of intermediate products and synthetic resins was determined by FT-IR and ¹H NMR.The results of the performance analysis show that due to the introduction of high heat-resistant,large-volume adamantane structure,the bismaleimide exhibited outstanding solubility in many organic solvents,such as solubility in chloroform over 40mg/m L;increased the processing window of diamine modified bismaleimide(114?);the cured product has excellence thermal stability,10%thermal decomposition temperature(T₁₀)above 470?.The decrease of water absorption of modified resin because of the hydrophobicity of adamantane structure.In order to improve the processability and practical value of resin matrix,a copolymerized resin was produced by copolymerization of diallyl bisphenol A with diphenylmethane and adamantane bismaleimide.The reaction of“ene”and“Diels-Alder”occurred mainly in the copolymer resin,and the apparent activation energy was slightly different from that of the traditional copolymerization system by phenomenological analysis.Moreover,The copolymer resin with 10%content of amantadane bismaleimide resin showed excellent comprehensive properties,the bending strength 117.4 MPa,the bending modulus3.77 GPa,thermal decomposition temperature above 420?,and water absorption of 120 h in70?hot water below 2%.In order to improve the mechanical and thermal properties of adamantane bismaleimide copolymer resin,the properties of composites were studied by using lamellar aluminophosphate as reinforcing material.As a result,the modified aluminophosphate by coupling agent aminopropyltriethoxysilane could be well dispersed in the matrix,and the binding ability with the matrix was perfect,a single 1wt%of incorporation can improves performance.Compared with pure resin,the thermal properties of composites were greatly improved,the residual amount of 600?was 30%in air atmosphere,and the glass transition temperature(Tg)was increased by 25?.Meanwhile,the composite had good mechanical properties,the storage modulus was 2.67 GPa,60%increased;the bending modulus was 137.4 MPa,17% increased.