Preliminary XRD and IR investigation of some starch based biodegradable systems (original) (raw)
Related papers
2016
New biodegradable materials, with applications in packaging, can be obtained by plasticization of starch with glycerin and water. The physical properties of new materials are different from those of the initial components, and some properties of the initial components are subject to modifications during the synthesis process. Such modifications were investigated by XRD and IR spectroscopy. For this aim some new types of packaging materials with different starch, glycerin and water (mass %) ratios were prepared and investigated after extrusion process. XRD measurements indicate a progressive degradation of the ordered phase of the starch in function of glycerin and water content of samples. It can be observed that increasing of water concentration leads to a progressive degradation of the ordered structure of pure starch, (samples P1 and P2), until a completely amorphous phase that appears at highest water concentration (sample P3 having starch/glycerin/ water 68/17/15 mass % ratio)....
XRD Investigation of Some Thermal Degraded Starch Based Materials
Journal of Spectroscopy, 2016
The thermal degradation of some starch based materials was investigated using XRD method. The samples were obtained by thermal extrusion of mixtures of different proportions of starch, glycerol, and water. Such materials are suitable for the manufacturing of low pollutant packaging. Thermal degradation is one of the simplest ways to destroy such materials and this process is followed by structural modification of the local ordering of samples, water evaporation, crystallization, oxidation, or destruction of the chemical bonds. These modifications need to be studied in order to reduce to the minimum production of pollutant residues by burning process. XRD measurements show modification of the local ordering of the starch molecules depending on the temperature and initial composition of the samples. The molecular ordering perturbation is more pronounced in samples with low content of starch.
Structural changes of the corn starch from Romania used to make biodegradable packaging
The effect of the components proportion and the effect of heat in the recipes used in order to obtain biodegradable corn starch-based packing made by thermoplastic extrusion of indigenous starch, with an amylose content of 21%, where pursued both at the macroscopic scale by rheometry, and trough microscopic methods, which provides information on atomic and molecular level. The components proportion affects the interconnection process of the polymeric chains and thus the viscosity and elastic behavior. At a given concentration, depending on heat treatment or exposure to plasticizers, the stability of the temporary junctions between polymeric chains may be affected, with consequences on the viscoelastic behavior Any dynamic effect on the molecular scale, determined by the action ofrecipe components proportion, and thermal processes leads to changes of the interconnection process of the polymeric chains and of the local conformation of the macromolecules. All these structural changes w...
Journal of Applied Polymer Science, 2018
ABSTRACTConcern about environmental issues has motivated research into the development of biodegradable packaging from renewable sources. Natural polymers such as starch constitute a good alternative for diminishing the use of nonbiodegradable and nonrenewable components in the packaging industry. However, depending on the botanical source, films with different properties are formed. The aim of this study was to evaluate the film‐forming capacity of different starch sources (cassava, corn, potato, and wheat) by casting with starch contents from 2 to 6%. Principal component analysis methodology was used to evaluate the correlation between the formulations and their physicochemical and mechanical properties. It was not possible to produce continuous films based on potato starch, probably because of its very low amylose content (10%). The corn‐, cassava‐, and wheat‐starch‐based films were characterized by their thicknesses (0.06–0.22 mm), moisture contents (19–26%), water solubilities ...
2021
Starch is a renewable resource and starch films play a vital role as an alternative for synthetic polymers in packaging applications. However, the films prepared from native starch fail to meet the process or product requirements due to high water absorption and inferior mechanical properties. In order to avoid these drawbacks, and to enhance the desired properties, starch can be modified using acid hydrolysis. In this study, the effects of acid hydrolysis time on the structural, thermal, and chemical properties of cassava starch and cassava starch thin films were investigated. Native cassava starch was hydrolyzed using 2.2 M hydrochloric acid with varying time intervals. With the increase of hydrolysis time, the relative crystallinity of cassava starch increased while the thermal decomposition temperature decreased in cassava starch. XRD and 13C-NMR spectrums results show that, cassava starch has been subjected to polymorphism changes from A (monoclinic cell) to B (hexagonal unit c...
