Rheological Properties and Extrudate Swell of PHBV-Bagasse Composites

2014 ◽  
Vol 931-932 ◽  
pp. 83-89
Author(s):  
Rapeephun Dangtungee ◽  
Suchart Siengchin ◽  
Chayada Puritung
Keyword(s):  
Particle Size ◽  
Shear Stress ◽  
Shear Rate ◽  
Surface Treatment ◽  
Shear Viscosity ◽  
Extrudate Swell ◽  
Melt Mixing ◽  
Capillary Rheometry ◽  
Wide Range ◽  
Twin Screw

Polyhydroxybutylate-co-hydroxyvalerate (PHBV) is biodegradable aliphatic polyester that produced by a wide range of microorganism. In this research aims to study the melt rheological and extrudate swelling behavior of PHBV filled with bagasse. The composites prepared by melt mixing (Two roll mill and Twin screw extruder). The effects of processing techniques for PHBV powder and bagasse loading, aspect ratio (particle size i.e. x<150μm, 150<x<250μm and x>250μm) and, surface treatment of bagasse were investigated by capillary rheometry at 180 °C. The dispersion of the bagasse was inspected by the scanning electron microscopy (SEM). A different compositions based on PHBV/bagasse were investigated according to the following weight ratios, i.e. 100/0, 95/5, 90/10, 80/20 and 70/30 wt% respectively. The results showed that the PHBV/bagasse composites exhibit pseudoplastic behaviour as the shear stress and extrudate swell increased with increasing shear rate while shear viscosity decreased. The apparent shear stress and apparent shear viscosity increased with increasing bagasse loading and, at a given apparent shear rate, the apparent shear stress increased slightly with increasing bagasse particle size. However, detrimental bagasse agglomeration was clearly observed to take place for sample with bagasse loading in excess of 20 wt%. The surface treatment of bagasse was carried out using silane coupling agent and benzoic acid. The results proved the effect of functionalization on the interfacial adhesion between PHBV and bagasse. Also, there was also further confirmed by rheology behaviour and SEM-EDS image.

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Rheological Behavior and Extrudate Swell of Polypropylene/Silicon Carbide Composites

2013 ◽  
Vol 747 ◽  
pp. 595-598 ◽  
Author(s):  
Apaipan Rattanapan ◽  
Nuttaphong Sornsuwit ◽  
Rapeephun Dangtungee
Keyword(s):  
Silicon Carbide ◽  
Shear Stress ◽  
Shear Viscosity ◽  
Rheological Behavior ◽  
Sem Analysis ◽  
Elongation Rate ◽  
Capillary Rheometer ◽  
Extrudate Swell ◽  
Elongation Viscosity ◽  
Sic Composites

The rheological behavior and extrudate swell of polypropylene (PP)/silicon carbide (SiC) composites were investigated. Polypropylene-grafted-maleic anhydride (PP-g-MA) was introduced into blending system as a compatibilizer. The effect of silicon carbide loading and surface modification on the rheological behavior of PP/SiC composites were studied using a capillary rheometer and SEM analysis. The results showed that the composites exhibit pseudoplastic behavior as the shear stress and extrudate swell increased with increasing shear rate, while shear viscosity decreased. Moreover, an increasing elongation rate leads to reduce elongation viscosity. The addition of PP-g-MA in PP/SiC composites has significantly decreased the apparent shear stress, apparent shear viscosity and percentage of extrudate swell.

Rheological Properties and Extrusion Performance Evaluation of Silica Filled Epoxidized Natural Rubber (ENR) Compounds as Compared to Natural Rubber/Butadiene Rubber (NR/BR) Compound

2016 ◽  
Vol 1133 ◽  
pp. 236-240
Author(s):  
Teku Zakwan Zaeimoedin ◽  
Mazlina Mustafa Kamal ◽  
Ahmad Kifli Che Aziz
Keyword(s):  
Performance Evaluation ◽  
Shear Rate ◽  
Natural Rubber ◽  
Rheological Properties ◽  
Shear Viscosity ◽  
Rheological Behaviour ◽  
Butadiene Rubber ◽  
Melt Mixing ◽  
Lower Shear ◽  
Internal Mixer

In tyre industries, rheological and processability properties of rubber and polymer are great of importance since there are alot extrusion processes involved in the tyre manufacturing other than calendaring and moulding processes. Uniformity and consistency in the flow behaviour and processability of rubber are essential in providing the solution to the rubber industries in order to improve productivity, products quality and energy conservation. In this works, effects of silane coupling agent on rheological behaviour and extrusion performance of silica filled ENR tread compounds were studied and compared to NR/BR tread compound. The compounds were prepared by melt mixing in tangential internal mixer, while the rheological properties of compounds were determined by Capillary Rheometer, Cure Rheometer and Mooney viscometer. The compound were further examined for its extrudability performance evaluation by extruded the rubber through 30mm cold feed extruder machine using ASTM Extrusion Die, ‘Garvey’ type. Results showed that, ENR/silica compounds exhibit higher shear viscosity curves as compared to NR/BR compound at low shear rate regime. However an opposite trend was observed towards high shear rate regime tested which ENR/silica compounds gave slightly lower shear viscosity curve compared to NR/BR compound. As for extrudability performance evaluation, NR/BR compound gave better extrusion characteristics and appearance as compared to ENR/silica compounds.

