Temperature and pH effects on the stability and rheological behavior of the aqueous suspensions of smart polymers based onN-isopropylacrylamide, chitosan, and acrylic acid

2012 ◽  
Vol 129 (1) ◽  
pp. 334-345 ◽  
Author(s):  
Nívia do Nascimento Marques ◽  
Priscila Schroeder Curti ◽  
Ana Maria da Silva Maia ◽  
Rosangela de Carvalho Balaban
Keyword(s):  
Acrylic Acid ◽  
Rheological Behavior ◽  
Ph Effects ◽  
Smart Polymers ◽  
Aqueous Suspensions ◽  
The Stability

scholarly journals Effects Of Environmental Factors On The Dispersion Behavior Of Iron Oxide In Aqueous Solutions With Poly Acrylic Acid

2015 ◽  
Vol 60 (2) ◽  
pp. 1561-1564
Author(s):  
E.-H. Lee ◽  
K.-M. Kim ◽  
W.-Y. Maeng ◽  
D.-H. Hur
Keyword(s):  
Molecular Weight ◽  
Acrylic Acid ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Solution Ph ◽  
Molecular Weights ◽  
Aqueous Suspensions ◽  
Magnetite Particles ◽  
The Stability ◽  
Poly Acrylic Acid

Abstract After preparing aqueous suspensions from magnetite particles with a poly-acrylic acid, we investigated the effects of several experimental parameters. We characterized the stability of the suspensions using visual inspection, sedimentation, adsorption, and thermal stability of the dispersant. The dispersion stability is affected by the solution pH, the concentrations of magnetite particles, the molecular weight, the concentration of the dispersants, and the temperature. The stability of the suspensions increased as the concentration of the dispersant and the temperature increased. In terms of the molecular weights of the dispersant, the suspensions with dispersant of low-molecular weight (1800) were more stable than those of high-molecular weight (250000) at room temperature. However, at high temperature the suspensions with high-molecular weight showed stability. The adsorption efficiency of the dispersant was very low. The dispersant of high-molecular weight showed a higher thermal integrity than that of low-molecular weight. From this work, we obtained the optimum conditions for stable aqueous suspensions of magnetite particles.

From biorefineries to bioproducts: conversion of pretreated pulp from biorefining streams to lignocellulose nanofibers

TAPPI Journal ◽  
2019 ◽  
Vol 18 (4) ◽  
pp. 233-241
Author(s):  
CHENGGUI SUN ◽  
RICHARD CHANDRA ◽  
YAMAN BOLUK
Keyword(s):  
Energy Consumption ◽  
Enzymatic Hydrolysis ◽  
Rheological Behavior ◽  
Material Basis ◽  
Softwood Pulp ◽  
Energy Consumptions ◽  
Hardwood Pulp ◽  
The Stability ◽  
Lignocellulose Nanofibers

This study investigates the use of pretreatment and enzymatic hydrolysis side streams and conversion to lignocellulose nanofibers. We used a steam-exploded and partial enzymatic hydrolyzed hardwood pulp and an organosolv pretreated softwood pulp to prepare lignocellulose nanofibers (LCNF) via microfluidization. The energies applied on fibrillation were estimated to examine the energy consumption levels of LCNF production. The energy consumptions of the fibrillation processes of the hardwood LCNF production and the softwood LCNF production were about 7040-14080 kWh/ton and 4640 kWh/ton on a dry material basis, respectively. The morphology and dimension of developed hardwood and softwood LCNFs and the stability and rheological behavior of their suspensions were investigated and are discussed.

scholarly journals Formation and Stability of Smooth Thin Films with Soft Microgels Made of Poly(N-Isopropylacrylamide) and Poly(Acrylic Acid)

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2638
Author(s):  
Elena Buratti ◽  
Ilaria Sanzari ◽  
Franco Dinelli ◽  
Themistoklis Prodromakis ◽  
Monica Bertoldo
Keyword(s):  
Acrylic Acid ◽  
Colloidal Particles ◽  
Polymer Network ◽  
Spin Speed ◽  
Glass Substrates ◽  
Smooth Film ◽  
The Difference ◽  
The Stability ◽  
Individual Particles ◽  
Poly Acrylic Acid

