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thermoplastic starch (TPS) to obtain nanocomposites by dual-melt extrusion process.
Sorbitol is an alcohol sugar widely used in the food industry, not only as a sweetener,
but also as a humectant, texturizer, and softener. In this study, cassava starch was
mixed with MMT to obtain starch nanocomposites in order to improve its mechanical
properties and water resistance. However, the starch was fi rst plasticized under heating
to obtain TPS, giving rise to a continuous phase in the form of a viscous melt which
can be processed by conventional plastic processing technique. In general, plasticizers
used include polyols such as glycerol, glycol, xylitol, and sorbitol. Plasticizers con-
taining amide groups such as urea, formaldehyde, and acetamide or a mixture of plas-
ticizers have also been studied. In this research, the plasticizers used for preparing TPS
were sorbitol and formamide. Thermoplastic cassava starch/sorbitol-modifi ed MMT
nanocomposites with various amounts of MMT were incorporated into the blend of
100 LDPE/80 PE wax in order to enhance the mechanical properties and biodegrad-
ability of the blend. The structure and morphology of the samples were investigated
by X-ray diffractometer and transmission electron microscope. The impact strength,
fl exural strength, and biodegradability were also examined.
Thermal and Thermomechanical Behavior of Polycaprolactone and Starch/
Polycaprolactone Blends for Biomedical Applications
Polycaprolactone (PCL) is among the most attractive and commonly used biodegrad-
able polyesters. It can be used in different biomedical applications, such as in scaf-
folds in tissue engineering, and for controlled release of drugs. On the other hand,
starch is one of the natural biodegradable polymers and is produced at a relatively
low price. The development and biodegradable properties of the blends of starch with
PCL (SPCL) has been well documented in the literature. Starch helps to lower the cost
of the ultimate product as well as to give some biodegradable characteristics to PCL.
Recently, SPCL has already been proposed for biomedical applications, including tis-
sue engineering scaffolds, and for different orthopaedic purposes. Besides adequate
physical properties, this blend exhibits good biocompatibility and low inflammatory
response.
Characterizing the thermal properties of such systems may be useful for the pro-
cessing of the material and for the prediction of some features during their potential
applications as biomaterials. Non-isothermal crystallization behavior is one of the im-
portant thermal properties of semi-crystalline polymers to be characterized, since most
processing techniques are melt-based and actually occur under non-isothermal condi-
tions, and the resulting physical properties (including mechanical and biodegradable
behavior) are strongly dependent on the morphology formed and the extent of crystal-
lization. Examinations concerned with the non-isothermal crystallization features of
PCL and its blends with starch have been published by several authors. For example,
Skoglund et al. presented overall crystallization characteristics of PCL. Vazquez et al.
reported the infl uence of sisal fi ber on the crystallization behavior of PCL. However,
there is little information concerning the infl uence of starch on the crystallization be-
havior of PCL. In this article, the melting behavior and the nonisothermal crystalliza-
tion kinetics of typical commercially available PCL and SPCL were studied by DSC.
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