Functional acrylate monomers

Urethane acrylates Urethane acrylates are formed by the reaction of isocyanates with hydroxy-functional acrylate monomers. After UV cure, they produce tough, flexible materials, which exhibit a good abrasion resistance. 

It is common in acrylic structural adhesives to use oligomers that have a desirable backbone and are terminated with free-radical-polymerizable bonds. A variety of isocyanate-terminated polyurethanes can be adapted to use in acrylic structural adhesives by reacting the terminal isocyanates with a hydroxy functional acrylic monomer such as 2-hydroxyethyl methacrylate.76,92 93... 

The use of iV-alkoxy pyridinium salts is not limited to cationic polymerization. Since, in addition to cationic species, ethoxy radicals are also formed upon direct and sensitized irradiation of pyridinium salts (see above), pyridinium salt based photoinitiating systems may be used to initiate the polymerization of vinyl monomers that are prone to free radical polymerization. Kayaman et al. [71] recently polymerized mono- and bi-functional acrylate monomers by photosensitization of pyridinium salts. It therefore appears that pyridinium salts can promote both cationic and free radical polymerization and are, thus, eminently suitable for use in hybrid systems. 

Sdierman and co-workers recently utilized CB[8] ternary complexation for the conjugation of small molecules to a polymeric backbone in water. The authors used RAFT polymerization to copolymerize a 2-naphthol-functional acrylate monomer with poly[oligo(ethylene glycol)]acrylate to form a water-soluble, 2-naphthol pendant acrylate copolymer. By using UV-Vis spectroscopy and multidimensional NMR techniques, the authors could determine that several methyl viologen (MV)-functional units could be noncovalently... 

Bucio, E. CedUlo, G Buiillo, G Ogawa, T. Radiation-induced grafting of functional acrylic monomers onto polyethylene and polypropylene films using acryloyl chloride. Polym. Bull. 2001, 46, 115-121. 

Polyacrylics. Polyacrylic adhesives and sealants are formulated from functional acrylic monomers, which achieve excellent bonding upon polymerization.Alkyl esters of acrylic or methacrylic acids up to 80,000 molecular weight constitute the main bonds of acrylic sealants. 

Typically, a solid epoxy of 3000 to 4000 EEW (Epikote 1007 or 1009 types or an analogue material manufactured by the chain extension of a lower M liquid epoxy resin) is modified to provide an acid functional epoxy. In general, the acid functionality ctm be conferred by two methods, acid capping (see resin 1 and resin 2) of the oxirane groups or by the graft polymerisation of an epoxy with a carbonyl functional co-polymer (see resin 3). The co-polymer can consist of Ae reaction product of a free radical polymerisation of any approved ethylenic unsaturated monomers containing carbon-carbon unsaturadon, e.g. carboxyl functional acrylic monomers, (acrylic add, methacrylic acid, etc.), the lower alkyl esters, vinyl monomers (acrylamides), vinyl esters (vinyl acetate, vinyl butyrate), vinyl aromatic monomers (styrene, a methylstyrene) etc. The acrylic caj ing resin is add fimctional, being based upon either methacrylic or acrylic acid. The former is normally preferred. An acid value of 50-100 mg KOH/g would be typical. 

Table 9. Functional Monomers for Copolymerization with Acrylic Monomers...

Fig. 3. Elastomer properties as a function of monomer composition, butyl acrylate (BA), ethyl acrylate (FA), and methoxyethyl acrylate (MEA). (a), (—) glass-transition temperature (------------) swelling in ASTM No. 3 oil (b) (-) residual elongation at break, %, after heat aging.

Liquid organic rubbers with reactive functionality can be prepared by several methods. End-functional oligomers are preferred. Chains attached to the network at only one end do not contribute as much strength to the network as those attached at both ends [34], Urethane chemistry is a handy route to such molecules. A hydroxy-terminated oligomer (commonly a polyester or a polyether) can be reacted with excess diisocyanate, and then with a hydroxy methacrylate to form a reactive toughener [35]. The methacrylate ends undergo copolymerization with the rest of the acrylic monomers. The resulting adhesive is especially effective on poIy(vinyl chloride) shown in Scheme 2. 

