What is Rubber: Definition and 253 Discussions

Rubber, also called India rubber, latex, Amazonian rubber, caucho, or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds, plus water. Thailand and Indonesia are two of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers.
Currently, rubber is harvested mainly in the form of the latex from the rubber tree (Hevea brasiliensis) or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then is refined into rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale.
Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. In most of its useful forms, it has a large stretch ratio and high resilience, and also is water-proof.

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  1. R

    How stretching a rubber band, affects the range of a shot?

    Homework Statement I did an experiment on how stretching a rubber band, affects the range or distance of a projectile shot. Variable list: Independent Variable Amount of stretching Dependent Variable Range or distance I created my catapults on my own and used two different rubbers bands...
  2. B

    Damping ability in rubber wheels

    Homework Statement I don't have a specific question, but I try to calculate very easy on a simple Gokart in a project. I try to figure out if there is a way to approximately determine what the damping ability of rubber wheels is because I don't have any suspension on it. Homework Equations I...
  3. lomachine

    Help with calculating stock blender for rubber mixing....

    Hello everybody, I am planning to design "stock blender" for two rolls rubber mixxing. I don't have any information about it in my language. So I want to find some documents or directions for its! THis is a picture a rubber mixxing with stock blender. Thanks guys!
  4. anon3005

    Friction of rubber box on concrete floor

    Homework Statement A 10 kg rubber box is resting on a concrete floor. A force of 200 N is then applied to this box in a horizontal direction. What is the magnitude of the friction force on the box? Homework Equations This is a question about applying Newton's laws so Fsmax = μs η and η = mg...
  5. C

    Rubber Band Spinning in midair

    Homework Statement A uniform thin circular rubber band of mass M and spring constant k has an original radius R. Now it is tossed into the air. Assume it remains circular when stabilized in air and rotates at angular speed ω about its center uniformly. Derive an expression for the new radius...
  6. P

    I Stretching a rubber band increase its mass but how?

    Stretching a rubber band increase its mass due to e=mcc, but how?
  7. Preston Feagan

    Looking to dissolve plant matter without affecting rubber.

    Hello! I'm having a bit of an issue here, and I came across this site while searching on how to dissolve plant matter. The thread I found had some ideas, but said a reason would be needed before any concrete advice could be given. So here's my request - I need to instantaneously dissolve plant...
  8. zoobyshoe

    The Rubber Band Theory of Bow Strings

    When I was 6 or 7 I decided to make a bow and arrow one day. I had never seen or handled one in real life, but it was intuitively obvious to me from TV that they way to do this was to tie the ends of a stretched rubber band to the ends of a stick. This would have worked, after a fashion...
  9. G

    B The rubber sheet analogy in Relativity

    Can anyone here settle(or contribute to ) a question that is ongoing at another forum? Who came up with the idea of the rubber sheet analogy in Relativity? Some there have wondered if it was the "rubber sheet geometry" as topology was described as ,apparently that may have ,perhaps...
  10. C

    B String constant of a folded and a cut up rubber

    Imagine that we wanted to build a slingshot, using one piece of rubber attached to two hooks - each on a side. We use a rubber, whose spring constant is k. My questions are: 1. If we began to string that slingshot and the rubber would begin to fold, what would happen with the string...
  11. M

    Medical EPDM Food grade / non food grade

    Hi all We are having a debate regarding peroxide cured EPDM where we a few employees are saying peroxide cured EPDM is food safe and can used as an FDA compliant material; the other group are saying that peroxide curing does not make it food safe. I lean more towards it is because the peroxide...
  12. P

    What Happens When You Bombard a Rubber Ball with Electrons?

    A friend of mine posed a question; if you take a rubber ball and bombard it with electrons, what would happen? I posited that some of the electrons would likely stay on the surface of the ball, giving it a negative charge. I then suggested that if under the "right" conditions you may be able...
  13. O

    Why isn't rubber a better thermal insulator than styrofoam?

