To Prepare Thermoplastic Starch Research Articles

Thermoplastic Starch/Ternary Deep Eutectic Solvent/Lignin Materials: Study of Physicochemical Properties and Fire Behavior

The goal of the work was to prepare thermoplastic starch (TPS), for the first time plasticized with ternary deep eutectic solvents (DESs) based on urea/resorcinol/choline chloride (URCC) in a 2:1:1 molar ratio and enriched with lignin as an environmentally friendly functional alternative for agricultural plastics. Potato starch was effectively modified with DES via twin-screw extrusion in the presence of lignin up to 10 pph (L10) without significant loss of elasticity (tensile strength 7.4 MPa, elongation at break 65%) and good thermocompressing properties (dynamic mechanical thermal analysis (DMTA) results) of highly amorphous materials (X-ray diffractometry (XRD) results) physically modified with DES (Fourier transform infrared (FTIR) results). The URCC mixture acted both as the plasticizer and as dissolving media for lignin, facilitating mutual processing. Moreover, cone calorimetry analysis of TPS materials revealed that they exhibited better fire-retardant properties than polymers commercially used as agricultural plastics (PE, PP, and PLA). Obtained results indicate that TPS/DES and TPS/DES+L materials can be used as, e.g., biodegradable, safe, and functional mulches that do not have to be removed from the cultivating fields.

Effect of elongational rheology on plasticization and properties of thermoplastic starch prepared by biaxial eccentric rotor extruder

Large amounts of plasticizers were added into natural starch for thermoplastic to make it processable due to the high crystallinity and large amount of intermolecular hydrogen bonds of starch. However, the traditional screw extruders based on shear deformation cannot disperse the plasticizer evenly and plasticize the starch well, which affects the comprehensive mechanical properties. In this paper, a self-developed biaxial eccentric rotor extruder (BERE) based on elongational rheology was introduced to prepare thermoplastic starch (TPS) sheets with glycerol as plasticizer at different speeds. The TPS sheets extruded by BERE all have excellent mechanical properties and optical transparency. Scanning electron microscopy, Fourier transformation infrared spectroscopy, X-ray diffraction, dynamic rheometer and universal mechanical tester were used to reveal the morphology, type and strength of hydrogen bonds, crystal structure, dynamic rheological and mechanical properties of TPS to research the effect of elongational rheology on its plasticization and properties. The results showed that the elongational rheology produced during processing process of BERE could obviously promote the dispersion of glycerol in starch and improve the melt-plasticizing effect of TPS, and the comprehensive mechanical properties of the TPS prepared by BERE is excellent with the elongation at break of 226.1%.

Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

Cassava starch was blended with glycerol to prepare thermoplastic starch (TPS). Thermoplastic starch was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented polyethylene grafted maleic anhydride particles (2 μm) dispersed in the thermoplastic starch matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of polyethylene grafted maleic anhydride (121 °C) decreased to 111 °C because of the small crystal size of the polyethylene grafted maleic anhydride phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of polyethylene grafted maleic anhydride. This reaction reduced the interfacial tension between thermoplastic starch and polyethylene grafted maleic anhydride, which improved the compatibility, mechanical properties, and morphology of the blend.

Physical Properties, Spectroscopic, Microscopic, X-ray, and Chemometric Analysis of Starch Films Enriched with Selected Functional Additives.

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. The results showed that the processing efficiency of thermoplastic starch with functional additives varied depending on the level of polyvinyl alcohol and keratin addition. Moreover, the FTIR data correlated with the changes in the physical properties of the tested films. The analysis of FTIR spectra revealed several changes in the intensity of bands originating from stretching vibrations characteristic of the –OH substituent. The changes observed depended on the presence/lack of the hydrogen bonding occurring upon interactions between the starch molecules and the various additives used. In addition, notable changes were observed in bands assigned to glycoside bonds in the starch.