In this work, soft microgels of Poly(N-Isopropylacrylamide) (PNIPAm) at two different sizes and of interpenetrated polymer network (IPN) composed of PNIPAm and Poly(Acrylic Acid) (PAAc) were synthesized. Then, solutions of these different types of microgels have been spin-coated on glass substrates with different degrees of hydrophobicity. PNIPAm particles with a larger diameter form either patches or a continuous layer, where individual particles are still distinct, depending on the dispersion concentration and spin speed. On the other, PNIPAm particles with a smaller diameter and IPN particles form a continuous and smooth film, with a thickness depending on the dispersion concentration and spin-speed. The difference in morphology observed can be explained if one considers that the microgels may behave as colloidal particles or macromolecules, depending on their size and composition. Additionally, the microgel size and composition can also affect the stability of the depositions when rinsed in water. In particular, we find that the smooth and continuous films show a stimuli-dependent stability on parameters such as temperature and pH, while large particle layers are stable under any condition except on hydrophilic glass by washing at 50 °C.

Influence of TMAH and NaOH on the stability of SiC aqueous suspensions

2020 ◽  
Vol 46 (8) ◽  
pp. 11208-11217
Author(s):  
Joanna Gnyla ◽  
Agnieszka Gubernat ◽  
Łukasz Zych ◽  
Marek Nocuń ◽  
Zuzanna Góral ◽  
...  
Keyword(s):  
Aqueous Suspensions ◽  
The Stability

scholarly journals Increasing the stability of Lumbricus terrestris erythrocruorin via poly(acrylic acid) conjugation

2018 ◽  
Vol 46 (sup2) ◽  
pp. 1137-1144 ◽  
Author(s):  
Kyle Spivack ◽  
Matthew Tucker ◽  
Devon Zimmerman ◽  
Matthew Nicholas ◽  
Osheiza Abdulmalik ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Lumbricus Terrestris ◽  
The Stability ◽  
Poly Acrylic Acid

Effect of pH on the Dispersion Stability of Aqueous Ferric Oxide Suspension

2007 ◽  
Vol 544-545 ◽  
pp. 717-720 ◽  
Author(s):  
C.H Lee ◽  
Eun Hee Lee
Keyword(s):  
Acrylic Acid ◽  
Zeta Potential ◽  
Ferric Oxide ◽  
Dispersion Stability ◽  
Effect Of Ph ◽  
Acidic Solutions ◽  
Aqueous Suspensions ◽  
Wide Ph Range ◽  
Ionization Behavior ◽  
Ph Range

We have studied the effect of pH on the dispersion stability of aqueous suspensions of Fe2O3 powders over a wide pH range in the presence of the poly (acrylic acid) (PAA). In order to investigate the ionization behavior of the PAA, pH of PAA solutions was measured. Sedimentation and zeta-potential measurements were conducted on aqueous Fe2O3 suspensions to characterize the dispersion stability of the suspensions. The PAA was ionized over a wide pH range and the quantity of ionization was abruptly increased at pH > 10. Thus, the dispersion of the Fe2O3 powders was observed even in acidic solutions and the dispersion stability of the suspensions increased as pH of the solutions increased. The magnitude of zeta-potential values increased with increasing pH.

Influence of Dispersants on Dispersion Stability of TiO2 Suspensions

2011 ◽  
Vol 356-360 ◽  
pp. 476-479 ◽  
Author(s):  
Yu Mou ◽  
Kun Miao Lü ◽  
Dong Mei Gao
Keyword(s):  
Aqueous Solution ◽  
Experimental Results ◽  
Dispersion Stability ◽  
Sodium Hexametaphosphate ◽  
Aqueous Suspensions ◽  
The Stability

TiO2nanoparticles are prone to aggregate in aqueous solution, which limits its extensive application. Several researches have been carried on the stability of TiO2suspensions. In this study, four common dispersants including ethanol, tetrahydrofuran (THF), polyvinylpyrrolidone (PVP), and sodium hexametaphosphate (SHMP) have been chosen to detect their effects on stability of TiO2aqueous suspensions. The experimental results showed that THF and SHMP were efficient dispersants for TiO2nanoparticles in aqueous solution.

Sign in / Sign up

Export Citation Format

Share Document