Properties Of Thermoplastic Starch Research Articles

Preparation and properties of thermoplastic starch under the synergism of ultrasonic and elongational rheology

Thermoplastic starch, as an eco-friendly alternative to petroleum-based plastics, possesses numerous advantages, including cost-effectiveness, complete biodegradability, and renewable sourcing. Nevertheless, the plasticizer dispersion and starch plasticization efficiency are poor via the processing method dominate by shear deformation. Thus, the aim of this study is proposing a new approach combining ultrasonic treatment and elongational rheology to prepare thermoplastic starch and evaluate its properties. This innovative approach facilitated the production of thermoplastic starch with glycerol as the plasticizer at varying rotor speeds. Furthermore, this study was carried out by using a self-developed ultrasonic-assisted vane mixer (UVM) based on elongational flow. The samples were analyzed using FTIR, WAXD, polarized optical microscope, dynamic rheometer, universal testing machine and thermogravimetric analysis. FTIR and dynamic rheological analysis showed that elongational rheology and ultrasonics stimulate hydrogen bond formation between starch and glycerol, elevating starch thermoplasticity. Tensile tests and thermogravimetric analysis highlighted that high-intensity elongational field improved the mechanical properties and thermal stability of the thermoplastic starch. Additionally, the incorporation of ultrasonic treatment yielded further improvements, yielding remarkable tensile strength (6.09 MPa) and elongation at break (139.3 %). This synergistic interplay between ultrasonics and elongational rheology holds immense potential for advancing thermoplastic starch manufacturing.

Development of Antibacterial Thermoplastic Starch with Natural Oils and Extracts: Structural, Mechanical and Thermal Properties.

In this study, the influence of the incorporation of eucalyptus (EO), tea tree (TT) and rosemary (RO) essential oils and Chiriyuyo extract (CE) on the structure and properties of thermoplastic starch (TPS) obtained from potato starch, glycerin and water was evaluated. All oils and the extract were used at a concentration of 0.5 g/100 g of TPS, while for TT, the effect of the concentration was also studied. The mixtures obtained were processed by extrusion and thermocompression molding. The sheets were characterized by XRD, FTIR, TGA, SEM and analyses of their mechanical properties, antimicrobial characteristics and biodegradability. The results show that the use of small concentrations of the oils in 70TPS does not induce changes in the TPS structure according to the results of XRD, FTIR and TGA, with each essential oil and CE affecting the mechanical properties unevenly, although in all cases, antimicrobial activity was obtained, and the biodegradability of TPS in soil was not modified. An increase in the concentration of TT in 60TPS causes marked changes in the crystallinity of TPS, providing a greater modulus with a higher concentration of TT. Regardless of the amount of TT, all sheets maintain antimicrobial characteristics, and their biodegradation in soil is delayed with a higher oil content.

Molecular dynamics simulation and properties of thermoplastic starch -- effect of water content on starch plasticization

To investigate the impact of water content on starch plasticization, the molecular dynamics (MD) simulation method was employed to investigate the hydrogen bonding energy, radial distribution function (RDF) and mean square displacement (MSD) of the starch/glycerol/water system at various water contents (ranging from 8% to 14%, based on the dry starch weight). Additionally, Glycerol-plasticized thermoplastic starches (GTPSs) were prepared using a twin-screw extruder with precise material proportions according to the simulation ratio. Subsequently, DSC, XRD, FT-IR, SEM and mechanical properties of GTPSs were evaluated. By conducting an analysis on the correlation between simulation results and TPS performance, it has been demonstrated that water molecules play a pivotal role in the plasticization process of starch. GTPS exhibits challenges in processing due to its inadequate melt fluidity at lower water content (≤11%). Conversely, excessive water content (≥13%) leads to a decline in the mechanical properties of GTPS. Considering both processing stability and material’s mechanical properties, a starch water content of 12% is deemed suitable for TPS preparation.

