Aliphatic polyester-clay nanocomposite

Le Digabel F, Boquillon N, Dole P et al (2004) Properties of thermoplastic composites based on wheat-straw lignocellulosic fillers. J Appl Polym Sci 93 428-436 Lee S -R, Park FI-M, Lim H et al (2002) Microstructuie, tensile properties, and biodegradability of aliphatic polyester/clay nanocomposites. Polymer 43 2495-2500 Lee SFI, Ohkita T, Kitagawa K (20(M) Eco-composite from poly(lactic acid) and bamboo fiber. Flolzforschung 58 529-536... 

Aliphatic Polyester Clay Nanocomposites by In-situ Polymerization... 

In 2002, Lee et al. [51] reported the biodegradation of aliphatic polyester-based nanocomposites under compost. Figure 9.13(A, B) represent the clay content dependence of biodegradation of APES-based nanocomposites prepared with two different types of MMT clays. They assumed that the retardation of biodegradation was due to the improvement of the barrier properties of the aliphatic APSE after nanocomposite preparation with clay. However, there are no data about permeability. 

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... 

Several researchers have focused their attention on the preparation of polylactide (PLA) nanocomposites. PLA is one type of hydrophobic aliphatic polyester, and as such, it is not water soluble. Therefore, solvent casting processes are carried out in nonpolar solvents such as chloroform or dichloromethane. In order to achieve intercalated stiuctures, the use of modified clays is mandatory (McLauchlin and Thomas 2009 Jaffar A 1-Mu I la 2011 Rhim et al. 2009 Chang and An 2002 Krikorian and Pochan 2003). Best results, i.e., partial or complete exfoliation, are... 

Combining the biodegradability of the polymer matrix with the possibility to improve its physical-chemical and thermo-mechanical performances represents a real opportunity. In addition to poly(e-caprolactone), which is derived from the petrochemical industry, this nanocomposite technology has been extended to other aliphatic polyesters such as poly(a-hydroxyacid)s, the most representative being poly(lactic acid) issued fi om sugar and (poly)saccharides fermentation. Poly(lactic acid) clay nanocomposites produced from renewable (non fossil) feedstock should allow for an interesting valorisation of surplus agricultural products. 

Aliphatic polyester layered silicate nanocomposites based on poly(e-caprolactone) (PCL) and on plasticized poly(L-lactide) (PLA) have been prepared first by melt blending of the respective polymer matrix with different (organo-modified) montmorillonites. It has been demonstrated that melt blending with organo-modified clay such as Cloisite 20A, 25A or SOB, yields intercalated nanocomposites with the possibility of partial exfoliation. Even at low organoclay content, substantial improvement of thermal stability, gas barrier properties and physical-mechanical performances have been noticed. However, melt blending of natural montmorillonite with PCL or neat (non plasticized) PLA leads to microphase-separated compositions. 

Dispersion of lamellar nanoclays into aliphatic polyesters is a valuable strategy to improve a series of properties, such as thermal stability, mechanical strength, permeabiUty to gases and moisture and flame resistance (Ray et al, 2003) even at clay contents of 3—5 wt%, thus much lower than the polymer microcomposites that contain more than 20 wt% of filler. PCL/clay nanocomposites are of special interest not only because of biocompatibilily and biodegradabiUty of PCL but also because of the miscibility of PCL with other polymers, including PVC. 

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