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The aim of this research was to evaluate the effects of barrel temperature (130-1807C), feed moisture (14.6-24.5%) and fiber content (0.0-15.0%) on the physicochemical and structural properties of starch-derived loose-fill packaging materials (LFPM). Two blends were analyzed: one of corn starch and henequen fiber (Agave americana) (CS-HF), and the other of potato starch and coconut fiber (PS-CF). An experimental laboratory extruder with a 2.9 mm internal diameter die-nozzle was used, and a hybrid central composite design was employed to study the LFPM, and the influence of some extrusion variables on mechanical properties, i.e. tensile strength (e),stress (s), flexion modulus (E f ), and structural properties; expansion index (EI), water absorption capacity (WAC), crystallinity by X-ray diffraction, viscosity profiles and scanning electronic microscopy (SEM). In both extruded blends feed moisture was the most significant variable, increasing the values of EI and e, and decreasing the values of s and E f when the feed moisture was decreased. The blend of PS-CF had the highest values of EI, e, s and E f, , and is the more appropriate for the preparation of LFPM. X-ray diffraction analysis of the LFPM samples suggested the formation of almost completely amorphous structures, similar to those of commercial LFPM prepared from polystyrene. This research indicated that blends from natural sources like corn starch with henequen, and potato starch with coconut fibers have the potential to be used in the preparation of LFPM with similar characteristics to commercial LFPM, with the additional advantage of being biodegradable.

Corn starch (native and phosphorylated) and potato films containing glycerol as plasticizer, and bagasse sugar cane as fiber, were produced by extrusion‐calendering process, and characterized for the mechanical properties (tensile stress at rupture σr, elongation at break εb, and Young's modulus E), water disintegration index (WDI), water absorption capacity (WAC), and luminosity. The evaluated processing variables were: feed moisture, fiber content, and type of starch. The response surface methodology was applied to analyze, and the model of significance was justified by a variance analysis (F‐test). The inclusion of fiber provides a mechanical reinforcement to the starch matrix favoring the elongation at break (εb) in thickness films (280–350 μm). Samples formulated with potato starch within the values of feed moisture 18.25, 20.5, and 5 wt % of fiber content, showed an increment in values of tensile stress at rupture (3.80–4.4 MPa) and Young's modulus (78.47–68.04 MPa). Corn starch films with high fiber content (10%) and low feed moisture (18.25%) values showed a decrement in elongation at break (12.93%). WAC and WDI were low with minimum and intermediate levels of feed moisture and fiber content (0–5%). Luminosity values were an indicative that do not exist degradation in film materials due to condition extrusion process used. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

In order to produce gelatin-starch polymer matrix reinforced with cellulose using twin-screw extrusion and compression molding, gelatin-potato starch and gelatin-corn starch formulations were plasticized with glycerol (25% w/w) and reinforced with cellulose (0.34% w/w and 0.68% w/w dry basis) to produce flat sheets. According to the analysis of variance performed, adding TEMPO-cellulose in the formulations decreased tensile strain at yield, but increased Young's modulus depending on the type of starch used in the formulation. Scanning electron microscopy and thermogravimetric analyses showed that the formation of a polymer matrix from gelatin/potato starch/TEMPO-cellulose and gelatin/corn starch/TEMPO-cellulose was successfully achieved.