scholarly journals Correlation between phase separation and rheological behavior in bitumen/SBS/PE blends

RSC Advances ◽  
2018 ◽  
Vol 8 (73) ◽  
pp. 41713-41721 ◽  
Author(s):  
Jianhui Xu ◽  
Tian Xia ◽  
Li Zhao ◽  
Bo Yin ◽  
Mingbo Yang
Keyword(s):  
Phase Separation ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Phase Morphology ◽  
Morphology Evolution ◽  
Modified Bitumen

The compositional ratio of SBS/PE influences the phase morphology evolution and corresponding rheological properties of modified bitumen.

scholarly journals Identifying the Long-Term Thermal Storage Stability of SBS-Polymer-Modified Asphalt, including Physical Indexes, Rheological Properties, and Micro-Structures Characteristics

2021 ◽  
Vol 13 (19) ◽  
pp. 10582
Author(s):  
Peng Wang ◽  
Hong-Rui Wei ◽  
Xi-Yin Liu ◽  
Rui-Bo Ren ◽  
Li-Zhi Wang
Keyword(s):  
Phase Separation ◽  
Rheological Properties ◽  
Softening Point ◽  
Storage Stability ◽  
Thermal Storage ◽  
Least Squares Regression ◽  
Modified Bitumen ◽  
Long Term Storage ◽  
Asphalt Performance

The thermal storage stability of styrene–butadiene–styrene tri-block copolymer modified bitumen (SBSPMB) is the key to avoid performance attenuation during storage and transportation in pavement engineering. However, existing evaluation index softening point difference within 48 h (ΔSP48) cannot effectively distinguish this attenuation of SBSPMB. Thus, conventional physical indexes, rheological properties, and micro-structure characteristics of SBSPMB during a 10-day storage were investigated in this research. Results showed that during long-term thermal storage under 163 °C for 10 days, penetration, ductility, softening point, recovery rate (R%), and anti-rutting factor (G*/sinδ) were decayed with storage time increasing. This outcome was ascribed to the phase separation of SBS, which mainly occurred after a 4-day storage. However, ΔSP48 after a 6-day storage met the specification requirements (i.e., below 2.5 °C). Thus, the attenuation degree of asphalt performance in field storage was not effectively characterized by ΔSP48 alone. Results from network strength (I) and SBS swelling degree tests revealed that the primary cause was SBS degradation and base asphalt aging. Moreover, conventional indexes, including penetration, ductility, and softening point, were used to build a prediction model for rheological properties after long-term storage using partial least squares regression model, which can effectively predict I, R, Jnr, G*/sinδ, and SBS amount. Correlation coefficient is above 0.8. G*/sinδ and I at the top and bottom storage locations had high coefficient with SBS amount. Thus, phase separation of SBSPMB should be evaluated during thermal storage.

A survey of the rheological properties, phase morphology, and crystallization behavior of PP‐POSS materials with weak phase separation

2020 ◽  
Vol 60 (9) ◽  
pp. 2272-2284 ◽  
Author(s):  
Otávio Bianchi ◽  
Heitor Luiz Ornaghi Jr ◽  
Johnny N. Martins ◽  
Charles Dal Castel ◽  
Leonardo Bresciani Canto
Keyword(s):  
Phase Separation ◽  
Rheological Properties ◽  
Crystallization Behavior ◽  
Phase Morphology ◽  
Weak Phase

scholarly journals Rheological behavior of cereal straw suspensions

2021 ◽  
Author(s):  
Sandra Ukaigwe
Keyword(s):  
Rheological Properties ◽  
Yield Stress ◽  
Rheological Behavior ◽  
Xanthan Gum ◽  
Mesh Size ◽  
General Purpose ◽  
Measuring Instrument ◽  
Fiber Concentration ◽  
Cereal Straw ◽  
Malt Barley

The rheological properties (yield stress and viscosity) of cereal straw suspensions are especially important in bioethanol production as they determine the mixing behaviour of the suspension during enzymatic hydrolysis. Yield stress measurements are generally difficult to perform in straw suspensions due to sedimentation, which commonly occur in the suspensions because of the difficulty encountered in loading the suspension into the measuring equipment. The process of placing the suspension in the measuring instrument causes a disturbance likely to induce the yielding of the suspension before the actual measurements are taken. Moreover cereal suspensions at high straw concentration (10-40 wt%) are soft solids and pourability is particularly difficult with solids. Rheological behavior of staw suspensions made from wheat, Oats and malt barley of fiber sizes 0.15 mm-4.20 mm (mesh sizes 20 to 100) and concentrations 5.0-15.0 wt% were studied. The suspensions were initially prepared by dispersing milled and sieved straws in distilled water at room temperature, followed by vortexing to aid the dispersion process; this was later modified to include a 30-minute de-aeration of the suspensions using vacuum and 2-minute mixing using a general purpose mixer at about 162 rpm. However, none these procedures produced a homogenous suspension. The viscosity of the dispersion medium was modified by the addition of Xanthan gum. This produced homogenous suspensions which remained suspended for about 20 minutes. The rheological properties of these suspensions were measured on a Bohlin rheometer in the controlled stress mode using a vane and cup measuring instrument, and the suspension yield stress determined by extrapolation and by regression of Herschel-Bulkley, Casson and Bingham models. Yield stress obtained from extrapolation ranged from 2-19 Pa, while model results ranged from 0.96- 8.15 Pa, for 5.0 wt% Oats straw suspensions with Xanthan gum strengths of 0.1-0.5 wt%. Extrapolation results for 7.5 wt% Oats staw suspensions with Xanthan gum strengths of 0.1-0.5 wt% ranged from 20-36 Pa while model results were in the range of 4.38-18.76 Pa. Wheat and malt barely straw suspensions evaluated using Herschel-Bulkley model at similiar Oats straw suspension conditions of 5.0 wt% fiber concentration with 0.3 wt% Xanthan gum strength produced statistically equivalent yields stress to Oats straw suspensions in the range of 2.31-4.04 Pa for fibers of mesh size 40-100. Cereal straw suspenions are non-Newtonian fluids with yield stresses that are highly straw concentration dependent.

