Thermoplastic Corn Starch Research Articles

Sandwich panel biocomposite of thermoplastic corn starch and bacterial cellulose

Inadequate disposition and long period for degradation of Petroleum-derived polymers promote damages in the environment, which could be minimized by the use of biodegradable polymers such as starch and cellulose. Films of thermoplastic corn starch (TPS) and bacterial cellulose (BC) were used to produce sandwich panel biocomposite. RXD, SEM and FTIR were used to verify the transformation of TPS from native corn starch. TPS/BC is flexible and transparent, but it is less transparent that TPS and BC due to its multilayer format. TPS/BC presented similar thermal events to TPS and BC samples and thermal stability similar to TPS. The FTIR spectrum of the TPS/BC showed bands observed in the BC and TPS spectra. BC, TPS and TPS/BC showed faster water absorption in the initial stage reaching a stability at about 50 h and presenting Fickian behavior. TPS/BC showed lower water absorption and a good adhesion between the phases observed by SEM images, which can be associated to hydrogen interactions in the interface improving mechanical properties. TPS/BC showed an increase of about 3.6 times in the tensile strength compared to TPS, indicating that BC is a good reinforcement for TPS.

Characteristic of thermoplastics corn starch composite reinforced short pineapple leaf fibre by using laminates method

In recent years, the increased demand of biodegradable polymers has sparked the research interest in the development of alternatives to conventional polymers. As such, starch considerably one of the best substitutes to the non-degradable polymers owing to its advantages. The main purpose of this study is to investigate the mechanical, physical and environmental characterization of bio-composites, which is in this case the thermoplastic corn starch (TPCS) reinforced with a 2 mm length of pineapple leaf fibre (PALF). The selection of different weight percentages in the range of 20 to 60 weight percentage (wt.%) of PALF contents were applied in this work. The mixtures of TPCS with different wt.% of PALF were made by using a hot compression moulding at 165 °C for 15 minutes. Several testing has been performed to determine the bio-composites characteristics. The results show that by incorporating 40 wt.% loading of PALF, the tensile and modulus strength has increased to the maximum. It is also seen that there is an inverse relationship between the moisture content and the wt.% loading of PALF. However, the water and moisture absorption show a direct relationship with wt.% loading of PALF. Meanwhile, the soil burial decreases when the wt.% loadings of PALF increase while the results for water solubility suggest vice versa. It is also found that the TPCS with 40 wt.% of PALF have a good miscibility between matrix/fibre in the bio-composites.

Flexible thermoplastic starch films functionalized with copper particles for packaging of food products

Biodegradable films based on thermoplastic corn starch (TPS) and copper particles with antimicrobial capacity were developed. Copper nanoparticles (Cu) and silica coated copper microparticles (Si-Cu) in the range of 0.25 to 5% were used. Composite films were obtained by melt-mixing and subsequent thermo-compression. Particles distribution within TPS matrix and the presence of some pores and cracks, induced by Si-Cu particles, was evaluated by SEM. The presence of both fillers gave composite films a brown pigmentation and decreased their transparency; these effects were more pronounced at higher particles concentrations. Regarding mechanical properties, copper particles at 1 and 5% acted as reinforcing agents increasing the maximum tensile strength but their presence lead to a decrease in elongation at break, affecting films ductility. Composites inhibited the growth of Gram+ and Gram- bacteria, demonstrating their antimicrobial capacity. Copper effectively migrated to a simulant of aqueous foods and naked particles concentration in the simulant medium resulted higher than the minimum inhibitory concentration for bacteria. The characteristics and properties of developed composite films make them an interesting material for food primary packaging, mainly for meat fresh products.

Effect of Oxidized Wood Pulp Fibers on the Performance of the Thermoplastic Corn Starch Composites

In this study, oxidized wood pulp fiber (OWPF) was prepared by oxidizing wood pulp fiber (WPF) with NaIO4, and OWPFs with different oxidation degrees were obtained and characterized by light microscope, XRD, and TG. Then, OWPFs with different oxidation degrees were incorporated into thermoplastic starch (TPS) to prepare OWPF/TPS composites. The cross-section morphology, water resistance, and physical and mechanical properties of the composites were investigated. SEM showed good dispersion of OWPF in the continuous TPS phase. The tensile strength of OWPF/TPS reached a maximum value of 5.02 MPa when the oxidation degree of OWPF was 0.5. Elongation at break of OWPF/TPS composites increased with the increasing oxidation degree of OWPF. Meanwhile, as a result of cross-linking, the water contact angle was also improved with the increased oxidation degree of OWPF. The study provided a new way to prepare a degradable TPS composite with satisfying properties to be used for packaging and catering.

