Synthetic binders properties

Most synthetic binders are softer and more flexible thant hard resins. Consequently, they impart good elasticity, impact resistance, and improved adhesion, even to critical undercoats, as well as offering adequate resistance to weathering and chemicals. These binders are produced with a property profile tailored to suit particular application methods and to comply with a range of technical requirements, including environmental protection, low toxicity, and suitability for recycling and disposal. 

Powder coatings have been widely accepted in the industrial coating market because they are completely solvent free and show excellent mechanical and physical properties (13). Usually they contain a synthetic binder, a reactive cross-linker, pigments, and several additives to improve flow and other film eharacteristics. Various application techniques have been developed in reeent years. Powder coatings are normally sprayed electrostatically on grounded substrates and are heat-cured thereafter. Because these systems do not contain organic solvents, no emission of organic solvents takes place. However, the need for an oven to melt the resin and start the chemical reactions makes this environmentally friendly process unsuitable for do-it-yourself markets. 

Over the last few years, the industry has developed synthetic binders that can be coloured in any colour with relatively less cost. Synthetic bitumens have almost the same properties as common paving bitumens. More information can be found in Shell Bitumen (2003) and the Web. 

The components of the synthetic binders can be transparent or opaque, virgin or recycled. These different properties improve the technical versatility of these materials. In addition, synthetic binders can be used to modify other characteristics, such as colour or properties of environmental interest, when recycled materials are employed. 

As mentioned previously, the difficulties in obtaining colourable blends from bitumen mixtures have forced the research and production of synthetic substances which are easily colourable, with mechanical properties similar to those of bitumen, allowing their use in most applications where coloured mixtures are advised. These products, known as binders or light synthetic binders, because of their light tones, are a mixture of substances that form a macroscopically compatible system. The colouring is easy and with 1-2% w/w pigment, colour shades are obtained which meet most of the desired colour range [5]. 

Synthetic binders have a similar behaviour to distillate bitumen oil, and have mechanical and rheological properties similar, or even better than, normal and modified bitumen. 

Nevertheless, the recycling operations of plastic waste produce a new recycled plastic with inferior properties compared to the virgin plastic [9]. Recycled plastics such as low-density polyethylene (LDPE), ethylene-vinyl acetate (EVA) and so on, can be used as bitumen modifiers [10-12] or even as raw materials in the formulation of synthetic binders [13, 14]. 

Synthetic binders are special formulations with a clear appearance that imitate, or even improve, the mechanical properties of bitumen [18]. Typical formulations consist of blending a tackifying resin, a dispersing oil [19] and a polymer [16,20,21]. This formulation enables the manufacture of organic binders from renewable raw materials of vegetal origin [18]. 

The aim of this chapter is to evaluate the effect of altering the composition of synthetic binders, in order to design new materials with selected properties. Rheological, thermal, microstructural and technological tests have been developed to characterise synthetic binders, describe the interactions among their components and to predict their properties. In references [20-22], the thermomechanical properties of binary blends were studied and correlated as a function of composition and temperature. 

The first attempt to predict the rheological properties of the synthetic binders was performed according to the following equation ... 

Technological tests have demonstrated the flexibility and vast possibilities of the synthetic binders, which have improved properties compared with commercial bitumen. 

These synthetic binders are mostly modified with functional monomers, such as vinylic acids, vinylic amides, acrylonitrile, etc., to improve the colloidal and rheological properties of coating colour formulations and the printing and/or converting characteristics of coated papers and paperboards. Some of the most important properties are ... 

Binders increase cohesion between the particles of fuel and oxidizer, facilitating better consolidation and resulting in better mechanical properties of the end products. In addition, an equally important function is to coat and protect metallic or non-metallic fuels (such as metal or non-metal powders) which may otherwise react with moisture and oxygen. They also modify the burning rate and hence the performance, and at the same time reduce sensitivity to impact or friction. A comprehensive list of binders, natural to synthetic resins used for pyrotechnic formulations follows. 

MDF (medium density fiberboard) a composite panel product manufactured from wood fibers and synthetic resin binders bonded together under heat and pressure the fibers and resin form a homogeneous board with consistent properties in each direction. 

In order to utilize the absorption properties or the synthetic zeolite crystals in processes, the commercial materials arc prepared as pelleted aggregates combining a high percentage of the crystalline zeolite with an inert binder. The formation of these aggregates introduces macro pores in the pellet which may result in some capillary condensation at high adsorhate concentrations. In commercial materials, the inacropores contribute diffusion paths. However, the main pan of the adsorption capacity is contained in the voids within the crystals. 

But you get more. A map is a tool that relates objects to each other. These relations may be distances as they appear on a roadmap, it may be frequencies or densities on a web exploration map or it may be metabolism-emotion relationships in a brain map. Hence the pharmacophoric map can be used as a filter by matching the property vectors and a library of synthetic and/or virtual ligands, sorting out putative binders. 

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