Functional Acrylics

COOH COOCH,NHCO nv n(Ainino resii) + C HgOH 

Crosslinking Reactions for Carboxy Functional Acrylic Resin 

However, the major use for heat cured, carboxy functional acrylics is in combination with either Bisphenol A based glycidyl ether epoxy resins, or hexamethoxy methyl melamine resins, for metal decorating applications, where their flexibility and deep draw properties are essential. 

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The attachment of trialkoxysilane functionality to polyolefins (HDPE, LDPE, PP) though grafting of vinylsilanes (e,g. 40, 41) or silane functional acrylates (e.g. 42) has been widely studied. 63 The principal application of these materials is the... 

Kinetic Model. All of the coatings used in this study are hydroxy functional acrylic copolymers crosslinked with melamine formaldehyde crosslinkers. The chemistry of crosslinking with melamine formaldehyde crosslinkers has been discussed in detail elsewhere (5.11). The type and rate of the reactions depend primarily on... 

Polyurethane-acrylic coatings with interpenetrating polymer networks (IPNs) were synthesized from a two-component polyurethane (PU) and an unsaturated urethane-modified acrylic copolymer. The two-component PU was prepared from hydroxyethylacrylate-butylmethacrylate copolymer with or without reacting with c-caprolactonc and cured with an aliphatic polyisocyanate. The unsaturated acrylic copolymer was made from the same hydroxy-functional acrylic copolymer modified with isocyanatoethyl methacrylate. IPNs were prepared simultaneously from the two-polymer systems at various ratios. The IPNs were characterized by their mechanical properties and glass transition temperatures. 

A second route (route B in Fig. 1) relies on an initiation process with an (meth)acryl hydroxyl compound and is adopted from the chemical ROP of lactones. The controlled character of these polymerizations ensures a virtually quantitative initiation and thus incorporation of hydroxy-functional initiator (e.g., acrylate) into the polymer chain. However, this is not automatically the case for lipase-catalyzed ROP due to the different mechanism. The latter follows an activated monomer mechanism in which the lipase activates any carbonyl group of a carboxylic acid derivative present in the system. It has recently been shown that acrylation using hydroxy-functional acrylate initiators like hydroxy ethyl(meth)acrylate (HEMA or... 

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. 

The perhydropyrazine (piperazine) heterocycle has been a favorite of the polymer chemist for the preparation of both addition and condensation polymers because of the desirable physical and chemical properties imparted by the ring. Piperazine-functional acrylate esters... 

Scheme 12 Mode of action of multi-functional acrylates in improving the grafting efficiency, through branching of grafted substrate chains...

Kugel AJ, Jarabek LE, Daniels JW et al. (2009) Combinatorial materials research applied to the development of new surface coatings XII novel, environmentally friendly antimicrobial coatings derived from biocide-functional acrylic polyols and isocyanates. J Coat Technol Res 6 107-121... 

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 clear-coat is referred to as a two-component (2K) clear-coat when isocyanate is used as the cross-linker. The isocyanate must be added to the hydroxy functional acrylic just prior to spray application to prevent premature cross-linking (or gelation). For this reason, the two-part mixing is referred to as 2K. Cure conditions for isocyanate-cured clear-coat range from room temperature (car refinish) to 250°F for 30 min. 

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. 

The perhydropyrazine (piperazine) heterocycle has been a favorite of the polymer chemist for the preparation of both addition and condensation polymers because of the desirable physical and chemical properties imparted by the ring. Piperazine-functional acrylate esters (140) readily polymerize under free radical conditions (74BRP1361878). Polymers obtained from these monomers, due to the presence of tertiary amino groups, exhibit enhanced dyeabilities and are susceptible to quaternization to form hydrophilic polymers or polyelectrolytes. 

The paint studied is a typical automotive thermosetting enamel which consists of an epoxy functional acrylic copolymer and butylated melamine crosslinking agent. The acrylic copolymer is composed of methyl methacrylate, n-butyl methacrylate, n-butyl acrylate, styrene, acrylonitrile, 2-ethyl hexyl acrylate and 2-hydroxyethyl methacrylate. Carbon black was used as the pigment. 

The utility of the bis cyclic ureas for curing of coatings was demonstrated by dispersing them in a functional acrylic polymer formulated for powder coating application, or by using them as additive in solvent based coatings or in aqueous polymer emulsions for electrocoating. 

To achieve good compatibility with functionalized acrylic and epoxy resins a bis cyclic urea with n=3> and R=-(CH2)7-(see Scheme I) was synthesized. Acrylic- and epoxypolymer solutions were prepared using 15% by weight of the bis cyclic urea (based on the dry polymer) and methyl ethyl ketone as solvent. Films cast from these solutions on steel sheets were clear, and had a thickness of 0.4 mil. 

Some commonly used graft monomers are acrylates, such as methacrylic acid (to enhance adhesion), acrylic esters and hydroxy functional acrylates (that can couple with polar materials, as wood). Maleic anhydride and n-vinyl pyrrolidone are also used, but with care taken to avoid potential volatilization during processing. The former is used as an adhesion promoter, the latter to enhance bio-compatibility. Specific properties depend both on the backbone or base material that is being grafted and on the graft monomer (Fig. 1). 

Amine functional acrylates, polymeric amines and copolymerizable tertiary amines which accelerate the cure of UV system have also been proposed (see, for example, (10.46) and Ref. [124] studied in Ref. [125]). 

Tests of the light stabilizing activity of monomeric HAS and the corresponding homo- and copolymers reveal mostly better properties of the monomers if physical persistence is not the decisive testing factor [8]. This was found e.g. in comparison of the functionalized urethane 182 and its copolymers with styrene or methyl methacrylate [303], The macromolecular architecture is expressed very distinctly. For example, a PP photografted HAS-functionalized acrylate was more efficient than the respective monomer or homopolymer. Another observation performed with A-(2,2,6,6-tetramethyl-4-piperidyl)methacry-lamide, piperidyl acrylate and methacrylate, their homopolymers and copolymers with dodecyl methacrylate and octadecyl acrylate revealed that the stabilizing effect in PP was in favour of copolymers [304]. Similar HAS-functionalized monomers were copolymerized with styrene. In this case, the copolymers were substantially less efficient in PS than the monomers. Masterbatches of PP-bound HAS prepared by reactive processing imparted a comparable effectivity as conventional HAS when tested at an equimolar basis [298]. 

Scheme 7.12 Photo-induced deprotection that leads to polarity change of a nitrobenzyl ester-functionalized acrylate polymer.

Functionalized acrylic acids. In a one-step reaction, malonic acid, paraformaldehyde, and a nucleophile (e.g., RR NH) give such products in good yields (5 examples, 78-92%). 

Contrary to the high reactivity of the active centers in cationic and anionic polymerizations, radical polymerizations are tolerant to many functionalities. It has been possible to polymerize a wide range of functional monomers such as substituted styrenes, functional acrylates and substituted acrylamide. 

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