Physical and Environmental Properties of Thermoplastics Corn Starch TPCS Reinforced Pineapple Leaf Fibre PALF Composite

The purpose of this research is to study the physical and environmental properties of thermoplastic corn starch (TPCS) reinforced with 2 mm length of pineapple leaf fibre (PALF) bio-composites. Weight percentages of PALF ranging from 20 wt.% to 60 wt.% were used in this investigation. Hot compression moulding technique was used to produce samples of TPCS with different wt.% of PALF at the temperature of 165 °C for the duration of 15 minutes. The physical tests that had been performed were density, moisture content, moisture absorption and water absorption while the environmental tests were water solubility and soil burial testing. The moisture content results showed a decreasing trend by increasing the PALF content. However, moisture absorption and water absorption revealed an increased yield with the increase in PALF content. Meanwhile, density results did not show much change even when the fibre content was raised up to 60 wt.%. In addition, the water solubility results showed an increasing trend as the fibre was increased from 20 wt.% to 60 wt.%. On the other hand, soil burial results revealed vice versa whereby an increasing fibre content caused the weight loss of bio-composites to gradually decrease from 20 wt.% of fibre loading to the maximum of fibre loading. In conclusion, the physical and environmental properties of TPCS/PALF bio-composites obtained from this study can be used to develop biodegradable products such as containers or disposable trays.

Microstructure and physical properties of thermoplastic corn starch foams as influenced by polyvinyl alcohol and plasticizer contents

Thermoplastic starch (TPS) foams was prepared by melt extrusion process and the effects of polyvinyl alcohol (PVA) and glycerol/water plasticizer contents on the physical and cellular properties of these foams were investigated. All TPS/PVA blended foams showed more uniform cellular morphology, lower density and higher cell density than the TPS foam. The density of TPS foam decreased about 70%, and cell density increased up to 60-fold by adding 20% PVA. In addition to the positive effect of the PVA on improving processability and cellular uniformity, it also acted as a polymeric plasticizer and adding it allowed to decrease another low molecular weight plasticizer content in TPS/PVA blends. As a result by statistical analysis significant improvements in expansion ratio (256%), cell density (60 times), and lower moisture absorption (60%) were achieved.

Thermoplastic corn starch reinforced with pine wood fibre and calcium carbonate precipitate filler

The shortage of oil and related minerals and also their extreme environmental drawbacks are the main reason for the quick-growing interest in biodegradable polymer composites production. Biodegradable polymer composites are mainly produced from renewable resources which are biologically degradable. In this research, corn starch was plasticized with glycerol. The plasticized thermoplastic corn starch was reinforced with calcium carbonate precipitate powder as a filler and pine wood fibre as reinforcement. Free thermoplastic plasticized corn starch (FTPS), thermoplastic corn starch reinforced with calcium carbonate (CTPS), thermoplastic corn starch reinforced with pine wood (WTPS), thermoplastic corn starch reinforced with pine wood fibre and calcium carbonate precipitate hybrid composite (HTPS) were produced and compared for their mechanical properties like tensile strength and, hardness. DSC and DMA analysis were also done for determining their thermal properties. Moreover, the water absorption test was also carried out to understand their resistance to moisture. WTPS exhibits better results in most of the measured proprieties given that TPS and wood fibre being both hydrophobic resulted in a homogeneous distribution and better interfacial adhesion.

The Influence of Different Compounding Sequence and Peanut Shell Powder Loading on Properties of Polylactic Acid/Thermoplastic Corn Starch Biocomposites