    I haven't studied materials in depth, but I would assume that something like rubber would make a good insulator because of its bounciness. The molecules of a substance contained in a rubber container would collide with the walls of the container in a very elastic collision, and the kinetic...
  14. S

    Conformability elastic material compressed on a wavy surface

    Hey there, I'm struggling in finding the useful equations to determine some conformability parameters for a finite elastic material (EPDM) compressed on a rigid slightly wavy surface. I would like to optimize the thickness of the elastic material in terms of indentation depth and thus contact...
  15. N

    How to find variation of modulus of rubber with temperature?

    I want to know the what is the effect of temperature on modulus of rubber, mathematical expression will be helpful
  16. S

    Rubber on a rotating disk (angular velocity, forces)

    Homework Statement We place a rubber on the edge of a rotating disk. What forces act on the rubber? At what angular velocity, why and in what direction will the rubber fly off the disk? Homework Equations http://images.tutorvista.com/cms/formulaimages/83/angular-speed-formula111.PNG The...
  17. D

    Do Rubber Band Propelled Planes Fly Further?

    Hello PF! I have a project/competition in freshman college Aerospace that calls for a plane that can stay in the air for as long a time as possible while going as far as possible. The requirements don't explicitly say we need rubber bands as a propulsion but pretty much prohibit everything but...
  18. C

    Why is the efficiency of a rubber band slingshot constant

    Homework Statement I need to explain for a lab, why the efficiency of a rubber band slingshot constant for different stretch lengths. I don't need math, just a general explanation of why kinetic energy of projectile/elastic potential energy in rubber band is constant. Homework EquationsThe...
  19. samjohnny

    Rubber Band Boltzmann Statistics

    Homework Statement Homework Equations $$ Z(1) = \sum_{i=1}^{} e^{\frac{E_i}{K_bT}} $$ where ##E_i## is each of the possible energy states available to a single link (in this case the right and the left states). $$ P=\frac{\sum_{i=1}^{} e^{\frac{E_i}{K_bT}}}{Z} $$ The Attempt at a Solution...
  20. JJD

    Rubber stiffness as a function of temperature?

    I'm aware of the concept of rubber as an entropic spring and how increasing the temperature increases the modulus/stiffness of the rubber. I've seen the experiment of how heating a strip of rubber supporting a load will cause it to shorten. But also a rubber will transition from its glass-like...
  21. G

    What materials bounce cowhide or vulcanized rubber most?

    I am trying to find out what material that cowhide or vulcanized rubber will bounce off the most? (High school student working on a patent, so really not too experienced with materials engineering.)
  22. S

    LaTeX Potential Energy Stored in latex rubber

    I am looking for a simple number which is the potential energy that can be stored in rubber. ( Joules per gram or something similar ) I know there are a number of forms of rubber and I keep reading numerous articles on how to calculate the energy content of a rubber band. Can anyone just tell...
  23. Tzabcan

    Projectile Motion -- the landing of a rubber duck....

    Homework Statement Calculate the magnitude and direction of the velocity of the rubber duck the second it lands? Homework EquationsThe Attempt at a Solution I'm confused, surely if it has landed then it has no magnitude or direction? as the object is now stationary.
  24. E

    Rubber Heat Resistance: Finding the Right Material

    I'm not sure if I'm supposed to post this here, if I'm not, I'm sorry. That being said, what kinds of rubber can be heated up to 30 degrees c without degradation but can be melted. I would like to sandwich a heating filament between two sheets of rubber and seal them together with heat.
  25. T

    Uniform Circular Motion for rubber stopper

    Homework Statement Picture- https://flic.kr/p/zi1ays The rubber stopper will be spun at a constant speed in a horizontal circle. The hanging mass is only in contact with the string.[/B] A) For the rubber stopper, state the forces and what they are exerted by and on B) Does the net force have...
  26. I

    Vfx: 12m/sVfy: -9.81m/sRubber Duckie Drop Homework

    Homework Statement A hot air balloon containing an AP Physics student ascends vertically at a constant speed of 8 m/s. While ascending, he accidentally drops his rubber duckie from the gondola of the ballong. Seven seconds after it is dropped the duckie bounces off a roof at point A and hits...
  27. I

    Safe in a car if hit by lighting....NOT b/c of rubber tires?

