Novel Coupling Agents for Silica-filled Rubbers with Superior Processing Safety and Improved Hysteresis of the Vulcanizates

2010 ◽  
Vol 38 (1) ◽  
pp. 80-98 ◽  
Author(s):  
M. Gerster ◽  
C. Fagouri ◽  
E. Peregi
Keyword(s):  
Mixing Time ◽  
Cost Savings ◽  
Coupling Agents ◽  
Tire Industry ◽  
Selective Functionalization ◽  
Current State ◽  
Rubber Compounds ◽  
Volatile Organic ◽  
Filled Rubbers ◽  
Ethanol Removal

Abstract One challenge facing green tire technology is to achieve good silica hydrophobation/dispersion within the polymer matrix without a detrimental increase in the rubber compound’s viscosity during compounding. This phenomenon is well known to be induced by premature and unwanted coupling and/or crosslinking of the traditional coupling agents. The current state-of-the-art polysulfides silanes, bis(3-triethoxysilylpropyl)tetrasulfide and to a lesser extent bis(3-triethoxysilylpropyl)disulfide (“Product Application—VP Si 75/VP X 75-S in the Rubber Industry,” Degussa Hüls Report No. PA 723.1E), need to be carefully incorporated with careful temperature control during the rubber compounding to prevent this “scorchy” behavior. This paper will present novel monofunctional silanes which are suited for preparing highly silica-loaded rubber compounds of superior processability, while applying fewer mixing passes, thereby reducing mixing times which can lead to improved productivity and cost savings. Additionally, these safer coupling agents can be processed at higher temperatures which can, again, lead to reduced mixing time and better ethanol removal thereby improving the tire’s physical properties and reducing the volatile organic compounds generated during the tire’s use. The rubber compounds produced using these monofunctional silanes are characterized by lower Mooney viscosity and improved processability. Advantageously, within these novel chemical classes of coupling agents, selective functionalization of the silanes allows production of tailor-made coupling agents which can respond to the specific requirements of the tire industry (Vilgis, T. A. and Heinrich, G., “Die Physic des Autoreifens,” Physikalische Blätter, Vol. 57, 2001, pp. 1–7).

Effects of Time and Temperature on the Reaction of Tespt Silane Coupling Agent During Mixing with Silica Filler and Tire Rubber

2002 ◽  
Vol 75 (2) ◽  
pp. 187-198 ◽  
Author(s):  
L. A. E. M. Reuvekamp ◽  
J. W. ten Brinke ◽  
P. J. van Swaaij ◽  
J. W. M. Noordermeer
Keyword(s):  
Coupling Agent ◽  
Mixing Time ◽  
Coupling Agents ◽  
Mixing Conditions ◽  
Rubber Compounds ◽  
Silica Filler ◽  
Silane Coupling ◽  
Sufficient Degree ◽  
Degree Of Coupling ◽  
Sulfur Donor

Abstract The addition of a coupling agent to silica-rubber compounds enhances the filler-matrix compatibility. Under certain mixing conditions the surface of the filler may be only partly activated, which may have an adverse effect on the properties in the final product. Some coupling agents may also act as sulfur donor. The dump temperature employed during mixing and the length of time the compound is exposed to that temperature govern the reaction mechanisms of the coupling agent and determine whether the agent leads to the formation of a silica-rubber bond or acts as a curing agent. A temperature of at least 130 °C is necessary to ensure that the reaction between the coupling agent and the silica proceeds, whereas the coupling agent starts to react with the rubber or to donate sulfur, resulting in scorching, at temperatures above 160 °C. An increase in the 300% modulus and/or G' at 100% strain above 150 °C is an indication of scorching caused by the sulfur in the coupling agent. No scorching is observed when a coupling agent without sulfur is used. Another important parameter is the mixing time. It was observed that the coupling agent must be mixed with the silica for at least 10 minutes at 150 °C to obtain a sufficient degree of coupling.

scholarly journals Data preprocessing workflow for exhaled breath analysis by GC/MS using open sources

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rosa Alba Sola Martínez ◽  
José María Pastor Hernández ◽  
Gema Lozano Terol ◽  
Julia Gallego-Jara ◽  
Luis García-Marcos ◽  
...  
Keyword(s):  
Biomarker Discovery ◽  
Data Preprocessing ◽  
Exhaled Breath ◽  
Sample Collection ◽  
Clinical Tool ◽  
Chronic Respiratory Diseases ◽  
Current State ◽  
Exhaled Breath Analysis ◽  
High Prevalence ◽  
Volatile Organic

AbstractThe noninvasive diagnosis and monitoring of high prevalence diseases such as cardiovascular diseases, cancers and chronic respiratory diseases are currently priority objectives in the area of health. In this regard, the analysis of volatile organic compounds (VOCs) has been identified as a potential noninvasive tool for the diagnosis and surveillance of several diseases. Despite the advantages of this strategy, it is not yet a routine clinical tool. The lack of reproducible protocols for each step of the biomarker discovery phase is an obstacle of the current state. Specifically, this issue is present at the data preprocessing step. Thus, an open source workflow for preprocessing the data obtained by the analysis of exhaled breath samples using gas chromatography coupled with single quadrupole mass spectrometry (GC/MS) is presented in this paper. This workflow is based on the connection of two approaches to transform raw data into a useful matrix for statistical analysis. Moreover, this workflow includes matching compounds from breath samples with a spectral library. Three free packages (xcms, cliqueMS and eRah) written in the language R are used for this purpose. Furthermore, this paper presents a suitable protocol for exhaled breath sample collection from infants under 2 years of age for GC/MS.

