Radiation polymerisation acrylic

Unsaturated polyester finishes of this type do not need to be stoved to effect crosslinking, but will cure at room temperature once a suitable peroxide initiator cobalt salt activator are added. The system then has a finite pot life and needs to be applied soon after mixing. Such a system is an example of a two-pack system. That is the finish is supplied in two packages to be mixed shortly before use, with obvious limitations. However, polymerisation can also be induced by ultra violet radiation or electron beam exposure when polymerisation occurs almost instantaneously. These techniques are used widely in packaging, particularly cans, for which many other unsaturated polymers, such as unsaturated acrylic resins have been devised. 

The mechanism of radiation vulcanisation of NR with 2-ethyl hexyl acrylate (EHA) was examined by 13C NMR [46]. All peaks in spectrum due to the acrylate decrease in intensities and broaden with increasing radiation dose. Using the solid-state CP technique, all peaks corresponding to EHA and NR were observed. The olefin peak at 129 ppm in the acrylate was absent, however, indicating that all the EHA had polymerised. 

The composition of ink will depend very much on the printing technique used. Adsorbing inks (e.g. used in most newsprint printing) contain typically mineral oil, unsaturated fatty acids and alkyd resins, whilst radiation curing inks (UV or IR) would be typically epoxy acrylates, urethane acrylates or similar prepolymers that can be polymerised further on irradiation. Finally xerographic inks contain yet other binders, e.g. styrene butadiene rubber or vinyl acrylates... 

Acrylonitrile is the starting material for the different acrylic compounds formed by various types of reactions. Fig.l shows the general scheme of the derivation of acrylonitrile and the polymerisation of the different monomers. The system within the dotted lines (Fig.l, right) is present in solutions for the modification techniques of polymers surfaces by radiation grafting. The use of this technique in technical application causes the need of a detailed analysis of the components of the system. The grafting by irradiation leads to a consumption of the monomer as well as to the formation of the so called homopolymers which are non-desired by-products of the graft copolymer. For the control of a grafting solution instrumental methods are needed which preferentially are based on electroanalytical techniques. 

The highest X-ray resist sensitivity has been obtained by using an elegant resist technique referred to as photo-locking [47]. The resist consists of a plasma-degradable acrylic polymer (poly(2,3-dichloropropyl acrylate)) and a volatile silicon-containing acrylate (bis-acryloxybutyl tetramethyl disiloxane, Figure 6.22) which can be readily polymerised by the absorbed radiation. 

Acrylics are thermoplastic resins based on acrylates or derivatives such as amides and esters. Acrylics are available as emulsions, solvent solutions, and monomer—polymer mixtures (one or two components) with a catalyst. Emulsion—solvent types set by evaporation and absorption of a solvent. Polymer mixtures set through polymerisation by heat, ultra-violet radiation and/or the action of a chemical catalyst. 

Keywords Acrylates Crosslinking Dual cure Epoxides Glass laminates Interpenetrating polymer networks Isocyanates Photo initiated cationic polymerisation Photoinitiators Photopolymerisation Pressure sensitive adhesives Release coatings Structural adhesives Thiol/polyene UV radiation curing Vinyl ethers. 

Vinyl ethers (VE) are amongst the most reactive monomers that polymerise cationically, and they are increasingly used in photocurable resins, either neat [63] or in association with epoxides [64,65], acrylates [66], maleimides [67] or unsaturated polyesters [68]. Vinyl ether end-capped polyurethane, polyether, polysiloxane and polyesters were shown to undergo fast and extensive polymerisation when exposed to UV-radiation in the presence of an aryliodonium salt, with the formation of tridimensional polymer networks. The photoinitiated catioiuc polymerisation of a divinyl ether can be formally written as follows ... 

The reactive liquid crystals were syndiesized at Philips research Conventional liquid crystals were purchased from Merck. The polymerisation of the mixtures was initiated by means of UV radiation using photoinitiator Irgacure 651 purchased from Ciba Speciality Chemicals. Hie structures of the acrylates are shown in Figure 2. 

Engineering acrylic adhesives are two-part systems which, when mixed or activated, polymerise (cure) to form an impact-resistant plastic layer which is well adhered to the surfaces of the adherends. The activator for the curing process may be a chemical (either mixed with the adhesive or applied to the adherend surfaces prior to the adhesive), or, for some varieties, UV or electron-beam radiation. The toughened or modified engineering adhesives have been widely used since the 1980 s in vehicle construction, wood to metal bonding, aerospace applications, panels and computer equipment. 

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