Synthesis Of Poly(Phthalazinone Ether Nitrile Sulfone Ketone)S And Its Application In High-temperature Adhesive

Aromatic heterocyclic polymers possess outstanding thermal stability, excellent mechanical properties and chemical stability in the result that they have been widely explored in application of high temperature adhesives. In general, traditional heat resistant adhesive are composed of many additives such as curing agent, filler and promoter to improve their properties, which always cause not only their cumbersome processing but also the costly problems. In this paper, amino and epoxy end-capped poly(phthalazione ether nitrile sulfone ketone)s (PPENSK) were designed and synthesized and then used to produce a kind of heat resistant adhesive. The reaction of amino group and epoxy group in the end of main chain of PPENSK can form cross-linked network to give the resulting polymer excellent thermal stability and good adhesion to a variety of matrix.Two kinds of end-capped poly(phthalazinone ether nitrile sulfone ketone)s (PPENSK), were prepared designed and prepared from the nucleophilic displacement polycondensation reaction of4-(4-hydroxylphenyl)(2H)-phthalazin-l-one with bis(4-chlorophenyl) sulphone, bis(4-fluorophenyl)ketone in the present of anhydrous potassium carbonate as catalyst, toluene as dehydrant and dimethyl sulfoxide as reactive medium. End-capped PPENSK reacted further with amino phenol and epoxy chloropropane to obtain amino-PPENSK and epoxy-PPENSK. Different end-capping methods were investigated. The obtained amino-PPENSK and epoxy-PPENSK were characterized by FT-IR and1H-NMR.Five kinds of adhesives were then prepared by blending different molecular weight amino-PPENSK and epoxy-PPENSK. The effects of the molar ratio of amino-PPENSK to epoxy-PPENSK and their molecular weight on the gel content of cured polymers and the shear strength of the resulting adhesives were investigated in details. The max gel content up to96%was obtained when the molar ratio of amino-PPENSK to epoxy-PEENSK was one to one. Under the condition of the same molar ratio,the largest shear strength was22.7MPa.With the increase of molecular weight, The gel content of adhesives as well as the shear strength all presents the downward trend.For low molecular weight amino-PPENSK/epoxy-PPENSK adhesive system, lower curing temperature should be used, while higher curing temperature process should be used to cure higher molecular weight adhesive system.The high temperature mechanical properties of five groups of adhesives had been explored. The results indicated that the highest shear strength at room temperature was up to 48.7MPa, with the shear strength at450℃up to14.2MPa and at500℃up to10.1MPa, respectively, was obtained when amino-PPENSK had the average number molecular weight of3000and epoxy-PPENSK had that of6000. All of five adhesives derived from amino-PPENSK/epoxy-PPENSK exhibit higher shear strengths at350～450℃,and shear strength were mainly from14MPa to30MPa.