Rubber-Bound Antioxidants. I. Amine Antioxidants Bound to Polychloroprene Rubber

1989 ◽  
Vol 62 (1) ◽  
pp. 13-32 ◽  
Author(s):  
Mohammed S. Al-Mehdawe ◽  
J. E. Stuckey
Keyword(s):  
Antioxidant Activity ◽  
Ir Spectroscopy ◽  
Secondary Amines ◽  
Crosslinking Reaction ◽  
Amino Group ◽  
High Shear ◽  
Alkyl Aryl ◽  
Complete Extraction ◽  
Shear Mixing ◽  
Higher Temperature

Abstract Amine antioxidants are found to react with chloroprene (CR) type-W rubber with its reactive chlorine atoms. These reactions take place during high-shear mixing in a torque rheometer, or in a Winkworth mixer at higher temperature, or during the vulcanization of the elastomers at 160°C. Mixed alkyl, aryl secondary amines are shown to react only at the alkyl-substituted amino group. The concentrations of the bound antioxidants are estimated by IR spectroscopy after complete extraction. Monsanto Rheometer studies show that, in many cases, the crosslinking reaction of CR rubber, which takes place through the chlorine atom, is reduced by the presence of the antioxidants. The effectiveness of the rubber-bound antioxidant is assessed by accelerated oven aging and stress techniques. It is shown that immobilization of amine antioxidants by combining them with the network does not impair their antioxidant activity.

scholarly journals Catalytic Antioxidant Activity of Bis-Aniline-Derived Diselenides as GPx Mimics

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4446
Author(s):  
Giancarlo V. Botteselle ◽  
Welman C. Elias ◽  
Luana Bettanin ◽  
Rômulo F. S. Canto ◽  
Drielly N. O. Salin ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Hydrogen Bond ◽  
Electronic Properties ◽  
Partial Charge ◽  
Amino Group ◽  
Diphenyl Diselenide ◽  
Charge Delocalization ◽  
Ipso Substitution ◽  
Efficient Route ◽  
Catalytic Performances

Herein, we describe a simple and efficient route to access aniline-derived diselenides and evaluate their antioxidant/GPx-mimetic properties. The diselenides were obtained in good yields via ipso-substitution/reduction from the readily available 2-nitroaromatic halides (Cl, Br, I). These diselenides present GPx-mimetic properties, showing better antioxidant activity than the standard GPx-mimetic compounds, ebselen and diphenyl diselenide. DFT analysis demonstrated that the electronic properties of the substituents determine the charge delocalization and the partial charge on selenium, which correlate with the catalytic performances. The amino group concurs in the stabilization of the selenolate intermediate through a hydrogen bond with the selenium.

Expanded vermiculite-filled flexible polymer composites

2021 ◽  
pp. 009524432110290
Author(s):  
Mukaddes Sevval Cetin ◽  
Ozan Toprakci ◽  
Omer Suat Taskin ◽  
Abdullah Aksu ◽  
Hatice Aylin Karahan Toprakci
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Contact Angle ◽  
Polymer Composites ◽  
Flame Retardancy ◽  
Composite Films ◽  
Filler Concentration ◽  
High Shear ◽  
Flexible Polymer ◽  
Shear Mixing

This study focuses on the fabrication and characterization of vermiculite-filled flexible polymer composites. Exfoliated vermiculite was incorporated into triblock thermoplastic elastomer copolymer, styrene- b-(ethylene- co-butylene)- b-styrene (SEBS), at various levels from 1 to 15 wt% by a high shear mixer. The composite films were obtained by the combination of solvent casting and compression molding. The morphological, structural, thermal, and mechanical properties and contact angle of the composites were determined. Some micro-morphological differences were observed between the samples and the difference was assumed to be caused by high shear mixing and filler concentration. High shear mixing was found effective in terms of the detachment of vermiculite layers at all concentrations. However, at low filler loading, that behavior was more obvious. At 1 wt% filler concentration, mechanical properties increased that was probably caused by good filler-matrix interaction stemmed from smaller particle size. At higher vermiculite concentrations, fillers found to show agglomerations that led to a decrease in mechanical strength and strain at break. Elastic and secant modulus showed an increasing trend. Contact angle measurements were carried out to determine the oleophilic character of the samples. An increase in the vermiculite content resulted in higher oleophilic character and the lowest contact angle was obtained at 15 wt% VMT loading. In addition to these, thermal stability, thermal dimensional stability and flame retardancy were improved by the incorporation of VMT. 15 wt% vermiculite-filled sample showed the best performance in terms of thermal stability and flame retardancy.

Scale-up effects on flow patterns in the high shear mixing of cohesive powders

2013 ◽  
Vol 102 ◽  
pp. 1-9 ◽  
Author(s):  
Mauro Cavinato ◽  
Riccardo Artoni ◽  
Massimo Bresciani ◽  
Paolo Canu ◽  
Andrea C. Santomaso
Keyword(s):  
Scale Up ◽  
Flow Patterns ◽  
High Shear ◽  
Shear Mixing ◽  
Cohesive Powders

scholarly journals Exfoliation of 2D materials by high shear mixing

2D Materials ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 015008 ◽  
Author(s):  
Sonia Biccai ◽  
Sebastian Barwich ◽  
Daniel Boland ◽  
Andrey Harvey ◽  
Damien Hanlon ◽  
...  
Keyword(s):  
2D Materials ◽  
High Shear ◽  
Shear Mixing

