Dynamic Viscoelasticity of Poly(ether Ester) Containing Zinc

2011 ◽  
Vol 197-198 ◽  
pp. 1263-1266
Author(s):  
Jing Guo ◽  
Cheng Nv Hu ◽  
Wen Fei Huang
Keyword(s):  
Real Number ◽  
Complex Modulus ◽  
Raw Materials ◽  
Loss Modulus ◽  
Flow Behavior ◽  
Complex Viscosity ◽  
Tetrabutyl Titanate ◽  
Pseudoplastic Fluid ◽  
The Real ◽  
Ether Ester

Hexanedioic acid, PEG6000 and zinc oxide (ZnO) was chosen as raw materials,and tetrabutyl titanate as catalyst to synthesize the poly(ether ester) containing zinc (PEEM). PEEM and Diphenyl-methane-diisocyanate (MDI) as chain extender was added into polycaprolactam whose molecular weight is about 4000 for synthesizing poly (ether ester amide) containing zinc (PEEAM). The rheological behavior of PEEAM was investigated by an advanced rheometric expansion system (ARES). Dynamic rheometer was used to measure the structures and properties of PEEAM. The dynamic rheological test indicated that the complex modulus (G*), the dynamic storage modulus (G”) and loss modulus (G’) of the PEEAM increase with the frequency (ω) increasing; the complex viscosity (η*) decreases linearly with the ω increasing, and decreases slightly with the temperature increasing, which indicates obvious flow behavior of pseudoplastic fluid. The Cole-Cole curves are convex, in the low frequency zone, the real number viscosity at 260°C is smaller than the real number viscosity at 230°C. The loss tangent (tan δ) presents a miximum with the increase of ω.

Mechanical Properties and Rheological Behavior of Injection Moulded Foaming Bamboo Powder–Polypropylene Composites

2011 ◽  
Vol 287-290 ◽  
pp. 1980-1986 ◽  
Author(s):  
Xia Xing Zhou ◽  
Qiao Jia Lin ◽  
Li Hui Chen
Keyword(s):  
Water Absorption ◽  
Rheological Behavior ◽  
Loss Modulus ◽  
Flow Behavior ◽  
Complex Viscosity ◽  
Pseudoplastic Fluid ◽  
Moulding Process ◽  
Polypropylene Composites ◽  
Injection Moulding Process ◽  
Bamboo Powder

Foamed composites of polypropylene containing bamboo powder were prepared using an injection moulding process. Measurement of density, flexural, tensile and notched impact properties of the prepared composites was carried out. Water absorption of the composites was investigated. The rheological behavior of composites was also investigated by rotary rheometer. The density of microfoamed composites was reduced by about 14%.When the bamboo powder was 50 phr (33.3% by weight), the integrated property was best ; the density was 0.886 g·cm-3 and the flexural, tensile and notched impact strength were 58.72 MPa, 30.86 MPa and 5.246 KJ·m-2 respectively; and the thickness swelling and water absorption were 1.31% and 0.7% after duration of 240 h. The results pointed out the composites showed a flow behavior of pseudoplastic fluid; the storage modulus and loss modulus increased and loss tangent decreased with the increase of bamboo powder content. The composite had a typical shear thinning characteristic and the complex viscosity increased with the content of bamboo powder increased.

Characterization of viscoelastic properties of minced beef meat thawed by ohmic and conventional methods

2019 ◽  
Vol 26 (4) ◽  
pp. 277-290 ◽  
Author(s):  
Mutlu Cevik ◽  
Filiz Icier
Keyword(s):  
Ambient Temperature ◽  
Viscoelastic Properties ◽  
Cold Water ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Creep Recovery ◽  
Recoverable Compliance ◽  
Meat Samples ◽  
Minced Meat

Frozen minced meat samples having fat contents of 2%, 10% and 18% were thawed using different methods (refrigeration thawing at ambient temperature of +4 ℃, under running cold water (+4 ℃) thawing, ohmic thawing for 10, 13 and 16 V/cm). Viscoelastic properties were determined by using rheological tests (oscillation and creep/recovery tests). Storage modulus, loss modulus, complex modulus, loss tangent, dynamic viscosity and complex viscosity values of minced meat samples increased as fat content increased. As frequency value increased, the modulus values of meat samples increased but dynamic and complex viscosity values of the samples decreased. The minced meat samples thawed by different methods had recoverable compliance values. The compliance values of meat samples during creep region can be well characterized by Burgers model. Ohmic thawing can be used as an alternative thawing method since it resulted in similar rheological properties of minced meat samples compared to refrigeration thawing at ambient temperature of +4 ℃ and under running cold water (+4℃) thawing.