    So I just learned Gausse's Law and it makes me think: People always say you're safe in a car if it get struck by lighting because of the rubber tires (odd, because tired are like 90%carbon) but isn't it also because a car is a Gaussian sphere? The interior is insulated, sort of, right? If this...
  28. L

    I The science behind getting stuck in mud

    Hey guys ! :) Last week I went on a Trip to this place 3500 ft above sea level, as I was walking my rubber boots got stuck on a big pile of mud (almost 30 to 40 cm) of my boots. I managed to take one out but the other was so stuck I had to play the natives to help me get it out. So my question...
  29. A

    Determine the force constant of the rubber band

    Homework Statement From the experiment I did my force was equal to 0.0686N +/- 0.00196N and my x (rubber band stretch) was equal to 0.003m +/-0.002. The question asks to determine the force constant k +/- ∆k. Homework Equations F = kx k = F/x ∆k = |k| ∆x/x +∆y/y The Attempt at a Solution k...
  30. A

    Calculate elasticity of rubber balloon

    Dear readers, For a Biomedical Engineering project I have to develop a model for the respiratory system of a neonate. This will be done by using pressure/volume data of the lungs. To model these, I would like to use a rubber balloon. However the calculation are more difficult than I thought...
  31. Silverlight

    How to Find Force on Rubber Tube from Piston System?

    Hello, first of all, this isn't a homework/school related question. Long story short, my father works for a chemical plant and a few of their valve/piston/transfer system things have been breaking, which he assumes is because of too much force. With everyone in a dispute and doing their own...
  32. M

    Heat transfer through brass and rubber

    Homework Statement Two identical brass plates, each 0.5 cm thick, are separated by a rubber spacer of thickness 0.1 cm which has the same cross sectional area. If the outer surfaces of the brass plates are kept at 0 °C and 100 °C respectively, calculate the temperature at each side of the...
  33. Abtinnn

    Rubber Sheet Analogy: How Mass Bends Spacetime

    I have a question on GR. To what extent is the rubber sheet analogy correct? To be more specific, in that analogy, an object with mass M bends the 2-D space (the sheet) into a third dimension (the sheet goes downward). Does this imply that in out universe, an object with mass bends the spacetime...
  34. Robsta

    Equation of state of a rubber band

    Homework Statement For a stretched rubber band, it is observed experimentally that the tension f is proportional to the temperature T if the length L is held constant. Show that: a) The internal energy U is a function of temperature only b) Adiabatic stretching of the band results in an...
  35. R

    Can a Dragon Direct Lightning If It Can't Create an Opposite Charge?

    Okay- first off, I know enough science to sound like an idiot, so please be gentle :-) Now, IF you had a dragon that generated an electrical charge, it wouldn't be able to direct it, lightning-style, without being able to generate an opposite charge at it's target- right? So in essence, to shot...
  36. H

    Measuring impact force on rubber spacers

    I need to find the impact force that can be absorbed by these spacers as shown in the image. The spacers are radially distributed over the shell, and they are supposed to dampen any external impact loads to reduce the effective stress inside the inner shell. Since the FEA model is not showing...
  37. T

    Basic Vibration Damping and Isolation

    Hello, I am studying and trying to understand Powertrain / Engine mounts used in automotive such as these: http://images.gasgoo.com/MiMwMDRfMDA0Izc4MDA3NzIwMA--/auto-part-engine-torque-strut-mount-engine-mounting-for-buick-enclave-chevrolet-traverse-gmc-acadia-25840458.jpg...
  38. A

    [Problem] Elastic potential energy

    Hi, I'm a second year Design Engineering student. This year we're having some basic physics class. We're doing projects on potential energy at this moment. I'm having a problem with the following; The assignment: The teacher assigned us that only 6 Joules of potential energy may be used to...
  39. M

    Can i paint PVC Nitrile rubber? with plasti-dip? toxic?