scholarly journals WORKABILITY AND RHEOLOGICAL PROPERTIES OF EVA-MODIFIED BITUMEN COMPARED WITH PG 76 BINDER

2018 ◽  
Vol 80 (4) ◽  
Author(s):  
Ebenezer Akin Oluwasola ◽  
Mohd Rosli Hainin ◽  
Mohd Khairul Idham ◽  
Modupe Abayomi
Keyword(s):  
Rheological Properties ◽  
Vinyl Acetate ◽  
Softening Point ◽  
Ethylene Vinyl Acetate ◽  
Climatic Conditions ◽  
Dynamic Shear ◽  
Modified Bitumen ◽  
Dynamic Shear Rheometer ◽  
Modified Binder

The failures of the flexible pavements are not only caused by harsh climatic conditions prevailing in most of the tropical countries but also due to increase in traffic. The ethylene vinyl acetate (EVA) modification of the bitumen can strengthen the properties of binders and also improve the quality of bitumen used for pavements construction. This paper reports the changes in physical and rheological properties of unaged 80-100 grade bitumen modified with different percentages of EVA and compared with the properties of PG 76 binder. The penetration, softening point and viscosity properties were studied. The rheological properties were measured using dynamic shear rheometer and the test was performed at temperatures ranging from 46 to 76 ⁰C at intervals of 6 ⁰C. It was noted that, after modification, the properties of binders had improved. The results show that 5% EVA content by weight in modified binder is adequate in terms of physical and rheological properties studied. In addition, the properties of 5% EVA modified 80-100 grade bitumen are similar to PG 76 binder.

Morphology Evolution in Immiscible Polymer Blends during Compounding

2006 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Melting Point ◽  
Polymer Blends ◽  
Rheological Properties ◽  
Morphology Evolution ◽  
Two Phase ◽  
Immiscible Polymers ◽  
Blend Morphology ◽  
Twin Screw ◽  
Buss Kneader ◽  
Batch Mixer

Polymer researchers have had a long-standing interest in understanding the evolution of blend morphology when two (or more) incompatible homopolymers or copolymers are melt blended in mixing equipment. In industry, melt blending is conducted using either an internal (batch) mixer (e.g., a Banbury mixer or a Brabender mixer) or a continuous mixer (e.g., a twin-screw extruder or a Buss kneader). There are many factors that control the evolution of blend morphology during compounding, the five primary ones being (1) blend composition, (2) rheological properties (e.g., viscosity ratio) of the constituent components, (3) mixing temperature, which in turn affects the rheological properties of the constituent components, (4) the duration of mixing in a batch mixer or residence time in a continuous mixer, and (5) rotor speed in a batch mixer or screw speed in a continuous mixer (i.e., local shear rate or shear stress). When two immiscible polymers are compounded in mixing equipment, two types of blend morphology are often observed: dispersed morphology and co-continuous morphology. Numerous investigators have reported on blend morphology of immiscible polymers, and there are too many papers to cite them all here. Some investigators (Han 1976, 1981; Han and Kim 1975; Han and Yu 1972; Nelson et al. 1977; van Oene 1978) examined blend morphology to explain the seemingly very complicated rheological behavior of two-phase polymer blends, and others (Favis and Therrien 1991; He et al. 1997; Ho et al. 1990; Miles and Zurek 1988; Scott and Macosko 1995; Shih 1995; Sundararaj et al. 1992, 1996) investigated blend morphology as affected by processing conditions. Today, it is fairly well understood from experimental studies under what conditions a dispersed morphology or a co-continuous morphology may be formed, and whether a co-continuous morphology is stable, giving rise to an equilibrium morphology, or whether it is an unstable intermediate morphology that eventually is transformed into a dispersed morphology (Lee and Han 1999a, 1999b, 2000). Let us consider the morphology evolution in an immiscible blend consisting of two semicrystalline polymers, A and B, in a compounding machine, and let us assume that the melting point (Tm,A) of polymer A is lower than the melting point (Tm,B) of polymer B.

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