Rheological Study of Steady Shear and Linear Viscoelastic Characteristics of Polyethylene and Polycarbonate Nanocomposites

2007 ◽  
Author(s):  
Michael P. Lalko ◽  
Leela Rakesh ◽  
Stanley Hirschi
Keyword(s):  
Critical Strain ◽  
Uv Light ◽  
Loss Modulus ◽  
Steady Shear ◽  
Functionalized Carbon Nanotubes ◽  
Polymer Properties ◽  
Oscillatory Rheometry ◽  
Linear Viscoelastic ◽  
Viscoelastic Characteristics ◽  
Strain Storage

The addition of nano-sized particles into a polymer matrix is an excellent way to manipulate polymer properties. Our current efforts try to understand how a material’s properties are influenced by parameters such as temperature, particle size, and particle concentrations of additives. This paper presents the rheological behavior of polycarbonate (PC) and low density polyethylene (LDPE) containing at least 2.5% and 5% weight fractions of functionalized and un-functionalized carbon nanotubes (CNTs). These materials were investigated using steady shear and oscillatory rheometry over a range of processing temperatures. The properties examined through rheological experimentation include: viscosity, critical strain, storage modulus (G′), and loss modulus (G ). The nanocomposites samples were examined using scanning electron microscopy (SEM) and UV light microscopy.

SYNTHESIS AND VISCOELASTIC BEHAVIORS OF POLY(ANILINE-CO-O-ETHOXYANILINE) PARTICLES SUSPENDED ELECTRORHEOLOGICAL FLUID

2001 ◽  
Vol 15 (06n07) ◽  
pp. 649-656 ◽  
Author(s):  
H. J. CHOI ◽  
J. W. KIM ◽  
M. S. SUH ◽  
M. J. SHIN ◽  
K. TO
Keyword(s):  
Particle Size ◽  
Silicone Oil ◽  
Loss Modulus ◽  
Chemical Oxidation ◽  
Steady Shear ◽  
Rheological Parameters ◽  
Linear Viscoelastic Region ◽  
Linear Viscoelastic ◽  
Er Fluids ◽  
Poly Aniline

Copolyanilines are synthesized by a chemical oxidation of aniline and o-ethoxyaniline with various molar ratios in an acidic media, and then characteristics of these polymers such as chemical structure, particle size and the particle size distribution were examined by using FT-IR, SEM and particle size analyzer, respectively. Suspensions of copolyaniline containing ethoxy group, namely poly(aniline-co-o-ethoxyaniline), in silicone oil have been investigated as one of many potential candidates for dry-base electrorheological (ER) fluid systems. Rotational rheometer (Physica) equipped with a high voltage generator was used to characterize the rheological properties of ER fluids from both steady shear and dynamic tests. From the steady shear experiment, we obtained flow properties and found that ER fluids exhibited the yield phenomenon. On the other hand, viscoelastic property was also obtained from the dynamic experiment. Since viscoelastic properties for ER fluids are mainly dominated by the particle chain structure, the state at different time scale was analyzed from the rheological parameters such as storage modulus (G'), loss modulus (G'') and tan δ. We conducted a strain amplitude sweep at 1 Hz under an applied electric field to determine a linear viscoelastic region first. The G' and G'' were then measured by a frequency sweep from 0.1 to 100 Hz in the linear viscoelastic region.

Thermal Property, Morphology, Mechanical and Rheological Properties of a Modified Bio-Polymers Prepared by Blending Poly(3-Hydrobutyrate-Co-4-Hydrobutyrate) with Chain Extenders

2010 ◽  
Vol 152-153 ◽  
pp. 924-930
Author(s):  
Mei Li ◽  
Zhi Qiang Li ◽  
Jun Xu ◽  
Dun Sheng Wei ◽  
Hong Wei Zhu ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Shear Viscosity ◽  
Loss Modulus ◽  
Freeze Fracture ◽  
Fracture Morphology ◽  
Steady Shear ◽  
Thermal Transitions ◽  
Remarkable Effect ◽  
Steady Shear Viscosity ◽  
Chain Extenders

Modified Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] was prepared by melt reactive blending P(3HB-co-4HB) with chain extenders (ADR-4367). Thermal transitions, spherulitic and freeze-fracture morphology, mechanical and rheological properties of the chain extended bio-materials were investigated. The results show that glass transition temperatures and crystallization temperatures increase, crystallinity and diameters of spherulites decrease, there are amorphous parts dispersed among the crystalline phase, and the bio-materials transfer from brittleness to toughness and ductility. Steady shear viscosity of the modified P(3HB-co-4HB) increases by about one order of magnitude, melts of the modified P(3HB-co-4HB) behave more viscoelasticity by storage modulus and loss modulus correlated with oscillatory shear frequency. Addition of ADR-4367 with contents of 4~6 wt% in the blends is enough to branching and coupling the co-polymer chains and brings remarkable effect on improving mechanical properties, steady shear viscosity and viscoelasticity.