Preparation, reinforcement and properties of thermoplastic starch film by film blowing

Abstract Starch is considered as the most promising material of biodegradable polymer films. However, up to date, the preparation of starch film by film blowing technique is still a challenge. Herein, cassava starch, glycerol and nano-silica (nano-SiO2) were used to prepare thermoplastic starch (TPS) films by film blowing technique. The effects of glycerol and nano-SiO2 on the mechanical properties, thermal properties and structure of TPS films were investigated. The results showed that the elongation at break of the TPS film with 40 parts of glycerol per 100 parts of dried starch (40 phs glycerol) was up to 108%. After the addition of 1 part of nano-SiO2 per 100 parts of dried starch (1 phs nano-SiO2), the tensile strength significantly increased by about 95%, while the elongation at break did not decrease. The thermal stability of starch increased with the increase of glycerol and nano-SiO2, while its melting transition temperature did not change significantly. The crystalline structure of starch changed after processing, and the crystallinity of starch decreased with increasing glycerol and nano-SiO2.

Mechanical properties improvement of thermoplastic corn starch and polyethylene-grafted-maleicanhydride blending by Na+ ions neutralization of carboxymethyl cellulose

Corn starch was melt-blended with glycerol (70/30) to prepare thermoplastic starch (TPS) at 140 °C for 10 min. The TPS was melt-blended with polyethylene grafted with maleic anhydride (PE-MAH) and carboxymethyl cellulose (CMC) to improve the properties of the TPS. Phase determination analysis and SEM images demonstrated that the morphology of the TPS/PE-MAH/CMC blend consisted of PE-MAH particles dispersed in the TPS matrix. The tensile strength and elongation were found to have improved with the addition of CMC 5 wt%. Adhesion between the polymers was observed by the asymmetric double-cantilever beam (ADCB) method. The PE-MAH/(TPS + CMC) sample showed high fracture toughness (Gc), which is related to the adhesion energy between the two polymers. This is suggestive of interactions between the MAH groups of PE-MAH and CMC. FT-IR results indicated that the neutralization and aggregation were formed by Na+ ions of CMC and the MAH of PE-MAH, which increased the interfacial adhesion between TPS and PE-MAH blend. The improvement in the mechanical properties of the TPS/PE-MAH/CMC blend is concluded to be because of the increase in the interfacial adhesion between TPS and PE-MAH by these neutralization and aggregation processes.

Reactive blending of thermoplastic starch and polyethylene-graft-maleic anhydride with chitosan as compatibilizer

Cassava starch was melt-blended with glycerol (70/30wt%/wt%) at 140°C to prepare thermoplastic starch (TPS). Chitosan (CTS) was premixed with starch and glycerol, in acidified water (lactic acid 2wt%), at 1, 5 and 10wt%/wt%. TPS/CTS was then melt-blended (160°C) with polyethylene-graft-maleic anhydride (PE-MAH). Phase determination and scanning electron microscopy indicated TPS/PE-MAH/CTS had a co-continuous morphology and CTS-induced phase inversion to give dispersed PE-MAH particles in a TPS matrix. Tensile strength at break and elongation, melt viscosity, fracture toughness and water contact angle of TPS/PE-MAH were improved by CTS incorporation. TPS/PE-MAH/CTS blends decreased the melting temperature of TPS and PE-MAH compared to the neat polymers. FTIR confirmed a reaction had occurred between amino groups (NH2) of CTS and the MAH groups of PE-MAH. This reaction and the enhanced miscibility between TPS and CTS improved the mechanical properties of the TPS/PE-MAH/CTS blend, particularly at 5wt%/wt% CTS.