PREPARATION AND CHARACTERIZATION OF THERMOPLASTIC STARCH FROM PINEAPPLE STEM: EFFECT OF PLASTICIZERS

This work studied the effect of types and amount of plasticizers on thermoplastic starch properties from pineapple stem with good mechanical properties, water resistant and biodegradable. Three plasticizers were studied: erythritol, xylitol, and sorbitol. Thermoplastic starch film was prepared by solution casting. When glycerol was used as co plasticizer, it could improve the flexibility of thermoplastic starch. Thermal properties of thermoplastic starch film by DSC showed that when the plasticizers were added, the heat of fusion (DHm) was reduced. Water absorption of thermoplastic starch films are maximum in 1 hour and constant after immersed in distilled water for 3 hours. Films can maintain in their shapes at least 13 days after that they dissolved. Thermoplastic starch from pineapple stem and plasticizers i.e. sorbitol and xylitol showed no significant difference in water absorption. Thermoplastic starch films from mixed plasticizers showed more hydrophilic when compared with film from single plasticizer. Films without glycerol show high tensile strength and modulus. Thermoplastic starch film from pineapple stem is water resistant and biodegradable in water. All thermoplastic starch degraded within 30 days after biodegradability test in soil. Thermoplastic starch film made from pineapple stem is considered a naturally biodegradable plastic.

Effect of oxidized, maleate and dual chemical modification through extrusion on thermoplastic starch properties

Effect of oxidized, maleate and dual chemical modification through extrusion on thermoplastic starch properties

Study of the Plasticization Effect of 1-Ethyl-3-methylimidazolium Acetate in TPS/PVA Biodegradable Blends Produced by Melt-Mixing.

The first step towards the production and marketing of bioplastics based on renewable and sustainable materials is to know their behavior at a semi-industrial scale. For this reason, in this work, the properties of thermoplastic starch (TPS)/polyvinyl alcohol (PVA) films plasticized by a green solvent, as the 1-ethyl-3-methylimidazolium acetate ([Emim+][Ac-]) ionic liquid, produced by melt-mixing were studied. These blends were prepared with a different content of [Emim+][Ac-] (27.5-42.5 %wt.) as a unique plasticizer. According to the results, this ionic liquid is an excellent plasticizer due to the transformation of the crystalline structure of the starch to an amorphous state, the increase in flexibility, and the drop in Tg, as the [Emim+][Ac-] amount increases. These findings show that the properties of these biomaterials could be modified in the function of [Emim+][Ac-] content in the formulations of TPS, depending on their final use, thus becoming a functional alternative to conventional polymers.

State of Knowledge on Starch as an Alternative Solution to Petrochemical Resources—A Review

The use of plastics from petrochemical resources poses environmental impacts, and one of the alternative solutions is the use of starch. The objective of this present work has been to present the literature on starch, and to highlight the debate in the development of composite films. The approach adopted was to present the state of the art on starch and thermoplastic starch matrix composites. The work shows that starch is available worldwide and can be used in the manufacture of biodegradable plastics; the debate remains on the reinforcement of thermoplastic starch to improve its physical and mechanical properties poor; then researchers must diversify the reinforcements to see the impact on the properties of thermoplastic starch.

Effects of nisin and EDTA on morphology and properties of thermoplastic starch and PBAT biodegradable films for meat packaging

Biodegradable active packaging was produced by compounding nisin (3, 6 and 9%) and nisin-ethylenediaminetetraacetic acid (EDTA) (3 and 6%) mixtures with poly(butylene adipate terephthalate) and thermoplastic starch blends (PBAT/TPS) by blown-film extrusion. Nisin and EDTA interacted with polymers, involving CO stretching of ester bonds and increased compatibility. This plasticized the films and modified the crystallinity, surface roughness and thermal relaxation behavior. Barrier properties were improved due to modified hydrophilic-hydrophobic properties, compact structures and crystallites that restricted vapor and oxygen permeation. PBAT/TPS films containing EDTA and nisin effectively inhibited lipid degradation in pork tissues corresponding with stabilizing the CO ester bond of triacylglycerol. Microbial growth was also inhibited, particularly in EDTA-containing films up to 1.4 log. Inactivation of microorganisms stabilized redness and delayed meat discoloration, preserving the quality of packaged pork. Interaction between nisin, EDTA and polymers modified the morphology and film properties and functionalized biodegradable food packaging to inactivate microorganisms.

