Dear Label_Name,

Greetings! I hope you are well.

I am writing on behalf of an international publishing house, Science and Education Publishing, USA (http://www.sciepub.com).

Science and Education Publishing (SciEP) is a multidisciplinary open access publisher of Journals covering the fields of Science, Technology and Medicine. All SciEP publications are subject to high-quality peer review, editorial and production processes and are freely available online.

Welcome to the April, 2013 edition of SciEP newsletter, providing monthly summaries of articles on science & education related topics of interest to scientist and professionals. The mission of our journals is to provide an open access forum for publishing new findings on issues pertinent to scientific and academic field. We also invite you to submit original research papers, review articles, short reports, or case studies are considered for publication in our Multidisciplinary Journals.

American Journal of Public Health Research
DOI: 10.12691/ajphr-1-1-3

The Implementation of a Tele-Homecare System with Service Oriented Architecture and HL7 Message Transmission Standard
Ching-Sung Wang

American Journal of Medical and Biological Research
DOI: 10.12691/ajmbr-1-1-2

The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico
Lelevich Sergey Vladimirovich, Khrustalev Vladislav Victorovich, Barkovsky Eugene Victorovich, Shedogubova Tatyana Aleksandrovna

American Journal of Medical Sciences and Medicine
DOI: 10.12691/ajmsm-1-1-1

Clinical and Histological Features in Wegener Granulomatosis
Li Cavoli Gioacchino, Passantino Rita, Bono Luisa, Tortorici Calogera, Ferrantelli Angelo, Giammarresi Carlo, Rotolo Ugo

American Journal of Infectious Diseases and Microbiology
DOI: 10.12691/ajidm-1-1-2

The Curse of Lymphatic Filariasis: Would the Continual Use of Diethylcarbamazine Eliminate this Scourge in Papua New Guinea?
Anne Lanham, Lillian Mwanri

We have released issues of some journals on February 2013.
American Journal of Public Health Research
American Journal of Medical Sciences and Medicine
American Journal of Medical and Biological Research
American Journal of Pharmacological Sciences
American Journal of Clinical Medicine Research
American Journal of Nursing Research
American Journal of Cancer Prevention
American Journal of Medicine Studies
American Journal of Infectious Diseases and Microbiology
American Journal of Cardiovascular Disease Research
American Journal of Biomedical Research
American Journal of Mechanical Engineering
American Journal of Microbiological Research
Journal of Preventive Medicine
American Journal of Food and Nutrition
American Journal of Hypertension Research
American Journal of Sports Science and Medicine
Journal of Cancer Research and Treatment
American Journal of Zoological Research
Journal of Biomedical Engineering and Technology
American Journal of Microbiological Research
Biomedical Science and Engineering

We are pleased to announce that submissions are now being accepted for peer review for all the journals across all our subject areas in SciEP.

Please submit your manuscript via our online submission system:
http://www.sciepub.com/author/signin

To unsubscribe from our mailing list, please click on the following link: unsubscribe

I am looking forward to hearing from you.

Kind regards,

David Rain
Email:join@sciepub.com
Science and Education Publishing (http://www.sciepub.com)

Effect of Shells Powder on Scorch and Cure Time of Elastomer Material

Mohammad H.Al-Maamori, Ali I. Al-Mosawi*

Technical Institute-Babylon, Iraq

Abstract: The effect of shells powder additive (60,90,120 pphr) on scorch and cure time of natural rubber was studied in this paper. Oscillating Disk Rheometer was used to measuring the above times by specified the behavior of master batch through scorch time. The obtained results shown that the shells powder don’t have negative effect on rubber properties during vulcanization, where the properties was enhanced after added this powder and the best percentage of addition was (120 pphr).

Keywords: natural rubber, shells powder, scorch, cure time

Received Month 18, 2013; Revised Month 22, 2013; Accepted Month 28, 2013

Citation: Mohammad H.Al-Maamori, Ali I. Al-Mosawi, Effect of Shells Powder on Scorch and Cure Time of Elastomer Material. American Journal of Materials Engineering and Technology, 1 (2). 19-21. January 2013. doi:10.12691/materials-1-2-1

1. Introduction

Rubber composite materials with different type of rubber are used in dampers and supports application [1]. Therefore it is occupied a wide field studies, because rubber has good characterization in the high elastic strain damping which is obtained from the suddenly impact loading because of different acceleration of the system, therefore a different modification of new type of rubber composite for loading resistance in addition to the interference of the usages conditions with the mechanical loads such as environment effects at high temperatures in the presence of oils and friction result in creation of blended polymers such as (NBR, SBR, NR, CR, ... etc) [2]. Also a new type of polymers which is supported by thermosetting polymers type is developed for heat resistance purposes, also different types of blended rubbers ate improved by supporting methods such as by using particles and fibers for dynamic properties improvement for high loads purposes [3].

2. Rubbers

Rubbers can be divided broadly into two types: thermosets and thermoplastics. Thermosets are three-dimensional molecular networks, with the long molecules held together by chemical bonds. They absorb solvent and swell, but do not dissolve; furthermore, they cannot be reprocessed simply by heating. The molecules of thermoplastic rubbers, on the other hand, are not connected by primary chemical bonds. Instead, they are joined by the physical aggregation of parts of the molecules into hard domains [4]. Hence, thermoplastic rubbers dissolve in suitable solvents and soften on heating, so that they can be processed repeatedly. In many cases thermoplastic and thermoset rubbers may be used interchangeably. However, in demanding uses, such as in tires, engine mounts, and springs, thermoset elastomers are used exclusively because of their better elasticity, resistance to set, and durability. The addition of various chemicals to raw rubber to impart desirable properties is termed rubber compounding or formulation [5].

