DIRECTED REGULATION OF THE STRUCTURAL AND RHEOLOGICAL PROPERTIES OF HEAT-INSULATING ACRYLIC AQUEOUS DISPERSIONS USING THE COMBINED USE OF HYDROPHILIC AND HYDROPHOBIC SILICATE FILLERS

2021 ◽  
pp. 11-21
Author(s):  
N. Saienko ◽  
R. Bikov ◽  
A. Skripinets ◽  
D. Demidov ◽  
A. Kariev ◽  
...  
Keyword(s):  
Activation Energy ◽  
Response Function ◽  
Substrate Surface ◽  
Polymer Coatings ◽  
Shear Stresses ◽  
Flow Activation Energy ◽  
Aqueous Dispersions ◽  
Water Dispersion ◽  
Combined Use ◽  
Second Degree

The formation technology and performance characteristics of coatings based on aqueous dispersions are largely determined by the properties of the initial film-forming materials, which should ensure uniform thin-layer distribution on the substrate surface and the formation of coatings with the required technological complex of properties. Among them, due to their functional properties and relatively low cost, the most widespread are water-dispersion polymer coatings based on acrylic film-formers. In this paper, mathematical models of the structural and rheological dependences of heat-insulating acrylic aqueous dispersions are considered depending on the combined content of hydrophilic-hydrophobic fillers. To describe these dependencies, it is advisable to use equations of the second degree. According to the mathematical theory of experiment, the second-order orthogonal central compositional design makes it possible to predict the behavior of the response function. Carrying out an experiment in accordance with this plan makes it possible to establish the analytical dependence of the response function on the corresponding factors in the form of a polynomial equation of the second degree. The main response functions were: conditionally static yield stress, viscosity at the minimum rate of onset of fracture (initial effective viscosity), viscosity of the “destroyed” structure according to the Newtonian nature of the flow, activation energy of viscous flow at minimum, average and maximum shear rates. On the basis of the established dependences, the optimal ratios of hydrophobized aerosil and aluminosilicate microspheres were selected, the combined use of which makes it possible to reduce shear stresses to create a homogeneous aqueous acrylic dispersion, to predict the activation energy at various technological stages of preparation and application of heat-insulating coatings. The established results made it possible to create a hydrophilic-hydrophobic aqueous acrylic dispersion, which, without the use of surfactants, makes it possible to simplify the production technology of heat-insulating water-dispersion coatings, namely, to exclude the stage of pretreatment of fillers, to reduce the rotation speed of the frame mixer, and also to increase the kinetic stability of the finished dispersion.

Rheological Study on of PBT with High Melt Flow Index

2012 ◽  
Vol 487 ◽  
pp. 644-648
Author(s):  
Yuan Liu ◽  
Lin Wang ◽  
Qing Yan Xu ◽  
Pei Jie Lin ◽  
Zhi Hong Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Apparent Viscosity ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Flow ◽  
Flow Activation Energy ◽  
Nonwoven Fabrics ◽  
Flow Activation ◽  
High Flexibility

Melt-blown generated PBT nonwoven fabrics usually have small fibril diameter, high flexibility, well heat and oil resistance. Therefore, they would have promising application such as vehicle filtering media. The rheological behavior of PBT with High Melt Flow Index for Melt-blown is investigated in this paper. It is a direction of the technology design and fabrication parameters .The relation of apparent viscosity and shear rate is analyzed, as well as flow activation energy and Non-Newtonian indexes. The results suggest that PBT with High Melt Flow Index is Non-Newtonian fluid. Apparent viscosity and flow activation energy show gradually decrease with increasing shear rate, exhibiting typical shear-thinning behavior.

scholarly journals Development of coalescents for paints and varnishes based on ionic liquids – the products of diethanolamine and inorganic acids interaction