Structural and Thermal Properties of Starch Plasticized with Glycerol/Urea Mixture

The paper presents the results of research on the influence of used plasticizing system on the structural and thermal properties of thermoplastic starch (TPS). The thermoplastic starch granulate was obtained by extrusion of native starch in the presence of a plasticizing system using a twin-screw extruder. Glycerol and urea were used as plasticizers in various proportions. In order to evaluate the effectiveness of the starch plasticization process, changes in its chemical structure were analyzed by infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and X-ray diffraction (XRD). TPS thermal stability was determined by thermogravimetric analysis (TGA). An improvement in the efficiency of the plasticization process has been found for a urea-containing plasticizing system compared to the composition of starch plasticized only with glycerol. In addition, the XRD analysis confirms the beneficial effect of urea on the inhibition of starch retrogradation process.

EFFECT OF AGAR AND KAPPA-CARRAGEENAN ON THERMAL AND MECHANICAL PROPERTIES OF THERMO PLASTIC STARCH (TPS)

Effect of Agar and kappa-Carrageenan on Thermal and Mechanical Properties of Thermo Plastic Starch (TPS) Thermoplastic starch needs to be blend with other materials because of its limited properties. In order to gain the desired properties, the interaction between the added component (filler, plasticizer, second polymer, etc) must be concerned as it can affect the performances of the final product. Thermoplastic starch has been successfully made with mixing and compression molding with the addition of agar and kappa-carrageenan. The effect of the added material has been studied with FTIR, Tensile, DSC, and TGA to investigate their mechanical and thermal properties. The FTIR spectrum has shown the shifting around the methyl group (C-H), a carboxyl group (C-O), and a hydroxyl group (O-H). Thermal analysis results presented different patterns in melting and degradation behavior. The tensile strength value did not show significant improvement with the presence of agar and kappa-carrageenan. It is shown that the addition of agar and kappa-carrageenan affects thermal behavior but does not significantly impact the mechanical properties.

Use of eggshell powder as a potential hydrolytic retardant for citric acid-filled thermoplastic starch

In this study, the effects of eggshell powder and citric acid on the properties of thermoplastic starch (TPS) were investigated. All components were melt-blended using an internal mixer. Citric acid led to the formation of crosslinking structures (as shown in the FTIR spectra at 1730 cm−1) and caused rapid sample biodegradation with accelerated hydrolysis. Conversely, addition of eggshell powder retarded the biodegradation. After storing the samples for 30 days, CaTPS (Cassava root TPS) without eggshell powder showed erosion over almost the entire surface, while the surface of CaTPS containing 20 phr of eggshell powder (CaTPSES20) remained unchanged. The residual TGA weight at 400 °C and the change in carbonate FTIR intensity peak of CaTPSES20 after the storage period provided both quantitative and qualitative evidence that eggshell powder can be considered a potential hydrolytic retardant for citric-acid-filled TPS.

Thermal, biodegradation and theoretical perspectives on nanoscale confinement in starch/cellulose nanocomposite modified via green crosslinker

In this research work, we propose a synergistic effect of a green crosslinker and cellulose nanomaterial on the crystallinity, viscoelastic, and thermal properties of starch nanocomposites. A disaccharide derivative was used as a bio crosslinker and nanofiber from pineapple leaf as a reinforcing phase for starch. Sucrose was oxidised using periodate, that can selectively oxidise the vicinal hydroxyl group of sucrose and form tetra aldehyde derivative. Crystallinity of films after crosslinking decreased with successive addition of crosslinker. The melting temperature of films increased because of formation of more dense structure after crosslinking. Morphological investigations were analysed by atomic force microscopy. Polymer chain confinement and mechanics were quantified. The crosslink densities of the films were calculated using two models, phantom model and affine model, using storage modulus data. By using very low amount of crosslinker and nanoreinforcement, the properties of thermoplastic starch were significantly improved.