Typical ingredients include crosslinking agents (also called curatives), reinforcements, anti-degradants, process aids, extenders, and specialty additives, such as tackifiers, blowing agents, and colorants. Because thermoplastic rubbers contain hard domains that interconnect the molecules and impart strength and elasticity, they do not require crosslinking agents or reinforcing fillers. However, the selection of appropriate curatives and fillers is critical to the performance of thermoset elastomers [6]. Natural rubber (NR) Natural rubber is produced from the latex of the Hevea brasiliensis tree. Before coagulation, the latex is stabilized with preservatives (e.g., ammonia, formaldehyde, sodium sulflte) and hydroxylamine may be added to produce technically-specified, constant-viscosity grades of NR [7]. Figure 1 shows the Isoprene units.

Figure 1. Isoprene units

Fillers not only reduce the cost of composites, but also frequently impart performance improvements that might not otherwise be achieved by the reinforcement and resin ingredients alone. Fillers can improve mechanical properties including fire and smoke performance by reducing organic content in composite laminates. Also, filled resins shrink less than unfilled resins, thereby improving the dimensional control of molded parts [8].

Important properties, including water resistance, weathering, surface smoothness, stiffness, dimensional stability and temperature resistance, can all be improved through the proper use of fillers. The thermosetting resin segment of the composite industry has taken advantage of the properties of fillers for many years. More recently, the thermoplastic industry has begun to make widespread use of inorganic fillers. Breakthroughs in chemical treatment of fillers that can provide higher filler loadings and improved laminate performance are accelerating this trend [9].

3. Experiments

a-Materials: Natural rubber, Shells powder containing (82.4%) calcium carbonate.

b- The Batch: The batch was prepared from Natural rubber Rubber (NR) with addition of some of materials (such as zinc oxide, stearic acid, sulfur, Antioxidant, Carbon black.etc), shell powder was added to rubber as a weight percentages (60,90,120 pphr).

c- Samples Preparing: Samples were prepared as slices of 6 mm in thickness and were divided as discs of 40mm in diameter and 6mm in thickness by using hydraulic mould in order to vulcanize them and study their cure time and scorch time.

d- Measuring of cure and scorch time: The test is carried out according to (ASTM D1646-68) by using oscillating disc Rheometer (ODR).The sample was held upper and lower jaws clutch under 3.5 bar pressure and 185°C for 6min.

The weight percentages of materials in master batch are shown in Table 1.

Table 1. Weight percentages of materials in master batch

4. Results and Discussion

Relation between the scorch time (This period of time before vulcanization starts is generally referred to as scorch time) vs. shell powder percentage was shown in Figure 2 We notice that the scorch time reduces with the increase in shell powder percent, this is due to the interference of the shell powder between the rubber chains which inhibit vulcanization by sulfur, until reached to (120pphr) percentage from shell powder which will increased scorch time [10].

Figure 3 shows the relation between the cure time vs. shell powder percentage, it is noticed that increase in shell powder percent causes decrease in cure time, this is due to the increasing of scorch time and this decreased the vulcanization time which will improved rate of the product [11].

Figure 2. scorch time vs. shell powder percentage

Figure 3. cure time vs. shell powder percentage

5. Conclusions

Reducing scorch time as shell powder percentage increases in the range of 0-90 pphr, until reached to (120pphr) percentage. Decreasing cure time as shell powder percentage increases in all ranges due to the increasing of scorch time.

References

[1]   | Auter K.Kaw “Mechanics of composite materials”, 2nd edition, Taylor and Francis Group, LLC, 2006.
[2]   | Andrew Ciesielski “An introduction to rubber technolog”, 1st edition, Rapra technology limited, 2000.
[3]   | Brian S. Mitchell “An introduction to materials engineering and science”, John Wiley &Sons, Inc., Hoboken, New Jersey, 2004.
[4]   | J.A. Brydson “Plastics materials”, 7th edition, Butterworth Heinemann, 1999.
[5]   | E.P. DeGarmo, J.T. Black, and R.A. kohser “Materials and processes in Manufacturing”, 10th Edition, john Wiley & Sons, 2008.
[6]   | Mohammad H.Al-Maamori, Auda J.Brahi “ Study the effect of kaolin in design of rubber batch for aircraft tires ”, Iraqi Journal for mechanical and materials Engineering, Special Issue, 1st Conference of Engineering College 17-18 May, 2009, pp 269-276.
[7]   | Ali I.Al-Mosawi, Haider K.Ammash, Ali J.Salaman “Properties of Composite Materials databook”, 1st edition, Misr- Almurtadah Inc. 2011.
[8]   | C.A. Harper “Handbook of plastics, Elastomer and composite”, McGraw-Hill, Handbook 2004.
[9]   | R-K Mattham “Rubber Engineering”, Tata McGraw-Hill publishing company, Delhi 1998.
[10]   | A. A. Zaman, A. L. Fricke, and C. L. Beatty “Rheological properties of rubber-modified asphalt”, journal of transportation engineering / November /December 1995, pp 461-467.
[11]   | Jatuporn Sridee “Rheological properties of natural rubber latex”, M.Sc thesis, Suranaree University of Technology, 2006.