2021 ◽  
Vol 2 (6 (110)) ◽  
pp. 21-29
Author(s):  
Yevhenii Levchenko ◽  
Olga Sverdlikovska ◽  
Denys Chervakov ◽  
Oleh Chervakov
Keyword(s):  
Ionic Liquids ◽  
Boric Acid ◽  
Complex Compound ◽  
Film Formation ◽  
Hardness Index ◽  
Aqueous Dispersions ◽  
Water Dispersion ◽  
Inorganic Acids ◽  
Ionogenic Compounds ◽  
Polyurethane Dispersions

This paper reports the synthesis of ionic liquids through the interaction between diethanolamine and orthophosphate and boric acids in order to establish the possibility of replacing volatile coalescents in a formulation for paints and varnishes with ionogenic compounds. The results from studying the influence of polymeric coalescents based on ionic liquids on the rheological properties of water-dispersion paints and varnishes of different nature are presented. It has been established that the synthesized coalescents could be used to modify the properties of paints and varnishes based on polyurethane and styrene-acrylic aqueous dispersions. It has been shown that the product of the interaction between diethanolamine and boric acid in aqueous solutions forms an ionogenic complex compound with a unipolar conductivity in terms of ОН─ ions. It was also established that when introduced to the formulation of water-dispersion paints and varnishes, the solutions of modifiers produce a diluting action. The influence of ionic liquids on the process of film formation of aqueous dispersions of polymers and pigmented paints and varnishes based on them was investigated. It was established that the synthesized ionogenic compounds are not inferior, in terms of their effectiveness, to the widespread conventional industrial coalescents of the Texanol→ type. Therefore, there is reason to assert the possibility of replacing the industrial coalescent Texanol→ in the formulation of pigmented water-dispersion paints and varnishes based on styrene-acrylic and polyurethane dispersions with fundamentally new synthesized ionogenic modifiers. Thus, the coatings with a coalescent based on ion liquid of diethanolamine borate have a higher level of conditional hardness, which exceeds by 17 % the hardness index of the paint made on the basis of the conventional Texanol→ type coalescent, without changing its decorative properties, such as color and shine

Rheological Behaviors of Graphene Oxide/Polyacrylonitrile Spinning Solutions

2017 ◽  
Vol 898 ◽  
pp. 2187-2196 ◽  
Author(s):  
Feng Mei Li ◽  
Ying Ying Zheng ◽  
Biao Wang
Keyword(s):  
Activation Energy ◽  
Graphene Oxide ◽  
Loss Factor ◽  
Viscosity Index ◽  
Structural Viscosity ◽  
Mechanical Loss ◽  
Flow Activation Energy ◽  
Rheological Behaviors ◽  
Flow Activation ◽  
Mechanical Loss Factor

The rheological behaviors of polyacrylonitrile (PAN) in NaSCN aqueous solutions containing different amount of Graphene oxide (GO) were investigated through both steady-state and dynamic rheological measurements. The parameters such as apparent viscosity (ηα), flow activation energy (Eη), structural viscosity index (Δη), storage modulus (G’), loss modulus (G’’) and mechanical loss factor (tanδ) were measured to illustrate the rheological behaviors of these solutions. The results showed that the apparent viscosity decreased with adding appropriate amount of GO, while the structural viscosity index, the flow activation energy and the mechanical loss factor of GO/PAN spinning solutions increased. Accordingly, a possible mechanism of GO effect on rheological behaviors of PAN solution was proposed in this work.

scholarly journals Correlation of Polymerization Conditions with Thermal and Mechanical Properties of Polyethylenes Made with Ziegler-Natta Catalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. Anwar Parvez ◽  
Mostafizur Rahaman ◽  
M. A. Suleiman ◽  
J. B. P. Soares ◽  
I. A. Hussein
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Hydrogen Pressure ◽  
Catalyst Activity ◽  
Thermal And Mechanical Properties ◽  
Polymer Yield ◽  
Flow Activation Energy ◽  
Ethylene Pressure ◽  
Polymerization Conditions ◽  
Ziegler Natta Catalysts

