Preparation of polymers from

Before discussing the polymerization of monocylic olefins, a brief review of the preparation of polymers from bicyclohep-tenes will acknowledge their historical contribution with respect to polymerization catalysts, polymer structure and properties. Their monomer reactivity in polymerization is much faster than the reactivity of the less strained monocyclic olefins. Anderson (1) and Truett (2) polymerized norbornene... 

Polymers derived from natural sources such as proteins, DNA, and polyhy-droxyalkanoates are optically pure, making the biocatalysts responsible for their synthesis highly appealing for the preparation of chiral synthetic polymers. In recent years, enzymes have been explored successfully as catalysts for the preparation of polymers from natural or synthetic monomers. Moreover, the extraordinary enantioselectivity of lipases is exploited on an industrial scale for kinetic resolutions of secondary alcohols and amines, affording chiral intermediates for the pharmaceutical and agrochemical industry. It is therefore not surprising that more recent research has focused on the use of lipases for synthesis of chiral polymers from racemic monomers. 

A new method of forming oxadiazoles starting from hydroxamyl chlorides andnitriles 44b) (see p. 821) has been applied to the preparation of polymers. From terephthaloyl derivatives a macromolecular compound has been isolated. As it precipitates immediately during the condensation, its molecular weight is low. It is soluble in concentrated sulfuric acid and melts at about 250° C. 

The preparation of polymers from heterocyclic monomers that contain polymerizable functional groups undoubtedly constitutes the most common method of incorporating heterocycles into polymeric materials. Polymer-forming reactions are of two possible types addition reactions and condensation reactions. Addition monomers in general contain a site of unsaturation, i.e. a double or triple bond, through which polymerization occurs by successive single bond formation from one monomer to the next. With condensation monomers a bond is formed between two monomers with concomitant elimination of a... 

Synthesis routes are reviewed for preparation of polymers from styrene, divinylbenzene (and possibly functionalized monomers) to give membranes, gel-form beads, and macroporous beads. Methods are summarized for functionalization of these polymers to give pendent groups such as -Br and -CH2CI, which can be converted into ligands such as -PPI12, -NR2>... 

Preparation of Polymers from Propargyl-Terminated Monmnets. 376... 

PREPARATION OF POLYMERS FROM PROPARGYL-TERMINATED MONOMERS... 

Preparation of polymers from dithiooxamide 22 In a three-necked 100 mL flask, equipped with a reflux condenser and a glass inlet tube, a mixture of cobalt chloride hexahydrate (2.38 g, 0.01 mol) in 20 mL ethanol and dithiooxamide 22 (1.2 g, 0.01 mol) in 20 mL ethanol and 5 mL DMSO were added and stirred at 70-80 °C, under a thin stream of nitrogen gas, for 24 h. At the end of the reaction, the mixture was poured into 300 mL of distilled water. The dark powdery precipitated polymer complex was filtered by suction in a Buchner funnel, washed thoroughly five times with hot distilled water, twiee with diethyl ether and then dried under vacuum at 40 °C for 24 h. The light-brown polymerie eobalt complexes were obtained in a yield of 87%. IR (KBr) -1300-1390 (C-N), -1080-1170 (C=S) cm". ... 

Free-radical polymerization is the most widely practised method of chain polymerization and is used almost exclusively for the preparation of polymers from olefinic monomers of the general structure CH2=CR R, where R and R are two substituent groups which may be identical, but more often are different. The structures of some common monomers and the homopolymers derived from them are shown in Table 1.1. 

There are many reports in the literature of preparations of polymers from various other substituted dienes. Most have no commercial significance. Some are, however, interesting materials. An example is a polymer of 2-r-butyl- 1,3-butadiene formed with TiCU and either alkylaluminum or aluminum hydride catalysts.The polymer is crystalline and melts at 106 C. It can be dissolved in common solvents. Based on X-ray data, the monomer placement is high ci5-l,4. 

Polymers have been used since the 19th century in paint manufacture and other applications, but during the last decade, investigation into vegetable oil-based polymers " has been directed towards other purposes. Since the onset of the petroleum shortage, the preparation of polymers from renewable sources has become indispensible. These have been used as the source materials for many industrially important polymers and resins, the details of which are the subject matter of this book. 

This section deals with two methods of metathesis polymerisation which, although much less wide-ranging in applications than the methods described above, are interesting tools for the preparation of polymers from vegetable oil derivatives. 

Two studies have been published on utilisation of AMP for preparation of polymers from vegetable oils. Both studies used fatty acids for the synthesis of long-chain diols. 

This goal was the objective of the present investigation, which is concerned with the preparation of polymers from naturally-occurring, multifunctional hydroxyacids and aminoacids. On degradation such polymers could revert in the body to their original natural products. The natural products chosen for this purpose were malic acid (I), which is an intermediate in the citric acid cycle, and aspartic acid (II), which is a common component of many proteins. High yield synthetic procedures were developed for the conversion of both compounds into cyclic monomers, which could be polymerized to polymers of controlled molecular weights. Malic acid was converted to the 3-lactone and aspartic acid to the 3-lactam, and each was polymerized to its respective polyester and polyamide, as outlined in the equations below ... 

The interesting monomer (66) has been obtained from pentafluorophenol by the sequence shown in Scheme 18, the preparation of polymers from... 

The renewed popularity of the Passerini multicomponent reaction is due to its apphcation in the preparation of polymers from renewable materials and pep-tidomimetics [14—17]. 

The preparation of polymers from bis(ketenes) by the route shown in Eq. (IV-24) has been attempted 16-18, 37). Only ill-defined products resulted 3-5,14,16-18, 32, 37). 

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