Multifunctional crosslinking agent

Imaginative use has been made of triazine and sulphatoethylsulphone reactive dye chemistry in the application of pretreatments to nylon [405]. The concept resembles that used to make cotton cellulose reactive before dyeing with aminoalkylated dyes, as discussed earlier (Schemes 10.67 and 10.68). In this case, nylon becomes the reactive partner by pretreatment with a reactive multifunctional crosslinking agent ... 

Figure 25.13 Polyaldehyde dextran may be used as a multifunctional crosslinking agent for the coupling of amine-containing molecules. Reductive amination creates secondary amine or tertiary amine linkages.

Two different chemical approaches have been used commercially to produce non-swelfing or durable press cellulose fabrics. The original approach is the incorporation of a polymerised finish in the pores of the fibres, so that water molecules cannot easily penetrate the fibre. The newer approach is the reaction of multifunctional crosslinking agents with the hydroxyl groups of adjacent cellulose molecules that hinder the swelfing of the cellulose fibre. 

Crosslinking - Reaction or formation of covalent bonds between chain-like polymer molecules or between polymer molecules and low-molecular compounds such as carbon black fillers. As a result of crosslinking, polymers such as thermosetting resins may become hard and infusible. Crosslinking is induced by heat, UV or electron-beam radiation, oxidation, etc. Crosslinking can be achieved either between polymer molecules alone as in unsaturated polyesters or with the help of multifunctional crosslinking agents such... 

Crosslinking of PVC is known to occur on irradiation, with a low yield [Ohnishi et al., 1962]. More efficient crosslinking may be induced by irradiating PVC in the presence of multifunctional crosslinking agents [Salovey, 1973]. For example, plasticized PVC has been used as a wire and cable insulation. To enhance the crosslinking of PVC during electron irradiation, triallyl cyan-urate (TAC), trimethylolpropane trimethacrylate (TMPTMA), or trimethylolpropane triacrylate (TMPTA) have been used as the additives [Bradley, 1984]. 

The incorporation of multifunctional crosslinking agents e.g., allyl methacrylate, allyl maleate and TAC) markedly increases the crossUnking yields [Chapiro, 1962 Parkinson and Keyser, 1973 Bradley, 1984]. Radiation-induced free radical formation in PS is known to facilitate grafting reactions [Chapiro, 1962 Dworjanyn and Garnett, 1992]. 

The use of clay as a multifunctional crosslinking agent is the most crucial point in the fabrication of NC gel with excellent properties. After NC gel was prepared successfully for the first time using exfoliated clay platelets [19], different kinds of inorganic or organic materials were adopted as multifunctional crosslinkers for NC... 

A second method of immunotoxin preparation by reductive amination involves the use a polysaccharide spacer. Soluble dextran may be oxidized with periodate to form a multifunctional crosslinking polymer. Reaction with antibodies and cytotoxic molecules in the presence of a reducing agent forms multivalent immunotoxin conjugates. The following sections discuss these options. 

Among the variety of polymer thermosets, epoxies enjoy the most widespread use and are certainly the most studied. They are usually synthesized from oligomeric, end-functional epoxy resins and multifunctional curing agents or hardeners . In addition, catalysts sometimes are employed to speed the crosslinking reactions or allow them to take place at lower temperatures. 

The MI method utilizes initiator-functionalized linear chains, which initiate the polymerization and crosslinking of a difunctional monomer (e.g., divinylbenzene). The active chain ends also attack the neighboring linear chains ends, and a core with crosslinked microgel is formed. In the meanwhile, certain numbers of linear chains are attached to the core. However, it is always difficult to obtain star polymers with narrow distribution of arm numbers. Quite often, many linear polymers are not attached to the core, which leads to problems in the course of the purification and for finally applications. By using multifunctional coupling agents, it is possible to get stars with uniform arm numbers. But the purification process is always unavoidable and difficult. 

Resist Formulations. In this study we used two aqueous resist systems, an etch and a solder mask. Both are based on polymeric acrylate resins with carboxylic groups and multifunctional acrylate monomers as crosslinking agents. The acid numbers of the etch and the solder formulation are 90 and 45 mg KOH/g respectively. 

Chem. Descrip. Pentaerythritol triacrylate CAS 3524-68-3 EINECS/ELINCS 222-540-8 Uses Diluent, crosslinking agent in radiation-curable overprint varnishes, printing inks, and lacquers Features Reactive multifunctional... 

Dihydrocarvone can be epoxidized to give the corresponding epoxylactone (72). This compound can be used as a multifunctional monomer and as a crosslinking agent in ring opening metathesis polymerization. 

If, during pulyiii(>ri/,alion, a. certain amount of a multifunctional monomer (a crosslinking agent) is added to the system, a crosslinked (network) polymer appears. Many linear polymers are crosslinked by vulcanization and radiation. Polymer inicrocrystallites can serve as linking knots as well. 

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