Rheology of Barium Sulfate Suspensions and Pre-thickened Beverages Used in Diagnosis and Treatment of Dysphagia

2007 ◽  
Vol 17 (3) ◽  
pp. 33137-1-33137-8 ◽  
Author(s):  
Mustapha M. Ould Eleya ◽  
Sundaram Gunasekaran
Keyword(s):  
Barium Sulfate ◽  
Loss Modulus ◽  
Diagnosis And Treatment ◽  
Creep Recovery ◽  
Frequency Spectra ◽  
Fluid Foods ◽  
Linear Viscoelastic ◽  
Dysphagic Patients ◽  
Treatment And Diagnosis ◽  
Barium Sulfate Suspension

Abstract Pre-thickened beverages and barium sulfate suspensions are used in the treatment and diagnosis of dysphagia. These liquids are labeled nectar consistency (NC), honey consistency (HC) etc. These labels are rather misleading and do not represent the actual rheological character of the liquids. We carefully investigated the rheology of these liquids to assist both in their formulation and use for dysphagic patients. Steady state flow properties, thixotropy, dynamic response, and creep recovery behavior were investigated for six beverages and two barium sulfate suspensions. All samples exhibited a shear-thinning behavior. The flow curves of all samples followed both Herschel-Bulkley and Casson models. HC barium sulfate suspension exhibited higher yield stress, σo, and higher storage modulus, G’, than their fluid food counterparts. In contrast, NC barium sulfate suspension had lower σo, and G’ than some of the liquid food counterparts. Frequency spectra of NC samples were similar to that of a macromolecular solution with both G’ and loss modulus, G’’, increasing with frequency; whereas those of HC samples were similar to that of a gel with a little dependency of G’ and G’’ over frequency. Stress sweep experiments showed that the linear viscoelastic region of fluid foods and barium sulfate suspensions extended up to 1 and 10 Pa, respectively. Thus, significant differences exist in the rheological properties of both pre-thickened and videofluoroscopy fluids currently used for diagnosis and treatment of dysphagia.

Physicochemical and Rheological Properties of Salmon Protein Powders

2006 ◽  
Vol 2 (2) ◽  
Author(s):  
Subramaniam Sathivel ◽  
Peter J Bechtel ◽  
Witoon Prinyawiwatkul
Keyword(s):  
Parallel Plate ◽  
Emulsion Stability ◽  
Nitrogen Solubility ◽  
Loss Modulus ◽  
Flow Behavior ◽  
Power Law Model ◽  
Flow Behavior Index ◽  
K Value ◽  
Viscoelastic Characteristics ◽  
Behavior Index

This study demonstrated feasibility of producing soluble protein powders from pink (PSP) and red (RSP) salmon heads. Differences were observed between physicochemical properties of the two protein powders, including nitrogen solubility, emulsion stability, and fat adsorption capacity. The flow and viscoelastic properties of the emulsions prepared with PSP and RSP were investigated using a parallel plate rheometer. The power law model and the Casson model were used to determine the flow behavior index (n), and consistency index (K) and yield stress. The emulsion containing PSP (PSPE) had a higher K value (8 Pa.s) than that (4.2 Pa.s) of the emulsion containing RSP (RSPE). Both PSPE and RSPE emulsions exhibited pseudoplastic behavior and viscoelastic characteristics. The G’ (an elastic or storage modulus) and G” (a viscous or loss modulus) values for PSPE were higher than RSPE.

Research and Development on the Antiaging Polymer Coatings

2014 ◽  
Vol 941-944 ◽  
pp. 1589-1592
Author(s):  
Li Ping Liu ◽  
Xiu Feng Cao
Keyword(s):  
Evaluation System ◽  
Uv Light ◽  
Polymeric Materials ◽  
Polymer Coatings ◽  
Polymer Materials ◽  
Study Progress ◽  
Polymer Properties ◽  
Complex Process ◽  
Aging Study ◽  
Research Problems

In recent years, polymer had been used in various situations and its use was increasing year by year. However, weathering was a complex process in which UV light, moisture and temperature variations all contributed to the deterioration of polymer properties. This paper reviewed the aging study progress of polymeric materials in recent years and the research problems. The evaluation methods of aging and antiaging of polymer materials were described, concerning with experiments, determinations and pathways of aging and antiaging. A relatively elaborate synthetical evaluation system of aging and antiaging was established.

Linear Viscoelastic Characteristics of Poly(trimethylene terephthalate)/Polycarbonate Blends in the Melt State

2005 ◽  
Vol 290 (11) ◽  
pp. 1091-1096 ◽  
Author(s):  
Ahmad Yavari ◽  
Ahmad Asadinezhad ◽  
Seyed Hassan Jafari ◽  
Hossein Ali Khonakdar ◽  
Shahin Ahmadian ◽  
...  
Keyword(s):  
Linear Viscoelastic ◽  
Viscoelastic Characteristics ◽  
Trimethylene Terephthalate

Impact of temperature on the linear viscoelastic region of wood

2009 ◽  
Vol 39 (11) ◽  
pp. 2092-2099 ◽  
Author(s):  
Jiali Jiang ◽  
Jianxiong Lu
Keyword(s):  
Critical Strain ◽  
Mechanical Performance ◽  
Chinese Fir ◽  
Relaxation Processes ◽  
Linear Viscoelastic Region ◽  
Testing Frequency ◽  
Linear Viscoelastic ◽  
Increasing Temperature ◽  
The Impact ◽  
Stored Elastic Energy

The impact of temperature on the linear viscoelastic region, which is characterized by critical strain, of Chinese fir ( Cunninghamia lanceolata (Lamb.) Hook.) was investigated at various temperatures between –100 and 220 °C for specimens with a moisture content of approximately 0.6%. The effect of oscillation frequency on the linear viscoelastic region under various constant temperatures was also examined. The results indicated that critical strain generally decreased with increasing temperature except at –80, –20, 40, 120, and 220 °C. These five exceptions were attributed to the occurrence of relaxation processes. With an increase in testing frequency from 1 to 20 Hz, the critical strain decreased slightly at all temperatures. It is suggested that the stored elastic energy and yield stress, which were obtained at critical strain, could be indicators to predict wood mechanical performance.

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