Solvents bonding

In particular for medical assemblies, the solvent bonding technique has been suggested. The method of solvent bonding includes the steps of (43,44)  

Providing a second article of a material of low crystallinity polymers, 

Applying a solvent to one of the articles to define an interface area, and 

Bonding the first article to the second article along the interface area. 

The first article may be a polymer composition with a COC as basic material. Suitable low crystallinity polymers to fabricate the second article include COCs and blends of COCs with poly(methyl pentene), other polyolefins, and styrenics. 

The high solvent resistance of PP prevents the solvation of the moulding surface, and, therefore, solvent bonding is not possible. 

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The rubber in unvulcanised filler-rubber mixes which is insoluble in a usual rubber solvent. Bonding Agent... 

One of the problems encountered when dealing with the interaction of Lewis acids and bases in a quantitative way is in evaluating the role of the solvent. Bond energies in molecules are values based on the molecule in the gas phase. However, it is not possible to study the interaction of many Lewis acids and bases in the gas phase because the adducts formed are not sufficiently stable to exist at the temperature necessary to convert the reactants to gases. For example, the reaction between pyridine and phenol takes place readily in solution as a result of hydrogen bonding ... 

Evaporation of the excess ether results in the formation of an "etherate" containing the solvent bonded to the magnesium. Generally, the formula for this product is represented as RMgX2-2R20, and the... 

Apart from the qualitative observations made previously about suitable solvents for study, the subject of solvates has two important bearings on the topics of thermochemistry which form the main body of this review. The first is that measured solubilities relate to the appropriate hydrate in equilibrium with the saturated solution, rather than to the anhydrous halide. Obviously, therefore, any estimate of enthalpy of solution from temperature dependence of solubility will refer to the appropriate solvate. The second area of relevance is to halide-solvent bonding strengths. These may be gauged to some extent from differential thermal analysis (DTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) solvates of "aprotic solvents such as pyridine, tetrahydrofuran, and acetonitrile will give clearer pictures here than solvates of "protic solvents such as water or alcohols. 

The strength of a solvent bond influences the rate of solvent substitution in a given compound. Kinetic measurements by means of the T-jump relaxation technique have illustrated that for the reactions of the solutions of SbCl5 with triphenylchloromethane in different solvents a relationship exists between the rate constant and the donicity of the solvent used. 

As a cavity has to he opened in a solvent in order to introduce a solute, the strength of the solvent-solvent bonding will be a factor in determining solubility. The cohesive pressure, c, is defined by eqn. 3.1. 

Clear polyester sheet stock and rods are available13 and, like reinforced polyester plastic, may be drilled, sawed, and machined. This clear plasic is harder than poly(methyl methacrylate) and much more solvent resistant than either po-lyfmethyl methacrylate) or polystyrene. As with all thermosetting plastics, it may not be heat-formed or solvent-bonded. However, bonding with epoxy cements is satisfactory. This plastic is claimed to give continuous service at 80°C and intermittent service up to 150°C. 

Polystyrene is an inexpensive transparent plastic which is often used in industry for the fabrication of parts by injection moulding. However, the tougher acrylic plastics are preferable for the construction of laboratory apparatus. Polystyrene is soluble in many organic liquids and, if strain free, may be solvent-bonded by the use of chlorinated hydrocarbons, benzene, or toluene. Special impact-resistant grades are available which are less susceptible to solvents and thus a little harder to solvent-bond than the conventional material. Polystyrene also may be welded. 

Figure 2.17 Schematic representation of a simplified fabrication process used for proposed GNEE NCE microchip, (a) Contact electrode exposure, (b) electrode developing, (c) platinum etching, (d) GNEE direct bonding, (e) master fabrication, (f) hot embossing, (g) alignment, and (h) low temperature solvent bonding [146],...

Version (b). This design of meander mixer was actually realized. It refers to a structure with a large number of mixing elements which was micro-machined by precision milling in a plastic material [47]. Irreversible sealing of the channel was accomplished by insertion of a thin PMMA foil via solvent bonding. 

The Standard includes a definition too for solvent bonding solvent welding (see Chapter 6). 

Solvent Bond dissociation energy (kcal/mol)a Polarity (ET(30)) (kcal/mol)b... 

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