Effect of Compatibilizer on Impact Strength and Morphology of Polystyrene/Zinc Oxide Nanocomposites

2012 ◽  
Vol 545 ◽  
pp. 330-334
Author(s):  
Sirirat Wacharawichanant ◽  
Pranee Saetun ◽  
Thunwawon Lekkong ◽  
Thongyai Supakanok
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Impact Strength ◽  
Impact Test ◽  
Screw Extruder ◽  
Melt Mixing ◽  
Zno Particles ◽  
Twin Screw ◽  
The Impact ◽  
Scanning Electron

This article investigated the effects of particle size of zinc oxide (ZnO) and polystyrene-co-maleic anhydride (SMA) compatibilizer on impact strength and morphology of polystyrene (PS)/ZnO71 (71 nm) and PS/ZnO250 (250 nm) nanocomposites. PS/ZnO nanocomposites with varying concentration of ZnO and SMA were prepared by a melt mixing technique in a twin screw extruder. It was found that the impact strength of PS nanocomposites increased up to a ZnO content of 1.0 wt%. Moreover, PS/ZnO250 nanocomposites had higher impact strength than PS/ZnO71 nanocomposites. The addition of SMA increased the impact strength of PS/ZnO nanocomposites with increasing SMA content. The result showed that SMA could improve impact strength of nanocomposites. The dispersion of ZnO particles on PS/ZnO nanocomposites was studied by scanning electron microscope (SEM). It was observed that the dispersion of ZnO particles of PS/ZnO nanocomposites without SMA was non-uniform and the agglomeration of ZnO particles in the polymer matrix increased with increasing ZnO content. The dispersion of ZnO particles of PS/ZnO nanocomposites after adding SMA was relatively good and only few aggregations exist. These observations support the results of the impact test where the PS/ZnO nanocomposites with SMA displayed higher impact strength than the PS/ZnO nanocomposites without SMA. The study showed that SMA was used as a compatibilizer to improve the dispersability and compatibility of ZnO particles in PS matrix.

Rheological Behavior of Highly Filled EPDM Compounds with Calcium Carbonate, Carbon Black, Silica and Zinc Oxide

1996 ◽  
Vol 69 (4) ◽  
pp. 628-636 ◽  
Author(s):  
Li Li Li ◽  
James L. White
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Calcium Carbonate ◽  
Shear Rate ◽  
Carbon Black ◽  
Shear Viscosity ◽  
Volume Fraction ◽  
Carbonate Carbon ◽  
Yield Value ◽  
Yield Values

Abstract The shear viscosity, creep and constant shear rate transients have been measured for 0.20 volume fraction compounds of an EPDM with calcium carbonate, carbon black, silica and zinc oxide of similar particle size at 100°C. Measurements have been made in a creep sandwich instrument, pressurized rotational rheometer and a capillary rheometer and cover nine decades of shear rate. All of the compounds exhibit enhanced viscosities and yield values; i.e. there are stresses below which there is no flow. The greatest yield values and increased viscosities are with the compounds with calcium carbonate and zinc oxide. More extensive studies were made with the EPDM-calcium carbonate system, where it was shown that, increasing particle size reduces shear viscosity and yield values. Further, surface treating calcium carbonate with stearic acid signifcantly reduces the shear viscosity and yield value of the corresponding EPDM compound.

Hydration Structure and Shear Viscosity of Water Nanoconfined Between Mica Surfaces

2006 ◽  
Author(s):  
Yongsheng Leng ◽  
Peter T. Cummings
Keyword(s):  
Molecular Dynamics ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Surface Force ◽  
Md Simulations ◽  
Force Balance ◽  
Density Distributions ◽  
Wide Range ◽  
Hydration Layers

Molecular dynamics (MD) simulations have been performed to investigate the structure, shear viscosity and dynamics of hydration layers of the thickness of D = 0.61 ∼ 2.44 nm confined between two mica surfaces. For D = 0.92 ∼ 2.44 nm films, water O density distributions indicate that the hydration layers are in liquid phase. The corresponding shear responses are fluidic and similar to those observed in surface force balance (SFB) experiment. However, further increase in confinement leads to the formation of a bilayer ice (D = 0.61 nm) which shows significant shear enhancement and shear thinning over a wide range of shear rate in MD regime, consistent with recent experimental results by shear resonant apparatus for the two mica surfaces in registry.

scholarly journals Theory for the rheology of dense non-Brownian suspensions: divergence of viscosities and– rheology

2019 ◽  
Vol 864 ◽  
pp. 1125-1176 ◽  
Author(s):  
Koshiro Suzuki ◽  
Hisao Hayakawa
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Stress Ratio ◽  
Volume Fraction ◽  
Microscopic Theory ◽  
Critical Behaviour

