Solubility, hyperbranched aliphatic

Recently, the authors of this chapter have prepared polymer/clay nanocomposites using a water-soluble hyperbranched aliphatic polyester (Bottom from Perstorp) [Decker et al., 2009]. The nanocomposites were prepared via a solution-intercalation method using deionized water as the solvent medium. The nanocomposite preparation recipe was similar to that used by Plummer et al. [2002]. There are several advantages of this system compared to many other polymer/clay nanocomposite systems. These include the fact that no surfactant is required, the polymer is amorphous, and a broad range of composites from 0 to 95 wt% can be easily prepared. This... 

Although low-molar-mass aliphatic polyesters and unsaturated polyesters can be synthesized without added catalyst (see Sections 2.4.1.1.1 and 2.4.2.1), the presence of a catalyst is generally required for the preparation of high-molar-mass polyesters. Strong acids are very efficient polyesterification catalysts but also catalyze a number of side reactions at elevated temperature (>160°C), leading to polymers of inferior quality. Acid catalysts are, therefore, not much used. An exception is the bulk synthesis of hyperbranched polyesters reported in Section 2.4.5.1, which is carried out at moderate temperature (140°C) under vacuum in the presence of p-toluene sulfonic acid catalyst. The use of strongly acidic oil-soluble catalysts has also been reported for the low-temperature synthesis of polyester oligomers in water-in-oil emulsions.216... 

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