Online Charging and Routing of Electric Vehicles in Stochastic Time-Varying Networks

2017 ◽  
Vol 2667 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Ehsan Jafari ◽  
Stephen D. Boyles
Keyword(s):  
Travel Time ◽  
A Priori ◽  
Cost Savings ◽  
Time Varying ◽  
Charging Station ◽  
Current State ◽  
Time Varying Networks ◽  
Charging Stations ◽  
Generalized Cost ◽  
Stochastic Time

This paper formulates the problem of online charging and routing of a single electric vehicle in a network with stochastic and time-varying travel times. Public charging stations, with nonidentical electricity prices and charging rates, exist through the network. Upon arrival at each node, the traveler learns the travel time on all downstream arcs and the waiting time at the charging station, if one is available. The traveler aims to minimize the expected generalized cost—formulated as a weighted sum of travel time and charging cost—by considering the current state of the vehicle and availability of information in the future. The paper also discusses an offline algorithm by which all routing and charging decisions are made a priori. The numerical results demonstrate that cost savings of the online policy, compared with that for the offline algorithm, is more significant in larger networks and that the number of charging stations and vehicle efficiency rate have a significant impact on those savings.

Mooney Viscosity Stability and Polymer Filler Interactions in Silica Filled Rubbers

2002 ◽  
Vol 75 (2) ◽  
pp. 215-245 ◽  
Author(s):  
Chenchy Lin ◽  
William L. Hergenrother ◽  
Ashley S. Hilton
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Ester ◽  
Hydrolytic Stability ◽  
Unsaturated Rubber ◽  
Polymer Filler ◽  
Rubber Compounds ◽  
Filled Rubbers ◽  
Mooney Viscosity ◽  
Sugar Fatty Acid Ester ◽  
Viscosity Stability

Abstract The change in Mooney viscosity (ML1+4) with aging was followed for silica filled compounds containing various silanes and polar additives. Several mechanisms for the aging stability are postulated and evaluated through experimentation. The type of silane or polar additive used can cause the ML1+4 to increase or even decrease during aging. When bis(triethoxy silanes) are used in silica filled rubbers, the ML1+4 growth during aging is caused by hydrolysis. Silica-silica bridging was found to be responsible for the ML1+4 growth in rubber compounds containing a more thermally stable polysulfide or a sulfur-free bis(triethoxy silane). When the bis(triethoxy silane) is bis(3-triethoxysilylpropyl) tetrasulfide (TESPT), a fraction of TESPT is attached to the unsaturated rubber to give polymer-silica attachments. These attachments further enhance the hydrolytic ML1+4 increase during aging. Chemical coating of the silica with a monofunctional silane or a physical coating with a trialkyl amine compound effectively stops the ML1+4 increase upon aging. The prevention of ML1+4 growth is so efficient that a reduction in the ML1+4 can be realized by absorption of ambient moisture. The extent of ML1+4 reduction caused by moisture depends on the degree of hydrophobation of the coated silicas. Hydrolytic stability was also studied with an amine or a sugar fatty acid ester that formed either strong or weak polar associations to the silica.

Influence of Different Coupling Agents on the Properties of Silica-Containing Rubber Compounds Based on Modified Rubbers Obtained by Emulsion and Solution Polymerisation

2002 ◽  
Vol 29 (3) ◽  
pp. 9-13
Author(s):  
N.A. Kondrat'eva ◽  
O.V. Sigov ◽  
Yu. K. Gusev ◽  
A.N. Kondrat'ev ◽  
E.F. Mironova ◽  
...  
Keyword(s):  
Coupling Agents ◽  
Rubber Compounds

Ultrafine Recycled Rubber

1980 ◽  
Vol 53 (5) ◽  
pp. 1215-1225 ◽  
Author(s):  
R. A. Swor ◽  
L. W. Jensen ◽  
M. Budzol
Keyword(s):  
Process Improvement ◽  
Cost Savings ◽  
Substantial Cost ◽  
Technical Advance ◽  
Rubber Compounds ◽  
New Process ◽  
Recycled Rubber ◽  
Product And Process ◽  
Unexpected Product ◽  
Processing Techniques

Abstract A technical advance in the size reduction of cured scrap rubber has been achieved by a new process. The performance of products whose particle dimensions are 90% under 20 µm in diameter has been described in this study. When small panicle size rubber made by this process is used to extend high quality compounds, the degree of retention of key properties of the extended compounds surpasses that of compounds extended with conventional recycled materials. Many unexpected product and process improvement characteristics have been reported. In most cases, the properties of the extended compound are close to those of the unextended compound, even at high loading levels. Initial trials using this unique paniculate rubber at up to 30% concentrations in bias-ply passenger tire treads have shown no performance deficiencies. The addition of RR does not require any special processing techniques, mixing cycles, or equipment. Substantial cost savings are possible by extending virgin rubber compounds with ultrafine recycled rubber.

