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Although many studies are being actively conducted to develop biodegradable plastic materials, most of these reports focused more on efficiency or performance improvement than on the reaction mechanism. This paper discussed the reaction mechanism applied to starch modification by etherification and esterification, which are the most studied in the...
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... In addition to addressing environmental difficulties, this study also seeks to address the problem of potential oil scarcity [1,4,7]. The traditional petrochemical polymers are anticipated to be replaced by the creation of natural polymers to minimize the use of fossil fuels and deal with environmental problems [8][9][10][11][12][13][14]. ...
The lactic acid oligomer was synthesized by varying the reaction time and processing it without a catalyst. Gel permeation chromatography (GPC) analysis was carried out to study the molecular weight distribution of lactic acid oligomers at different reaction times (4, 6, 8 and 24 h). The chromatogram of the lactic acid oligomer from 4 to 6 h showed three peaks, while 8 and 24 h showed two. In reaction times of 4 and 6 h, there were peaks from lactide (a cyclic dimer of lactic acid). When the reaction continued for 8 and 24 h, the lactide disappeared. The cyclic structure was cleaved, producing linear dimer lactic acid with an average molecular weight of 179 Da and 171 Da, respectively. The weight average molecular weight of the lactic acid oligomer increases with the reaction time. The highest weight average molecular weight was shown by the reaction time of 24 h, i.e., 680 Da. The 1HNMR and FTIR analyses were conducted to identify the structure of the lactic acid oligomer product. Furthermore, the lactic acid oligomer from the reaction time of 24 h was applied to modify starch. The modified starch was characterized by 1HNMR, FTIR, solubility, and TGA analyses.
... Nutritionally, starch accounts for most carbohydrate components of foods, serving as the indispensable energy content of human diets (Wang et al., 2021). Technologically, the capacity of starch to form aqueous dispersions of diverse rheological properties makes it suitable as a thickener, emulsifier, stabilizer, binder, surfactant, adsorbent, adhesive, and biodegradable plastic (Lee & Chang, 2019;Otache et al., 2021;Kim & Jung, 2022). ...
... Esterification reaction is the substitution of a nucleophilic acyl molecule with a compound that has an acid chloride, acid anhydride, or carboxylic acid structure under the influence of an acid catalyst ( Fig. 2.4) (Kim & Jung, 2022). The hydrogen bonding capacity of amylose or amylopectin is decreased as the hydroxyl group of glucose is esterified by this chemical process. ...
... Fischer's esterification of starch. (Adapted fromKim & Jung, 2022) ...
Starch is one of the most abundant naturally occurring macromolecules and has received enormous research attention owing to its wide availability, low cost, biodegradability, biocompatibility, renewability, and excellent film-forming ability. It possesses some unique physical and chemical properties; however, due to strong hydrophilicity and other limitations, its industrial application is restricted in its native form. To cope with these challenges, there is a need to modify the starch. In this chapter, recent advances in physical modification such as heat moisture, high pressure, deep freezing and thawing, radiation, and ultrasonic treatment; chemical modification such as ozonation, succinylation, cross-linking, cationization, esterification, and etherification, among others as well as enzymatic modification. The physical, chemical, and structural changes enacted by both the physical and chemical, as well as enzymatic modification, were as well discussed. The modification of starch using chemicals resulted in low glycemic features, which in turn help in the overall glycemic load of foods.KeywordsStarch modificationPhysical modificationChemical modificationEnzymatic modificationRadiation treatment
... Among the forms of chemical modification by 17 . An attractive esterification option is the acetylation, which modifies the hydrophobic behavior of the polymer, making acetylated starches attractive in many industrial applications 18 . It has been shown that in aqueous suspension, nucleophilic substitution is more convenient starting from gelatinized materials, since the previous physical modification favors partial fractionation of the amylose and amylopectin structures 19 . ...
Due to the technological, energetic and economic impact of spray drying in the production of acetylated gelatinized starch from native starch of Manihot esculenta Crantz (Cassava), the objective of this work is to optimize the dynamic profitability indicators considering as optimization criteria the production capacity and the drying air temperature, and establishing the detailed design of the installation under optimum conditions. A composite central experimental design was generated for the indicators Net Present Value (NPV), Internal Rate of Return (IRR) and Discounted Payback Period (DRP). The regression models of the profitability indicators were optimized by ridgeline analysis through the Response Surface Methodology. For the evaluation of the indicators, the economic indexes of the process were determined, after technological selection, material and energy balances and technological design. The optimum economic variant has an NPV of USD 2 862 010, an IRR of 45,51 % and DRP of 3 years and is reached when 3454,45 tcassava/y are processed and the air feed temperature to the spray dryer is 184 °C, but the energy index is not favorable. An option that adequately combines energy, environmental and technical-economic results can be used by processing 3150 tcassava/y with 130 °C in the air feed to the dryer, reaching favorable economic results with NPV of USD 2 767 166, IRR of 37,99 % and DRP of 3,45 years and drastically reducing fuel consumption, although increasing the size of the spray dryer.