Melt granulation: A comparison of granules produced via high-shear mixing and twin-screw granulation

2020 ◽  
Vol 591 ◽  
pp. 119941
Author(s):  
Kristina E. Steffens ◽  
Marvin B. Brenner ◽  
Michael U. Hartig ◽  
Marius Monschke ◽  
Karl G. Wagner
Keyword(s):  
High Shear ◽  
Twin Screw ◽  
Shear Mixing ◽  
Twin Screw Granulation ◽  
Melt Granulation

Tin-Tannin-Lignosulfonate Complex: An Improved Lignosulfonate-Based Drilling Fluid Thinner

2012 ◽  
Author(s):  
M. N. Mohamad Ibrahim ◽  
S. B. Chuah ◽  
Cheng P. Y.
Keyword(s):  
Ir Spectroscopy ◽  
Key Words ◽  
Drilling Fluid ◽  
Cross Linking ◽  
Fluid Mud ◽  
Spectroscopy Analysis ◽  
Higher Temperature ◽  
The Cross

Satu penipis lumpur gerudi yang diperbaiki iaitu kompleks stanum–tanin–lignosulfonat, telah dihasilkan dengan melakukan pengubahsuaian terhadap penipis komersil iaitu lignosulfonat. Tindak balas yang terlibat termasuk tindak balas rangkai silang antara asid lignosulfonat dengan tanin pada suhu 105°C dengan kehadiran formaldehid yang berfungsi sebagai pemula tindak balas tersebut. Campuran tersebut selanjutnya dikelatkan dengan ion stanum. Tindak balas pengubahsuaian tersebut ditentusahkan menerusi analisis spektroskopi inframerah (IR) dan prestasinya sebagai agen penipis berpolimer bagi lumpur bentonit akueus dinilai. Prestasi reologi penipis terubahsuai tersebut kemudiannya dibandingkan dengan lignosulfonat. Keputusan menunjukkan bahawa penipis terubahsuai mempunyai prestasi penipisan yang lebih baik berbanding lignosulfonat pada suhu tinggi dan juga ketahanan yang lebih tinggi terhadap pencemaran garam. Kata kunci: lignosulfonat; bendalir/lumpur gerudi;ion stanum; tannin; prestasi reologi An improved drilling fluid thinner, tin–tannin–lignosulfonate (TTLS) complex; was formulated by imposing slight modifications to a commercially available thinner, lignosulfonate. The reactions involved include reaction of a lignosulfonate acid with tannin at 105°C in the presence of formaldehyde to initiate the cross-linking reaction. The mixture was further chelating with stannous ions. The modifications reactions were verified by an infrared (IR) spectroscopy analysis and its performances as a polymeric thinning agent for aqueous bentonite mud were evaluated. The rheological performances of the modified thinner were then compared with lignosulfonate. The modified thinner shows better thinning performance at higher temperature and indicates more tolerance to salt contamination compared to lignosulfonate. Key words: lignosulfonate; drilling fluid/mud; thinner; stannousion; tannin; rheological perfomances

Effect of High Shear Mixing Parameters and Degassing Temperature on the Morphology of Epoxy-Clay Nanocomposites

2013 ◽  
Vol 652-654 ◽  
pp. 159-166 ◽  
Author(s):  
Muneer Al-Qadhi ◽  
Nesar Merah ◽  
Khaled Mezghani ◽  
Zafarullah Khan ◽  
Zuhair Gasem ◽  
...  
Keyword(s):  
Mixing Time ◽  
Diglycidyl Ether ◽  
Clay Nanocomposites ◽  
High Shear ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
Clay Dispersion ◽  
Mixing Speed ◽  
Shear Mixing ◽  
Mixing Method

Epoxy-clay nanocomposites were prepared by high shear mixing method using Nanomer I.30E nanoclay as nano-reinforcement in diglycidyl ether of bisphenol A (DGEBA). The effect of mixing speed and time on the nature and degree of clay dispersion were investigated by varying the mixing speed in the range of 500-8000 RPM and mixing time in the range of 15-90 minutes. The effect of degassing temperature on the morphology of the resultant nanocomposites was also studied. Scanning and transmission microscopy (SEM & TEM) along with x-ray diffraction (XRD) have been used to characterize the effect of shear mixing speed, mixing time and degassing temperature on the structure of the resultant nanocomposites. The SEM, TEM and XRD examinations demonstrated that the degree of clay dispersion was improved with increasing the high shear mixing speed and mixing time. The results showed that the optimum high shear mixing speed and mixing time were 6000 rpm and 60 min, respectively. It was observed that the structure of the nanocomposites that have been degassed at 65oC was dominated by ordered intercalated morphology while disordered intercalated with some exfoliated morphology was found for the sample degassed at 100oC for the first 2 hours of the degassing process.

Biodiesel production under mild reaction conditions assisted by high shear mixing

2019 ◽  
Vol 130 ◽  
pp. 174-181 ◽  
Author(s):  
Manuel Sánchez-Cantú ◽  
Maribel Morales Téllez ◽  
Lydia M. Pérez-Díaz ◽  
Reyna Zeferino-Díaz ◽  
J. Ciciolil Hilario-Martínez ◽  
...  
Keyword(s):  
Biodiesel Production ◽  
High Shear ◽  
Reaction Conditions ◽  
Shear Mixing
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