Rheological studies of uncured epoxy–organoclay nanocomposite coatings

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Davood Zaarei ◽  
Ali Asghar Sarabi ◽  
Farhad Sharif ◽  
Seyed Mahmoud Kassiriha ◽  
Mohsen Moazzami Gudarzi
Keyword(s):  
Storage Modulus ◽  
Loss Modulus ◽  
Film Formation ◽  
Flow Behavior ◽  
Complex Viscosity ◽  
Nanocomposite Coating ◽  
Nanocomposite Coatings ◽  
Strong Increase ◽  
Polymeric Fluids ◽  
Shear Mixing

AbstractWe investigated the influence of loading two different types of organoclay on the linear viscoelastic properties of an uncured epoxy nanocomposite coating. Meanwhile, the effect of sonication in the dispersion process on the characteristics of nanocomposite has been studied. To achieve fully dispersed structures of clay-epoxy, we applied high shear mixing and high-intensity ultrasound during the synthesis of clay-epoxy nanocomposites.The flow properties of the compositions with clay loadings more than 4 wt% of low CEC quaternary ammonium modified clay, as analyzed by rheomechanical spectroscopy (RMS), showed a solid-like behavior. While the neat resin system exhibited Newtonian flow, some nanodispersed coatings exhibited pseudo plastic flow behavior, typical of polymeric fluids such as gels and pastes. With varying the type of the clay the resultant coatings exhibited a storage modulus ranging from 0.01 to over 400 Pa and a loss modulus ranging from 4 to over 200 Pa. Moreover, the complex viscosity was ranging from 12 to 1100 Pas as the clay loading increased from 0 to 8wt %. The strong increase in modulus of one type of the clays was due to the mainly intercalated and dispersed silicate platelets. The increase rate in storage modulus of these compositions decreased at higher organoclay loadings and was not linear. These results can lead to the prediction of film formation properties and application conditions of these nanocomposite coatings

Dynamic Rheological Behaviors of the Bone Scaffold Reinforced by Chitin Fibres

2005 ◽  
Vol 475-479 ◽  
pp. 2387-2390 ◽  
Author(s):  
X.M. Li ◽  
Qing Ling Feng
Keyword(s):  
Viscoelastic Properties ◽  
Loss Factor ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Materials Processing ◽  
Bone Scaffold ◽  
Rheological Behaviors ◽  
Wide Range ◽  
Yielding Behavior

In this study, a novel bioabsorbable porous bone scaffold reinforced by chitin fibres was prepared, the porosity of which is about 90 % and the pore size is approximately 200µm. The Advanced Rheological Enlarged System (ARES) was used to study the dynamic rheological behaviors of the ropy materials which would be made into the reinforced scaffold. The increase of the fibres’ volume content (Cf) enhanced the complex modulus (G*) and complex viscosity (h*) of the materials, the reason of which is that the fibres formed networks in the materials. When Cf increased from 35 % to 45 %, the storage modulus (G’) and loss modulus (G’’) curve showed obvious yielding behavior, which indicates that G’ and G’’ of the materials are hardly variable in a wide range. When Cf was more than 35 %, the loss factor (tand) was obviously lower than 1 and the materials exhibited viscoelastic properties, which result in a disadvantage for materials’ processing.

Analysis of Effects of High Temperature on Asphalt Binder

2013 ◽  
Vol 325-326 ◽  
pp. 97-101
Author(s):  
Phu Cuong Cao ◽  
Zhong Yin Guo ◽  
Yong Shun Yang ◽  
Zhi Chao Xue
Keyword(s):  
High Temperature ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Asphalt Binder ◽  
Great Influence ◽  
Complex Viscosity ◽  
Modified Asphalt ◽  
Resistance Parameter ◽  
Variation Of Parameters ◽  
Sbs Modified Asphalt

The study of effects of high temperature on asphalt binder based on viscoelasticity theory will help clarify the influence mechanism of temperature on asphalt binder. Based on the theory of viscoelasticity, the Dynamic Shear Rheology test is used as study method. The objective of this study is to analyze and determine the features of asphalt binder under the effect of high temperature. Meanwhile, study subjects are AH70 asphalt, SBS modified asphalt and MAC modified asphalt. The result indicates that temperature increases have great influence on asphalt binder, which are shown by the variation of parameters quickly decrease. The relationship between temperature and such parameters as complex modulus, storage modulus, loss modulus, complex viscosity, storage viscosity, loss viscosity, rutting resistance parameter and fatigue resistance parameter can be described as regression of power function.