Ways and Mechanism of Improving the Mechanical Properties of Thermoplastic Starch

Ways and Mechanism of Improving the Mechanical Properties of Thermoplastic Starch

Influence of Al2O3 particle size on properties of thermoplastic starch–TiO2–Al2O3 composites

Thermoplastic starch (TPS), an inexpensive, renewable, widely available and biodegradable biopolymer, has been promoted as a promising alternative to synthetic polymers based on fossil resources. However, it exhibits weak mechanical properties and high moisture uptake. Reinforcing fillers have been used to improve the properties of thermoplastic starch. This work studies the effects of Al2O3 particle size on dielectric, thermal, physical, mechanical and morphological properties of thermoplastic starch–TiO2–Al2O3 composites at the fixed TPS:TiO2:Al2O3 weight ratio 97:2:1. The Al2O3 particle sizes tested were 0.05 μm, 1 μm and 5 μm. Dielectric, thermal, mechanical and morphological properties were determined. With increasing Al2O3 particle size, slight increases were observed in contact angle, hardness and thermal stability, while dielectric constant, dissipation factor and glass transition temperature decreased. However, the Al2O3 particle size did not significantly affect tensile properties. Scanning electron microscopy was used to investigate the morphology in the composites. In summary, the incorporation of TiO2 and Al2O3 in thermoplastic starch could extend its potential in flexible films, compost bags and packaging applications.

Thermoplastic Starch–PVA Nanocomposite Films Reinforced with Nanocellulose from Oil Palm Empty Fruit Bunches (OPEFBs): Effect of Starch Type

ABSTRACT This research studied the effect of three types of starch on the properties of thermoplastic starch (TPS)–Poly (vinyl alcohol) (PVA)–cellulose nanocomposite films. Three different types of starch with amylose and amylopectin contents used were corn starch, cassava starch, and sago starch. Meanwhile, the nanocellulose was isolated from oil palm empty fruit bunches (OPEFBs) by mechanical treatment using ultrafine grinder. The nanocomposite films were made by evaporation casting method. It was found that the difference of amylose content in the native starch affected the properties of nanocomposite films. Meanwhile, the nanocellulose added into matrix TPS–PVA could increase tensile strength of TPS–PVA nanocomposite films.

Strength retention and moisture resistant properties of citric acid modified thermoplastic starch resins

The strength retention and moisture resistant properties of thermoplastic starch (TPS) resins were significantly enhanced by modifying with proper amounts of citric acid (CA) (i.e. TPS100CAx specimens) or by melt-blending with poly(lactic acid) (PLA) (i.e. (TPS100CA0.1)xPLAy specimens). In contrast to the distinguished retrogradation effect found for all conditioned TPS specimens, one can barely find any recrystallized starch crystals in TPS100CAx and/or (TPS100CA0.1)xPLAy specimens maintained at 20 °C/50% RH for less than 42 days. The tensile/impact strength retention values of properly prepared conditioned TPS100CA0.1 and (TPS100CA0.1)30PLA70 specimens were equivalent to 1.5 MPa/0.28 KJ/m2 and 41.8 MPa/1.63 KJ/m2, respectively, which were more than 4/4 times and 105/23 times higher than those of corresponding TPS specimens maintained at 20 °C/50% RH for 70 days. In comparison with conditioned TPS specimens, significantly less and shorter drawn debris were found on the fracture surfaces of the corresponding conditioned TPS100CA0.1 and (TPS100CA0.1)30PLA70 specimens with the same amounts of conditioned time. As revealed by Fourier transform infrared spectroscopy, Solid-state 13C Nuclear Magnetic Resonance analyses, disruption of intra and interhydrogen-bondings within starch molecules did occur after addition of small amounts of CA during the modification processes of TPS100CAx specimens. The relatively unchanged in retrogradation effect, significantly less drawn debris and considerable improvement in moisture resistant and/or strength retention properties of the conditioned TPS100CAx and/or (TPS100CA0.1)xPLAy specimens is most likely due to the efficient hydrogen-bonding CA molecules with the moisture-absorbing hydroxyl (free or hydrogen-bonded) of starch molecules that prohibits moisture absorption during their conditioning processes.

