Anhydride functional monomers

Among the carboxylic acid and anhydride functional monomers that have been employed in the synthesis of these thickener polymers are acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, maleic anhydride, and citraconic anhydride. The copolymers containing maleic and citraconic anhydride monomers are either hydrolyzed or partially esterified to obtain the required carboxyl functionality. Among these carboxylic monomers, maleic anhydride and particularly methacrylic acid are most frequently favored. Carboxylic homopolymers, where they can be formed, might be considered the simplest examples of ASTs were it not for the fact that they are not copolymers as defined, and some are water soluble in their un-ionized states. Examples of carboxylic homopolymers are the un-ionized free-radical-polymerized atactic forms of polyacrylic acid (i) and polymethacrylic acid (2), which are both readily soluble in water. 

Synthesis. Functionalized monomers (and oligomers) of sebacic acid (SA-Me2) and 1,6 -bis(/ -carboxyphenoxy)hexane (CPH-Me2) were synthesized and subsequently photopolymerized as illustrated in Figure 1. First, the dicarboxylic acid was converted to an anhydride by heating at reflux in methacrylic anhydride for several hours. The dimethacrylated anhydride monomer was subsequently isolated and purified by dissolving in methylene chloride and precipitation with hexane. Infrared spectroscopy (IR), nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis results indicated that both acid groups were converted to the anhydride, and the double bond of the methacrylate group was clearly evident. 

The monomer 91 was prepared in a multistep process and the authors did not quote the yield obtained for the final product (Fig. 41). In the first step the dianhydride 87, was reacted with m-nitroaniline 88 to form the mono imide anhydride 89 without any of the bis imide product being reported. Once this material was isolated the remaining anhydride functionality was reacted with 4-aminobenzocyclobutene 60 to form the JV-benzocyclobutenyl imide, 90. The nitro group was reduced to the amine (H2,10% Pd/C) which in turn was reacted with maleic anhydride to afford the final AB monomer, 91. Polymerization of 91 was carried out in a DSC (10 °C/min to 450 °C) [14]. Monomer 91 had a melting point of 99 °C and the final homopolymer had a Tg of257 °C [14]. A TGA of the homopolymer indicated that at 508 °C the polymer suffered a 10% weight loss. 

Figure 1.13 Functional Monomers Used for Monolith Grafting 7-Oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid (I), 7-Oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride (II), and N-Phenyl-7-oxabicyclo[2.2.1]5-heptene-2,3-dicarboximide (III)...

The introduction of functional groups is suitable to control the chemical and physical properties of the polymer. However, the introduction of functional groups may cause a reaction of the unshared electron pairs of the functional groups with the active catalytic sites. Thus, the active sites of the catalyst are destroyed. In order to overcome this problem, a procedure has been developed, where the functionalized monomers, such as maleic acid, nadic acid or their anhydrides are grafted after the polymerization reaction (4,37). Grafting takes place as a radical reaction, using e.g., dicumyl peroxide. Other attempts use excessive amounts of catalysts. 

The third advantage associated with metallocene catalysts is that the predominant mechanism for chain termination is by /3-hydride elimination. This produces a vinyl double bond at the end of each polymer chain. Further functionalization of the vinyl group by graft polymerization with maleic anhydride and other functional monomers is far more effective than is typical for polyolefins obtained by conventional catalysts. 

There are a few alternative approaches to imide copolymers that allow the resin producer to make imide-modified high heat ABS without incurring the cost of the synthesized imide monomer. One is by reacting styrene-maleic anhydrides with a primary amine, either during the polymerization reaction with styrene or in a separate step. Mitsubishi Monsanto has practiced imidiza-tion on a commercial scale and described a process which follows the formation of S-MA with addition of amine and AN [60]. They described the manufacture of maleimide copolymers by heating the SMA copolymers with aniline in an extruder [61]. The maleimidation of the anhydride function is not complete, as there is unreacted amine or maleic anhydride in the product. The polymer stability and physical properties depend on the mole percent of maleimidation. 

Chlorinated, sulfonated, chlorosulfonated or epoxidized polymers, homopolymers and copolymers of functionalized monomers, e.g. poly(methacryl aldehyde), poly(2,3-epoxypropyl acrylate), poly(4-vinylphenol), poly(propylene-co-10-unde-cene-l-ol), poly(butadiene-co-methacryl aldehyde), poly(butadiene-co-acrylic acid), poly(ethylene-co-alkyl acrylate), poly(alkyl acrylate-co-2,3-epoxypropyl acrylate), poly(alkyl acrylate-co-maleic anhydride), poly(styrene-co-4-vinylbenzyl chloride)... 

