Phenolic resin epoxy blend

Benzene, toluene, and xylene are made mosdy from catalytic reforming of naphthas with units similar to those already discussed. As a gross mixture, these aromatics are the backbone of gasoline blending for high octane numbers. However, there are many chemicals derived from these same aromatics thus many aromatic petrochemicals have their beginning by selective extraction from naphtha or gas—oil reformate. Benzene and cyclohexane are responsible for products such as nylon and polyester fibers, polystyrene, epoxy resins (qv), phenolic resins (qv), and polyurethanes (see Fibers Styrene plastics Urethane POLYiffiRs). 

Heat resistant resin compositions based on BMI/aminophenol-Epoxy blends are achieved by reacting a BMI/p-aminophenol 1 1 adduct with epoxy resin (62). Both the secondary amine and phenol functionality may react with the epoxy resin and subsequently cure through an imidazole catalyst. Imidazole catalysts promote both the epoxy/phenol reaction and the anionic maleimide crosslinking. The formation of a 1 2 BMI/aminophenol adduct, as in Fig. 20, is claimed in a patent (63). The hydroxy terminated BMI/aminophenol adduct is an advantageous curing agent for epoxy resins when high temperature performance is desired. 

Epoxy-phenolic adhesives are made by blending epoxy resins with phenolic resins to improve the high-temperature capabilities of the standard epoxy resins. Developed in the early 1950s, they were the first high-temperature epoxy adhesives to become commercially available.2,3... 

These adhesives are generally based on blends of solid epoxy resins with resole-type phenolic resin. The epoxy resin component is often not the predominant component in the blend, depending on the end properties required. Phenolics are compatible with epoxy resins and will react through the phenolic hydroxyl group. The amount of phenolic resin used is generally much greater than that required to crosslink with the epoxy, so one can debate whether (1) the epoxy toughens the phenolic adhesive or (2) the phenolic increases the heat resistance of the epoxy. 

Typically tape or film epoxy adhesives are modified with synthetic thermoplastic polymers to improve flexibility in the uncured film and toughness in the cured adhesive. Epoxy resins can also be blended with phenolic resins for higher heat resistance. The most common hybrid systems include epoxy-phenolics, epoxy-nylon, epoxy-nitrile, and epoxy-vinyl hybrids. These hybrid film adhesives are summarized in Table 13.2, and structural properties are shown in Table 13.3. 

Keywords. Cyanate ester, Polycyanurates, Phenolic-triazine, Polymer matrix composite, Cure kinetics, Polymer blends, Cyanate-epoxy blend, Bismaleimide-triazine resins, Aerospace structure... 

A second generation of phenolic dispersions, patented by J. S. Fry (33). involved the post dispersion of phenolic resins in a mixture of water and water-miscible solvents. To conform with air pollution regulations, the solvent was held to 20 volume %, or less, of the volatiles. A heat-reactive phenolic resin dispersion (34) and a phenolic-epoxy codispersion have become commercially available based on the above technology. Supplied at 40-45% solids, these products, which have a small particle size (0.75-1.0 ym), are better film formers than the earlier dispersions. Used alone or in blends with other waterborne materials, corrosion-resistant baking coatings may be formulated for coil coating primers, dip primers, spray primer-surfacers, and chemically resistant one-coat systems. Products of this type are also tackifiers for acrylic latexes, and such systems have been employed as contact, heat seal, and laminating adhesives for diverse substrates. 

As previously mentioned, several commercial hybrid thermosets are known to be co-reacting thermosets, i.e. when the mixture of two different thermosetting monomers or prepolymers is cured, there is a simultaneous graft or co-reaction between the components along with the crosslinking reactions. These systems may therefore be considered as co-polymerizing thermosets and not as true blends. Examples of such systems are phenolic novolak/epoxy resin (or epoxy novolaks) ... 

Notable among the thermoplastic materials are polyethylene, polypropylene, polyvinyl chloride, the styrene synthetic rubber blends, the acrylics, and the fluorocarbons. Notable among the thermosetting reinforced materials are the polyesters, epoxy, and the furan resins as custom-made reinforced materials, and the phenolic and epoxy resins molded, filament-wound, and/or extruded with reinforcement. AU these materials are available as piping, sheet stock, and miscellaneous molded and fabricated items. These materials, particularly polyvinyl chloride, polypropylene, and reinforced polyesters, are now being used extensively for ventilating ductwork in handling corrosive fumes. They have proved to be economically improved over metals such as stainless steel, lead. 

Nylons are synthetic thermoplastic polyamides of relatively high molecular weight that have been used as the basis for several types of adhesive systems. They are used as solution adhesives, as hot-melt adhesives, and as components of other adhesive-alloy types (nylon-epoxy and phenolic-nylon). The high-molecular-weight products are generally referred to as modified nylons. Low- and intermediate-molecular-weight materials are also available. The latter two are more commonly used in hot-melt formulations and the modified nylons are often blended with small amounts of a phenolic resin to improve surface wetting (hence nylon-phenolic). 