A preponderance of chains that both begin and end in S results and this means that short chains are much richer in S than in the acrylic monomers (Figure 7.3). This also has an influence on the fraction of chains that contain the functional monomer (Figure 7.4). The fraction of HEA in very short chains is much less than that in the polymer as a whole and a significant fraction of these short chains contain no functional monomer. 

Various (meth)acrylic monomers have been successfully grafted onto polyolefins. Most studies deal with functional monomers. Grafting yields obtained with PP are usually low (<20%) and are dependent on the particular monomer. Liu et al.jM carried out a comparative study on the grafting of various functional methacrylates onto PP. The experiments were performed in a batch mixer at 180 °C with 7 wt% monomer and 0.05 wt% 22 as an initiator. Grafting levels (wt%) obtained under these conditions were as follows HPMA (I), TBAEMA (1), GMA (0.8), IIEMA (0.4), DMAEMA (0.3), 32 (0.2). Grafting yields to PE appear generally higher. 

Recently it has been shown that anionic functionalization techniques can be applied to the synthesis of macromonomers — macromolecular monomers — i.e. linear polymers fitted at chain end with a polymerizable unsaturation, most commonly styrene or methacrylic ester 69 71). These species in turn provide easy access to graft copolymers upon radical copolymerization with vinylic or acrylic monomers. 

Star polymers are a class of polymers with interesting rheological and physical properties. The tetra-functionalized adamantane cores (adamantyls) have been employed as initiators in the atom transfer radical polymerization (ATRP) method applied to styrene and various acrylate monomers (see Fig. 21). 

In our own research, the functional termination of the living siloxanolate with a chlorosilane functional methacrylate leading to siloxane macromonomers with number average molecular weights from 1000 to 20,000 g/mole has been emphasized. Methacrylic and styrenic monomers were then copolymerized with these macromonomers to produce graft copolymers where the styrenic or acrylic monomers comprise the backbone, and the siloxane chains are pendant as grafts as depicted in Scheme 1. Copolymers were prepared with siloxane contents from 5 to 50 weight percent. 

Polymerization employing Co complexes as catalysts or else polymers incorporating functionality that includes Co ions represent aspects of polymerization reactions of interest here. Cobalt-mediated free-radical polymerization of acrylic monomers has been reviewed.55 Co11 porphyrins act as traps for dialkylcyanomethyl radicals.1098 Alkyl complexes of Co(TMesP)... 

However, the practical, direct synthesis of functionalized linear polyolefins via coordination copolymerization olefins with polar monomers (CH2 = CHX) remains a challenging and industrially important goal. In the mid-1990s Brookhart et al. [25, 27] reported that cationic (a-diimine)palladium complexes with weakly coordinating anions catalyze the copolymerization of ethylene with alkylacrylates to afford hyperbranched copolymers with the acrylate functions located almost exclusively at the chain ends, via a chain-walking mechanism that has been meticulously studied and elucidated by Brookhart and his collaborators at DuPont [25, 27], Indeed, this seminal work demonstrated for the first time that the insertion of acrylate monomers into certain late transition metal alkyl species is a surprisingly facile process. It spawned almost a decade of intense research by several groups to understand and advance this new science and to attempt to exploit it commercially [30-33, 61]. 

Methacrylate monoliths have been fabricated by free radical polymerization of a number of different methacrylate monomers and cross-linkers [107,141-163], whose combination allowed the creation of monolithic columns with different chemical properties (RP [149-154], HIC [158], and HILIC [163]) and functionalities (lEX [141-153,161,162], IMAC [143], and bioreactors [159,160]). Unlike the fabrication of styrene monoliths, the copolymerization of methacrylate building blocks can be accomplished by thermal [141-148], photochemical [149-151,155,156], as well as chemical [154] initiation. In addition to HPLC, monolithic methacrylate supports have been subjected to numerous CEC applications [146-148,151]. Acrylate monoliths have been prepared by free radical polymerization of various acrylate monomers and cross-linkers [164-172]. Comparable to monolithic methacrylate supports, chemical [170], photochemical [164,169], as well as thermal [165-168,171,172] initiation techniques have been employed for fabrication. The application of acrylate polymer columns, however, is more focused on CEC than HPLC. 

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