Bioplastic films with excellent physical properties and barrier properties were successfully prepared from poly(butylene adipate‐co‐terephthalate) (PBAT), thermoplastic starch (TPS), and poly(propylene carbonate)‐g‐polyurethane (PPCU). The rheological, mechanical, barrier, dynamic mechanical properties, and microstructure of the PBAT/TPS/PPCU blend films were studied. The proportion of PPCU controlled the morphology and continuous development of PBAT/TPS/PPCU blends. The increase of PPCU led to the formation of different phase morphologies of the PBAT/TPS/PPCU blends, including “island‐sea,” “quasi‐co‐continuous,” and “co‐continuous” structures. This phase transformation of PPCU emerges as a pivotal driver in the improvement of mechanical properties, resulting in a substantial enhancement from 23.4/24.7 MPa to 37.7/35.6 MPa. Furthermore, the addition of 40%PPCU led to a remarkable 29.6% reduction in the water vapor permeability of the PBAT/TPS/PPCU film. Finally, the increase of PPCU can improve the aging resistance of PBAT/TPS/PPCU films. The films exhibit good mechanical properties and barrier performance, indicating PBAT/TPS/PPCU film potential as environmentally viable substitutes for conventional plastics in the packaging domain.
Despite the extensive literature on the retrieval of digestible starches from archaeological contexts, there are still significant concerns regarding their genuine origin and durability. Here, we propose a multi-analytical strategy to identify the authenticity of ancient starches retrieved from macrolithic tools excavated at Upper Paleolithic sites in the Pontic steppe. This strategy integrates the morphological discrimination of starches through optical microscopy and scanning electron microscopy with single starch chemo-profiling using Fourier transform infrared imaging and microscopy. We obtained evidence of aging and biomineralization in the use-related starches from Palaeolithic sites, providing a methodology to establish their ancient origin, assess their preservation status, and attempt their identification. The pivotal application of this multidisciplinar approach demonstrates that the macrolithic tools, from which starches were dislodged, were used for food-processing across the Pontic Steppe around 40,000 years ago during the earliest colonization of Eurasia by Homo sapiens .
Esterification is a normal method for starch modification while reaction condition is not clear. Here, pure corn starch and vinyl acetate were chosen for starch esterification. Reaction conditions involving esterifying agent content, pH, reaction time and temperature were explored. Dess‐Martin periodinane (DMP) pretreatment was adopted to accelerate esterification. Main results reveal that a content of 30 wt% vinyl acetate, pH = 9, time as 1 h and temperature as 45°C is an optimized condition for vinyl acetate esterification and DMP oxidization can enhance it. After modification, variations in microstructure, surface morphology and macroscopic properties such as viscosity, transparency, adhesion property were explored by FT‐IR, XRD, SEM, TGA, UV–Vis, viscosity, and slushing experiments. Main results reveal that after esterification carbonyl groups were introduced, lattice plane occurred expansion, surface morphology was destroyed, water absorption capacity, viscosity, and gelatinization temperature decreased while transparency, thermal‐stability and adhesion property increased. DMP treatment enhanced the previous variations. It seems via a middle‐level DMP pretreatment and vinyl acetate esterification starch solution viscosity and gelatinization temperature decreased greatly while transparency and adhesion force increased greatly, possibly having a potential use in textile industry. For instance, using as slurry its manufacture cost can be decreased with decreased energy consumption, economical.
Binary and ternary blends with poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and thermoplastic starch (TPS) were prepared by a melt process to produce biodegradable biomass plastics with both economical and good mechanical properties. The mechanical and structural properties of each blend were evaluated. Molecular dynamics (MD) simulations were also conducted to examine the mechanisms underlying the mechanical and structural properties. PLA/PBS/TPS blends showed improved mechanical properties compared with PLA/TPS blends. The PLA/PBS/TPS blends with a TPS ratio of 25-40 wt% showed higher impact strength than PLA/PBS blends. Morphology observations showed that in the PLA/PBS/TPS blends, a structure similar to that of core-shell particles with TPS as the embedding phase and PBS as the coating phase was formed, and that the trends in morphology and impact strength changes were consistent. The MD simulations suggested that PBS and TPS tightly adhered to each other in a stable structure at a specific intermolecular distance. From these results, it is clear that PLA/PBS/TPS blends are toughened by the formation of a core-shell structure in which the TPS core and the PBS shell adhered well together and stress concentration and energy absorption occurred in the vicinity of the core-shell structure.
