scholarly journals Effect of Alkali Treatment on Structure and Properties of High Amylose Corn Starch Film

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1705 ◽  
Author(s):  
Yang Qin ◽  
Hui Zhang ◽  
Yangyong Dai ◽  
Hanxue Hou ◽  
Haizhou Dong

Alkali treatment is used for melt extrusion film formation with corn starch, but optimal conditions for this procedure are still unknown. In this study, the changes in properties and structure of high amylose corn starch (70%) films with different concentrations of sodium hydroxide (NaOH), prepared by melting extrusion, were investigated. With increasing sodium hydroxide concentrations, the tensile strength of the high-amylose starch film decreased gradually, while the elongation at break increased. The tensile strength of the high amylose starch (HAS) film with 2% NaOH-treatment was 10.03 MPa and its elongation at break was 40%. A 2% NaOH-treatment promoted the orderly rearrangement of starch molecules and formed an Eh-type crystal structure, which enlarged the spacing of the single helix structure, increased the molecular mobility of the starch, and slowed down the process of recrystallization; a 10% NaOH-treatment oxidized the hydroxyl groups of the high amylose corn starch during extrusion, formed a poly-carbonyl structure, and initiated the degradation and cross-linking of starch molecule chains.

2013 ◽  
Vol 772 ◽  
pp. 34-37
Author(s):  
Hao Tang ◽  
Hai Tian Jiang ◽  
Bin Guo ◽  
Pan Xin Li

Corn starch was irradiated by 60Coγ ray, and then the thermoplastic starch plastic (TPS) was prepared by adding glycerol. Microstructure, thermal and mechanical properties of the corn starch and starch plastic were studied in details by FTIR, DSC and SEM. Results showed that the starch macromolecular structure was damaged by irradiation, and with increased irradiation time, the temperature of melt endothermic peak and tensile strength decreased, elongation at break increases for starch plastic, the thermoplastic property of starch was enhanced obviously.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Teresa Nabais ◽  
Grégoire Leclair

Substituted amylose (SA) polymers were produced from high-amylose corn starch by etherification of its hydroxyl groups with chloroacetate. Amorphous high-amylose sodium carboxymethyl starch (HASCA), the resulting SA polymer, was spray-dried to obtain an excipient (SD HASCA) with optimal binding and sustained-release (SR) properties. Tablets containing different percentages of SD HASCA and tramadol hydrochloride were produced by direct compression and evaluated for dissolution. Once-daily and twice-daily SD HASCA tablets containing two common dosages of tramadol hydrochloride (100 mg and 200 mg), a freely water-soluble drug, were successfully developed. These SR formulations presented high crushing forces, which facilitate further tablet processing and handling. When exposed to both a pH gradient simulating the pH variations through the gastrointestinal tract and a 40% ethanol medium, a very rigid gel formed progressively at the surface of the tablets providing controlled drug-release properties. These properties indicated that SD HASCA was a promising and robust excipient for oral, sustained drug-release, which may possibly minimize the likelihood of dose dumping and consequent adverse effects, even in the case of coadministration with alcohol.


2015 ◽  
Vol 35 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Keshak Babu ◽  
Achinta Bera ◽  
Kamlesh Kumari ◽  
Ajay Mandal ◽  
Vinod Kumar Saxena

Abstract Biodegradable blended films from methylcellulose (MC) and potato starch (PST) have been developed by the casting process. In the present work the influences of concentrations of MC and PST on rheological properties, swelling, mechanical properties such as tensile strength, percentage elongation at break and water vapor transmission rate (WVTR) of the prepared blended films have been studied. Fourier transform infrared (FTIR) analysis of pure MC, PST, their mixture and the mixture with glutaraldehyde and urea was performed to investigate the interactions in blended films. The blended films of MC and PST showed an increase in tensile strength due to the cross linking reactions of the amylopectin molecule of PST in the physical gel state. The change of percentage elongation at break increased with MC concentration and the opposite trend was found in the case of the WVTR due to the network structure of the blended films. The blended films showed a large improvement in the abovementioned properties compared with each single component, due to the interaction formed between hydroxyl groups of PST and the methoxy groups of MC. Experiments were also conducted to investigate the controlled urea release through blended films and the kinetics of the process. Interesting results were found with the prepared MC and PST blended films.


