Physically drying

The initial drying of currently applied alkyd paints is accomplished by evaporation of solvent (physical drying). Subsequently, the eventual curing of the alkyd paint is completed by the formation of a polymer network, which is mainly formed by chemical crosslinks (oxidative drying) but in some cases also physical interactions between the fatty acid side chains occur, such as crystallization or proton-bridge formation [129]. Efficient network formation is crucial in the formation of dry films with good mechanical properties. Due to the presence of unsaturated units in the investigated LOFA- and TOFA-PHA bin-... 

The common methods for the multi-site adsorption of DNA on carbonaceous-based material can be classified into physical (dry and wet) adsorption and electrostatic adsorption. 

These essentially comprise a mixture of a skin-forming component, which comprises two distinct phases blended together, a high zero-shear viscosity material and a low zero-shear viscosity material, and a foam core-foaming component, which includes a blowing agent, physically dry blended together. The three materials are preferably selected from suitable homopolymers and copolymers of ethylene. CANADA... 

Physical Dry heat (>160°C) Sterilization Less effective than moist heat... 

The physicallydried binding agents include acrylic resins, polyesters, silicones, cellulose derivatives and others. Polyamides and polyolefins are used as raw material for powder lacquers. Differing from physically dried lacquers, chemically dried lacquers contain crosslinked macromolecules. The raw materials used as binding agents can in this case be used without solvents because of their low viscosities and react with the substrate by one of the above mentioned polymerization reactions. 

Rico, E., Toldra, F., and Flores, J. (1990). Activity of cathepsin D as affected by chemical and physical dry-curing parameters. Z. Lebensm. Unters. Forsch. 191, 20-23. 

Physical dry etching or sputter etching and ion Anisotropic profile is... 

Fluid displacive resin-embedding of wet sediment is a passive procedure, samples are never physically dry and the fabric is supported by fluid throughout. Chemical dehydration prevents the cracking (common in vacuum dried sediment), and the technique requires no specialized drying, or resin-impregnating equipment. Water-saturated samples are more successfully embedded using fluid replacement than those which are partially dry. 

Plastisols and organosols are a special case of physically drying coatings systems in which the binders consist of finely dispersed poly( vinyl chloride) or thermoplastic poly(meth)acrylates suspended in plasticizers. Organosols also contain some solvent. On drying at elevated temperatures, the polymer particles are swollen by the plasticizer, a process known as gelation. 

Chlorinated rubber and related chlorinated polymers form coating films by physical drying. Plasticizers or resins have to be added since otherwise brittle films are formed. 

Chlorinated Rubber-Acrylic Resin Combinations. Physically drying acrylic resins are used for these combinations. These combinations have the same drying rates as normal chlorinated rubber paints (see Section 2.3.2). They have improved flow properties (particularly when applied by pouring techniques), improved weather resistance (chalking and yellowing), and favorable mechanical properties (adhesion and extensibility). Applications include topcoats for ship superstructures and priming coats on galvanized surfaces. 

Paints and coating materials based on vinyl resins are generally physically drying. Only in a few cases vinyl resins can be chemically cross-linked with other reactants via incorporated reactive groups. The properties of the paints are therefore primarily determined by the chemical and physical nature of the vinyl resin. Despite the large number of available vinyl resins this class of binders has some common features. 

Linear, low molecular mass polyester resins are available with molecular mass up to 7000 branched grades have a molecular mass of up to 5000. These resins are not suitable for physically drying paints they should be regarded as prepolymers for reaction systems with cross-linking resins. Classes of polyester prepolymers, their preferred cross-linking agents, and uses are summarized in Table 2.4. 

Novolacs are solid at normal temperature and generally have a well-defined melting point. The largely inert behaviour of novolacs means that they can only be used for physically drying paints and coatings. They are extremely good soluble in polar solvents such as alcohols, ketones, and esters, but are insoluble in aromatic and aliphatic hydrocarbons (e.g., xylene, benzene). Spirit varnishes are novolacs dissolved in alcohol that are primarily used as unpigmented varnishes they have an... 

Depending on the application, relatively hard distillation bitumen, oxidation bitumen, or high-vacuum bitumen (hard bitumen) are used for physically drying bitumen paints. Waterborne bitumen paints and thick coatings (bitumen emulsions) are produced from moderately hard distillation bitumen. 

Film formation occurs via evaporation of water from the paint film and coalescence of the high molecular mass binders the release of water takes place relatively quickly (physical drying). The minimum film-forming temperature depends on the chemical structure of the polymers. Film formation can be facilitated by the addition of organic solvents (e.g., alcohols, butylglycol ethers) or by the action of heat. 

Hybrid Systems. Combinations of water-soluble and water-dispersed binders may be used to achieve synergistic effects (e.g., to control the amount of organic solvents or the application behavior). Polymer dispersions or powdered binders may be used as water-dispersible binders [3.43]. The use of polymer dispersions allows the solids content of water-soluble binders to be increased, the level of organic solvents to be reduced, and the physical drying time to be shortened. The use of water-soluble binders provides a broad application spectrum and yields paint films with well-balanced properties. 

Neutral paint strippers include halogen-free organic solvents (e.g., glycols, glycol ethers, l-methyl-2-pyrrolidinone) which are generally used at 20-40°C. In contrast to the alkaline paint removers, neutral paint strippers result in purely physical dissolution of the paint from the substrate. Their use is therefore restricted to removing physically drying paints. 

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