scholarly journals Influence of starch origin on rheological properties of concentrated aqueous solutions

2011 ◽  
Vol 65 (6) ◽  
pp. 645-655
Author(s):  
Zeljko Stojanovic ◽  
Katarina Jeremic ◽  
Slobodan Jovanovic
Keyword(s):  
Aqueous Solutions ◽  
Rheological Properties ◽  
Corn Starch ◽  
Loss Modulus ◽  
Potato Starch ◽  
Fractal Dimensions ◽  
Elastic Behavior ◽  
Starch Solution ◽  
Concentrated Aqueous Solutions ◽  
Slow Aggregation

The rheological properties of corn and potato starch concentrated aqueous solutions were investigated at 25?C. The starches were previously dispersed in water and the solutions were obtained by heating of dispersions at 115-120?C for 20 minutes. The solutions of potato starch were transparent, while the corn starch solutions were opalescent. The results of dynamic mechanical measurements showed that the values of viscosity, h, storage modulus, G?, and loss modulus, G?, of the corn starch solutions increased with the storage time. This phenomenon was not observed for the potato starch solutions. It was assumed that the increase of h, G? and G? is the result of starch solutions retrogradation. The potato starch solutions retrogradation did not occur probably because of the phosphates presence. The viscosity of 2 mass % corn starch solution is less than the viscosity of 2 mass % potato starch solution. By increasing the concentration of corn starch solution the gel with elastic behavior was formed. The corn starch solutions formed gel as early as at 4 mass % concentration, while potato starch solutions achieved the gel state at the concentration of 5 mass %. The value of exponent m (G? and G? ? wm) during the transition of potato starch solutions to gel is 0.414, which gives the fractal dimensions for corn starch of 2.10. The obtained value of fractal dimension corresponds to slow aggregation. The corn starch solutions with the starch concentrations higher than 4 mass % form weak gels. For these solutions the values of modulus in rubber plateau were determined. It was found that the modulus in rubber plateau increased with the concentration by the exponent of 4.36. Such high exponent value was obtained in the case when the tridimensional network is formed, i.e. when supermolecular structures like associates or crystal domains are formed.

scholarly journals Enhancement of the rheological properties of bentonite mud using natural polymers

2021 ◽  
Vol 7 (1) ◽  
pp. 047-059
Author(s):  
Muhammed Rufai ◽  
Koyejo Oduola
Keyword(s):  
Rheological Properties ◽  
Corn Starch ◽  
Potato Starch ◽  
Drilling Fluid ◽  
Research Work ◽  
Cassava Starch ◽  
Gel Strength ◽  
Natural Polymers ◽  
Saw Dust ◽  
Before And After

This research work focuses on finding more effective polymers that can improve the rheological properties of bentonite mud. Various mud samples were formulated with natural polymers obtained from corn starch, cassava starch, purple potato starch, yellow potato starch and saw dust consisting of different masses which were not treated or purified by any chemical method before and after preparation along with the control mud. Rheology tests were carried out to determine the plastic viscosity, apparent viscosity, yield point, gel strength among others. API standards were followed throughout the experimental study and the result from this investigation showed that increasing the concentration of polymers enhances the mud rheological properties studied at ambient condition, wherein thermal stability was exhibited up till 100°C. Thus, environmental friendly alternatives have been discovered for drilling fluid additives which are cheap, organic, bio-degradable, non-toxic and easily available

Rheological properties of guar and its methyl, hydroxypropyl and hydroxypropyl-methyl derivatives in semidilute and concentrated aqueous solutions

Polymer ◽  
2010 ◽  
Vol 51 (9) ◽  
pp. 1972-1982 ◽  
Author(s):  
Daniela Risica ◽  
Andrea Barbetta ◽  
Luca Vischetti ◽  
Cesare Cametti ◽  
Mariella Dentini
Keyword(s):  
Aqueous Solutions ◽  
Rheological Properties ◽  
Concentrated Aqueous Solutions ◽  
Methyl Derivatives

Rheological properties of concentrated aqueous solutions of anionic and cationic polyelectrolyte mixtures

2008 ◽  
Vol 50 (7) ◽  
pp. 751-756 ◽  
Author(s):  
V. E. Dreval’ ◽  
G. B. Vasil’ev ◽  
E. A. Litmanovich ◽  
V. G. Kulichikhin
Keyword(s):  
Aqueous Solutions ◽  
Rheological Properties ◽  
Cationic Polyelectrolyte ◽  
Concentrated Aqueous Solutions

Electrical conductivity and rheological properties of carbon black based conductive polymer composites prior to and after annealing

2021 ◽  
pp. 096739112110012
Author(s):  
Qingsen Gao ◽  
Jingguang Liu ◽  
Xianhu Liu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Rheological Properties ◽  
Network Formation ◽  
Loss Modulus ◽  
Conductive Polymer ◽  
Complex Viscosity ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.

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