Linear polymers of some vinyl monomers containing a terminal acetylenic group

The synthesis and polymerization of representative acrylic‐type esters containing a terminal acetylene group, CH2C(R)COO(CHR′)mCCH, where R and R′ are H and CH3 and m = 1 or 2, by anionic initiation to linear polymers are described. In contrast, crosslinked polymers were formed when radical and cationic initiators were used. Crosslinked polymers were also obtained with organolithium compounds but not with sodium naphthalene and sodium benzalaniline; this observation is discussed and compared to the behavior of the acetylenic acrylic esters which do not contain a terminal acetylenic hydrogen. The unpolymerized acetylenic bonds in the resulting linear polymers were shown to be present by infrared spectroscopic methods and by the following post‐reactions of these bonds: (1) the heat‐ and radical‐initiated crosslinking of the polymers through the acetylenic bonds; (2) the post‐bromination of the acetylenic bonds; and (3) the reaction of decaborane with the acetylenic bonds. The anionic copolymerization of acrylonitrile and styrene with these acetylenic monomers were performed and compared to the copolymerizations with 1‐acryloxy‐2‐butyne and 1‐methacryloxy‐2‐butyne. Dibromination of the linear polymers affords self‐extinguishing polymers, while decaboronation yields soluble polymers which do not soften up to 300°C. The linear polymers may be classified as “self‐reactive” polymers which yield thermosetting polymers.