Influence of κ-Carrageenan, Modified Starch and Inulin Addition on Rheological and Sensory Properties of Non-fat and Non-added Sugar Dairy Dessert

2020 ◽  
Vol 16 (4) ◽  
pp. 462-469
Author(s):  
Zhaleh Sheidaei ◽  
Bahareh Sarmadi ◽  
Seyede M. Hosseini ◽  
Fardin Javanmardi ◽  
Kianoush Khosravi-Darani ◽  
...  
Keyword(s):  
Storage Modulus ◽  
Loss Modulus ◽  
Viscoelastic Behavior ◽  
Textural Properties ◽  
Complex Viscosity ◽  
Sensory Properties ◽  
Modified Starch ◽  
Consumer Health ◽  
Added Sugar ◽  
Textural Parameters

<P>Background: The high amounts of fat, sugar and calorie existing in dairy desserts can lead to increase the risk of health problems. Therefore, the development of functional and dietary forms of these products can help the consumer health. </P><P> Objective: This study aims to investigate the effects of &#954;-carrageenan, modified starch and inulin addition on rheological and sensory properties of non-fat and non-added sugar dairy dessert. </P><P> Methods: In order to determine the viscoelastic behavior of samples, oscillatory test was carried out and the values of storage modulus (G′), loss modulus (G″), loss angle tangent (tan &#948;) and complex viscosity (&#951;*) were measured. TPA test was used for analysis of the desserts’ texture and textural parameters of samples containing different concentrations of carrageenan, starch and inulin were calculated. </P><P> Results: All treatments showed a viscoelastic gel structure with the storage modulus higher than the loss modulus values. Increasing amounts of &#954;-carrageenan and modified starch caused an increase in G′ and G″ as well as &#951;* and a decrease in tan &#948;. Also, firmness and cohesiveness were enhanced. The trained panelists gave the highest score to the treatment with 0.1% &#954;-carrageenan, 2.5% starch and 5.5% inulin (sucralose as constant = 0.25%) and this sample was the best treatment with desirable attributes for the production of non-fat and non-added sugar dairy dessert. </P><P> Conclusion: It can be concluded that the concentration of &#954;-carrageenan and starch strongly influenced the rheological and textural properties of dairy desserts, whereas the inulin content had little effect on these attributes.</P>

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.

scholarly journals A Characterization Study of Morphology and Properties of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/Aloe Vera Fibers Biocomposites: Effect of Fiber Surface Treatments

Proceedings ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 38
Author(s):  
Celia Idres ◽  
Mustapha Kaci ◽  
Nadjet Dehouche ◽  
Idris Zembouai ◽  
Stéphane Bruzaud
Keyword(s):  
Thermal Stability ◽  
Surface Morphology ◽  
Water Absorption ◽  
Loss Modulus ◽  
Aloe Vera ◽  
Fiber Surface ◽  
Complex Viscosity ◽  
Absorption Capacity ◽  
Characterization Study ◽  
Efficient Route

This paper aims to investigate the effect of different chemical modifications of biocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) and aloe vera bio-fibers incorporated at 20 wt%. The fiber surface was modified with alkaline, organosilanes, and combined alkaline/organosilanes. Surface morphology, thermal stability, water absorption capacity, and rheological behavior of the modified biocomposite materials were studied, and the results compared to both unmodified biocomposites and neat PHBH. The study showed that the modified biocomposites with both alkaline and organosilanes exhibited an improved surface morphology, resulting in a good fiber/matrix interfacial adhesion. As a result, increases in complex viscosity, storage modulus, and loss modulus were observed, whereas water absorption was reduced. Thermal stability remained almost unchanged, with the exception of the biocomposite treated with alkaline, where this property decreased significantly. Finally, the coupling of alkaline and organosilane modification is an efficient route to enhance the properties of PHBH biocomposites.

scholarly journals An algebraic proof of the real number PCP theorem

2017 ◽  
Vol 40 ◽  
pp. 34-77 ◽  
Author(s):  
Martijn Baartse ◽  
Klaus Meer
Keyword(s):  
Real Number ◽  
Algebraic Proof ◽  
The Real ◽  
Pcp Theorem
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