CHARACTERIZATION OF TAPIOCA STARCH PLASTICIZED BY 1-ETHYL-3-METHYLIMIDAZOLIUM ACETATE

Starch is one of natural materials that been used for producing biodegradable materials. The starch-based materials are produced through a process known as gelatinization with the presence of plasticizer and elevated temperature. Properties of starch-based materials are lacking in terms of viscosity, water absorption, thermal and mechanical properties compare with synthetic materials. Researchers are involved in finding ways for improvement of starch-based materials properties and one of that is introducing new plasticizer. 1-ethyl-3-methylimidazolium acetate, [Emim][OAc] is an ionic liquid that used as plasticizer to produce thermoplastic starch. Starch plasticized by [Emim][OAc] were prepared with different total plasticizer contents (50%,70%) and [Emim][OAc]/water ratio (1:6,1:4,2:3 wt%). The thermoplastic starches were characterized in terms of morphology, crystalline structure and thermal degradation. The results showed that 70% of total plasticizer contents were mixed well during gelatinization process. [Emim][OAc] contributed to granule disruption as shown by SEM. Based on the XRD analysis, it was shown that thermoplastic starch at 70% total plasticizer contents and 1:4 wt% ratio of [Emim][OAc]/water, caused disruption of the A-type crystalline structure, generated VH-type crystalline structure and thus increased the mobility of the amorphous starch. The presence of [Emim][OAc] promotes the thermal degradation of starch molecules as described by TGA. Therefore, plasticizer contents and [Emim][OAc]/water ratio are vital parameters that influences the properties of thermoplastic starch.

Effect of natural fibres on the mechanical properties of thermoplastic starch

Abstract This paper presents the results covering the mechanical properties of thermoplastic potato starch granules with flax, cellulose fibre, and pine bark addition. A modified single screw extrusion-cooker TS-45 with L/D = 18 and an additional cooling section of the barrel was used as the processing unit. The establishment influence of the fibre addition, as well as the extrusion-cooker screw speed, on the mechanical properties of the thermoplastic starch granules was the main objective of the investigation. The maximum force during compression to 50% of the sample diameter, elastic modulus, and compression strength were evaluated. Significant differences were noted depending on the amount of fibre used, while only an insignificant influence of screw speed on the mechanical properties of the granulate was reported. An increased amount of fibres lowered the maximum force as well as the elastic modulus and compression strength of the thermoplastic starch granulates.

Chemical-Mechanical Hydrolysis Technique of Modified Thermoplastic Starch for Better Mechanical Performance

The effects of chemical-mechanical hydrolysis on the properties of thermoplastic starch (TPS) were studied. In the presence of citric acid (CATPS) and glycerol (GTPS) along with mechanical hydrolysis, a native starch granule was transformed into a continuous phase as shown by scanning electron microscope (SEM). As shown by thermogravimetric analysis (TGA), the improvement in thermal stability confirmed that the addition of citric acid along with mechanical hydrolysis enhanced the adhesion between glycerol, citric acid and starch. It was proven by Fourier transform infrared (FTIR) spectroscopy, that citric acid form stronger hydrogen bonding than glycerol. Strong hydrogen bond formation induced the improvement in mechanical properties of GTPS. Tensile strength of citric acid modified TPS with 2% citric acid (CATPS) higher than GTPS because citric acid improved the interaction of starch molecule and slippage of starch chain.

Development of thermoplastic starch blown film by incorporating plasticized chitosan

The objective of the present work was to improve blown film extrusion processability and properties of thermoplastic starch (TPS) film by incorporating plasticized chitosan, with a content of 0.37–1.45%. The effects of chitosan on extrusion processability and melt flow ability of TPS, as well as that on appearance, optical properties, thermal properties, viscoelastic properties and tensile properties of the films were investigated. The possible interactions between chitosan and starch molecules were evaluated by FTIR and XRD techniques. Chitosan and starch molecules could interact via hydrogen bonds, as confirmed from the blue shift of OH bands and the reduction of V-type crystal formation. Although the incorporation of chitosan caused decreased extensibility and melt flow ability, as well as increased yellowness and opacity, the films possessed better extrusion processability, increased tensile strength, rigidity, thermal stability and UV absorption, as well as reduced water absorption and surface stickiness. The obtained TPS/chitosan-based films offer real potential application in the food industry, e.g. as edible films.