Three different blending sequences were used to prepare the peanut shell powder (PSP)‐filled polylactic acid (PLA)/thermoplastic corn starch (TPCS) biocomposites. The blending sequences can be summarized as (1) S1: PLA was added, followed by TPCS and PSP, (2) S2: PLA was added, followed by PSP and TPCS, and (3) S3: TPCS was added, followed by PLA and PSP. Various loadings of PSP filler were used from 0 to 40 wt%. The correlation between different blending sequences and PSP filler loading of PLA/TPCS biocomposites were discussed in terms of processing torque, tensile properties, surface morphology, and thermal degradation. Results showed that S1 system is the best blending sequence to prepare PLA/TPCS biocomposites compared to S2 and S3 systems. S1 system had established the low stabilization torque, better tensile strength, elongation at break, and thermal stability. Scanning electron microscopy (SEM) analysis of S1 system revealed better adhesion between filler and the matrix. Incorporation of PSP had influenced the properties of PLA/TPCS biocomposites. Increment of PSP loading increased stabilization torque and tensile modulus while decreasing tensile strength, elongation at break, and thermal stability of PLA/TPCS biocomposites. SEM analysis also managed to detect holes and cavities as the filler pulled out on the tensile fractured surface due to poor adhesion between filler and matrix.

Mechanical Properties of Thermoplastics Corn Starch (TPCS) Reinforced Pineapple Leaf Fibre (PALF) Composite

The aim of this study is to investigate the mechanical characterization of bio-composites on thermoplastic corn starch (TPCS) reinforced with 2 mm length of pineapple leaf fibre (PALF). The selection of different weight percentages of fibres (20, 30, 40, 50 and 60) weight percentage (wt.%) of PALF contents were applied in this study. The mixtures of TPCS with different wt.% of PALF were made by using a hot compression moulding at 165 °C for 15 minutes. The mechanical testing that has been performed are tensile, flexural and impact testing to determine the effect of fibre loading on bio-composites characteristics. The results show that by incorporating 40 wt.% loading of PALF, the tensile strength and tensile modulus has increased to the maximum. However, the flexural testing result shows that 50 wt.% loading of PALF show the highest strength and modulus. Meanwhile, the impact testing result shows decrement when the loadings of PALF increases. Scanning electron microscopy (SEM) show that the TPCS with 40 wt.% of PALF have a good miscibility between matrix/fibre in the bio-composites. Overall, the TPCS/PALF composites enhance the properties of the bio-composites for short-life application: that is, plate, container, disposable tray, packaging etc.

Exploitation of by-products from cassava and ahipa starch extraction as filler of thermoplastic corn starch

Advances in bio-based composite materials offer potential opportunities for economic revalorization of agroindustrial residues such as starchy tubers peels and bagasse. In this work, cassava and ahipa peels and bagasse are studied as potential fillers of thermoplastic corn starch (TPS) films. It was assessed the effect of studied organic fillers on thermal stability as well as optical, water vapor barrier, and mechanical properties of TPS. In all cases, type (peel or bagasse) and content (0.5 and 1.5 wt %) of the filler had a great impact on the biocomposites properties. Results demonstrated that these fillers modify TPS properties and gives utility to these residues with low economic cost.

Potential of using multiscale corn husk fiber as reinforcing filler in cornstarch-based biocomposites

In this study, biodegradable composite films were prepared by using thermoplastic cornstarch matrix and corn husk fiber as a reinforcing filler. The composite films were manufactured via a casting technique using different concentrations of husk fiber (0–8%), and fructose as a plasticizer at a fixed amount of 25% for starch weight. The Physical, thermal, morphological, and tensile characteristics of composite films were investigated. The findings indicated that the incorporation of husk fiber, in general, enhanced the performance of the composite films. There was a noticeable reduction in the density and moisture content of the films, and soil burial assessment showed less resistance to biodegradation. The morphological images presented a consistent structure and excellent compatibility between matrix and reinforcement, which reflected on the improved tensile strength and young modulus as well as the crystallinity index. The thermal stability of composite films has also been enhanced, as evidenced by the increased onset decomposition temperature of the reinforced films compared to neat film. Fourier transform infrared analysis revealed increasing in intermolecular hydrogen bonding following fiber loading. The composite materials prepared using corn husk residues as reinforcement responded to community demand for agricultural and polymeric waste disposal and added more value to waste management.

