• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

NaturalRubber NR. (Hevea, rubber, natural cis-polyisoprene)

Extracts from this document...

Introduction

RUBBER Natural Rubber NR. (Hevea, rubber, natural cis-polyisoprene) (slide 1) I'm going to talk to you about rubber, I'll talk about natural rubber first and then go on to talk about the way in which its natural state can be modified and manipulated so its advantageous properties can be used. (slide 2) Natural rubber is an excellent engineering material and is used as the main material in many everyday items the most prevalent being car tires which I'll discuss later also. (slide 3) Natural rubber is obtained from the milky white fluid called latex, found in many plants however synthetic rubbers are produced from unsaturated hydrocarbons (basically this means that there are carbon atoms in the rubber molecule that have a potential to be bonded to more hydrogen. Latex is a milky fluid found in specialized cells, called lactiferous cells. To gather the latex from plantation trees, a diagonal cut angled downward is made through the bark; this cut extends one-third of the circumference of the trunk. ...read more.

Middle

So that makes quite an interesting material chemically. I'll talk to you now a bit about natural rubber's advantageous physical properties. One of which is its long fatigue life, due to this it is commonly first choice for spring applications as it can be stretched compressed and distorted many times before becoming deformed. It also has a high strength without the need for reinforcing fillers like many other polymers- (Strength in this instance being an indication of its yield stress, which just to refresh your memory is the stress at the point when the material has reached its elastic limit.) It can also be compounded to give a wide range of hardness. It has a very good low temperature flexibility which means its form can be manipulated easily without needing to be heated, to think of a commonplace example 'rubber gloves need to be misshapen at room temperature without becoming permanently deformed. (slide 4) And now for synthetic rubbers. ...read more.

Conclusion

Other automobile parts, hose electrical insulation and footwear are normally made up of ethylene-propylene rubbers (RPDM) due to their high resistance to weathering and sunlight. (slide 5) Some synthetic materials have been developed to replace rubber. Urethane elastomers are called spandex and they consist of urethane blocks and polyether the urethane blocks give strength and heat resistance, the polyester and polyether blocks provide elasticity; they are the most versatile elastomer family because of their hardness, strength, oil resistance, and aging characteristics. Other uses range from airplane wheels to seat cushions. Other synthetics are highly oil-resistant, but their high cost limits their use. Silicone rubbers are organic derivatives of inorganic polymers, they are very stable and flexible. Over natural rubber: better aging and weathering, more resistance to oil, solvents, oxygen, ozone, and certain chemicals, and resilience over a wider temperature range. The advantages of natural rubber are less build-up of heat from flexing and greater resistance to tearing when hot. So basically although rubber in its natural state has many physical properties that make it a useful material we can modify and manipulate this natural material to make high performing compounds that can be found in everyday use. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Resistant Materials section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Resistant Materials essays

  1. Material Selection for Oil and Gas Material 3

    We may look at ASME Section VIII, Div. 1 - Pressure Vessels as well as ASTM A 125 Standard Specification for Steel Springs, Helical, Heat-Treated. Safety Criteria Because of a need for high integrity, we will need to have a critical value of safety ?f ? 0.15 KIC ?

  2. Material Selection for Oil and Gas Material 2

    We also know, that we want to minimize corrosion, and this is directly related to Chromium. Therefore, we would like to maximize chromium. Material Cr % ?u (MPa) ?f % Density ?cr ? CCR = (Cr)(?u) (?cr)/(Den)(k) Rank AISI 316 19 580 55 8 97 16.3 450857 1 Alloy C-22

  1. EFFECT OF MOISTURE ON THE MECHANICAL PROPERTIES OF NYLON

    Very unusual processing conditions are required to yield material out side the ranges given. The specific gravity of molded part can be measured by a hydrostatic technique involving the weighing of specimen in air and in a solvent not rapidly absorbed.

  2. Oil, natural gas, and coal are the main sources of energy for modern use. ...

    During this time the seas and swampy areas were rich in microscopic plants and animals. When these died they slowly sank to the bottom forming thick layers of organic material. This in turn became covered in layers of mud that trapped the organic material.

  1. Technical Report The Construction of Alloy Wheels

    Although the concept of low pressure casting was developed in the early part of the century, it was not fully developed for the production of aluminium castings until the second world war and it was not until the mid 1950's that the process was used in the automotive sector.

  2. Critically discuss the importance of materiality for theories of practical reasoning.

    Thus the possibility of dissociation from one's embeddedness (at least mentally) through process of critical reflection allows for the more liberal position of autonomous agents choosing their life-plans and goals in life. In essence it is important to maintain a medium between both the embedded and unencumbered self.

  1. Six sigma methology for solving automotive engineering problems.

    Also, to be identified at this stage are the variables that influence the outcome as understood at that stage and feasibility of their modification. The real task involved in the whole process is in the Problem Formulation stage where the identified design variables need to be normalized or combined so

  2. Aristotle and Cause.

    Material is necessary but it does not give us the whole answer. 2-Secondly there is the efficient cause. This is the agent, which brings something about for example in the case of a statue it is the person chiselling away and the act of chiselling that causes the statue.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work