Modeling the spatial characteristics of extrusion flow instabilities for styrene-butadiene rubbers: Investigating the influence of molecular weight distribution, molecular architecture, and temperature

2021 ◽  
Vol 33 (9) ◽  
pp. 093108
Author(s):  
Christos K. Georgantopoulos ◽  
Masood K. Esfahani ◽  
Carlo Botha ◽  
Michael A. Pollard ◽  
Ingo F. C. Naue ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Flow Instabilities ◽  
Molecular Architecture ◽  
Spatial Characteristics ◽  
Styrene Butadiene

EFFECT OF REVERSIBLE ADDITION-FRAGMENTATION CHAIN TRANSFER EMULSION STYRENE–BUTADIENE RUBBER ON THE PROPERTIES OF SILICA COMPOUNDS

2020 ◽  
pp. 000-000 ◽  
Author(s):  
Hyunsung Mun ◽  
Kiwon Hwang ◽  
Gwanghoon Kwag ◽  
JaeKon Suh ◽  
Duseong Ahn ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Raft Polymerization ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Narrow Molecular Weight Distribution ◽  
Reversible Addition ◽  
Raft Agent ◽  
Styrene Butadiene

ABSTRACT In recent years, solution styrene–butadiene rubber (SSBR), which has a narrow molecular weight distribution, controllable microstructure, and chain end functionality, is mainly used as base rubber for passenger car tire tread compounds. However, SSBR has a lower molecular weight than that of emulsion SBR (ESBR) because it is difficult to increase the molecular weight of SSBR. In contrast, ESBR can easily increase the molecular weight; however, it has a broad molecular weight distribution. The reversible addition-fragmentation chain transfer (RAFT) polymerization technique is applicable to the emulsion polymerization. Polymers with narrow molecular weight distributions can be obtained by the RAFT polymerization because the RAFT agent prevents the coupling reaction of the growing chain radicals. In this case, ESBR having a narrow molecular weight distribution, which is an advantage of SSBR, and a high molecular weight, which is an advantage of ESBR, can be synthesized. Therefore, we synthesized RAFT ESBR and fabricated its compounds with silica filler. We confirmed that the physical properties of the RAFT ESBR silica compound are different from those of the ESBR silica compound. In addition to the narrow molecular weight distribution of the RAFT ESBR, the trithiocarbonyl group of the RAFT agent in the RAFT ESBR chain molecules affects the physical properties.

scholarly journals Effect of Aging on the Rheological and Molecular Weight Distribution of Asphalt Binder Treated with Polyphosphoric Acid

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Tao Ma ◽  
Kai Yang ◽  
Rui Li ◽  
Jiujian Shen
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Polyphosphoric Acid ◽  
Asphalt Binder ◽  
Chemical Properties ◽  
Gel Permeation Chromatography ◽  
Weight Analysis ◽  
Styrene Butadiene

Asphalt binder behaves as a viscoelastic material and its inherit performance is dominated by rheological and chemical properties. Aging of asphalt binder is a prominent distress for long-term in-service asphalt pavement. In this work, the effect of aging on base asphalt modified by polyphosphoric acid (PPA) has been investigated. For the objective, virgin asphalt binder was modified by various dosages of PPA, styrene-butadiene-styrene (SBS), and PPA/SBS compound modification. The short- and long-term aging processes were simulated by Rolling Thin-Film Oven Test (RTFOT) and Pressure Aging Vessel (PAV) procedure. Rheological property of five aged modified binders was evaluated by the Dynamic Shear Rheometer (DSR). Meanwhile, gel permeation chromatography (GPC) was conducted to measure the molecular weight distribution and dispersion coefficient during the aging process. The high-temperature stiffness of PPA polymer binders is slightly higher than that of SBS and PPA/SBS compound modified asphalts. The aging ratio and molecular weight analysis verify the lower thermal-oxidative susceptibility of PPA/SBS compound modified asphalts. This study offers an understanding for the promotion and application of PPA modifier.

Quantitative Analysis of Copolymers by GPC/FT-IR

1996 ◽  
Vol 50 (3) ◽  
pp. 349-356 ◽  
Author(s):  
Michael X. Liu ◽  
James L. Dwyer
Keyword(s):  
Molecular Weight ◽  
Infrared Spectroscopy ◽  
Quantitative Analysis ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Spectral Peak ◽  
Combined Method ◽  
Calibration Standards ◽  
Ft Ir ◽  
Styrene Butadiene

A combined method of chromatography and infrared spectroscopy is employed to map the distribution of monomers in copolymer samples. The method relies on the measurement of spectral peak ratios of the sample, using polymer samples of known composition as calibration standards. The inherent variation of the method was established by measuring a homopolymer of invariant composition. The samples examined were styrene/butadiene copolymers, synthesized by two different polymerization protocols. The technique provided sensitive measurement of comonomer composition across the molecular weight distribution of the samples and is generally applicable to copolymers that can be fractionated by chromatographic methods.

Interaction and Molecular Weight Distribution Behavior in Polymer Blends of Styrene-Butadiene-Rubber and Bitumen

2010 ◽  
Vol 168-170 ◽  
pp. 973-980 ◽  
Author(s):  
You Qing Jiang ◽  
Yun Bo Zhang
Keyword(s):  
Molecular Weight ◽  
Polymer Blends ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Gel Permeation Chromatography ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Modified Bitumen ◽  
Styrene Butadiene ◽  
Distribution Behavior

Styrene-Butadiene-Rubber (SBR) modified bitumen had improved properties in softening points, ductility, and aging resistance. It is due to variation of molecular weight (MW) and molecular weight distribution (MWD) of the product made during the blending between SBR and bitumen. Gel permeation chromatography (GPC) analytical results indicated interaction in polymer blends that bitumen macromolecular chain biting and chemical forces as well as intermolecular recombination formed new bitumen polymer blends.

Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.)

2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe
Keyword(s):  
Molecular Weight ◽  
Protein Content ◽  
Ammonium Sulfate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Protease Activity ◽  
Protein Concentration ◽  
Temperature Stability ◽  
Partial Purification ◽  
Ammonium Sulfate Precipitation

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 

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