Thermosetting adhesives properties

Epoxies are made from Bisphenol A and epichlorohydrin. They are tough, resistant to heat, and have good adhesive properties. They can be mixed on-site by adding a catalyst and filler to the already linked Bisphenol A/epichlorohydrin that causes the cross-linking and the sec in thermoset. 

The thermoset included here is derived from bisphenol-A dicya-nate. It can be thermally trimerized yielding a triazine or cyanurate network (8,9,10) as seen in the reaction scheme (Table 1). The critical molecular weight between crosslinks is relatively low, resulting in an extremely tight, brittle network. The material is usually used as a prepeg because a total cure produces a hard, infusible, and insoluble matrix. It possesses excellent adhesive properties and is currently used as a metal coupling agent. It offers many superior properties relative to conventional epoxies derived from bisphenol-A. 

Results are presented of experiments undertaken by Gaiker in the manufacture of sandwich panels containing foam cores based on PETP recycled by a solid state polyaddition process developed by M G Ricerche. Panels were produced with glass fibre-reinforced unsaturated polyester and epoxy resin skins, and allthermoplastic panels with PE, PP, PS and glass fibre-reinforced PETP skins were also produced. EVA hot melt adhesives and thermoset adhesives were evaluated in bonding glass fibre-reinforced PETP skins to the foam cores. Data are presented for the mechanical properties of the structures studied. 

In general these produets are pressed to eonsolidate the mat and to cure the thermoset adhesive. Whereas in plywood pressing the main object is to achieve good contact between the veneer layers with as little inerease in density as possible, in the case of these produets the average density is one of the key variables in determining panel properties and will normally be 30-100% greater than the bulk density of the wood from which the panels are made. A major advance in all these products is the ability to control the density profile through the thiekness of the panel. 

Virtually all polymeric materials, not just those designed to function in an aqueous environment, will be exposed to environmental water at some stage of their service lives, and water imbibition can have adverse effects on their physical and mechanical properties.Although the polymer itself may be able to tolerate such degradation, if water is absorbed at the interfaces of high moduli materials, substantial swelling pressures and the generation of unwanted stresses can be anticipated. Combined STRAFI and MRM studies of some commercial thermoset adhesives used in the construction industry have... 

Since several reactive groups may exist at the respective monomer molecules A and B, net-like linked polymer molecules with thermoset adhesive layer properties occur in polyaddition. Due to the various selection possibilities regarding the chemical structure of the components A and B, curing behavior can be influenced as well. Differences are made between ... 

The adhesive properties of epoxy resins coupled with their dielectric behavior have made them attractive to the electronic industry. The evaluation of thermally cured rubber modified epoxy thermosets has been the subject of recent studies (1, 2), which dealt with the dependence of morphology on the curing parameters, e.g., catalyst, cure schedule, time of gelation, etc. This work utilizes one of the new series of photocationic initiators (PCI) developed by Crivello, et al (3) which are presently commercially available. These onium salts initiate the reaction by absorbing the actinic radiation, generating radicals and producing a protonic acid. The radicals can lead to polymerization of olefinic moieties (4) while the acid initiates the polymerization of the epoxy groups (3). 

Layer void impregnation, application of discrete isolated sections of consolidant where laminants have lost adhesion. Lac-querware surfaces separated from their ground or dissociated laminates can often be stabilized with this method. Judicious use of molten waxes or thermosetting adhesives is generally successful because of their unique physical and mechanical properties. 

The more viscous, mastic-type cements include some of the epoxies, urethanes and sflicones. Epoxies adhere well to both thermosets and thermoplastics. But epoxies are not recommended for most polyolefin bonding. Urethane adhesives have made inroads into flexible packaging, the shoe industry, and vinyl bonding. Polyester-based polyurethanes are often preferred over polyether systems because of their higher cohesive and adhesive properties. Sflicones are especially recommended where both bonding and sealing are desired. 

CAS 21645-51-2 EINECS/ELINCS 244-492-7 Uses Flame retardant, smoke suppressant filler in polymeric materials incl. PVC, thermosets, elastomeric copolymers, rubber, latex, paints, wire and cable, coatings, paper, and adhesives Properties Dry, free-flowing powd. 4-6 p median particle size 0.1% on 325 mesh sp.gr. 2.42 bulk dens. 40 Ib/fP Ooose), 70 Ib/fP (packed) brightness (Hunter Y) 92-94 ref. index 1.57 KC-750 [Georgia Marble]... 

CAS 12001-26-2 EINECS/ELINCS 310-127-6 Uses Filler for joint compds., adhesives, sealants, electrode coatings reinforcing agent (inc. stiffness, prevents waqting, improves dimensional stability) in thermoplastic resin composites insulator aiding dielec, props, in thermoset resin composites Features Reduces shrinkage, cracking in adhesives Properties 48 p median size bulk dens. 21 Ib/fE... 

Kwan, KS. (1998) The Role of Penetrant Structure in the Transport and Mechanical Properties of a Thermoset Adhesive, Ph.D. Thesis, Faculty of the Virginia Polytechnic Institute, Blacksburg, 285f. 

The water-based component is the main adhesive component in EPI adhesives. Generally, it consists of water, poly(vinyl alcohol) (PVA), one or more water-based emulsions, filler(s) and a number of additives such as defoamers, dispersing agents and biocides [1, 4, 5, 8, 9]. As with traditional thermosetting and thermoplastic wood adhesives, properties such as viscosity and solids content vary with the intended application. In the European market the typical viscosities are 2000-8000 mPa s at 25°C and the solids content is normally 50% or more. The adhesives are normally neutral with a pH in the range of 6-8 [3]. The storage stability of the EPI adhesive component is typically half a year when stored at a temperature between 10 and 30°C. 

Dimer acids are used mainly as polyamides. Non-reactive polyamides, produced from dimer acids and diamines in stoichiometric amounts, are flexible and tough and have excellent adhesive properties. They are used as shoe adhesives, in printing inks, for surface coatings and in textile applications. Reactive polyamides, with free amine groups which can react further, are used as components of thermosetting epoxy systems in surface coatings. 

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