Carboxyl-substituted polymers from

FIGURE 22.8 Flow rate effect on the elution of polyacrylamide. Degradation of polymer during the analysis occurs in each case at flow rates just above those shown. Unmodified MW = 12-15 x I0 carboxyl substitution = 9.5%. , unmodified A, sheared for 30.0 min , sheared for 12 hr O, sonicated for 1.0 min O, sonicated for 5.0 min. (From Ref 23, Copyright 1988. Reprinted by permission of John Wiley Sons, Inc.)... 

For example, polymers having hydroxyl end groups can be prepared by reaction of polymer lithium with epoxides, aldehydes, and ketones III-113). Carboxylated polymers result when living polymers are treated with carbon dioxide (///) or anhydrides (114). When sulfur (115, 116), cyclic sulfides (117), or disulfides (118) are added to lithium macromolecules, thiol-substituted polymers are produced. Chlorine-terminus polymers have reportedly been prepared from polymer lithium and chlorine (1/9). Although lithium polymers react with primary and secondary amines to produce unsubstituted polymers (120), tertiary amines can be introduced by use of p-(dimethylamino)benzaldehyde (121). 

Most thermal stabilizers for poly (vinyl chloride) are metal salts of carboxylic acids or mercaptans. The commonly used metals are cadmium, barium, zinc, lead, calcium, and dibutyltin. Originally it was assumed the metal salts act as scavengers for hydrogen chloride. However, Frye and Horst (7, 8) found evidence for the introduction of ester groups in the polymer from metal carboxylate stabilizers, which led them to postulate that thermal stabilizers function by substituting the unstable chlorine atoms with the ligands of the stabilizer to yield derivatives which are more thermally stable than the original chloride. 

Plourde [17] has described the radical addition of alkyl, substituted alkyl and benzyl thiols to polymer-supported cychtol allyl ethers. Treatment of immobilized allyl ether 117 with benzyl thiol in the presence of AIBN provided, after base-induced cleavage from the support and purification, sulfide 119 in high yield and purity (Scheme 25). Similar reactions with hydroxyl- and carboxyl-substituted alkyl thiols also resulted in good yields of products as single regioisomers [17]. 

The N-acylation of 3 with the presynthesized active ferrocenoic acid hydroxysuccinimide ester in a water—acetonitrile—tetrahydrofuran medium gave the polymeric ferrocenoylpiperazide 10 (Scheme 3). The analogous reaction of 6 afforded the ferrocenoylamino—substituted polymer 11 (Scheme 4). Coupling reactions performed with ferrocenylethanoic acid and the copolymers 5 and 8 gav e rise to the formation of the conjugates 12 and 13, respectively (Schemes 5,6), and the conjugate 14 was obtained from the reactant pair 3—ferrocenylpropanoic acid and 7 (Scheme 7). In these reactions, the free carboxylic acids were transformed in situ into the reactive hydroxysuccinimide esters, and these were allowed without isolation to interact with the polymeric substrates in aqueous acetonitrile. Under very similar conditions the acylation of 4, 5, and 8 with 4-ferrocenylbutanoic acid proceeded... 

Oxidation of LLDPE starts at temperatures above 150°C. This reaction produces hydroxyl and carboxyl groups in polymer molecules as well as low molecular weight compounds such as water, aldehydes, ketones, and alcohols. Oxidation reactions can occur during LLDPE pelletization and processing to protect molten resins from oxygen attack during these operations, antioxidants (radical inhibitors) must be used. These antioxidants (qv) are added to LLDPE resins in concentrations of 0.1—0.5 wt %, and maybe naphthyl amines or phenylenediamines, substituted phenols, quinones, and alkyl phosphites (4), although inhibitors based on hindered phenols are preferred. 

As a suitable model reaction, the coupling of various substituted carboxylic acids to polymer resins has been investigated by Stadler and Kappe (Scheme 7.8) [28]. The resulting polymer-bound esters served as useful building blocks in a variety of further solid-phase transformations. In a preliminary experiment, benzoic acid was attached to Merrifield resin under microwave conditions within 5 min (Scheme 7.8 a). This functionalization was additionally used to determine the effect of micro-wave irradiation on the cleavage of substrates from polymer supports (see Section 7.1.10). The benzoic acid was quantitatively coupled within 5 min via its cesium salt utilizing standard glassware under atmospheric reflux conditions at 200 °C. 

The workhorse of the VLSI industry today is a composite novolac-diazonaphthoquinone photoresist that evolved from similar materials developed for the manufacture of photoplates used in the printing industry in the early 1900 s (23). The novolac matrix resin is a condensation polymer of a substituted phenol and formaldehyde that is rendered insoluble in aqueous base through addition of 10-20 wt% of a diazonaphthoquinone photoactive dissolution inhibitor (PAC). Upon irradiation, the PAC undergoes a Wolff rearrangement followed by hydrolysis to afford a base-soluble indene carboxylic acid. This reaction renders the exposed regions of the composite films soluble in aqueous base, and allows image formation. A schematic representation of the chemistry of this solution inhibition resist is shown in Figure 6. 

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