Ground Rice-Hull Ash as a Filler for Rubber

1975 ◽  
Vol 48 (2) ◽  
pp. 271-288 ◽  
Author(s):  
H. E. Haxo ◽  
P. K. Mehta
Keyword(s):  
Fine Particles ◽  
Amorphous State ◽  
Partial Replacement ◽  
Rice Hull ◽  
Coupling Agents ◽  
Rice Hull Ash ◽  
Silane Coupling Agents ◽  
Rice Hulls ◽  
Rubber Compounds ◽  
Reinforcing Filler

Abstract A ground rice hull ash prepared by a new burning process has been found to be a moderately reinforcing filler for rubber. This filler, 85-90% amorphous silica and 10-15% carbon, is made by a controlled incineration process in which the bulk of the organic components of the rice hulls is removed, leaving the skeletal silica structure of the hull intact and in the amorphous state. The resultant ash is easily ground to produce fine particles, generally in the range of 0.1-2.0 μm. This filler does not adversely affect either the vulcanization characteristics or the aging of SBR, natural rubber, nitrile rubber, butyl rubber, neoprene, EPDM, and propylene oxide rubber compounds. As it is predominantly silica, it responds effectively to silane coupling agents in improving properties of the rubber compounds. It is concluded that RHA filler is a satisfactory substitute for MT black and that, in blends with blacks, it can be effectively used as a partial replacement for finer and more reinforcing blacks.

Systematic review on recent studies on sugar cane bagasse and bagasse cellulose polymer composites

2017 ◽  
Vol 31 (10) ◽  
pp. 1416-1432 ◽  
Author(s):  
Tshwafo E Motaung ◽  
Mokgaotsa J Mochane
Keyword(s):  
Polymer Composites ◽  
Sugar Cane ◽  
Sugar Cane Bagasse ◽  
Coupling Agents ◽  
Chemical Treatments ◽  
Commercial Use ◽  
Current State ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Bagasse Fibre

Sugar cane bagasse (SCB) is one of the abundant and available natural fibres in many countries as a by-product from sugar cane mills after an extraction of sugar. Attempts have been made to convert this by-product into useful eco-friendly cement-bonded composites and polymer composites, which can be used for various internal and external applications in buildings. Some researchers extracted cellulose from SCB and incorporated it in different polymeric matrices. The investigations included optimization of parameters and chemical treatments such as bagasse content or coupling agents for a production of effective composites. The influence of different parameters on the setting of the composite material such as botanical components of the fibre, thermal or chemical treatment of the fibre and bagasse fibre content have shown enhancement in properties. The recent work cited in this review suggests that SCB can be used to prepare fibre-reinforced polymer composites for commercial use. Furthermore, there seems to be a little research done on the application of SCB nanocellulose–polymer composites. In fact, this review discusses the current state of SCB as filler in polymer composites with citation of the latest research. It furthermore exposes more research options for SCB and its ash.

scholarly journals Recent Advances of Pervaporation Separation in DMF/H2O Solutions: A Review

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 455
Author(s):  
Zongqi Zhang ◽  
Siquan Xu ◽  
Yuanfeng Wu ◽  
Shengbin Shi ◽  
Guomin Xiao
Keyword(s):  
Aqueous Solutions ◽  
Point Of View ◽  
Research Progress ◽  
Organic Mixtures ◽  
Separation Technology ◽  
Current State ◽  
Azeotropic Mixtures ◽  
Volatile Organic ◽  
Membrane Technologies ◽  
Pervaporation Separation

N,N-dimethylformamide (DMF) is a commonly-used solvent in industry and pharmaceutics for extracting acetylene and fabricating polyacrylonitrile fibers. It is also a starting material for a variety of intermediates such as esters, pyrimidines or chlordimeforms. However, after being used, DMF can be form 5–25% spent liquors (mass fraction) that are difficult to recycle with distillation. From the point of view of energy-efficiency and environment-friendliness, an emergent separation technology, pervaporation, is broadly applied in separation of azeotropic mixtures and organic–organic mixtures, dehydration of aqueous–organic mixtures and removal of trace volatile organic compounds from aqueous solutions. Since the advances in membrane technologies to separate N,N-dimethylformamide solutions have been rarely reviewed before, hence this review mainly discusses the research progress about various membranes in separating N,N-dimethylformamide aqueous solutions. The current state of available membranes in industry and academia, and their potential advantages, limitations and applications are also reviewed.

Sign in / Sign up

Export Citation Format

Share Document