A systematic microscopic theory for the rheology of dense non-Brownian suspensions characterized by the volume fraction $\unicode[STIX]{x1D711}$ is developed. The theory successfully derives the critical behaviour in the vicinity of the jamming point (volume fraction $\unicode[STIX]{x1D711}_{J}$), for both the pressure $P$ and the shear stress $\unicode[STIX]{x1D70E}_{xy}$, i.e. $P\sim \unicode[STIX]{x1D70E}_{xy}\sim \dot{\unicode[STIX]{x1D6FE}}\unicode[STIX]{x1D702}_{0}\unicode[STIX]{x1D6FF}\unicode[STIX]{x1D711}^{-2}$, where $\dot{\unicode[STIX]{x1D6FE}}$ is the shear rate, $\unicode[STIX]{x1D702}_{0}$ is the shear viscosity of the solvent and $\unicode[STIX]{x1D6FF}\unicode[STIX]{x1D711}=\unicode[STIX]{x1D711}_{J}-\unicode[STIX]{x1D711}>0$ is the distance from the jamming point. It also successfully describes the behaviour of the stress ratio $\unicode[STIX]{x1D707}=\unicode[STIX]{x1D70E}_{xy}/P$ with respect to the viscous number $J=\dot{\unicode[STIX]{x1D6FE}}\unicode[STIX]{x1D702}_{0}/P$.

Correlation of Dynamic and Steady Flow Viscosities of Food Materials

2001 ◽  
Vol 11 (3) ◽  
pp. 134-140 ◽  
Author(s):  
Chenxu Yu ◽  
Sundaram Gunasekaran
Keyword(s):  
Shear Rate ◽  
Steady Flow ◽  
Shear Viscosity ◽  
Steady Shear ◽  
Cream Cheese ◽  
Sharp Drop ◽  
Steady Shear Viscosity ◽  
Condensed Milk ◽  
Tomato Ketchup ◽  
Wide Range

AbstractEight commercial foods representing a wide range of viscosities (i.e. honey, condensed milk, mayonnaise, tomato ketchup, cream cheese, yogurt, process and Mozzarella cheeses) were investigated. Their steady shear viscosity and dynamic complex viscosity were determined by rheological measurements at two temperatures using a Bohlin-CVO rheometer. Based on experimental data, shear rate dependence of steady flow apparent viscosity and frequency dependence of dynamic viscosity was established and compared. It was determined that for condensed milk, tomato ketchup and mayonnaise, a modified Cox-Merz relation could be established. For cream cheese, a generalized Cox-Merz relation was proposed; and for yogurt, a deviation from the Cox-Merz rule was found. For Mozzarella and process cheeses a sharp drop in steady shear viscosity was noticed between 1~10 s-1 shear rate range. The Cox-Merz rule was not applicable for these cheese samples.

scholarly journals Polymeric suspensions viscosity evolution under a constant electric field

2019 ◽  
Vol 20 (2) ◽  
pp. 272-284
Author(s):  
Ahmed Zelifi ◽  
◽  
Lounis Mourad ◽  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Electric Field ◽  
Shear Viscosity ◽  
Particle Concentration ◽  
Constant Electric Field ◽  
Foam Layer ◽  
Experimental Apparatus ◽  
White Foam ◽  
Electrochemical Phenomenon

The present paper illustrates the effect of the coupling of an electric field with a shear field on a suspension ER. When the suspensions are simultaneously under flow and under the influence of a low electric field organized into packed lamellar formations, the shear stress increases with the increase of the higher polarisable particle concentration both in the electrostatic and hydrodynamic forces. In the absence of an electric field, the flow, alone, produces no segregation.The curves obtained after analyzes illustrate the changes on the shear viscosity under the simultaneous effect of an electric field and shear rate of the three suspensions study. We also observed the appearance of a white foam layer at the experimental apparatus which results in the electrochemical phenomenon due to some values of electric field. The latter can be exploited for a possible further research.

scholarly journals Effect of Octyl Salicylate With Respect To the Physical Appearance of Mono/Di Caprylic and Capric Fatty Acids Formulations

2016 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Fatty Acids ◽  
Particle Size ◽  
Shear Stress ◽  
Shear Rate ◽  
Flow Behavior ◽  
Physical Appearance ◽  
Newtonian Fluids ◽  
Particle Sizes ◽  
Medium Chain ◽  
Medium Chain Fatty Acids

Caprylic and capric acids are classified as medium-chain fatty acids. In this study, the behavior of the caprylic and capric acids formulations containing octyl salicylate were investigated. The formulations were prepared using homogenization proses. The characteristics of the formulation such as particle size, flow behavior, microscopic view and absorbance of the formulations were investigated. Particle sizes of the formulations were found ranging from 352.7 - 704.2 nm. The viscosity of the formulations changed as the shear rate was varied and could be classified as non-Newtonian fluids. The viscosity decreases when the fluid undergoes longer shear stress with time. The formulations containing octyl salicylate shows higher absorbance as compared to the formulations without octyl salicylate. The addition of octyl salicylate affected the system in terms of behavior, appearance and stability

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