Acrylate comonomers

The chief application of macromonomers is, however, to provide easy access to graft copolymers 69,70,71,84,851 by free radical copolymerization with a vinylic or acrylic comonomer. This grafting through process offers graft length control and provides randomness of graft distribution. 

Keywords Acrylate comonomers, Ethylene, Mechanism, Palladium catalysts, Polar groups, Polymerization catalysis, Random copolymers... 

It is well known that primary amines are efficient initiators for the polymerization of Leuch s anhydrides (oxazolidinediones) and that initiation proceeds by the addition of the amine to the monomer. This pathway has been utilized recently to synthesize polypeptide macromonomers bearing a terminal p-vinylbenzyl group 88). Copolymerization of these macromonomers with a vinylic or acrylic comonomer yields graft copolymers with polypeptide grafts. Alternately, the monomer adduct (IV) was copolymerized with styrene, and the primary amine functions of this polymer were used to initiate the polymerization of an oxazolidinedione whereby polypeptide grafts are formed 89). Such graft copolymers may be of interest for biomedical applications. 

Free-radical copolymerization of a macromonomer with a vinylic or acrylic comonomer has been and is still the major field of application of macromonomers since it provides easy access to graft polymers. A large number of patents and papers deal with this problem, and even though the characterization of the graft copolymers is often far from being adequate, this method has proved successful in numerous applications. 

This behavior (reactivity of these acrylic comonomers), is in good agreement with that of classical radical copolymerization. However, the authors did not mention a loss of reactivity as observed in other studies of MMA. 

Table 1 shows that most acrylics have low glass-transition temperatures. Therefore, in copolymers they tend to soften and flexibilize the overall composition. Plasticizers also lower the transition temperature. However, unlike incorporated acrylic comonomers, they can be lost through volatilization or extraction. 

At present, the kinetic parameters for prediction of copolymerization rates are scanty, except for a few low conversion copolymerizations of styrene and some acrylic comonomers. Engineering models of high conversion eopolymerizations are, however, overdetermined, in the sense that the number of input parameters (kinetie rate constants, activation energies, enthalpies of polymerization, and soon)... 

Several examples of pyrolysis results for acrylonitrile copolymers are given below. One such copolymer is poly(acrylonitrile-co-methyl acrylate), CAS 24968-79-4. The copolymer has a relatively low level of methyl acrylate comonomer and has idealized formula [-CH2-CH(CN)-]x[CH2-CH(COOCH3)- y (y < x). The pyrogram for this copolymer was obtained at 600° C in He using conditions similar to other experiments previously... 

The free radical polymerization of pinenes and limonene is of little interest, because of the modest yields and DPs obtained with their homopolymerizations. However, their copolymerization with a variety of conventional monomers has been shown to produce some interesting materials, particularly in the case of controlled reversible addition fragmentation chain-transfer (RAFT) systems involving P-pinene and acrylic comonomers [5]. 

Generally, the radical copolymerisation reactions of acrylic comonomers are performed in an adequate solvent, by drop wise addition of monomer - initiator (peroxides) mixture. 

Figure 7. (a) (top) Height of the low angle x-ray diffraction peak in various copolymers of ChMA as a function of composition after annealing, (b) (bottom) Slope of lines from Figure 7a vs. number of carbon atoms in the aliphatic chain of the non-mesogenic meth-acrylic comonomer. 

Fig. 2.6 I mpact of the copolymer composition on the solubility in supercritical ethylene. Arrows indicate an increasing amount of the acrylate comonomer(s) in the polymer backbone. Symbols are experimental data. Lines are modeling results with the PC-SAFT...

Amide comonomers have a less pronounced effect than acid comonomers. Acrylate comonomers do not initiate the cyclization reaction [78,79], whilst MMA results in a lower carbon yield than MA. The bulky side groups of an ester comonomer lower the crystallinity and crystal size but improve the segmental mobility of the polymer chains [22,23]. The size of the ester molecule also affects the structural parameters of the precursor and the resultant carbon fibers have a lower average orientation and mechanical properties [21]. 

Acrylic polymers are made with some hydroxyalkyl acrylate comonomer, and the -OH groups are then cured by methylol melamine or epoxy resin. 

In acrylic latices, the hard monomer is methyl methacrylate and the plasticizing monomer an acrylate, such as butyl acrylate or one of the acrylate comonomers mentioned above. Acrylic latices usually contain copolymers of acrylic or methacrylic acid as colloids and thickeners, these being solubilized by neutralization with base. Whatever the type of latex, coalescing solvents are also normally added to improve film formation. These may or may not be water miscible and include alcohols, glycols, ether-alcohols, ether-alcohol esters and even hydrocarbons, all of high boiled point. 

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