Composite films with UV barrier capacity to minimize flavored waters degradation

Abstract Secondary packages for commercial flavored waters were developed from composite films to reduce beverage UV degradation. Bottle packs of orange and grapefruit flavored waters (OFW and GFW), were wrapped with films based on high density polyethylene, poly(styrene- b -butadiene- b -styrene), and thermoplastic corn starch (0 and 5% w/w bentonite). A commercial protective film (CPF) was employed as reference. Packs were placed in a UV chamber, and the effect of radiation on beverages was evaluated by colorimetry, UV–vis spectroscopy, vitamin C content (VCC), and total phenolic compounds (TPC). Wrapping films minimized OFW color variation, being this effect more evident employing composite films and comparable to CPF. Use of composite materials as secondary packages reduced the oxidative degradation of natural juices compounds, which is the main responsible of the changes observed by UV–vis spectroscopy. VCC in both flavored waters was too low, therefore after 6 days UV irradiation it could not be detected. Regarding TPC, no protective effect of all studied films was evidenced. Composite films containing 5% w/w bentonite increased UV barrier capacity of studied matrices, being the protective effect more efficient than the corresponding to CPF.

Extraction, chemical composition, and characterization of potential lignocellulosic biomasses and polymers from corn plant parts

Corn is a plant that can be used as a potential source of biomass for various biomaterial applications. Thermoplastic corn starch and corn hull, husk, and stalk fibers were extracted from different corn plant parts. The chemical composition, physical properties, thermal stability, crystallinity index, and surface morphology of the extracted samples were characterized on a powder basis. The corn husk and corn starch revealed an excellent combination of properties. Corn husk provided the highest cellulose content as well as the most favorable surface morphology. Corn starch revealed acceptable amylose content and tolerable thermal stability. The cellulose and starch demonstrated an excellent correlation between the function and structure of biomolecules. Hence, both corn starch and husk have potential for use in many applications of the biomaterial.

Improving physical properties and retrogradation of thermoplastic starch by incorporating agar

To develop functional and sustainable packaging materials from starch and to enhance their properties, agar was added to thermoplastic corn starch (TPS) in a wide concentration range and the products were prepared either by casting or melt blending with a high glycerol content. The role of agar in the mechanical and barrier performance of films, as well as the compatibility of TPS and agar was systematically evaluated. In addition, the retrogradiation of starch in various blends after long storage periods was widely characterized. Results proved that the addition of agar to TPS resulted in films with promising barrier and tensile properties. Stiffness and strength increased considerably by increasing agar content, while deformability of blends was better than those of pure TPS. Agar incorporation decreased water permeability and solubility and improved light transmittance. Retrogradation of the dry blends was significantly smaller than that of pure TPS owing to the strong starch/agar interaction.

Structural and Thermal Properties of Agricultural Mulch Films Based on Native and Oxidized Corn Starch Nanocomposites

The current need to put an end to the accumulation of synthetic polymer waste during the cultivation and harvest of food has promoted scientific research for the development of biodegradable agricultural mulch films. Native and oxidized thermoplastic corn starch, with and without the addition of natural and modified bentonite (Bent) with an eco‐friendly natural polymer such as chitosan (CS) are proposed as an alternative for this field. The hydrogen‐bonding interactions affecting the structural and thermal properties of the designed films are followed and analyzed by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and rheometry. Results indicate that chemical modification carried out onto starch's structure leads to a reduction in the OH polar groups, which affects their films interaction with nano‐clays and glycerol. Besides, nanocomposites which present an intercalated structure demonstrate less effective intercalation when oxidized starch is used as the matrix. Additionally, a higher degree of crystallinity is observed, which could indicate a lower degree of compatibility between polymer and plasticizer. Thermal characterization confirms that the glass transition temperature of plasticized corn starch increases when oxidation is performed due to the decreased compatibility between the plasticizer agent and the oxidized corn starch.

Effect of wheat straw oxidation on thermoplastic starch composites: Mechanical, thermal, and rheological process behaviors

The objective of this work is to evaluate the reinforced effect of wheat straw (WS) after oxidation in thermoplastic corn starch (TPS).The mechanical properties (tensile strength and elongation at break) of TPS and oxidized wheat straw (OWS)/TPS composites were evaluated by the tensile measurements. The composites were characterized further using scanning electron microscopy (SEM), dynamic mechanical thermal analysis, and torque measurements. In general, OWS played a key role for enhanced mechanical and thermal properties in composites, and the composites had slightly poorer rheological processing behaviors, compared to the TPS. The highest tensile strength (7.66 MPa) was achieved using WS oxidized with 0.045 mol·L−1 sodium periodate. The damage and erosion produced on WS after oxidation positively affected the properties of the composites. With respect to the findings of this study, it may be stated that OWS can be used as a promising natural filler for other composites.