The properties of blends of maleic‐anhydride‐grafted polyethylene and thermoplastic starch using hyperbranched polyester polyol as a plasticizer

The first aim of this study was to prepare thermoplastic starch (TPS), namely blends of tapioca starch and hyperbranched polyester polyol and to evaluate the hyperbranched polyester polyol (HBP) as a plasticizing agent for tapioca starch. The second aim was to prepare blends of maleic‐anhydride‐grafted low‐density polyethylene (LDPE‐g‐MA) and TPS, and to evaluate the effect of the mass ratio LDPE‐g‐MA/TPS on the structural, thermal, rheological, morphological, and mechanical properties of the blends. The melting and crystallization temperatures of the LDPE‐g‐MA/TPS blends did not correlate well with the ratio of LDPE‐g‐MA/TPS. The blends exhibited a reduction in the A‐type crystallinity and a pseudoplastic rheological behavior. V‐type crystallinity was not observed for neither TPS nor LDPE‐g‐MA/TPS blends. Scanning electronic microscophy provided an evidence for the presence of starch granules in all the blends and for low interaction degree between LDPE‐g‐MA and TPS. Young's modulus and tensile strength of the LDPE‐g‐MA/TPS blends decreased with the decreasing LDPE‐g‐MA/TPS ratio. POLYM. ENG. SCI., 55:2526–2533, 2015. © 2015 Society of Plastics Engineers

Studies on the effect of storage time and plasticizers on the structural variations in thermoplastic starch

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.

Study on the Effect of Distillation Residue in Corn Polyols Industry on Thermoplastic Starch

This study used distillation residue obtained from bio-refinery process of corn starch and glycerol as a plasticizer to prepare thermoplastic starch (TPS). Various weight ratios of distillation residue and glycerol was investigated, HPLC method was used to analysis the components of the distillation residue. The composition and structure of TPS were evaluated by FTIR, XRD and TGA. The results indicated that with the addition of mixed plasticizers, the structure of TPS was changed obviously from a crystal state to an amorphous one with an increasing thermal stability of TPS. The better TPS structure can be obtained when the weight ratio of distillation and glycerol is 3:7.

Biodegradable PBAT/Starch Nanocomposites

Starch-based biodegradable banocomposites of poly(butylene adipate-co-terephthalate) [PBAT] and organically modified nanoclays were prepared using melt intercalation technique in Haake Torque Rheocord 9000. Two different organically modified nanoclays Cloisite C20A and Cloisite C30B at various wt% (1, 3, 5) have been used for fabrication of nanocomposites. Starch was gelatinized to prepare thermoplastic starch (TPS) for increasing the compatibility with the PBAT matrix. Subsequently, films of PBAT/TPS blends at various TPS contents (10, 20, 30, 40) wt% and PBAT/TPS Organoclay biodegradable blend nanocomposites at different wt% of nanoclays were prepared using solvent casting method. The interfacial region between the biodegradable polymer matrix and the clays were also modified with grafting of Maleic anhydride (MA) with PBAT chains, during melt blending through two stage reactive extrusion process. Mechanical tests revealed an increase in tensile modulus and elongation at break with the incorporation of 30 wt% TPS and C30B nanoclay to the tune of 44.45% and 776.9% as compared with PBAT matrix. PBAT/TPS30 wt%/C30B3wt% shows maximum tensile modulus and elongation at break due to intercalation of silicate layers resulting from similarity in the surface polarity and interactions of C30B with TPS. Morphology of PBAT/TPS30%/C30B3% biodegradable blend nanocomposite studied using WAXD and SEM indicated intercalation and improved dispersion of TPS within PBAT with incorporation of C30B. Dynamical mechanical analysis of PBAT/TPS/C30B biodegradable blend nanocomposite revealed an increase of storage modulus and glass transition temperatures of PBAT with addition of nanoclays. Further Biodegradation test also confirmed higher biodegradability of PBAT in presence of TPS and C30B.

