Crystalline morphology of thermoplastic starch/talc nanocomposites induced by thermal processing

Abstract

A structural study about the changes induced by plasticization of native corn starch was carried out in this work. The influence of talc nanoparticles presence during starch thermal processing was also evaluated. Macroscopic observation of the granules appearance evolution during melt-mixing and thermo-compression was supported by a theoretical description related to these processing methods. Melt-mixing induced a polymorphic transformation from A- to V h -type and a reduction in the degree of crystallinity. Homogenous appearance of the plasticized starch was in accordance to the disruption of granules integrity, evidenced by SEM. This observation agreed to the distinctive XRD pattern of plasticized starch from unprocessed granules. Talc incorporation did not require the adjustment of processing parameters in order to obtain a homogenous thermoplastic material, with an adequate particles distribution within the matrix. Regardless talc presence, plasticized starch presented a V h -type crystalline structure. Thermo-compression led to particles alignment promoted by talc laminar morphology.

Physical-Chemical Evaluation of Active Food Packaging Material Based on Thermoplastic Starch Loaded with Grape cane Extract

“…The band at 1645 cm −1 is ascribed by δ(O-H) groups from water. It has been reported in the literature that the absorbance band around 1050 cm −1 represents the amount of crystalline structure, and the bands around 1020 and 995 cm −1 are characteristic of the amorphous starch [32]. Thermal processing of starch causes a shift of bands located around 1020 and 995 cm −1 to higher frequencies, whereas the band located around 1050 cm −1 completely disappears in the case of the TPS sample.…”

Edible and Functionalized Films/Coatings—Performances and Perspectives

“…Sorbitol was used as a plasticizer. In terms of tensile strength, Canna edulis showed higher values, while for In addition, the degree of polymerization varies significantly among sources [78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. There are some methods for fractionation, separation, and chemical modification to comply with edible films/coatings formulation.…”

“…Films based on additives such as chitosan, alginate, carrageenan, and pectin present good gas barrier properties. Some functional groups attached to biopolymer chains induce lower permeability for gases: -OH, -CN, -Cl, -F and -COOCH 3 (from higher to lower) [13,16,81,124,154]. Table 2 presents some of the permeation characteristics of the different formulations used to prepare edible films.…”

Development of Bio-Based and Biodegradable Plastics

“…Starch-based polymer can be used in the food industries as packaging materials and edible films. In light of their excellent biocompatibility, biodegradability while yielding non-toxic by-products, and ideal mechanical properties, biomedical industries utilize starch-based polymers in tissue engineering [68].…”

“…These have been mainly used for primary packaging because they are edible. Starch is a preferred option due to its low cost and abundance [68]. Studies have, however, reported a slight decline or deterioration in mechanical properties of starch-derived packaging materials.…”