Aliphatic macromonomers

Quercus suber, Betula pendula, Cork, Suherin, Chemical composition. Aliphatic macromonomers. Polyurethanes, Polyesters... 

Hie most representative member of this class of polyesters is the low-molar-mass (M 1000-3000) hydroxy-terminated aliphatic poly(2,2/-oxydiethylene adipate) obtained by esterification between adipic acid and diethylene glycol. This oligomer is used as a macromonomer in the synthesis of polyurethane elastomers and flexible foams by reaction with diisocyanates (see Chapter 5). Hydroxy-terminated poly(f -caprolactonc) and copolyesters of various diols or polyols and diacids, such as o-phthalic acid or hydroxy acids, broaden the range of properties and applications of polyester polyols. 

Due to low hydrolytic and chemical resistance and to low melting point, aliphatic polyesters have long been considered to be limited to applications such as plasticizers or macromonomers for the preparation of polyurethane foams, coatings, or... 

Last but not least, some of us have recently synthesized polyimide-aliphatic polyester triblock and graft copolymers in collaboration with Hedrick and his coworkers [ 97,98]. Well-defined aminophenyl or diaminophenyl end-functional polyester oligomers have been synthesized on purpose and used as end-cappers or macromonomers leading to the aforementioned triblock or graft copolymers, respectively. The polyimide-polyester copolymers so obtained proved to be highly efficient promoters of polyimide nanofoams (for more details see Sect. 4.2). 

To the first category belong the homo- and copolymerization of macromonomers. For this purpose, macromolecules with only one polymerizable end group are needed. Such macromonomers are made, for example, by anionic polymerization where the reactive chain end is modified with a reactive vinyl monomer. Also methacrylic acid esters of long-chain aliphatic alcohols or monofunctional polyethylene oxides or polytetrahydrofurane belong to the class of macromonomers. 

To overcome the difficulties of ESI-MS, Simonsick and Prokai added sodium cations to the mobile phase to facilitate ionization [165,166]. To simplify the resulting ESI spectra, the number of components entering the ion source was reduced. Combining SEC with electrospray detection, the elution curves of polyethylene oxides) were calibrated. The chemical composition distribution of acrylic macromonomers was profiled across the molar mass distribution. The analysis of poly(ethylene oxides) by SEC-ESI-MS with respect to chemical composition and oligomer distribution was discussed by Simonsick [167]. In a similar approach aliphatic polyesters [168], phenolic resins [169], methyl methacrylate macromonomers [169] and polysulfides have been analyzed [170]. The detectable mass range for different species, however, was well below 5000 g/mol, indicating that the technique is not really suited for polymer analysis. 

The present chapter aims essentially at presenting the potentials of suherin as a renewable source of chemicals and more specifically of macromonomers. Suberin is a naturally occurring aromatic-aliphatic crosslinked polyester widespread in the plant kingdom, where it plays a key role as a protective barrier between the plant and the surrounding environment. It is found mainly in the cell walls of normal and wounded external tissues of aerial and/or subterranean parts of many plants, mainly in the outer bark of higher plants and in tuber periderms [ 1 ]. 

Andreopoulou AK, Kallitsis JK (2002) From terphenyi-dendronized macromonomers to aromatic-aliphatic poiyethers bearing two pendant dendrons per repeating unit. Macromoiecuies 35 5808... 

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