OTHER RESIN-MODIFIED SYSTEMS

Other Uses. Anisotropic and isotropic carbon are produced from furfural-modified systems glassy carbon is produced primarily from furfuryl alcohol or BHMF resins (78,79). 

Synthetic resins, such as phenoHc and cresyUc resins (see Phenolic resins), are the most commonly used friction material binders, and are usually modified with drying oils, elastomer, cardanol [37330-39-5] an epoxy, phosphoms- or boron-based compounds, or even combinations of two. They ate prepared by the addition of the appropriate phenol and formaldehyde [50-00-0] in the presence of an acidic or basic catalyst. Polymerization takes place at elevated temperatures. Other resin systems are based on elastomers (see Elastomers, synthetic), drying oils, or combinations of the above or other polymers. 

Illustrative performance properties for a "general purpose polycarbonate," and for the same resin modified with the additive formulations "700" (without PTFE) and "800" (with PTFE) are summarized in Table IV (adapted from reference 32). It is clear that the objective of minimal effect on performance properties has been attained for this system. It is evident that flame retardant effectiveness attained with minimal levels of additive can provide optimum solutions to the problem of decreasing flammability without sacrifice in performance properties. Work documented to date suggests that in depth studies of thermal degradation such as reported for aromatic sulfonates in polycarbonates (28) would be rewarding for other systems. 

Formulators in the adhesives industry do not normally manufacture epoxy resins. Generally, formulators buy epoxy resins, modify them with other materials, do similar compounding to the curative, and then package the product as a complete adhesive system ready for the end user. There are many excellent textbooks6-8 available giving information about the preparation, chemistry, and use of epoxy resins in general applications. It is not the intention here to go into such detail but to focus only on epoxy adhesive systems. 

The viscosity of the epoxy resin is only one factor in determining the final viscosity of the formulated system. Some curing agents and resinous modifiers produce little effect on mixed viscosity however, others can have a significant effect by either increasing or decreasing viscosity. Fillers, in general, increase viscosity in direct relationship to their concentration in the system. Diluents can be used to decrease viscosity. 

Resinous modifiers. Epoxy resins have the ability to interact with other resins to form heteropolymers. These are also known as plastic alloys. Improved properties can be achieved with modified systems which are otherwise not possible with a single resin for example epoxies can form plastic alloys with poly(vinyl formal) to improve the impact resistance and peel strength of adhesive formulations. 

Several heterogeneous catalysts have been investigated for the liquid and vapor phase nitration processes. An early attempt by McKee and Wilhelm (3) used sihca gel as a solid catalyst for the nitration of benzene and toluene in the vapor phase. Various other heterogeneous catalysts systems have also been studied such as sulfonated polyorganosiloxanes (4), acidic resins (5), modified clays (6), zeolites (7,8), sulfated zirconia... 

Even though most of the supported ionic liquid catalysts prepared thus far have been based on silica or other oxide supports, a few catalysts have been reported where other support materials have been employed. One example involves a polymer-supported ionic liquid catalyst system prepared by covalent anchoring of an imidazolium compound via a linker chain to a polystyrene support [79]. Using a multi-step synthetic strategy the polymeric support (e.g. Merrifield resin among others) was modified with l-hexyl-3-methylimidazolium cations (Scheme 5.6-4) and investigated for nucleophilic substitution reactions including fluorina-tions with alkali-metal fluorides of haloalkanes and sulfonylalkanes (e.g. mesylates, tosylates and triflates). 

Uses Flow control agent, resin modifier, surf, modifier, anticratering agent for powd. coatings, epoxy, polyester, acrylic, vinyl, urethane, and other systems plasticizer... 

Of all the thermosetting plastics, epoxies are more widely used than any other plastic, in a variety of applications. There are resin/hardener systems (two-part) that cure at room temperature, as well as one-part systems that require extreme heat cures to develop optimum properties (e.g., 121°C and 177°C). Proper selection of various hardeners, resins, modifiers, and fillers allows the development of desired properties for a particular application. Because of the wide versatility and basic adhesive qualities, epoxies make excellent structural adhesives that can be engineered to widely different specifications. Essentially no shrinkage occurs during polymerization because epoxies are completely reactive producing no volatiles during cure. Epoxy adhesives can be formulated to meet a wide variety of bonding... 

Polybutadiene-type resins n. Unsaturated, thermosetting hydrocarbons cured by a peroxide-catalyzed, vinyl-type polymerization reaction, or by sodium-catalyzed polymerization of butadiene or blends of butadiene and styrene. Liquid systems, curable in the presence of monomers, are used for casting, encapsulation, and potting of electrical components, and in making laminates. Molding compounds, often containing fillers and modified with other resins or rubbers, may be compression or transfer molded. Syndiotactic 1,2-butadiene, introduced in 1974 in Japan, is thermoplastic, with semicrystalline nature, with good transparency and flexibility without plasticization. In the presence of a photosensitizer such as p,p -tetramethyl... 

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