Cyanoacrylates are solvent free adhesives that cure rapidly when pressed into a thin film between two surfaces. Their ease availability and use in various formulations made them attractive to manufacturers a wide variety of medical devices. Unfortunately, earlier generations of cyanoacrylates had several limitations, such as poor thermal resistance and peel strength. Subsequent developments in cyanoacrylate technology have greatly expanded the performance of these adhesives.
The glass transition temperatures of the poly(alkyl α-cyanocrylates) were determined by the dilatometric technique, and some of the values were checked by differential thermal analysis. The data indicate that the Tg's appear to decrease with increase in the size of the alkyl group, for a given molecular weight range. It was also found that the Tg of poly(methyl or butyl α-cyanoacrylate) increased with molecular weight. All cyanoacrylates, excepting methyl and ethyl esters, formed only low molecular weight polymers in aqueous surroundings.
Various developments in the synthesis of alkyl 2-cyanoacrylates, their analytical and test methods, adhesive compositions for different applications including those in the medical field, handling and storage, and health and safety hazards are reviewed.
Twenty-six alkyl, alkenyl, cycloalkyl, and substituted alkyl 2-cyanoacrylates were synthesized in the pure state. The purity was determined by gas-liquid chromatography, and a correlation between the log retention time and the number of carbons in the compounds within the homologous series was deduced. Their physical properties such as parachor and molar refraction were determined and the data were fitted to a linear relation to the number of carbons present in the ester within a homologous series of cyanoacrylates.
The effect the curing conditions on the properties of adhesive joints formed using cyanoacrylate-based adhesives is investigated. The temperature dependences of relative rigidity and mechanical loss tangent are studied by torque analysis for poly(ethyl-, allyl-, allyloxyethyl-, allyloxyisopropyl-, propargyloxyethyl-, and propargyl-) cyanoacrylates after their thermal treatment in the temperature range of 20–250°C. The glass transition parameters of polycyanoacrylates and the dependence of the curing intensity on the structure of initial monomers and polymers are determined.
Cyanoacrylate polymers are commercially important materials as structural ad- hesives. They combine rapid curing and high strength and are widely used to bond a diverse range of substrate surfaces, including metals, ceramics, plastics, rubbers, and biologically derived materials. The corresponding monomers were first isolated in 1947 by Ardis at B. F. Goodrich (1). Subsequently, Eastman Ko- dak patented them as adhesive compositions in 1957 (2) and the first commer- cial adhesive formulation, based on methyl 2-cyanoacrylate, was introduced in 1958 (3).
Instant adhesives (cyanoacrylate adhesives ) are one-part solvent-free adhesives that cure immediately at room temperature and offer strong bonding strength. Instant adhesive was first developed in 1949 by Alan E. Ardis at Goodrich Company in the U.S., and was later developed into a product by F. B. Joyner and G. F. Hawkins at Eastman Company and marketed as Eastman 910 in 1959. Since then, various adhesive manufacturers around the world have improved and modified methods of synthesizing the main components, monomer.
Instant Adhesives (cyanoacrylate-based) sets instantly at room temperature, has powerful adhesive strength, has only one easy-to-use component, and contains no dangerous solvents. Development of the adhesive began in 1949 by Alan E. Ardis of Goodrich Corporation in the US. Then in 1959 it was introduced into the market by FB Joyner and GF Hawkins of Eastman Corporation as Eastman 910. Later improvements and modifications of the synthetic method of the major-ingredient monomer were performed by the leading adhesive manufacturers.
As already described in Three Bond Technical News 21, instant adhesives are one-part solvent-free adhesives that cure rapidly through polymerization at room temperature. These adhesives are used in a wide range of applications across various industries as a result of their strong adhesive strength. However, instant adhesives includes some disadvantages: low resistance to heat, water, and impact. Numerous patents and reports have been submitted on methods of improving these properties.
Water-borne pollutants, particularly those of oelaginous nature, may be treated with monomers which polymerize in the presence of moisture, preferably, monomeric esters of 2-cyanoacrylic acid. Upon polymerization, significant portions of the pollutant are incorporated within a polymer matrix, thus reducing the danger to shore and marine ecology and aesthetics.
