Chemical composition, aliphatic polyesters

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

Pitt et al. [65], and more recently, Albertsson et al. [73], have prepared chemically cross-linked aliphatic polyesters by ROP of the corresponding cyclic ester monomers in the presence of Y,y -bis(e-caprolactone)-type comonomers (Scheme 17). The cross-linked films displayed different swelling behaviors, degradability, and elastomeric properties depending on the nature of the lactone and composition of the comonomers feed. 

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. 

Aliphatic polyesters also present a prominent y absorption caused by motions taking place in the amorphous phase. Neither the location nor the intensity of this process is sensitive to the degree of crystallinity. The variations observed in the intensity of the y relaxations in Figure 12.29 are due to changes in the chemical composition rather than to changes in the crystal-Unity. 

Y. Fujita and O. Sawa, Ester compound, plasticizer for biodegradable aliphatic polyester resin, and biodegradable resin composition, US Patent 7166654, assigned to Daihachi Chemical Industry Co., Ltd. (Osaka, JP), January 23, 2007. 

The hydrolytic degradation behaviour of aliphatic polyesters depends on many factors such as matrix morphology, stereocomplexation, PLA configuration, chemical composition, size and porosity, dmg loading, etc. (Li, 1999,2006 Li and Vert, 1999). The influence of the factors on the degradation is discussed in the following sections. 

The chemical resistance of polyester amide glass fibre composite is excellent [126]. A solvent mixture of CF3COOH/CHCI3 was used as a solvent for thermotropic LC polyester, based on 4-chlorocarbonyl phenyl esters of aromatic dicarboxylic acids and phenols or aliphatic diols for viscosity measurement. This indicates thermal stability in various organic solvents. [127]. Unsaturated aromatic LC polyesters, synthesized with the aim to fix the LC state, can be crosslinked by using styrene. The crosslinked matrix can be degraded by refluxing in 3 M aqueous sodium hydroxide solution and methanol in a vol. ratio of 3 2 [128]. 

Samsung Fine Chemicals has slightly changed the brand name into S-EnPol which now comprises both aliphatic polyesters based on succinic acid (G4000 series - Section 10.2.2) and aliphatic-aromatic copolyesters based on a composition of terephthalic acid, adipic acid and 1,4-butanediol (PBG7000 series) which is changed with respect to the previous G8000 series. 

Polyethylene terephthalate - e-caprolactone-co-polyesters Aliphatic polyethers Characterisation and chemical composition [137]... 

---