Selection and Use of Age Resistors in Rubber Compounds

1934 ◽  
Vol 7 (4) ◽  
pp. 663-687
Author(s):  
Richard A. Crawford
Keyword(s):  
Surface Treatment ◽  
Early Development ◽  
Reducing Agents ◽  
Adhesive Properties ◽  
Temperature Changes ◽  
Rubber Industry ◽  
Beneficial Effects ◽  
Organic Bases ◽  
Rapid Deterioration ◽  
Rubber Compounds

Abstract THE early development of the rubber industry was handicapped by two serious defects in rubber articles. They were not stable to temperature changes, and they deteriorated rapidly with age. Although the process of vulcanization corrected the first difficulty, rapid deterioration with age was common until the discovery of certain organic accelerators, such as p-aminodimethylaniline, the aldehydeamines, and mercaptobenzothiazole. Prior to these discoveries a number of materials had been patented for the purpose of improving the age-resisting properties of rubber, but many of them were of little merit and most of the others possessed some accelerating value, a fact which was not appreciated at the time. Typical of the more useful early patents for age-resisting materials are American patents by Murphy in 1870 (15), Moore in 1901 (14), and Martin in 1922 (12), and the German and English patents of the Ostwalds in 1908 and 1910 (19, 20). Murphy patented phenol, cresol, and cresylic acid, either added to the uncured stock or as dipping solutions for vulcanized articles for the purpose of improving their resistance to aging. Moore used reducing agents, including hydroquinone, pyrogallol, and p-aminophenol hydrochloride, to preserve the adhesive properties of rubber cements. Martin suggested aniline and other organic bases as a surface treatment for vulcanized articles. The Ostwalds also recognized the beneficial effects of aniline on rubber and stated that it could be added at any convenient stage of manufacture. (It is interesting to note that these inventors considered that addition of aniline to uncured stock or dipping the cured article in aniline were equivalent, and they, therefore, evidently did not recognize the accelerating effect of aniline.)

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

The Effect of Carbon Black Parameters on the Fatigue Life of Filled Rubber Compounds

1974 ◽  
Vol 47 (1) ◽  
pp. 231-249 ◽  
Author(s):  
E. S. Dizon ◽  
A. E. Hicks ◽  
V. E. Chirico
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Carbon Black Particle ◽  
Chemical Action ◽  
Beneficial Effects ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
The Matrix ◽  
Black Particle ◽  
As Stress

Abstract Fatigue is defined as decay caused by cyclic deformations at an amplitude less than necessary for fracture in one cycle. Such failures are initiated by flaws which act as stress concentrators. These flaws occur in the material either through mechanical or chemical action during service or through agglomeration of certain ingredients during mixing and fabrication. This paper deals with the latter process, where the nature and size of the flaws as well as the properties of the matrix are contingent on carbon black variables. Using the tearing energy concept of fatigue developed by Lake and Lindley, it was shown that the size of the flaw is primarily determined by carbon black particle size. On the other hand, the cut growth constant depends on carbon black structure. When translated to actual fatigue life using the Monsanto Fatigue-to-Failure Tester, these relationships mean that under constant strain conditions, compounds containing coarse carbons will have a significantly higher fatigue life than those with fine carbons. Under conditions of constant strain, higher structure carbons will impart a slight positive effect. However, under conditions of constant stress, the beneficial effects of structure become magnified. Other factors known to affect fatigue life were also considered. These are : set, stress relaxation, hysteretic energy dissipation, and flaw size distribution.

scholarly journals Comparison of Adhesive Properties of Polyurethane Adhesive System and Wood-plastic Composites with Different Polymers after Mechanical, Chemical and Physical Surface Treatment

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 397 ◽  
Author(s):  
Barbora Nečasová ◽  
Pavel Liška ◽  
Jakub Kelar ◽  
Jiří Šlanhof
Keyword(s):  
Surface Treatment ◽  
Plasma Source ◽  
Adhesive System ◽  
Test Methods ◽  
Surface Treatments ◽  
Adhesive Properties ◽  
Bonded Joint ◽  
Polymer Adhesive ◽  
Naoh Solution ◽  
The Cost

