Droplet like structure

Figure 2.5 Mater-Bi technology Droplet-like structure (dark grey amylopectin light grey amylose black complexing agent). (Reproduced with permission from C. Bastioli, Handbook of Biodegradable Polymers, 2005. 2005, Smithers Rapra.)...

A droplet-like structure, where a core of an almost amorphous amylopectin molecule is surrounded by complexed amylose molecules, has been confirmed by transmission electron microscopy (TEM) analysis of film slices [90], The droplet size is comparable with that of the microdispersion obtained by boiling. 

Fourier transform infrared (FTIR) second-derivative spectra of thermoplastic starch and vinyl alcohol copolymer systems with droplet-like structure, in the range of starch ring vibrations between 960 and 920 cm , provide for an absorption peak at about 947 cm (Figure 2.7), as observed for amylose when complexed (V-type complex) by low-molecular-weight molecules such as butanol and fatty acids. 

The sort of droplet-like structure developed by Novamont (see Figure 2.5) is easily dispersible in rubbers and allows a decrease of hysteresis in the final rubber compositions, which... 

Fig. 4. Droplet-like structure of thermoplastic com starch/EVOH blend in film from, after disagregation in boiling water (129).

The scheme of a droplet-like and a layered structure which can be produced as a result of Mater-Bi technology is reported in Figures 9 and 10. The droplet-like structure (Fig. 9) is constituted by a core of an almost amorphous... 

Fig. 9. Mater-Bi technology droplet-like structure. Green, amylopectin red, amylose blue, complexing agent.

The sort of droplet-like structure developed by Novamont (Figure 8.5) is easily dispersible in rubbers and allows a decrease of hysteresis in the final rubber compositions, which is useful for low rolling resistance treads in tyres. The first industrial application in this field was made by Goodyear in 2001, when the Biotread GT3 tyre was launched in Europe [132-136]. 

Figure 8.5 Mater-Bi technology Droplet-like structure...

As mentioned above, an additional type of interaction, which is considered to be crucial for the integrity of biopolymers, is that which has been termed the hydrophobic or apolar interaction. The driving force for hydrophobic interactions appears to be largely entropic. By forming an oil-droplet-like structure, hydrophobic side chains avoid the increased order and unfavorable, decreased entropy that would occur were they to be incorporated into a water lattice. The genesis of these forces has been a subject of great interest, and several accounts are available (Tanford, 1973 Franks, 1975 Lewin, 1974). 

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