Adhesive Properties of Cured Phenylethynyl Containing Imides

Considerable attention has been directed towards acetylene terminated oligomers over the last 20 years' and recent work has focused on phenylethynyl terminated imide (PETI) oligomers. These reactive oligomers possess several features which make them attractive candidates for use as composite matrices and adhesives. The phenylethynyl group can be readily incorporated into many different functionalized oligomers. The reactive oligomers possess relatively low melt viscosities and thermally cure without the evolution of volatile by-products. Once cured, they typically display high glass transition temperatures (Tgs), excellent solvent resistance and high mechanical properties. new modified phenylethynyl-terminated imide (LaRC MPEI) oligomers were synthesized at various molecular weights utilizing a small amount of trifunctional amine. As long as the amount of triamine is relatively small, this approach produces a mixture of linear, star-shaped and branched polymer chains that has lower melt and solution viscosity than an equivalent molecular weight linear phenylethynyl terminated imide oligomers. The work reported herein involves the synthesis and characterization of a copolymer using this approach and the preparation of blends utilizing a phenylethynyl containing reactive plasticizer of lower molecular weight called LaRC LV-121. The chemistry and properties of this new MPEI as well as some blends of MPEI with LV-121, are presented and compared to the linear version, LARC-PETI-5.