The cost of most primary materials is increasing, therefore, finding innovative solutions for the re-use of residual waste has become a topic discussed more intensely in recent years. WPCs certainly meet some of these demands. The presented study is focused on an experimental analysis of the effect of surface treatment on the adhesive properties of selected WPCs. Bonding of polymer-based materials is a rather complicated phenomenon and modification of the bonded area in order to improve the adhesive properties is required. Two traditional types of surface treatments and one entirely new approach have been used: mechanical with sandpaper, chemical with 10 wt % NaOH solution and physical modification of the surface by means of a MHSDBD plasma source. For comparison purposes, two high-density polyethylene based products and one polyvinyl-chloride based product with different component ratios were tested. A bonded joint was made using a moisture-curing permanently elastic one-component polyurethane pre-polymer adhesive. Standardized tensile and shear test methods were performed after surface treatment. All tested surface treatments resulted in an improvement of adhesive properties and an increase in bond strength, however, the MHSDBD plasma treatment was proven to be a more suitable surface modification for all selected WPCs.

Goodyear Medalist Lecture. Goodyear Medalist Lecture Towards Understanding of the Rheology of Rubber Compounds and their Processing

2009 ◽  
Vol 82 (2) ◽  
pp. 131-148 ◽  
Author(s):  
James L. White
Keyword(s):  
Rheological Properties ◽  
Processing Technology ◽  
Early Age ◽  
Technical Literature ◽  
Technical Problems ◽  
Rubber Industry ◽  
Professional Career ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
The Usa

Abstract The problems of the rheological properties of rubber compounds and the understanding of the processing operations that are used to produce rubber products have received relatively little study in the literature compared to thermoplastics. This seems in part due to an almost 200 year old tradition of industrial secrecy and the vertically integrated nature of the synthetic rubber producer — tire manufacturer combines in the USA. Thus while abundant information has always been available from thermoplastics suppliers on processing technology, little has been available on rubber. Because I began my professional career in the rubber industry and became from an early age concerned with its technical problems, I have not been swayed to the same extent by the thermoplastics dominated technical literature as others in the polymer community.

Adhesion of Dairy Propionibacteria to Intestinal Epithelial Tissue In Vitro and In Vivo

2002 ◽  
Vol 65 (3) ◽  
pp. 534-539 ◽  
Author(s):  
GABRIELA ZÁRATE ◽  
VILMA I. MORATA de AMBROSINI ◽  
ADRIANA PEREZ CHAIA ◽  
SILVIA N. GONZÁLEZ
Keyword(s):  
Surface Characteristics ◽  
Epithelial Tissue ◽  
Intestinal Epithelial ◽  
Adhesive Properties ◽  
Bacterial Surface ◽  
Beneficial Effects ◽  
Adhesion Ability ◽  
Dairy Propionibacteria

Adhesion to the intestinal mucosa is a desirable property for probiotic microorganisms and has been related to many of their health benefits. In the present study, 24 dairy Propionibacterium strains were assessed with regard to their hydrophobic characteristics and their autoaggregation and hemagglutination abilities, since these traits have been shown to be indicative of adherence in other microorganisms. Six strains were further tested for their capacity to adhere to ileal epithelial cells in vitro and in vivo. The results of the study showed that propionibacteria were highly hydrophilic, and hemagglutination and autoaggregation were properties not commonly found among these microorganisms. No relationship was found between surface characteristics and adhesion ability, since hemagglutinating, autoaggregating, and nonautoaggregating bacteria were able to adhere to intestinal cells both in vitro and in vivo. Microscopic examination revealed that autoaggregating cells adhered in clusters, with adhesion being mediated by only a few bacteria, whereas the hemagglutinating and nonautoaggregating strains adhered individually or in small groups making contact with each epithelial cell with the entire bacterial surface. The in vitro assessment of adhesion was a good indication of the in vivo association of propionibacteria with the intestinal epithelium. Therefore, the in vitro method presented here should be valuable in screening routinely adhesive properties of propionibacteria for probiotic purposes. The adhesion ability of dairy propionibacteria would prolong their maintenance in the gut and increase the duration of their provision of beneficial effects in the host, supporting the potential of Propionibacterium in the development of new probiotic products.

