Silicates polyester layered-silicate

Maid P, Batt CA, Giannelis EP (2007) New biodegradable polyhydroxybutyratedayered silicate nanocomposites. Biomacromolecules 8 3393-3400 Maid P, Batt CA, Giannelis EP (2003) Biodegradable polyester/layered silicate nanocomposites. Mater Res Soc Symp Proc 740(15) 3... 

Suh, D.J. Lim, Y.T. Park, 0.0. The property and formation mechanism of unsaturated polyester-layered silicate nanocomposite depending on the fabrication methods. Polymer 2000, 41, 8557-8563. 

P. (2003) in Biodegradable Polymers and Plastics. New Aliphatic Polyester Layered-Silicate Nanocomposites... 

Miyagawa, H., Mohanty, A.K., Burgueno, R., Drzal, L.T., Misra, M., 2006. Characterization and thermophysical properties of unsaturated polyester-layered silicate nanocomposites. Journal of Nanoscience and Nanotechnology 6, 464—471. 

This chapter aims at reviewing the production of such aliphatic polyester layered silicate nanocomposites and the related improvements in terms of physical, mechanical, and thermal properties. Special attention will be focused on a selected polyester, i.e., poly(e-caprolactone) (PCL), considered as a model of the family of aliphatic polyesters. These results will be then briefly extrapolated to another well-known polyester, poly(lactide) (PLA). Materials performances will be discussed and analyzed in terms of the investigated production process and related nanostructural morphology. 

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. 

I. Pantoustier, N., Lepoittevin, B., Alexandre, M., Kubies, D., Calberg, C., Jerome, R., Dubois, Ph., 2002, Biodegradable polyester layered silicate nanocomposites based on poly(e-caprolactone). Polym. Eng. Sci. 42(9) 1928-1937. 

Lepoittevin B, Pantoustier N, Alexandre M, Calberg C, Jerome R, Dubois Ph (2002c), Polyester layered silicate nanohybrids by controlled grafting polymerisation , J. Mater. Chem., 12, 3528-3532. 

New trends involve the use of nanoparticles in synthetic fibers. Polymer-layered silicates, nanotubes, and POSS have been successfully introduced in a number of textile fibers, mainly poly-amide-6, polypropylene, and polyester. Although they reduce the flammability of these fibers, but on their own are not effective enough to confer flame retardancy to a specified level. However, in presence of small amounts of selected conventional FRs (5-10 wt %), synergistic effect can be achieved. With this approach fibers having multifunctional properties can also be obtained, e.g., water repellency or antistatic properties along with fire retardancy. Most of the work in this area at present is on the lab scale and there is a potential to take this forward to a commercial scale. 

As most work reported to date on thermosetting layered silicate nanocomposites involves epoxy resins, this review will focus on this class of thermosetting materials. However, some work pubUshed on other thermosets such as vinyl ester resins and imsaturated polyesters will be included where appropriate. 

The compatibilisation between starch and aliphatic polyesters can be promoted either by the processing conditions and/or by the presence of compatibilisers between starch and aliphatic polyesters. Examples of preferred compatibilisers are amylose/EVOH V-type complexes and starch-grafted polyesters as well as chain extenders such as diisocyanates, epoxides, and layered silicate organoclay [134, 135]. These types of materials are characterised by excellent compostability, mechanical properties and reduced sensitivity to water. 

Accordingly, a two-step method, named masterbatch process, has been approached for the preparation of PCL layered silicate nanocomposites by combining the in-situ intercalative polymerization and the melt blend intercalation process d. In such a process, a highly clay-filled (organo-modified) PCL is first prepared by in-situ intercalation pol)mierization of e-CL, followed by its addition as masterbatch, that is blended with the molten polyester matrix (commercial PCL CAPA 650). As it will be shown, this method permits to prepare PCL-based nanocomposites with a high degree of exfoliation, which cannot be achieved by directly mixing PCL and clay. 

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