    Here's what I'm trying to paint: http://www.forcefieldbodyarmour.com/product/net-upgrade-armour-flat/2418 I'm trying to paint this black. Can i paint these yellow pads with some sort of non toxic spray paint? Or what about plastidip (which i think is nontoxic). I was even thinking of using a...
  40. I

    Friction Force of a rubber ball

    Homework Statement If a 2.5 kg rubber ball is rolled across the dry concrete floor with an acceleration of 4.0 m/s^2[E]. Determine the friction force required to stop the ball. (Drawing a free body diagram will help illustrate this situation) Homework Equations Fk= µk(Fn) F=maThe Attempt at a...
  41. A

    What is the momentum transferred in a rubber ball collision?

    Homework Statement Homework Equations p=mv[/B]The Attempt at a Solution My thoughts- Answer is C as KE is not conserved since velocity of ball has decreased. Option A also seems correct.[/B]
  42. D

    Storing Energy in a Rubber Band: Does Mass Increase?

    Does this mean if I had a rubber band and weighed it, then stretched and weighed it while being stretched out, that it would weigh more at that time? Since at that time it has stored energy, which equates to mass?
  43. Nathanael

    Will the Bug Ever Reach the End of the Stretching Rubber Band?

    Homework Statement "You have a 1 km long rubber band with one end attached to the wall, and the other in your hand. The bug begins to crawl towards you on the rubber band, starting from the wall, at a rate of 1 cm/sec. As he crawls the first centimeter you extend the rubber band 1 km; when he...
  44. I

    MHB Sony Vaio Parts: Cover Lids & Rubber Feet

    where can i get a cover lid for a 14.5" sony vaio. or the little rubber feet for sony vaio pcg-61611L
  45. C

    Mass of a rubber stopper being swung in a horizontal circle

    Homework Statement Homework Statement [/b] The purpose of this lab is to determine the mass of a rubber stopper being swung in a horizontal circle. I made an apparatus that resembles the picture attached, with a string (with a rubber stopper on one end, and a weight on the other end) put...
  46. D

    Rotating rubber wheels made to contact. Find final angular veloctiy

    Homework Statement A solid rubber wheel of radius R and mass M rotates with angular veloctiy \omega_0 about a frictionless pivot. A second rubber wheel of radius r and mass m, also mounted on a frictionless pivot, is brought into contact with it. What is the final angular velocity of the first...
  47. A

    Young's modulus of rubber sheet using the inflation technique

    A rubber sheet (thickness 0.2mm) was mounted in an open-type Ussing chamber (6mm aperture) such that hydrostatic pressure could be applied to one side and the resulting inflation of the membrane tracked with an OCT instrument (OCT: ocular coherence tomography). From the geometry of the membrane...
  48. C

    Calculate Rubber Band Force to Hold 5 kg Box Without Deforming >1mm

    Hello i need to know what should i do, Consider i have a box, top half and bottom half. so now i have to hold the top half and bottom half together with the rubber band then how do i know what rubber band will be enough to exert force so that both parts of box are hold together. also i...
  49. S

    Damping Properties of Rubber: Understanding the Impact of Strain Amplitude

    Hey Guys, Can anyone tell me why the damping properties of rubber will decrease as the strain amplitude increases? Thanks
  50. A

    The effect of aerofoil shape on rubber powered model aircraft

    Model aircraft display a wide range of aerofoil shapes, and many of these models fly despite the shape of the cross section of the wing. Models with flat wings, cambered wings, thick wings, thin wings - all of these fly succesfully. What is the function of aerofoil shape on free flight...
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