Acrylic monomers oligomers

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. 

Unsaturated acrylic oligomers are made from unsaturated acrylic monomers. For example, an epoxy acrylate may be made by reaction of acrylic acid with epoxy resin. 

Feldman et a .210 211 and Wulff et ul v have examined other forms of template controlled oligomerization of acrylic monomers. The template (23) has initiator and transfer agent groups attached to a rigid template of precisely defined structure.210 "11 Polymerization of MMA in the presence of 23 gave a 3 unit oligo(MMA) as ca 66% of the polymeric product. The stereochemistry of the oligomer was reported to be different" from that of atactic PMMA. 

Saegusa et al. succeeded in preparing alternating oligomers from ethylene phenyl-phosphonite, acrylic monomer and carbon dioxide through zwitter ions280. ... 

Vmyl ethers can also be formulated with acrylic and unsatiiraterl polyesters containing maleate or fumarate functionality. Because of their ability to form alternating copolymers by a free-radical polymerization mechanism, such formulations can be cured using free-radical photoinitiators With acrylic monomers and oligomers, a hybrid approach has been taken using both simultaneous cationic and free-radical initiation. 

A typical UV-cured coating has three or sometimes four main ingredients (1) a multifunctional acrylate monomer, (2) a reactive oligomer, (3) possibly a monoacrylate as reactive diluent, and (4) a photoinitiator (Table 2.20). 

As these reactive oligomers have a high viscosity, they are diluted with a multifunctional and if necessary a monofunctional acrylate monomer. The acrylate monomers reduce the viscosity of the mixture for easier application on substrates. The multifunctional acrylate monomers increase the crosslink density the monofunctional monomers decrease it. 

Miscellaneous Copolymers. VP has been employed as a termonomer with various acrylic monomer—monomer combinations, especially to afford resins useful as hair fixatives. Because of major differences in reactivity, VP can be copolymerized with alpha-olefins, but the products are actually PVP grafted with olefin or olefin oligomers (151,152). Likewise styrene can be polymerized in the presence of PVP and the resulting dispersion is unusually stable, suggesting that this added resistance to separation is caused by some grafting of styrene onto PVP (153). The literature contains innumerable references to other copolymers but at present (ca 1997), those reviewed in this article are the only ones known to have commercial significance. 

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 compositions are liquid at room temperature and have a viscosity lower than 20cps at printing temperature, which is higher than room temperature. The curable components are generally combinations of (meth)acrylic monomers and oligomers. 

Pacansky et al. (1987) described the fabrication of dual-layer photoreceptors by radiation curing. The layers were coated with a polymerizable acrylate monomer or oligomer as the liquid component, then cured by a 175 kV electron beam or ultraviolet exposure. These methods were used for the preparation of generation layers containing bisazo and hydroxysquaraine pigments. 

UV-radiation is used to achieve rapid curing and to avoid set-off effects in offset printing. The binders in UV-inks are highly reactive acrylate monomers and oligomers to which photoinitiators are added. These initiators start the cross-linking reaction in response to UV-radiation. Photoinitiators are low... 

C atalysts (peroxides) and monomers/oligomers (acrylate and epoxy) can also be separated. 

After light absorption by the photocatalyst the next step is photoproduction of free radicals that initiate polymerization of the acrylate unsaturated monomers, oligomers, and polymers contained in the UV-curable coating system. 

Figure 3.84. Voxel obtained by irradiation of a mixed urethane acrylate oligomer and a urethane acrylate monomer in the presence of a mixture of benzoyl cyclohexanol and morpholino phenyl amino ketones at 780 nm using a 150-fs pulsed Ti sapphire mode-locked laser operating at 76 MHz, where light was focused by a 1.4 numerical aperture objective lens (a) scanning electronic microscopic images of the voxel and (b) longitudinal and lateral voxel size as function of the exposure time. (From Ref. [580] with permission of the American Institute of Physics.)...

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