Carbohydrate Polymers, 2015
Starch was combined with plasticizers such as glycerol, sorbitol, glycerol/sorbitol and urea/ethanolamine blends by means of high shear extrusion process to prepare thermoplastic starch (TPS). Effect of storage time and plasticizers on the structural stability of melt processed TPS was investigated. Morphological observation, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy reveal that melt extrusion process is efficient in transforming granular starch into a plasticized starch for all plasticizer compositions. XRD analysis highlights major changes in the microstructure of plasticized starch, and dependence of crystalline type and degree of crystallinity mainly on the plasticizer composition and storage time. Dynamical mechanical analysis (DMA) yields a decrease of the peak intensity of loss factor with aging time. The effect of ageing on tensile strength also appears to be highly dependent on the plasticizer composition. Thus, through different plasticizer combinations and ageing, starch-based materials with significant differences in tensile properties can be obtained, which may be tuned to meet the requirements of a wide range of applications.
Journal of Polymers and the Environment, 2020
This work aimed to study the effect of modified cassava starches, and PVA grade on the properties of biodegradables sheets produce with starch/PVA blends by an extrusion-calendering process; using native starch, distarch phosphate, acetylated distarch phosphate, acetylated distarch adipate or oxidized starch; PVA with 88% and 98% hydrolysis degrees (HD), and glycerol as a plasticizer. The sheets had tensile strength, Young's modulus, and elongation that ranged from 1.0 to 6.8 MPa; 3.2 to 16.2 MPa and 130 to 443%, respectively. Sheets produced with higher HD PVA had better mechanical properties, independent of starch type. Materials produced with all starch types presented similar response for the same PVA, except those with oxidized starch, that had the poorer mechanical properties. All the sheets were visually homogeneous and had good processability. Sheets produced with higher HD PVA (98%) had better mechanical properties and higher crystallinity than those produced with lower HD PVA (88%) because the higher the HD, the higher the number of hydroxyl groups, which leads to a better interaction with the starch. The biodegradable sheets can be produced on an industrial scale because they have adequate mechanical properties and use well-known industrial techniques.
Materials, 2021
Biodegradable materials are used in the manufacture of packaging and compostable films and various types of medical products. They have demonstrated a large number of potential practical applications in medicine and particularly in the treatment of various cardiac, vascular, and orthopedic conditions in adults as well in children. In our research, the extrusion-cooking technique was applied to prepare thermoplastic starch (TPS), which was then utilized to obtain environmentally friendly starch-based films. Potato starch was the basic raw material exploited. Polyvinyl alcohol and keratin were used as functional additives in amounts from 0.5 to 3%, while 20% of glycerol was harnessed as a plasticizer. The processing of the thermoplastic starch employed a single screw extruder-cooker with an L/D ratio of 16. The film blowing process was carried out using a film-blowing laboratory line with L/D = 36. FTIR Spectroscopy was applied for the assignment of the prominent functional groups. Th...
Starch - Stärke, 2018
Starch is a natural polymer consisting of amylose and amylopectin. The amylopectin region of starch contains crystalline structures known as starch nanocrystals. These starch nanocrystals can be extracted by acid hydrolysis of the respective native starches. Morphology, the degree of crystallinity and yield of starch as well as starch nanocrystals obtained, depends on the botanical origin of the source used. The starch nanocrystals thus obtained has been shown to enhance the properties of several polymeric packaging materials incorporated with the same. In this study, an attempt is made to obtain starch nanocrystals from a few natural sources like rice (Oryza sativa), ragi (Eleusine coracana), wheat (Triticum astivum) and sorghum (Sorghum bicolour) by acid hydrolysis of the isolated starches using sulphuric acid. A comparative evaluation of morphological, spectral and thermal characteristics of the native starches as well as starch nanocrystals isolated from them was carried out. Detailed examination of FTIR, DSC and TGA data indicated that more amount of bound water is interacting with starch compared to starch nanocrystals, thereby influencing its spectral and thermal characteristics.