Effective Aging Inhibition of the Thermoplastic Corn Starch Films through the Use of Green Hybrid Filler

Abstract

Recently, hybrid fillers have been widely used to improve the properties of biopolymers. The synergistic effects of the hybrid fillers can have a positive impact on biopolymers, including thermoplastic corn starch film (TPCS). In this communication, we highlight the effectiveness of hybrid fillers in inhibiting the aging process of TPCS. The TPCS, thermoplastic corn starch composite films (TPCS-C), and hybrid thermoplastic corn starch composite film (TPCS-HC) were stored for 3 months to study the effect of hybrid filler on the starch retrogradation. TPCS-C and TPCS-HC were prepared by casting method with 5 wt% of fillers: nanocellulose (NC) and bentonite (BT). The alteration of the mechanical properties, aging behavior, and crystalline structure of the films were analyzed through the tensile test, Fourier transform infrared (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and water absorption analysis. The obtained data were correlated to each other to analyze the retrogradation of the TPCS, which is the main factor that contributes to the aging process of the biopolymer. Results signify that incorporating the hybrid filler (NC + BT) in the TPCS/4BT1NC films has effectively prevented retrogradation of the starch molecules after being stored for 3 months. On the contrary, the virgin TPCS film showed the highest degree of retrogradation resulting in a significant decrement in the film’s flexibility. These findings proved the capability of the green hybrid filler in inhibiting the aging of the TPCS.

Thermoplastic starch hybrid biocomposite films with improved strength and flexibility produced through crosslinking via carboxylic acid

“…Based on the reported tensile properties, especially elongation at break, the reported values for crosslinked TPS films in other studies were much lower than our optimal crosslinked TPCS hybrid filler films at pH2. From our previous study, 7 an impressive high tensile strength and elongation at break of the TPCS hybrid nanofillers films was reported and this trend is rarely reported and obtained. In this study, the high tensile strength, and the high elongation at break were further enhanced by adding carboxylic acid into the TPCS hybrid nanofiller films.…”

“…From the previous research work in this area of studies, 8,39 TPCS with 4 wt% of nano bentonite (B) and 1 wt% of nanocellulose (C) possessed the excellent homogeneity between the nanofiller interaction which enhance significantly the TPCS film' toughness. Therefore, the ratio of 4B:1C were selected to promote flexibility of CR-TPCS films with different carboxylic acid.…”

“…The detailed toughening mechanism of the hybrid TPCS biocomposite films is being reported in our previous publication, showing the exfoliation of nano bentonite that responsible for the enhancement of the mechanical strength, whereas the small and evenly distributed aggregated nanocellulose responsible for triggering the accelerated chain relaxation of the TPS during straining. 7 Besides that, the hybrid nanofillers were also reported to effectively inhibit the retrogradation rate of the films and prolong the films' stability. 8 Currently, non-toxic chemical crosslinking is in high demand as most of the common chemical crosslinkers have been raise the toxicity issues by certain researchers in their unreacted forms.…”

“…7 Besides that, the hybrid nanofillers were also reported to effectively inhibit the retrogradation rate of the films and prolong the films' stability. 8 Currently, non-toxic chemical crosslinking is in high demand as most of the common chemical crosslinkers have been raise the toxicity issues by certain researchers in their unreacted forms. Chemical crosslinkers such as glutaraldehyde, 9 formaldehyde, 10,11 boric acid 11 and epichlorohydrin 12 are identify to be toxic to human cells which limiting its application in food packaging even though they were proved has high efficiency for stimulate high crosslinked density.…”

Effect of TiO2 Nanoparticles and Extrusion Process on the Physicochemical Properties of Biodegradable and Active Cassava Starch Nanocomposites

“…The relative intensity of the peak at 18° decreased while that of the peaks corresponding to the Vh-type structure at 19.6° increased in S 120 samples compared to S 80 ( Figure 4 ). These results are due to a better starch processing in S 120 and thus to the possible greater interaction between starch and glycerol, suggesting that more glycerol molecules are within the helical structure of the starch in this film [ 33 , 53 ]. As a consequence, lower RC values were obtained for the films processed at 120 rpm ( Table 1 ).…”