scholarly journals EFFECT OF TEMPERATURE AND pH OF MODIFICATION PROCESS ON THE PHYSICAL-MECHANICAL PROPERTIES OF MODIFIED CASSAVA STARCH

Molekul ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. 248 ◽  
Author(s):  
Yudi Wicaksono ◽  
Nuri Nuri ◽  
Budipratiwi Wisudyaningsih
Keyword(s):  
Mechanical Properties ◽  
Cassava Starch ◽  
Effect Of Temperature ◽  
Swelling Power ◽  
Starch Modification ◽  
Compression Properties ◽  
Modification Process ◽  
The Difference ◽  
Starch Modifications ◽  
Pvp K30

The use of cassava starch for excipient in the manufacturing of the tablet has some problems, especially on physical-mechanical properties. The purpose of this study was to determine the effect of the differentness of temperature and pH in the process of modification on the physical-mechanical properties of modified cassava starch. Modifications were performed by suspending cassava starch into a solution of 3 % (w/v) PVP K30. The effect of the difference of temperature was observed at temperatures of 25; 45 and 65 0C, while the effect of the difference of pH was observed at pH of 4.0; 7.0 and 12.0. The results showed that the temperature and pH did not affect the physical-mechanical properties of the modified cassava starch. Modification of cassava starch at pH and temperature of 7.0 and 45 0C was produced modified cassava starch with the most excellent solubility, while the best swelling power were formed by the modification process at pH and temperature of 7.0 and 25 0C. Overall, the most excellent compression properties of modified cassava starch resulted from the modification process at pH 12.

scholarly journals Effect of pH on Physicochemical Properties of Cassava Starch Modification Using Ozone

2018 ◽  
Vol 156 ◽  
pp. 01027 ◽  
Author(s):  
Isti Pudjihastuti ◽  
Noer Handayani ◽  
Siswo Sumardiono
Keyword(s):  
Physicochemical Properties ◽  
Water Solubility ◽  
Amylose Content ◽  
Reaction Times ◽  
Cassava Starch ◽  
Carboxyl Content ◽  
Effect Of Ph ◽  
Swelling Power ◽  
Starch Modification ◽  
High Amylose

Nowadays, starch modification is carried out in order to change the native properties into the better ones, such as high stability, brightness, and better texture. The objectives of this study are to investigate the effect of pH on carboxyl content, swelling power, and water solubility of starch. This research was divided into two main stages, i.e. starch modification by ozone oxidation and analysis. The physicochemical properties of modified cassava starch were investigated under various reaction pH of 7-10 and the reaction time between 0-240 minutes. Reaction condition at pH 10 provided the higher value of carboxyl content and water solubility, but the lower of swelling power. This increase in solubility indicates that the modified oxidation starch readily dissolves in water, due to its small size granules and high amylose content. The significant changes of both parameters were achieved in the first 120 minutes of ozone reaction times. The graphic pattern of water solubility was in contrast with swelling power.

Preparation and Properties of Sponge Rubber Based on Natural Rubber and Cassava Starch

2014 ◽  
Vol 931-932 ◽  
pp. 68-72
Author(s):  
Komsun Temna ◽  
Nitinart Saetung ◽  
Anuwat Saetung
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Cassava Starch ◽  
Interfacial Interaction ◽  
Morphological Properties ◽  
Elongation At Break ◽  
Cure Time ◽  
The Difference ◽  
Cure Characteristic

In this work, the sponge rubbers based on cassava starch masterbatch in latex phase with the difference technique (non-gelatinized and gelatinized cassava starch) were preformed. The cassava starch contents from 0 to 70 phr were also studied. The cure characteristic, mechanical and morphological properties were investigated. It was found that the scorch time and cure time were increased with an increasing of cassava starch contents in both techniques. The mechanical properties i.e., tensile strength, elongation at break and tear strength were decreased with an increasing of cassava starch contents, except 500% modulus. However, the sponge based on gelatinized technique gave the better mechanical properties than that of non-gelatinized cassava starch. The SEM micrographs of sponge NR from gelatinized technique were also able to confirm a good interfacial interaction between hydrophilic cassava starch and hydrophobic NR.

Numerical and experimental investigations of the effect of temperature and moisture on the repose angle of railway ballast

2021 ◽  
pp. 095440972110393
Author(s):  
Jianxing Liu ◽  
Ping Wang ◽  
Ganzhong Liu ◽  
Shuai Du ◽  
Rong Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Angle Of Repose ◽  
Effect Of Temperature ◽  
Experimental Investigations ◽  
Railway Ballast ◽  
Influence Of Temperature ◽  
Surface Method ◽  
The Difference ◽  
Validity Tests

The angle of repose (AOR) is one of the key parameters used to comprehensively characterize the basic mechanical properties and stacking properties of granular materials. In this research, the influence of temperature and moisture on the stacking performance of railway ballast was studied through tests of the AOR. Additionally, the parameters of the discrete element method (DEM) for ballast beds with various temperatures and moisture levels were calibrated and combined with the response surface method. Then, the AORs of the ballast in different environments were simulated with the DEM, and the micromechanical properties of the ballast in dry, wet, low-temperature, and frozen environments were compared. The results showed that the AOR of the ballast in a frozen environment was smaller than that in a dry environment at the same low temperature (the difference could reach 8.48° at −30°C). The AOR of the ballast increased with the decrease of the temperature in a dry environment (18.44% increase between 20°C and −30°C). The AOR of the ballast decreased with the decrease of the temperature in a wet (frozen) environment (22.86% decrease between 20°C and −30°C). In addition, the validity tests of the AOR simulations of ballast proved that the obtained parameters could be used in the DEM models of ballast for the corresponding temperature and moisture. At the same time, it was found that with the change of temperature and moisture, the force chain network of the ballast would also change.

Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silver Nitrate ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Hardness Tester ◽  
Acrylic Resins ◽  
The Difference

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.

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