Rheological Characterization of Starch Gelatinization: Effects of plasticizer/starch ratio and clay content in corn-starch/glycerol thermoplastic starch (TPS)

2014 ◽  
Vol 1622 ◽  
pp. 161-167
Author(s):  
Sandra Lara ◽  
Felipe Salcedo
Keyword(s):  
Corn Starch ◽  
Clay Content ◽  
Thermoplastic Starch ◽  
Heating Rates ◽  
Rheological Characterization ◽  
Gel Properties ◽  
Rheological Study ◽  
Formulation Variables ◽  
Oscillatory Temperature

ABSTRACTThis work presents a systematic rheological study of the gelatinization process of corn-starch plasticized with glycerol, showing the effects of the glycerol/starch ratio, water/starch ratio, and clay (montmorillonite) content. Gelatinization temperatures at different heating rates in rheological oscillatory temperature-sweep experiments were determined for different corn-starch/glycerol/clay formulations. The influences of the different formulation variables on the gelatinization processes and on the gel properties are analyzed. Some hypotheses postulating how the different intermolecular interactions present in the composites are responsible for these effects are discussed.

scholarly journals Contribution to the rheological study of cementitious pastes with addition of residues from the processing of ornamental rocks

2018 ◽  
Vol 11 (6) ◽  
pp. 1284-1307 ◽  
Author(s):  
V. Y. SATO ◽  
A. P. L. GALINA ◽  
J. E. S. L. TEIXEIRA
Keyword(s):  
Rheological Parameters ◽  
Cement Matrix ◽  
Rheological Characterization ◽  
Cement Pastes ◽  
Rheological Study ◽  
Mineral Addition ◽  
Flow Test ◽  
Ornamental Stones ◽  
Thixotropic Fluid

Abstract Brazil is one of the world's largest producers and exporters in the field of ornamental stones. On the other hand, the production and processing of ornamental stones result in a large volume of unused material in the form of sludge, usually discarded inappropriately in sedimentation ponds or landfills. Several researches have been carried out aiming the reuse of this material in cementitious matrixes. In the field of rheology, there are still incipient national studies that use the rheological parameters obtained experimentally to determine the behavior of cement matrix based on Portland cement. Thus, the objective of this work is to characterize rheologically the behavior of cementitious pastes with and without addition of ornamental rock processing residue (RBRO) in its natural condition. Cement pastes were prepared with three a/c ratios (0.45, 0.55, 0.65) and four residue addition contents (0%, 5%, 10%, 15%) and submitted to the flow test. In tests for characterization of the residue, the RBRO presented as a material of specific fineness and mass near the cement, having low reactive activity, indicating that the residue can be used as an inert mineral addition in the cementitious matrix. In the rheological characterization tests of the pulps studied, it was observed in the flow tests that the samples behaved as a non-Newtonian, pseudoplastic and thixotropic fluid.

scholarly journals Spectroscopic Characterization and Gel Properties of Agar from Two Gelidium Species from the Atlantic Coast of Morocco

2021 ◽  
Vol 11 (5) ◽  
pp. 12642-12652
Keyword(s):  
Atlantic Coast ◽  
13C Nmr Spectroscopy ◽  
Spectroscopic Characterization ◽  
Rheological Characterization ◽  
Gel Properties ◽  
Melting Temperatures ◽  
Agar Yield ◽  
Yield And Quality

The commercial value of agar in the phycocolloid market depends mostly on the agar yield and quality. The present study investigates the agar content and characterization of two Gelidiales Gelidium corneum and Gelidium microdon from the Moroccan Atlantic coast. Spectroscopic and rheological characterization of extracted agar without and with alkali pretreatments were evaluated. The highest agar yield was detected for mild alkaline pretreatment (N2CO3). The native agar content in G. corneum was 16.21%, while those pretreated with NaOH and N2CO3 ranged from 6.2 to 20.50 %. The agar yields of G. microdon showed values of 12.23%, 14.87%, and 17.73%, corresponding respectively to native agar, NaOH, and Na2CO3 pretreatments. Agar with alkali pretreatments depicted the better gelling property with higher gel strength and elevated gelling and melting temperatures. 13C NMR spectroscopy showed that G. Corneum has a typical unsubstituted and weakly methylated agar pattern. However, G. microdon revealed the presence of methyl and sulfate groups at the C4 of 4-O-L-galactose residues, responsible for the low gelling ability of the native agar. The decline of sulfate groups after alkali pretreatments were proved by FTIR spectroscopy. This study demonstrates that G. microdon produces a quality of agar similar to that of G. corneum. Thus G. microdon could be regarded as a potential additional source of agar industry in Morocco.

Rheological characterization of corn starch isolated by alkali method

2010 ◽  
Vol 24 (2-3) ◽  
pp. 172-177 ◽  
Author(s):  
Ljubica Dokić ◽  
Tamara Dapčević ◽  
Veljko Krstonošić ◽  
Petar Dokić ◽  
Miroslav Hadnađev
Keyword(s):  
Corn Starch ◽  
Rheological Characterization

Preparation and Characterization of Corn Starch/Clay Nanocomposite Films: Effect of Clay Content and Surface Modification

2018 ◽  
Vol 70 (3-4) ◽  
pp. 1700251 ◽  
Author(s):  
Rouhollah Khodaeimehr ◽  
Seyed Jamaleddin Peighambardoust ◽  
Seyed Hadi Peighambardoust
Keyword(s):  
Surface Modification ◽  
Corn Starch ◽  
Clay Content ◽  
Nanocomposite Films

Light-cured dental composites characterization by Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 428-429
Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Service Performance ◽  
Dental Composite ◽  
Dental Composites ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Research Meeting ◽  
Formulation Variables

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.

Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE
Keyword(s):  
Normal Force ◽  
Weight Ratio ◽  
Good Combination ◽  
Rheological Characterization ◽  
Nonlinear Viscoelastic ◽  
Coating Composition ◽  
Linear And Nonlinear ◽  
Work Done ◽  
Tissue Production

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.

CHEMICAL AND RHEOLOGICAL CHARACTERIZATION OF A VEGETABLE-BASED EMULSION

2019 ◽  
Author(s):  
Luiz Eduardo Rodrigues Vieira ◽  
Leonardo Rosa Ribeiro da Silva ◽  
Felipe Chagas Rodrigues de Souza ◽  
Wisley Sales ◽  
Álisson Rocha Machado
Keyword(s):  
Rheological Characterization

RHEOLOGICAL CHARACTERIZATION OF PERUVIAN COPPER ORE SLURRIES

2020 ◽  
Author(s):  
Joel López Bonilla ◽  
Cesar Celis ◽  
Danmer Maza
Keyword(s):  
Rheological Characterization ◽  
Copper Ore
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