Functionalization anhydride-functionalized synthetic polymer

Already active polymers such as maleic anhydride copolymers will be simply mixed with enzymes to produce immobilized enzymes. Normally, natural or synthetic polymers need to be activated by treating them with reagents before adding the enzyme. The activation involves the chemical conversion of a functional group of the polymer. The enzyme s active site should not be involved in the attachment, in which case the enzyme would lose its activity upon immobilization. 

Poly(amino acids)2892 and polypeptides2893 can also be grafted onto starch. Starch was first alkylated in the presence of lithium naphthalene, and then the alkoxy derivatives were reacted with /V-carboxy anhydrides. Poly(amide amines) were produced by reacting amines with dioic acids on starch and then crosslinking with epichlorohydrin or 1,2-dichloroethane 2894 Grafting of starch with a synthetic polymer chain, for instance, polystyryl carboxylate anions prepared by an anionic polymerization, can be carried out on a blend of starch and cellulose functionalized by sulfonation, mesylation, or tosylation. In this manner, cellulose-starch graft copolymers were prepared.2895... 

The polyacrylate polymers and a derivative of a vinyl acetate maleic anhydride copolymer cause V30 to decrease monotonically with increasing polymer concentration, similar to the CMC polymers (Figure 46). The polymers PVA and poly(vinyl pyridinium) (PVP) hydrochloride markedly increased V30 at low concentration at concentrations above 1 g of polymer per gram of added bentonite PVA functions as a static fluid loss additive. The maximum in the API fluid loss at low PVA concentrations approximately coincides with the maximum in the yield stress and plastic viscosity found by Heath and Tadros (75). The increased static fluid loss is consistent with Heath and Tadros s conclusion that bentonite is flocculated by low concentrations of PVA. The concentration of PVA required to decrease V30 below that of the neat bentonite suspension is significantly larger than the concentration of CMC, where effective static fluid loss control can be achieved at polymer bentonite weight ratios of about 0.1 g/g. More effective fluid loss control has been achieved with other synthetic polymers such as poly(vinyl sulphonate)-poly(vinyl amide) copolymer (40) and other sulphonated polymers (39). 

Polymers used in medicine fall into two main categories those that are sufficiently inert to fulfill a long-term structural function as biomaterials or membranes, and those that are sufficiently hydrolytically unstable to function as bioeradible materials, either in the form of sutures or as absorbable matrices for the controlled release of drugs. For the synthetic organic polymers widely used in biomedicine this often translates to a distinction between polymers that have a completely hydrocarbon backbone and those that have sites in the backbone that are hydrolytically sensitive. Ester, anhydride, amide, or urethane linkages in the backbone usually serve this function. 

Oxidation is the first step for producing molecules with a very wide range of functional groups because oxygenated compounds are precursors to many other products. For example, alcohols may be converted to ethers, esters, alkenes, and, via nucleophilic substitution, to halogenated or amine products. Ketones and aldehydes may be used in condensation reactions to form new C-C double bonds, epoxides may be ring opened to form diols and polymers, and, finally, carboxylic acids are routinely converted to esters, amides, acid chlorides and acid anhydrides. Oxidation reactions are some of the largest scale industrial processes in synthetic chemistry, and the production of alcohols, ketones, aldehydes, epoxides and carboxylic acids is performed on a mammoth scale. For example, world production of ethylene oxide is estimated at 58 million tonnes, 2 million tonnes of adipic acid are made, mainly as a precursor in the synthesis of nylons, and 8 million tonnes of terephthalic acid are produced each year, mainly for the production of polyethylene terephthalate) [1]. 

The results of these studies and others reported previously demonstrate that the 1-oxypyridinyl group is an effective catalyst for the transacylation reactions of derivatives of carboxylic and phosphoric acids when incorporated in small molecules and polymers. Furthermore, this catalytic site exhibits high selectivity for acid chlorides in the presence of acid anhydrides, amides, and esters. Therefore, catalysts bearing this group as the catalytic site can be used successfully in synthetic applications that require such specificity. The results of this work suggest that functionalized polysiloxanes should be excellent candidates as catalysts for a wide variety of chemical reactions, because they combine the unique collection of chemical, physical, and dynamic-mechanical properties of siloxanes with the chemical properties of the functional group. Finally, functionalized siloxanes appear to mimic effectively enzyme-lipophilic substrate associations that contribute to the widely acknowledged selectivity and efficiency observed in enzymic catalysis. 

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