CO, CH4, CO2, acetone, ketene. ethene. propene. 1-butene, benzene, toluene, xylene, cydopentene, methyl ethyl ketone, diethyl ketone, methyl-n-propyl ketone, di-n-propyl ketone, methyl vinyl ketone, methyl Isopropenyl ketone, methyl isopropyl ketone, ethyl vinyl ketone, trace amounts of methyl-n-bulyl ketone, cyclopentanone, cydohexanone. acrolein, ethanal. butanal. chain fragments, some monomer CO. CH4, COj, ketene, 1-butene, propene, acetone, methyl ethyl ketone, methyl n-propyl ketone, 1,4-cyclohexadiene. toluene, l-methy. l.3-cydohexadlene, 2-hexanone, cydopentene, 1-methyl cydopentene. mesityl oxide, xylenes, benzene, ethene, cyclopentanone, 1.3-cyclopentad iene, diethyl ketone, short chain fragments, traces of monomer CO, CH4, COi, ketene, 1-butene, propene, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl-n-propyl ketone, diethyl ketone, methyl propenyl ketone, 3-hexanone. toluene, 2-hexanone. 1,3-cydopentadiene, cyclopentanone, 2-melhylcydopenlanone, mesityl oxide, xylenes, benzene, propionaldehyde, acrolein, acetaldehyde ethene, short chain fragments, traces of monomer CO, COj, H2O, CH4. acetone, ketene, ethene, propylene, 1-butene, methyl vinyl ketone, benzene, acrylic add, toluene, xylene, short chain fragments such as dimer to octamer with unsaturated and anhydride functionalities... 

Gamma-Butyrolactone (GBL) is an intermediate for the manufacture of Pyrrolidones which have a wide range of uses such as speciality solvents, functional monomers and pharmaceutical intermediates. GBL can be made by the vapour phase dehydrogenation of 1,4-butanediol over a copper/pumice catalyst at 200°C. It is also available as a by-product with THF in the Davy McKee two step butane diol process starting from maleic anhydride (MAN) via diethylmaleate [27]. 

Increases in the levels of water swell of the PVA hydrogels were initially presumed to be possible according to the mechanism commonly followed by covalently cross-linked hydrogels, namely, the incorporation of monomer components with exceptional affinities for water (typically, charged species such as carboxylic acid functional monomers). Thus, copolymers of VTFA and maleic anhydride were prepared, which when solvolyzed in methanolic ammonium hydroxide, would be expected to give poly [(vinyl alcohol)-co-(maleic acid)] products. Film samples of such copolymer hydrogels were prepared, and surprising sensitivity of water swell to acidic comonomer content was observed (Table IV). 

The mechanism becomes more complex in the case of acylating reagents as both the endo- as well as the exocylic oxygen are able to react [53]. When the endoclyclic oxygen is involved, a six-membered intermediate can be formed. The reaction of this intermediate with additional monomer units can result in both ester as well as anhydride functionalities present at the chain-end as shown in Fig. 21.4. 

A similar metal-coordination monomer can be prepared as outlined below [4]. In this case, the primary amino groups in diethylenetriamine are first protected as their phthalimides by heating in phthalic anhydride. The secondary amine is subsequently coupled to 4VBC in the presence of potassium carbonate in acetonitrile. After deprotection of the amines with hydrazine, the functional monomer is isolated, which can be further metallated with, e.g., Cu to yield a potent metal coordinating monomer. 

To achieve a high-level of control over polymerizations, and resulting polymer microstructures, the preparation of pure exo isomers of the monomers were targeted. Exo-endo mixtures that were obtained as the cycloaddition adducts were not always separable by selective reciystallizations. Compounds 5, 6, 8, and 9 were separated from their endo isomers through selective recrystallization to give white crystalline solids. Cobalt-catalyzed transformation of the anhydride into a substituted imide linkage resulted in the protected amine functionalized monomer structure in excellent yield. For monomers 6, 8 and 9, pure exo isomer was isolated by successive recrystallizations from cold ether overall yields were 40 to 56%. 

The thiol-ene addition reaction associated with oleochemistry is a very versatile tool for the polymerisation of a,ro-diene monomers bearing, for example, ester, ether, and anhydride functional groups in the main chain. Due to the availability of specific monomers, the AA/BB approach is the choice for conducting polymer syntheses most of the time. 

Authors stated that 2.5 mol% of azobisisobutyronitrile (AIBN) was used as an initiator to obtain complete conversion of the monomer after 2 h, at 80 °C. Low temperatures are favourable for thiol-ene additions. However, for polymerisations, the reaction temperature should be increased to avoid crystallisation of the polymer during polymerisation [33]. Gel permeation chromatography (GPC) analyses showed that fatty acid-based polyesters with Mn = 12 kDa (reactions 2 and 3, Scheme 6.11) could be synthesised via thiol-ene polymerisation. However, this approach was less suitable for the polymerisation of reactions 1 and 3, Scheme 6.11, which led to a Mn value of only 5 kDa. The high reactivity of the anhydride functionalities towards nucleophiles (in this case the thiol groups) caused the scission of the monomer or polymer backbone via thioester formation, leading to a decrease in molecular weight [33]. 

Later, Barrett created the term ROMPgel for linear polymers, which swell but do not dissolve in certain solvents because of solubility restrictions governed by the nature of the functional monomer used. Such ROMPgels were prepared with a variety of different functional groups including phosphines [3], allyl-boronates [25], a polymeric Tosmic reagent [26], naphthalenes, and biphenyls [27], alkylphosphonates [28], as well as anhydrides [29], some in a precipitation polymerization setup similar to the one described by our group. 

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