Article ID Journal Published Year Pages File Type
5187763 Polymer 2007 15 Pages PDF
Abstract

A range of olefin-containing polyesters were prepared by acyclic diene metathesis (ADMET) and were then subjected to cyclo-depolymerization (CDP). CDP involves metathesis of the 1,2-disubstituted olefinic linkages and gives a homologous family of strainless macrocyclic oligomers (MCOs). When Grubbs' “first generation” catalyst was used at 23 °C the CDPs were sluggish and required reaction times of several days, but with the “second generation” Grubbs' catalyst at 40 °C CDPs were complete in only 2-4 h. Macrocyclic olefin-containing lactones were also prepared by ring-closing metathesis. Under appropriate reaction conditions (i.e. neat cyclics or very concentrated solutions of cyclics) the strainless macrocycles successfully underwent ring-opening metathesis polymerizations (ROMPs). Unlike most ROMPs reported in the literature, which are usually enthalpically-driven, these ROMPs are entropically-driven (ED-ROMPs). The results obtained clearly demonstrate that 21-, 24-, 27-, 28-, 38-, 45-, 52-, 63-, 64-, 68- and 84-membered macrocycles polymerized successfully. Two of the ED-ROMPs were carried out in films. These ROMPs appeared to proceed in part in the solid phase, i.e. were examples of solid state polymerization.

Related Topics
Physical Sciences and Engineering Chemistry Organic Chemistry
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