Technical documentation

The synthesis of methacrylates having an acetylene moiety activated by an electron-withdrawing group and a radical polymerization of the methacrylates are described. The methacrylates were prepared from alkynoic acids via ω-hydroxyalkyl alkynoates in two steps. This was done by the radical polymerization of the synthesized methacrylates, polymthacrylates having the acetylene moieties activated by the electron-withdrawing group as the side-chain that were obtained in high yields.

The conditions for the Knoevenagel synthesis of 2-cyanoacrylates containing double and triple bonds in the alkoxycarbonyl group have been studied. It was found that the esters are formed in 10–70 % yields by the condensation of the respective cyanoacetates with formaldehyde in the 1∶1 ratio in the presence of piperidine, followed by the pyrolysis of the oligomers formedin vacuo at 170–200 °C in the presence ofpara-toluenesulfonic acid.

The thermal degradation of poly(allyl methacrylate) has been investigated using thermal volatilisation analysis (TVA), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The main pyrolysis products have been identified and the characteristics of the reactions deduced and discussed. Mechanisms have been proposed to account for the products formed.

Allyl methacrylate, AMA was polymerized in CCl4 solution by α,α′‐azoisobutyronitrile at 50°C. The thermal degradation mechanism of PAMA was characterized by MS, TGA‐FT‐IR and FT‐IR‐ATR methods. The mass spectrum and TGA thermogram showed two stage degradation. The first stage of degradation was mostly linkage type degradation for the fragmentation of pendant allyl groups at 225–350°C. In the second stage, at 395–515°C, the degradation is random scission and depolymerization types. This was also supported by direct thermal pyrolysis of polymer under vacuum.