The oligomer solution is then catalyzed by triethanol amine, metal octoates, or dibutyl tin diacetate and heated to increase the viscosity. At this point, it is cooled and can be stored until used. These silicone oligomers are used to make glass fabric laminates and reinforced molding powders. Phenyl silicon is compatible with epoxy, aUcyd, urea, melamine, and phenolic resins and may be blended with them to increase their resistance to heat, flame, water, and weather. 

Volnme resistivities have been reported on phenol-formaldehyde [37], carbon fibre reinforced ABS terpolymer [35], natural rubber [38], polystyrene (PS) [35], HDPE-natnral fibre composites [34], carbon black filled PP-epoxy-glass fibre composites [5], XLPE [32], nanoclay reinforced EPDM-g-TMEVS [31] and epoxy resin/PANI blends [33]. 

Most phenolic adhesives are based on resoles, novolacs (or resorcinol-modified novolacs), and phenolic alloys. The last mentioned class includes the important blends of phenolic resins with epoxies, vinyl, polyamide, and nitrile rubber. Phenolic-based adhesives perform well on various types of surfaces the more common substrates are shown in Table III. 

Pulisol-9 (WIZ chemicals) is an effective solvent for cleaning moulds, metals, and similar articles. A blend of high activity and penetration solvents, which is neutral and evaporates slowly, it is a transparent liquid which can remove traces of polyurethanes, polyesters, epoxy and phenolic resins, as well as release agents, waxes, rubbers, and fats. The flash point is 31°C. The cleaner is used undiluted and applied with a cloth or brush, left to act for a few minutes and then wiped with a clean, absorbent cloth. For used moulds, more than one application may be necessary for new moulds, one application is sufficient. Protective gloves should be worn. 

Epoxy and phenolic resins can be blended to provide linings with a cross-linked copolymer that shows the characteristics of both polymers. Epoxy-phenolic linings are air cured with good chemical and temperature resistance and are more easily repaired than phenolics. However, they do not have the comparable solvent resistance. 

Laminates contain different reinforcement materials (woven/non-woven glass/organic fibers, expanded PTFE, etc.), resin types (phenolic, epoxy, cyanate ester, polyimide, BT, etc.), resin formulations (blended, functionality, etc.), hardeners (dicyanodiamide [dicy],phenol-novolak, cresol-novolak, p-aminophenol, isocyanurate, etc.), and sometimes fUler particles (ceramic or organic). The ratio of aU of these individual components can vary widely.To define a test strategy for laminates, it is important to understand the different main components of the materials as well as the conditions during manufacturing, as these wiU have a large influence on their properties and quality. 

Various types of polymeric modifiers have been researched as possible candidates to impart impact resistance of epoxy resins. Sometimes, properties other than impact resistance are to be modified. For example, for adhesive applications, the main focus is usually on improving shear and peel strength. In these cases, epoxies blended with elastomeric nitrile rubbers (Hycar CTBN, B.F. Goodrich), phenolics, nylons (soluble types such as DuPont Zytel-61), and pol5nirethanes are commonly used. For impact modification, there are several approaches, as discussed below. 

In addition, blending with epoxy/amine blends has been reported as a suitable route to improve the mechanical properties of phenolic resins and to reduce the cure temperature [a.368]. The results reported demonstrate that the epoxy/amine content should be kept below 15 wt% to avoid a significant reduction of the thermal stability of the blend. Flame resistance experiments identified the aromatic diglycidyl ether of bisphenol-A-based (epoxy equivalent of 190 g/mol) epoxy/amine system as one of the best epoxy resins to produce thermally stable blends with the phenolic resol. 

Semi-IPNs include the early polymer blend of phenolic resin combined with natural rubber to yield improved toughness for phenolic based compositions. With the addition of sulfur, simultaneous IPNs have also been reported. The addition of engineering polymers (PSF, PES, PPO, PEI) to epoxy illustrates a more recent area of research, involving systems classified as semi-IPNs. The phase separation and morphology of PEI/epoxy semi-IPNs was reported by... 

Epoxy vinyl ester, phenolic, methacrylate, styrene-divinylbenzene, cyanafe ester, and dicyclopentadiene (DCPD) resins have been made in Pittman s laboratory in which various POSS macromers have been chemically incorporated. For example, a low-viscosity aliphatic epoxide resin was blended with macromer 32 (Fig. 15) and aliphatic triamine curing agents, and these blends were cured in five stages to both 120°C and 150°C. The incorporation of 5 and 25 wt % of 32 into these epoxy resins gave an increase in the storage modulus versus that of the neat epoxy. " The... 

EPON 422 Blend of epoxy and phenolic resins, filled with aluminum dust and supported on 112-Volan A glass cloth dicyan diamide curing agent Shell Chemical Corp. 

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