Preparation and characterization of thermoplastic starch composite reinforced by plasma-treated poly (hydroxybutyrate) PHB

The present work aims to study the effect of the addition of poly (hydroxybutyrate) PHB as reinforcement in thermoplastic cornstarch (TPS) produced by the thermal compression molding method. Initially, the physical and chemical properties of TPS with different amounts of glycerol as the plasticizer (25, 30 and 35 wt%), are evaluated. Then, the composites, including 35% glycerol and different PHB contents (10, 20 and 30 wt%), are prepared. Additionally, the surface of the PHB granules is modified by plasma treatment using atmospheric air and sulfur hexafluoride (SF6) gas. In order to evaluate the influence of the PHB contents before and after the plasma treatment, the composites are characterized by FTIR, TGA, DSC, XRD, SEM, and mechanical tests. SEM showed a homogeneous distribution of PHB granules in the TPS matrix. On the other hand, the micrographs of the composites, using the high concentration of plasma-treated PHB, showed the agglomerated particles in the starch matrix, which represented stress concentrators, and showed weak interfacial adhesion leading to the poor mechanical properties. The thermogravimetric analysis of the composites with PHB treated by plasma showed a higher thermal stability compared to the composites of TPS and untreated PHB.

Improvement in adhesion of cellulose fibers to the thermoplastic starch matrix by plasma treatment modification

This work deals with provision and characterization of the biopolymer-based composites achieved by incorporation of cellulose fibers as the reinforcement within the glycerol plasticized matrix formed by thermoplastic cornstarch biopolymer. The function of starch-based polymers is limited due to poor mechanical properties. However, it is improved with forming a biocomposite of thermoplastic starch (TPS) as matrix and the cellulose fibers (CF) as reinforcement. The surface of cellulose fibers is successfully modified using the air plasma treatment with the aim of improving the matrix/fiber adhesion. The modified fibers are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The TPS/CF composites are prepared using high friction and hot compression procedure. Tensile test results and SEM images of the fracture surfaces show significant improvement of adhesion between treated cellulose fibers and TPS matrix. Thermogravimetric analysis shows a considerable decomposition at approximately 250–350 °C. XRD proved the significant increase in crystallinity percentage of composites compared to TPS.

Reinforcement of Thermoplastic Corn Starch with Crosslinked Starch/Chitosan Microparticles.

Microparticles of corn starch and chitosan crosslinked with glutaraldehyde, produced by the solvent exchange technique, are studied as reinforcement fillers for thermoplastic corn starch plasticized with glycerol. The presence of 10% w/w chitosan in the microparticles is shown to be essential to guaranteeing effective crosslinking, as demonstrated by water solubility assays. Crosslinked chitosan forms an interpenetrating polymer network with starch chains, producing microparticles with a very low solubility. The thermal stability of the microparticles is in agreement with their polysaccharide composition. An XRD analysis showed that they have crystalline fraction of 32% with Va-type structure, and have no tendency to undergo retrogradation. The tensile strength, Young’s modulus, and toughness of thermoplastic starch increased by the incorporation of the crosslinked starch/chitosan microparticles by melt-mixing. Toughness increased 360% in relation to unfilled thermoplastic starch.

Properties of Thermoplastic Corn Starch Based Green Composites Reinforced with Barley (Hordeum vulgare L.) Straw Particles Obtained by Thermal Compression

Currently, greater environmental awareness promotes research and development advances in biodegradable materials; they represent an alternative that decreases the environmental impact caused by traditional synthetic plastics. This study consists of the development and characterization of thermoplastic corn starch-based composites, reinforced with barley straw particles made by thermal compression. The study materials were prepared by using three particle concentrations (5, 10, and 15 %), while the matrix (0 %) was used as a reference. A mechanical evaluation of all samples was carried out, as well as that of their water absorption properties. They were also characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), and flammability tests. The inclusion of straw in the thermoplastic matrix increased water absorption and quickened carbon formation, although it also increased its tensile strength (7 MPa) and the Young’s modulus of activity (MOE) (420 MPa) with a 15 % reinforcement. The FTIR analysis highlights the presence of a carbonyl signal (1720 cm-1) caused by a thermal breakdown (caramelization) linked to barley particles. Moreover, X-ray diffraction demonstrated a VA-type crystallinity pattern (anhydrous) within the biocomposites and an increase of the crystallinity index, through incorporating barley particles in the thermoplastic corn starch-based matrix.