scholarly journals A Recent Overview: In Situ Gel Smart Carriers for Ocular Drug Delivery

2021 ◽  
Vol 11 (6-S) ◽  
pp. 195-205
Author(s):  
Mandeep Singh ◽  
Dhruv Dev ◽  
D.N. Prasad
Keyword(s):  
Drug Delivery ◽  
Delivery Systems ◽  
Eye Drops ◽  
Adhesive Properties ◽  
In Situ Gel ◽  
Temperature Changes ◽  
Polymeric Systems ◽  
Protective Layers ◽  
In Situ Gelling

Delivery of the drug to the ocular area is blocked by the protective layers covering the eyes; it has always been a major problem to find effective bioavailability of the active drug in the ocular area due to the short duration of precorneal majority ocular stay. Direct delivery systems combine as well as oil, solution, and suspension, as a result, many delivery systems are not able to effectively treat eye diseases. Many works have been done and are being done to overcome this problem one of which is to use in-situ to build polymeric systems. Ocular In-situ gelling systems are a new class of eye drug delivery systems that are initially in solution but are quickly transformed into a viscous gel when introduced or inserted into an ocular cavity where active drugs are released continuously. This sol-to-gel phase conversion depends on a variety of factors such as changes in pH, ion presence, and temperature changes. Post-transplanting gel selects viscosity and bio-adhesive properties, which prolongs the gel's stay in the ocular area and also releases the drug in a long and continuous way unlike conventional eye drops and ointments. This review is a brief overview of situ gels, the various methods of in situ gelling systems, the different types of polymers used in situ gels, their gel-based methods, and the polymeric testing of situ gel. Keywords: In-situ gel, Polymers, and ion triggered in-situ gel, Mechanism, Evaluation parameters

INVESTIGATION OF HEMPSEED PROCESS OIL AS THE ALTERNATIVE IN NATURAL RUBBER COMPOUNDING PROCESS

2021 ◽  
Author(s):  
Julijana Blagojević ◽  
◽  
Olga Govedarica ◽  
Kojić Predrag ◽  
Oskar Bera ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Rotor Speed ◽  
Elongation At Break ◽  
Rubber Industry ◽  
Mineral Oils ◽  
Rubber Compounds ◽  
Reinforcing Fillers ◽  
Environmentally Friendly Process ◽  
Batch Mixer ◽  
Selection Of

Good selection of natural rubber compounds is substantial in rubber industry. Behavior of products based on natural rubber is determined by rubber blending components, especially nature of process oil and concentration of reinforcing fillers. Rubber process oil main purpose is to improve dispersibility of fillers and reduce the viscosity of the rubber compound, therefore enable better processing. Mineral oils are mostly used process oils in natural rubber compounding, but, due to their toxicity and new requirements for preservation of the environment, more and more well-known manufacturers have turned to the use of environmentally friendly process oils. In this study, influence of the hempseed oil as process oil on the products properties in natural rubber compounding was investigated. Properties of hempseed oil as process oil were experimentally determined or calculated. Blending of natural rubber was performed in a laboratory by internal batch mixer, at the constant temperature of 90°C and a rotor speed of 60 rpm. Main rubber properties such as hardness, tensile strength, elongation at break, modulus at 100 and 300% elongation, and rheological properties were determined. Also, voltage and amperage were experimentally measured for calculating power consumption during effective mixing phase in rubber blending.

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