2018 ◽  
Vol 33 (5) ◽  
pp. 646-658 ◽  
Author(s):  
Yin Peng ◽  
Dongdong Zha ◽  
Guo Bin ◽  
Li Bengang ◽  
Li Panxin

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.


2020 ◽  
Vol 4 (2) ◽  
pp. 36-42
Author(s):  
Na yad ◽  
Maribel L. ◽  
Is on ◽  
Michael Jomar B ◽  
Ma ningas ◽  
...  

The goal of this research is to create biodegradable plastics made from Paragis grass (Eleusine indica) cellulose-pulp that can be used as alternatives to traditional plastics. The bioplastics were made by combining cellulose pulp from paragis grass leaves, sorbitol, acetic acid, and corn starch, with a constant amount of 8g corn starch and varying amounts of cellulose pulp (20g, 30g, and 40g), as well as 10ml sorbitol and 3 ml acetic acid. Collection and processing of paragis grass, cellulose pulp manufacturing, and bioplastic film manufacture were some of the methods used. Tensile strength, biodegradability, water absorption, and water solubility tests are used to characterize bioplastic. The mechanical properties testing shown that bioplastic produced with variation of corn starch to paragis grass cellulose pulp ratio had a tensile strength of 0.549 MPa, 0.878 MPa and 1.03 MPa; elongation at break (%) of 7.33%, 6.97% and 6.54%; biodegradability (weight loss) of 91.65%; 90.05%; and 69.46%; water absorption (weight gain) of 91.80%, 83.06% and 53.74%; and water solubility (weight loss) of 86.96%, 66.46% and54.91% respectively. The study found that Treatment 3 (40g paragis grass) has higher tensile strength (1.03 MPa) and tear strength, ability to degrade in four weeks, low water absorption (53.74%), and water solubility (54.91%).The result showed that cellulose-pulp from Paragis grass leaves could be used to make bioplastic. This research would aid in the reduction of plastic waste that pollutes the Earth’s soil, air, and water, as well as the mitigation of its consequences. It can also help reduce environmental pollution by using biodegradable plastic.


2020 ◽  
pp. 096739112097288
Author(s):  
Sohan Lal ◽  
Vinod Kumar ◽  
Sanjiv Arora

The present study described reduces of plastic based non-biodegradable food packaging material and sustainability toward the environmental protection. The polyvinyl alcohol (PVA) based ternary blend biodegradable films with bio-materials (corn starch and pectin) in ratio 1:5, 1:2, 1:1 and 2:1 were synthesized by solution casting method in water as a solvent to improve the tensile strength, high % elongation at break, and sustained packaging properties. Citric acid and glycerol were used for cross-linking and plasticizing purposes which are also bio-degradable and non-toxic. Blend films were characterized by FTIR and checked out the cross-linking of different components. The dispersion of contents in films was analyzed by SEM images. Thermal stability and degradation behavior of casted films were studied with thermogravimetry and thermal stability increased in blends as compared to neat PVA film. Biodegradability of cast films was also checked by Soil Burial method and bio-degradation increased with time i.e. almost 50% degrades in 30 days and 68% after 90 days. Tensile properties of blend films were tested and found that tensile strength (18.85 MPa) and elongation at break (516%) are high in blend films as compared with neat PVA film (12.04 MPa, 170%). The films are eco-friendly and biodegradable, might be a replacement of plastic material in food packaging having improved tensile properties.


2021 ◽  
Vol 55 (7-8) ◽  
pp. 849-865
Author(s):  
PARTHIBAN FATHIRAJA ◽  
SUGUMAR GOPALRAJAN ◽  
MASILAN KARUNANITHI ◽  
MURALIDHARAN NAGARAJAN ◽  
MOHAN CHITRADURGA OBAIAH ◽  
...  

