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RTV silicones are made from a mixtures of silicone polymers, fillers, and organoreactive silane catalysts. Silicones are formed from a Si–O bond, but can have a wide variety of side chains. [3] The silicone polymers are often made by reacting dimethyl dichlorosilane with water. [4] Linear dimethylpolysiloxane polymer reaction
Solvent bonding differs from adhesive bonding, because the solvent does not become a permanent addition to the joined substrate. [4] Solvent bonding differs from other plastic welding processes in that heating energy is generated by the chemical reaction between the solvent and thermoplastic, and cooling occurs during evaporation of the solvent ...
It can be appreciated that the siloxanes would have low barriers for rotation about the Si−O bonds as a consequence of low steric hindrance. This geometric consideration is the basis of the useful properties of some siloxane-containing materials, such as their low glass transition temperatures .
Silicone caulk can be used as a basic sealant against water and air penetration. In organosilicon and polymer chemistry, a silicone or polysiloxane is a polymer composed of repeating units of siloxane (−O−R 2 Si−O−SiR 2 −, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in ...
When bonding plastics, in particular with solvent-based adhesives, diffusion processes can also play a role. In this case, the plastic at the substrate surface is dissolved by the solvent contained in the adhesive. This leads to an increased mobility of the plastic's polymer chains, which in turn allows penetration by those of the adhesive.
Polyurethane dispersion, or PUD, is understood to be a polyurethane polymer resin dispersed in water, rather than a solvent, although some cosolvent may be used.Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG (polyethylene glycol) incorporated into, or pendant from, the polymer backbone. [1]
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Adhesive bonding with organic materials such as BCB or SU-8 has simple process properties and the ability to form high-aspect ratio micro structures. The bonding procedure is based on polymerization reaction of organic molecules to form long polymer chains during annealing. This cross-link reaction forms BCB and SU-8 to a solid polymer layer. [3]