Adhesive glass cyanoacrylic

Epoxies generally have excellent adhesion to metals, ceramics and glass, although on most amorphous thermoplastics epoxies will usually he outperformed by MMA, UV adhesives or cyanoacrylates. Epoxies will bond well to thermoset plastics and are widely used for bonding sheet moulding compound door and body panels in the transportation industries. Epoxies do not adhere well to elastomers, fluoropolymers or polyolefin plastics. 

Super glue is a polymer of methyl cyanoacrylate. Because both the cyano and carbonyl groups of the monomer help stabilize carbanions, this compound is sensitive to polymerization by the anionic mechanism. The tube of glue contains very pure monomer, which does not polymerize until it contacts an initiator. However, contact with any nucleophile causes rapid polymerization. Therefore, when the tube is opened, polymerization is initiated by water in the air, by SiOH groups on a glass surface, by FeOH groups on an iron surface, or by various nucleophiles that are part of the proteins in skin. The adhesion between the polymer and the surface to which it is applied is very strong because the polymer chains are covalently linked to the nucleophiles that are part of the surface ... 

The directives apply to all materials used in the make up of electrical and electronic components and include paint, plastics, adhesives and rubbers, plastic parts, protective coating materials, epoxy adhesives, cyanoacrylate adhesives, polyurethane adhesives as well as complete computer motherboards. Computer and peripheral equipment are made up of different materials consisting of plastic, ferrous and non-ferrous metals, trace heavy metals, glass, foams, rubber, carbon powder and additives. Other non-metal materials posing environmental and health problems present in electrical and electronic products are beyond the scope of this book and will not be discussed here. The supportive components used in these products fall within the following ten product categories in the directive which are ... 

In many cases, glass and even porcelain bondings are carried out as repairs in households. In such cases, it has to be pointed out that, compared to the two-component reactive adhesives, in particular epoxides, cyanoacrylates show only a limited bond strength in the face of high temperature and humidity stress in connection with rinsing agents in the cleaning equipment. 

The importance of the transscleral route in the penetration of topically administered macromolecules was demonstrated by denying corneal access by affixing a glass cylinder to the corneoscleral junction with cyanoacrylate adhesive (44). Significant intraocular levels of inulin (5 kDa) were obtained by topical administration outside the cornea in their paradigm. Neither reentry from the general circulation nor delivery by local vasculature accounted for the intraocular levels of the drug. 

Grinder-Polishers with extra wheels and Minimet (Buehler), the latter with slide holder for thin sections 2 Glass plates (300x300 mm) Vacuum impregnator Epoxy and hardener and polyethylene cups (several varieties of each) Cyanoacrylate adhesive (Super Glue )... 

During the transformation of a monomer into a polymer, many atoms separated by van der Waals distances ( 5 A) participate in the formation of covalent bonds (1-3 A). Therefore during polymerization, an increase in the macroscopic density ensues, while on the molecular level a decrease in free volume and entropy occurs while the cooperativity of motions increase. Concomitantly the glass temperature can increase by more than 100 °C. Several important adhesive systems are based on this increase. The cyanoacrylate Super Glue starts as a monomer with a Tg <0 °C and it polymerizes to a linear soluble polymer with a Tg which is in the neighborhood of 100 °C upon appUcation under anaerobic conditions. For linear polymers the simple equation [74]... 

Environmental performance The durability (see Durability - fundamentals) of cyanoacrylate adhesive bonds is reasonably good on rubbers and some polymer substrates. However, on glass and metals, both thermal and moisture durability are low. 

Moisture resistance This may be increased on metal and glass substrates by including cross-linking agents, which may yield a more hydrolytically stable polymer or by using hydrophobic monomers such as fluorinated cyanoacrylates. Silane adhesion promoters also improve moisture durability. There is also evidence to suggest that inclusion of some of the anhydrides described above has a beneficial effect. 

Disadvantages of cyanoacrylate adhesives include poor thermal and moisture resistance on metals and glass, brittleness, sensitivity to surface preparation and poor cure through... 

Methyl-2-cyanoacrylate n. A fast setting adhesive used for bonding cellulosics, nylon, polyesters, acrylics, polystyrene, and polyurethanes to each other and to other materials such as woods, metals, and glass. Catalyzed by atmospheric moisture or lightly applied methanol, the adhesive polymerizes without loss of solvent. For best results, the surfaces to be bonded should mate closely. 

Cyanoacrylate polymers (Figure 8.2, Table 8.3 also see Figure A3.41) are polymerized in situ from monomers (Schoenberg, 1990). The reaction is initiated in the film of moisture on the surface. It is thus dependent on the nature of the surface and the relative humidity of the air. Alkaline surfaces such as glass promote rtqtid adhesion, whereas acid surfaces such as wood require polymerization activators. 

On the exterior of the vehicles, rubber profiles around windows and doors and the trunk lid are "lap bonded with cyanoacrylate adhesives because continuously extruded profiles cannot be used for sharp comers. To obtain effective sealing and better sliding in the case of sliding windows, these profiles are flocked by means of polyurethane-based flocking adhesives. The lenses of headlamps are joined to the housing by polyamide or polyurethane hot-melt adhesives and epoxy resins. The layers of laminated safety glass are bonded with a film based on poly(vinyl butyral). 

---