In this study, the synthesis of polyethylenes has been carried out with titanium-magnesium supported Ziegler-Natta catalysts in laboratory-scale reactors. A correlation of different polymerization conditions with thermal and mechanical properties of polyethylenes has been established. It is seen that there is lowering of molecular weight (Mw), polymer yield, and catalyst activity at high hydrogen pressure and high temperature. The Mw, polymer yield, and catalyst activity are improved with the increase in ethylene pressure. Dynamic mechanical analysis (DMA) results show that the increase in temperature and hydrogen pressure decreases storage modulus. The samples with higher Mw showed high activation energy. The melting point decreases with the increase in hydrogen pressure but increases slightly with the increase in ethylene pressure. It is seen that the increase in reaction temperature, ethylene pressure, and hydrogen pressure leads to an increase in crystallinity. The tensile modulus increases with the increase in hydrogen pressure and can be correlated with the crystallinity of polymer. The Mw has a major influence on the flow activation energy and tensile strength. But the other mechanical and thermal properties depend on Mw as well as other parameters.

Thermal Oligomerisation of Cardanol

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Francisco Helder A. Rodrigues ◽  
José Roberto R. Souza ◽  
Francisco Célio F. França ◽  
Nágila M. P. S. Ricardo ◽  
Judith P. A. Feitosa
Keyword(s):  
Activation Energy ◽  
Double Bond ◽  
Average Molecular Weight ◽  
Hydrocarbon Chain ◽  
Relative Mass ◽  
Cashew Nut Shell Liquid ◽  
Flow Activation Energy ◽  
H Nmr ◽  
Cashew Nut ◽  
Flow Activation

AbstractCardanol was extracted from technical Cashew Nut Shell Liquid (CNSL), a naturally occurring meta-substituted long chain phenol and oligomerized by heating at 140 °C. Products were characterized by rheology, infrared and 1H NMR spectroscopy and thermogravimetric analysis (TGA). Increase in viscosity and the flow activation energy was found with increasing time of heating. The relative absorbance of double bond of the hydrocarbon chain decreased with time of heating and indicated that the oligomerization is taking place through the unsaturation of the side chain. Decrease in internal double bond as well as in vinyl bond, observed by 1H NMR, pointed out to the participation of these two kinds of unsaturation as well as monoene, diene and triene. The oligomerization is a slow process. With 40 h of heating, the average molecular weight increases only by 46%. Great differences were found in TGA curves of cardanol with different times of oligomerization. Thermal stability increases with time of heating. The degree of oligomerization could be determined from relative mass loss of the first event of TG, or from flow activation energy.

A study on the relationship between polycarbonate microstructure and performance as determined by a combined experimental and molecular dynamics simulation method

e-Polymers ◽  
2014 ◽  
Vol 14 (6) ◽  
pp. 407-415 ◽  
Author(s):  
Xiujuan Wang ◽  
Xiuting Zheng ◽  
Meng Song ◽  
Sizhu Wu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Force Field ◽  
Molecular Simulation ◽  
Degradation Kinetics ◽  
Dynamics Simulation ◽  
Thermal Degradation Kinetics ◽  
Polar Group ◽  
Flow Activation Energy

AbstractThe influence of the microstructure of polycarbonate (PC) on performance was systematically investigated by both experimental method and molecular simulation. Yield stress, impact strength, molecular weight, and transmittance were used to distinguish the degradation processes between different PCs, and thermal degradation kinetics was studied to obtain the activation energy. At the molecular level, through 13C nuclear magnetic resonance (NMR) spectroscopy, it was observed that PCs have a more polar group of benzene rings, resulting in the high density, dielectric constant, and tensile modulus. Meanwhile, molecular dynamics (MD) simulation was employed under a polymer consistent force field force field. Specific volume and mechanical property were analyzed to investigate the thermodynamic property. The molecular dynamics simulation and experimental results on half decomposition temperature (T1/2), refraction index, flow activation energy, average density, cohesive energy density, glass transition temperature (Tg), and elastic modulus had good agreement. Therefore, it was indicated that the molecular simulation could successfully study the characteristics and properties. The fundamental studies would be expected to supply useful information for designing materials and optimizing processing technology.

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