N, N, N′, N′-Tetrakis(2-hydroxyethyl)ethylenediamine as a new plasticizer for thermoplastic starch and its effect on the physical and mechanical properties of starch-based nanocomposites

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Preparation and properties of thermoplastic pea starch using N,N‐bis(2‐hydroxyethyl)formamide as the plasticizer

AbstractN,N‐bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for pea starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and pea starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscope (SEM), pea starch granules were completely disrupted, and the homogeneous materials were obtained. The crystallinity of pea starch and BHF‐plasticized thermoplastic pea starch (BTPS) was characterized by X‐ray diffraction (XRD). Rheological properties of TPS were analyzed. The water resistance of BTPS was better than that of glycerol‐plasticized thermoplastic pea starch (GTPS). At RH 33%, the tensile strength of BTPS was higher than that of GTPS for TPS containing 30% plasticizer. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

Starch based biodegradable PBAT nanocomposites: Effect of starch modification on mechanical, thermal, morphological and biodegradability behavior

Starch based Biodegradable Nanocomposites of poly (butylene adipate-co-terephthalate) [PBAT] and organically modified nanoclays were prepared using melt intercalation technique in Haake Torque Rheocord 9000. Two different organically modified nanoclays Cloisite C20A and Cloisite C30B at various wt% (1,3,5) have been used for fabrication of nanocomposites. Starch was gelatinized to prepare thermoplastic starch (TPS) for increasing the compatibility with the PBAT matrix. Subsequently, films of PBAT/TPS blends at various TPS contents (10,20,30,40) wt% and PBAT/TPS Organoclay biodegradable blend nanocomposites at different wt% of nanoclays were prepared using solvent casting method. The interfacial region between the biodegradable polymer matrix and the clays were also modified with grafting of maleic anhydride (MA) with PBAT chains, during melt blending through two stage reactive extrusion process. Mechanical tests revealed an increase in tensile modulus and elongation at break with the incorporation of 30 wt% TPS and C30B nanoclay to the tune of 44.45% and 776.9% as compared with PBAT matrix. PBAT/TPS30wt%/C30Bwt% shows maximum tensile modulus and elongation at break due to intercalation of silicate layers resulting from similarity in the surface polarity and interactions of C30B with TPS. Morphology of PBAT/TPS30%/C30B3% biodegradable blend nanocomposite studied using WAXD and SEM indicated intercalation and improved dispersion of TPS within PBAT with incorporation of C30B. Dynamic mechanical analysis of PBAT/TPS/C30B biodegradable blend nanocomposite revealed an increase of storage modulus and glass transition temperatures of PBAT with addition of nanoclays. Further biodegradation test also confirmed higher biodegradability of PBAT in presence of TPS and C30B.

N-(2-Hydroxypropyl)formamide and N-(2-hydroxyethyl)- N-methylformamide as two new plasticizers for thermoplastic starch

N -(2-Hydroxypropyl)formamide (HPF) and N -(2-hydroxyethyl)- N -methylformamide (HMF) were used independently as new plasticizers for corn starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between HPF (or HMF) and starch was proven by Fourier-transform infrared spectroscopy. By scanning electron microscopy, starch granules were shown to be completely disrupted and homogeneous materials were obtained. The crystallinity of corn starch, HPF-plasticized TPS (PTPS) and HMF-plasticized TPS (MTPS) was characterized by X-ray diffraction. The crystallinity of TPS was affected by the structure of plasticizer. The water resistance of PTPS was better than that of MTPS. At medium relative humidity (RH), both tensile strength and elongation at break of PTPS were higher than those of MTPS. At high RH, the elongation at break of PTPS was higher than that of MTPS, while the tensile strength of PTPS was close to that of MTPS.

Impact of Pre‐Processing of Montmorillonite on the Properties of Melt‐Extruded Thermoplastic Starch/ Montmorillonite Nanocomposites

AbstractA simple and environmentally‐friendly processing method was used to prepare thermoplastic starch (TPS)/ montmorillonite (MMT) nanocomposites. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) demonstrated that glycerol could enlarge the d‐spacing and destruct the layered structure of MMT effectively during the pre‐processing of MMT. So the enlarged d‐spacing and fragmentized platelets of glycerol activated‐MMT were a precondition to form intercalated or exfoliated TPS‐based nanocomposites during the melt extrusion processing. These highly dispersive and compatible TPS/activated‐MMT nanocomposites had increased thermal stability and tensile properties as compared with non‐activated composites. Especially, the tensile strength of nanocomposites could be enhanced to 8.6 MPa, the improvement was about two times the initial tensile strength of TPS.

