Alkyl and Aromatic Esters

Unsaturated carboxylic acids such as meth- acrylic acid, crotonic acid, vinylacetic acid, and sorbic acid and aromatic carboxylic acids reacted with terminal ace- tylenes in the presence of a catalytic amount of bis(05- cyclooctadieny1)ruthenium-P-n-Bui3n benzene a t 80 "C to give enol esters having a terminal methylene group in excellent yields with high regioselectivity.

This invention is directed to a fast curing polymer composition which does not require baking or thermosetting to provide a cross-linked coating binder. The composition comprises a polymer which is a homopolymer or copolymer of alpha, beta unsaturated monomers having pendent acetylenic groups which cross-link upon air drying to provide a coating binder.

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.

Phenolic materials containing propargyl groups are prepared by reacting a polyhydric, phenolic material with propargyl bromide, the reaction being conducted in an aqueous sodium hydroxide solution. The products can be thermally polymerized to polymers which are useful as adhesives and as matrix resins in the fabrication of composites

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.

Anionic polymerization of 2-propynyl methacrylate (1), 3-trimethylsilyl-2-propynyl methacrylate (2), 2-butynyl methacrylate (3), and 3-pentynyl methacrylate (4) was carried out in tetrahydrofuran at −78°C for 1 h. The employed initiator systems were (diphenylmethyl)potassium/diethylzinc (Et2Zn) and 1,1-bis(4′-trimethylsilyphenyl)-3-methylpentyllithium/lithium chloride (LiCl).

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 has been polymerized by free-radical methods and found to yield a soluble polymer in carbon tetrachloride, dioxane, and diallyl ether solutions. The overall rate equation in diallyl ether is Rp = k[ln]0.7[M]1.6. It is suggested that propagation and cyclization reactions proceed only via addition to the methacrylyl groups of the monomer. Some degradative chain transfer occurs with the allyl groups, and it is considered that the solvents may ensure the production of soluble polymers by reactions in which allyl–radical side chains are terminated without crosslinking.

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.

The adhesive bond of allyl 2-cyanoacrylate between steel substrates has been analyzed and compared to that of ethyl 2-cyanoacrylate. Mechanical strength as well as thermomechanical, calorimetric, thermogravimetric, and dynamic mechanical response was observed. It was demonstrated that the allyl 2-cyanoacrylate bonds exhibit improved temperature resistance owing to the formation of heat-induced crosslinks in the adhesive layer, resulting in much improved lap-shear strengths.