The aim of the study has been to develop a biodegradable film from marine polysaccharides. The optimization of polysaccharides quantity for the composite film was sought by empirical response surface methodology. The Box–Behnken Model Design was applied to optimize the concentration of chitosan (1.0-2.0% (w/v), agar (1.0-2.0% (w/v) and glycerol (0.1-0.5% (w/v) as independent variables to achieve the goal. The overall desirability function fits with the quadratic model (0.862043) at a significant level (p < 0.05) for the optimum concentration of chitosan (1.5% (w/v), agar (2.0% (w/v) and glycerol (0.41% (w/v) to obtain the minimum water vapor permeability (7.25 10-10g m m-2 Pa-1 s-1) and maximum tensile strength (12.21 Ma P), elongation at break (7.32%) and puncture resistance (16.18 N) in the optimized composite film. The absolute residual errors of experimental and predicted responses were between 1.24 and 3.56% acceptable levels. Attenuated total reflection–Fourier transform infrared spectroscopy confirmed the intermolecular non-covalent hydrogen bond between the hydroxyl groups of agar and glycerol with the amino group of chitosan. 3D atomic force microscopy images revealed that the chitosan, agar and glycerol film has layer-by-layer smooth surface properties due to homogenous interaction among the polysaccharides; this provides the film with good mechanical properties and with functional application. Chitosan was found to be responsible for the lower level of water vapor permeability and higher puncture resistance of the film. Tensile strength and elongation at break were influenced by agar and glycerol. The whiteness of the film was negatively affected with the concentration of chitosan.


2012 ◽  
Vol 15 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Maria Alejandra Bertuzzi ◽  
Juan Carlos Gottifredi ◽  
Margarita Armada

In the present study, a better knowledge of the influence of plasticizer content, storage relative humidity and film thickness on the mechanical properties of high amylose corn starch based films gelatinized at low temperature, is presented. The mechanical properties, tensile strength and percentage of elongation at break of high amylose corn starch films plasticized with glycerol were evaluated using tension tests. The films exhibited an increase in elongation and a decrease in tensile strength with increasing plasticizer concentration. When the glycerol level was high, some fissures were detected in the dry films, possible due to phase separation (starch-glycerol) phenomena. Film crystallinity is related to the reorganization capacity of the polymer chain, and thus the relative film crystallinity should increase with plasticizer content (glycerol and water). The mechanical properties were found to be strongly dependent on the water content due to the hydrophilic nature of starch films. The influence of moisture sorption on tensile strength was similar to that of plasticization with glycerol. The relationship between polymer chain mobility and water content explained this behavior. Elongation suffered a different effect and maximum values were reached at 45% relative humidity. The final drop in elongation was due to a softening of the structure at high relative humidity. The thicker the film the longer the drying time required, leading to greater relative crystallinity due to the corresponding increase in the possibility for chain reorganization. As a consequence, linear increases in tensile strength and elongation were observed with film thickness over the whole range studied (30 to 100 µm).


Author(s):  
Jeanger P. Juanga-Labayen ◽  
Qiuyan Yuan

This study investigates the efficacy of using discarded textile (cotton and polycotton) and paper waste (newspaper and corrugated cardboard) as substrates to form sheets with optimum tensile strength. The effect of alkali treatment (sodium hydroxide (NaOH) and sodium bicarbonate (NaHCO3)), compressive loads (200 N and 500 N), and the use of binding agents (blackstrap molasses, sodium alginate, and cornstarch) were studied to optimize the tensile strength of homogeneous sheets. The alkali treatment using 5% NaOH for 5 h of soaking demonstrated the highest increase in tensile strength of 21% and 19% for cotton and newspaper, respectively. Increasing compressive load from 200 N to 500 N showed the highest increase in tensile strength of 37% and 42% for cotton and newspaper, respectively. Remarkably, among the binders, cornstarch at 20% concentration obtained an increase in tensile strength of 395%, 320%, 310%, and 185% for cotton, polycotton, corrugated cardboard, and newspaper sheets, respectively. The optimum results obtained from this study will be utilized to develop biodegradable seedling pots using discarded textile and paper waste.


2012 ◽  
Vol 455-456 ◽  
pp. 851-855
Author(s):  
Jin Hua Yan ◽  
Hui Xia Xu ◽  
Yan Li

A fatty acid-starch complex was prepared to apply in the linerboard surface treatment (sizing). Compared with the raw corn starch and commercial size press cationic starch, the fatty acid-starch complex displayed better water resistance, higher tensile strength and higher bending stiffness of treated samples. Two different fatty acids of C16 like palmitic acid and C18 like stearic acid were compared. Both C16 and C18 fatty acids showed similar results. Small amount of clay addition to the complex could increase the tensile strength and bending stiffness of sized samples, while keeping the good water resistance. PCC also could increase the tensile strength with the small amount of addition to the fatty acid-starch complex as surface sizing agent in our study. The SEM pictures of surface treated samples using the complex with and without clay and PCC were taken and the bonding characteristics and surface film formation were investigated.


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