N,N‐Bis(2‐hydroxyethyl)formamide as a New Plasticizer for Thermoplastic Starch

AbstractN,N‐Bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for corn starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscopy (SEM), starch granules were completely disrupted and a continuous phase was obtained. The crystallinity of corn starch and BHF‐plasticized TPS (BTPS) was characterized by X‐ray diffraction (XRD). The thermal behavior of glycerol‐plasticized TPS (GTPS) and BTPS was investigated by differential scanning calorimetry (DSC). The water resistance of BTPS was better than that of GTPS. Generally, at low relative humidity (RH), the tensile strength of BTPS was higher than that of GTPS. At high RH, the elongation at break of BTPS was higher than that of GTPS.

N-(2-Hydroxyethyl)formamide as a new plasticizer for thermoplastic starch

N-(2-Hydroxyethyl)formamide (HF) was synthesized efficiently and used as a new plasticizer for corn starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between HF and starch was proved by Fourier-transform infrared (FT-IR) spectroscopy. Scanning electron microscope (SEM) revealed that starch granules were completely disrupted and a continuous phase was obtained. The crystallinity of corn starch and HF-plasticized TPS (HTPS) were characterized by X-ray diffraction (XRD). The glass transitions of glycerol-plasticized TPS (GTPS) and HTPS were investigated by differential scanning calorimetry (DSC). The water resistance of GTPS was better than that of HTPS. In addition, the flexibility of HTPS was better than that of GTPS at low relative humidity.

Effect of citric acid and processing on the performance of thermoplastic starch/montmorillonite nanocomposites

Abstract A facile two steps extrusion processing conditions are used to prepare thermoplastic starch (TPS)/glycerol modified-montmorillonite (GMMT) nanocomposites. X-ray diffraction (XRD) and transmission electron microscopy (TEM) demonstrate glycerol can enlarge the d-spacing and destruct the multilayer structure of montmorillonite (MMT) effectively using high speed emulsifying machine (HSEM) in the first modification step. So the enlarged d-spacing and destructed platelets of MMT are favorable to form intercalated or exfoliated TPS/GMMT nanocomposites in the second melt extrusion processing. However, scanning electron microscopy (SEM) and XRD show the possible competition between TPS matrix and plasticizer for the intercalation between MMT layers can deteriorate the plasticization of TPS. In addition, citric acid (CA) can increase the plasticization of TPS and dispersion of MMT in nanocomposites effectively detected by fourier transform infrared (FT-IR) spectroscopy and SEM. At the same time, this facile processing conditions and CA can improve the mechanical properties and water vapor permeability (WVP) of TPS/GMMT nanocomposites obviously.

The Effects of Different Plasticizers on the Properties of Thermoplastic Starch as Solid Polymer Electrolytes

AbstractPlasticizers with amide groups (urea and formamide) and polyols (glycerol, glucose, and sorbitol) were used to prepare thermoplastic starch (TPS) containing NaCl salt as solid polymer electrolytes (SPE). Fourier Transform infrared (FT‐IR) spectroscopy revealed that both plasticizers and Na+ could form the interaction with starch, and plasticizers containing amide groups had stronger hydrogen bond‐forming abilities with starch than polyols. These interactions prevented starch molecules from crystallizing again, indicated by X‐ray diffraction (XRD). Scanning electron microscope (SEM) showed that starch granules were in a molten state and a continuous phase of TPS was formed. Among TPS as SPE, formamide‐plasticized TPS (FPTPS) had the largest elongation at break and lowest tensile stress. The conductance of TPS was sensitive to water. TPS plasticized by solid plasticizers had the higher sensitivity of the conductance to water contents at the low water contents (<0.1). The relationship of the conductance and water contents was in agreement with the second‐order polynomial correlation when water contents were below 0.45. FPTPS had the best conductance as a whole. At the medium water content (0.2), the conductance of FPTPS containing NaCl was about 10−3 S · cm−1.magnified image