Thermosetting Emulsions

Much smaller quantities of thermosetting emulsions are used compared with either thermosetting solution polymers or thermoplastic emulsions. This is because one of the big advantages of emulsion resins of a very high molecular weight is of much less importance for thermosetting systems, where molecular weights are increased by 

The functional groups of some of the thermosetting emulsions can cause instability of the latex, either during processing or in the final product. High levels of bit formation are not uncommon in preparing thermoset latices. 

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Aqueous Thermosetting Emulsions. The basic concept of a thermosetting emulsion is a logical extension of solvent-based thermosetting chemistry (22. 23). Reaction functionality is copolymerized into the polymer backbone, and after application, the... 

Aqueous thermosetting emulsions Good resistance/ durability properties Film thickness limitations... 

Scherlund, M., Malmsten, M. and Brodin, A., Stabilization of a thermosetting emulsion system using ionic and nonionic surfactants, Int. J. Pharm., 173, 103-116 (1998). 

The first five of these techniques involve deformation and this has to be followed by some setting operation which stabilises the new shape. In the case of polymer melt deformation this can be affected by cooling of thermoplastics and cross-linking of thermosetting plastics and similtir comments can apply to deformation in the rubbery state. Solution-cast film and fibre requires solvent evaporation (with also perhaps some chemical coagulation process). Latex suspensions can simply be dried as with emulsion paints or subjected to some... 

Core-shell emulsion polymers with a core or rubbery stage based on homopolymers or copolymers of butadiene are used as impact modifiers in matrix polymers, such as ABS, for styrene acrylonitrile copolymer methyl methacrylate (MMA) polymers, poly(vinyl chloride) (PVC), and in various engineering resins such as polycarbonate) (PC) poly(ester)s, or poly(styrene)s, further in thermosetting resins such as epoxies. 

Core-shell polymers were commercially introduced as impact modifiers for poly(vinyl chloride) PVC, in the 1960s. They are produced by a two-stage latex emulsion polymerization technique (Cruz-Ramos, 2000). The core is a graftable elastomeric material, usually crosslinked, that is insoluble in the thermoset precursors. Typical elastomers used for these purposes are crosslinked poly(butadiene), random copolymers of styrene and butadiene,... 

Core-shell rubber (CSR) particles are prepared by emulsion polymerization, and typically exhibit two or more alternating rubbery and glassy spherical layers (Lovell 1996 Chapter 8). These core-shell particles are widely used in thermoplastics, especially in acrylic materials (Lovell, 1996), and have also been used to modify thermosets, such as epoxies, cyanates, vinyl ester resins, etc. (Becu et al., 1995). 

It is not possible to produce a dispersion of rubber particles in the thermoset precursors due to their agglomeration. It is possible, however, to synthesize a stable emulsion or suspension of rubber particles in one of the monomers. These particles, stabilized by copolymers and surfactants, may be considered as a limiting case of CSR particles when the shell thickness tends to zero. The use of dispersed acrylic rubbers (Sue et al., 1996a and Ashida et al., 1999) and poly(dimethyl-siloxane) (PDMS) emulsions (Rey et al., 1999), have been reported. 

When one polymer of an IPN was plastic and the other was rubber, the combination showed synergistic properties reinforced rubbers, impact resistant plastics, or noise damping materials were reported. Because of the macroscopic network structure formed in IPN s, they are thermoset and cannot be molded. However IPN s have been made by emulsion polymerization so that each individual emulsion particle is an IPN in miniature form containing both networks (75, 76, 77, 78, 82, 83). Emulsion polymerization allows the molding of IPN s if the crosslink density of the miniature IPN s is not too high. 

Hand building finishes that retain their stiffening and fullness effects after repeated launderings are considered to be durable. These products are usually aqueous emulsions of polymers that form water-insoluble films on the fibre surface when dried. The three main types of products are vinyl acetate-containing polymers, acrylic copolymers and thermosetting polymers. 

ARIDRY SN-25 is a fine silicone emulsion which produces highly durable water repellency on treated fabrics. ARIFIX SN is the catalyst recommended for use with ARIDRY SN-25. These products can be run alone or in conjunction with thermosetting resins, cationic dye fixtures and most all of the organic and inorganic accelerators. Some of the waxy type softeners are compatible with a resin-silicone mix, but each must be checked carefully to be sure that it does not cause back-wetting. 

Is a single package, semi-durable water-repellent emulsion of the zirconium/wax emulsion type. This product may be used with thermosetting resin finishing baths to give water repell-ency with the desired finish. 

Polyvinyl acetate homopolymer emulsion. High molecular weight, large particle size resin. May be used with thermosetting resins, starches, softeners, nondurable water repellents and plasticizers. Base for adhesives. T(g) 28C. 

IMPREGNOLE FH emulsion provides very good water repellency on all fibers and blends. It may be applied in conjunction with most thermosetting resins, polyvinyl acetate and many starches while maintaining its high spray ratings. 

Type Hydrophobic thermosetting resin Appearance White liquid emulsion pH 4.0... 

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