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. P

    Purpose of the rubber in the image in a water pump

    I would like to know the purpose of the rubber in this water pump and a metal piece behind it in this water pump of a vehicle. The water pump is located in the engine near the distribution belt. Best Regards There are two version of the rubber : one with a hole or without it.
  2. Twigg

    What is the most incompressible elastomer?

    Hi all! Usually, one would model a rubber as incompressible (##\nu \rightarrow \infty## or equivalently ##\kappa \rightarrow \infty##, where ##\nu## is Poisson ratio and ##\kappa## is bulk compressibility). However, I am trying to use rubber in an application where performance will improve the...
  3. D

    I Elastic Constants for Natural Rubber

    Hi, Looking for the Elastic Constants for any rubber-like material such as Natural Rubber. It can be inorganic or organic. The constants I am looking for take the form of a fourth-rank tensor. I only need the first order elasticities, not the zeroth or higher (not Cij or Cijklmn.. just Cijkl)...
  4. N

    Rubber Band Fumes: Is My Cake Inedible?

    I just baked a cake, and accidentally left a rubber band around the cake tin (which was holding the greaseproof paper in place). Is the cake inedible due to fumes given off by the rubber band?? Thanks :)
  5. V

    Forces when car wheels "lay rubber"

    Suppose the car is moving to the right, so if the wheels roll without slipping, they are rolling clockwise. To get the wheel to slip, a counterclockwise torque would need to be applied to cause the wheel to have some angular acceleration. If the wheel was slipping, then the bottom of the wheel...
  6. Steven Bolgiano

    I Thermodynamic Pros/Cons coating light metal tanks with rubber

    Hi Folks, I promise there is an actual question at the end of this note. I couldn't see where to attach images on this forum page, so here is a link to a rough illustration and a photo of the project site in progress (the cabinet for the digester is partially built)...
  7. G

    Question about humidity and plastic and rubber

    Is it possible to maintain an environment with low humidity to preserve electronic devices from oxidation without this low humidity drying out plastic and rubber from electronic devices and DVD discs that are plastic and in that environment? in my room I have two digital hygrometers and an air...
  8. E

    Restoring force on a ball connected to two rubber bands

    Hello there, I am wondering, in this solution, I guessed that the restoring force is given by that equation in the problem because the vertical component of the force acting on the ball is -2Tsin(x). since sin(x) = y/L with L being the hypotenuse part of the triangle formed by displacing the...
  9. G

    Question UV plastic and rubber

    I have a PS2 Slim 90000 and its case is ABS plastic and it has rubber parts, this device is located on a wooden table, the lights with UV in my house and the sunlight coming into the house will dry out, crack and damage the ABS plastic and the rubber of this device? my house uses LED bulb
  10. shin

    Calculating Friction & Time for a Bullet Penetrating Rubber

    A 7.80 g bullet is initially moving at 500 m/s just before it penetrates a block of solid rubber to a depth of 4.50 cm. (a)What is the magnitude of the average frictional force (in N) that is exerted on the bullet while it is moving through the block of solid rubber? Use work and energy...
  11. S

    Conductivity of hydrogel with rubber silicone in NMES device

    I have a question in regards to a neuromuscular device. Can silicone be combined with hydrogel or the rubber silicone encased in hydrogel to form a wrist watch strap combined with a NMES device. If this is possible how would the hydrogel conduct the NMES device and what is the durability of...
  12. D

    Replicating vulcanised rubber bands?

    How did you find PF?: Via Google search. Hi everyone, I am an enthusiastic vintage wireless restorer/hobbyist attempting to preserve rare and unloved wireless sets from extinction. There seems no limit to the effort I will go to in attempting to faithfully reproduce missing parts in my...
  13. shk

    Properties of materials like rubber bands

    I appreciate some helps with this question. I understand that soft noodles is not as strong as calamari squid and breaks easily . I also know that that calamari squid does not have elastic behaviour since behaves like rubber band and it goes back to it's original shape after reloading. But I'm...
  14. J

    What kind of rubber is "Environmentally Friendly Rubber Material"?

    How many kinds of rubber are there? And what does "Environment Friendly Rubber Material" mean? Hundreds of thousands of babies put these in their mouth and lick them continuously.
  15. J

    Elasticity of a rubber band

    If you take a rubber band and fix it in a stretched position for an extended period of time, would it eventually lose its elasticity? If yes, then how can you calculate how long it would take until its elasticity decreases by a certain amount, say, fifty percent? If no, why not? How does the...
  16. D

    Are fumes from burned rubber bands toxic?

    Hi everyone I think I might have cooked a rubber band that got stuck to the bottom of the bowl of my rice cooker. The rice didn't smell of fumes, and I ate it before noticing the burned bit on the bottom of the bowl. I'm not sure it's a rubber band, but it was very sticky and not crispy like...
  17. terminator 87

    Questions about UV light and dry plastic and rubber

    UV causes dryness of plastic and rubber and lights have UV so keeping it in the dark away from light inside boxes prevents this but notice this photo where the box where the arrows are marked the clarity q enters this region of the closed box is enough for the long term the UV of this clarity...
  18. P

    Heat engine that uses a rubber band (Thermodynamics)

    Nota that the path a to b is isothermal since J is proportional to L, then we can find the value of T_a and T_b using the equation of state and the figure. We have, \begin{equation} J_0=\alpha L_0T_b \end{equation} or \begin{equation} T_b=T_a=\frac{J_0}{\alpha L_0}=T_0 \end{equation} Also, by...
  19. G

    Question about using the Lagrangian for a spinning rubber band problem

    Hello, I am having trouble applying Lagrangian to this problem: 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 ##\omega## about...
  20. Ballbearing101

    Impulse on Rubber and Metal Hammers

    The rubber hammer is more elastic so the time of contact will increase. Ft=m(v-u) Does this mean it is more effective as less force is needed for the same change in momentum of the hammer (and the nail) so it requires less force from you? Or does it mean it is less effective as it imparts less...
  21. L

    B Does a rubber mat on a device prevent static build up

    Does a rubber mat on a device prevent static build up and discharge on a metal device well using it
  22. IamVector

    Ant and rubber band problem

    why can't we use Cartesian coordinates and in which way to proceed?
  23. S

    Correct statement regarding the load vs length graph of a rubber band

    Option (B) is wrong because energy should be received by rubber band when it is being stretched Option (D) is wrong because energy should be released by rubber band when it goes back to natural length The area between graph of stretching and contracting represents energy dissipated in rubber...
  24. P

    Charged metal ball wrapped in rubber or other insulator

    If I have a metal electric conducting ball the size of an average snowball (Happy Holidays) and give it a charge of say 0.1 Coulombs and set it on a wooden table, will it ever discharge if not touched by anything else? If so, if it is wrapped in an electrical insulator, will it ever discharge...
  25. Lidor

    A force exerted on a plastic ball in a rubber tube

    Hello, How can I calculate the force that must be exerted on a ball inside a rubber tube? Thanks
  26. MPavsic

    I Rubber band and a Merry Go Around

    Maybe someone already did this experiment? We have rubber band stretched and attached to the fence of Marry Go Around. When Marry is not rotating we are oscillating rubber band vertically, and oscillation remains vertical. What would happen if we oscillate the rubber band vertically when Marry...
  27. vivek_salman

    Shearing / Cutting Force - Rubber bale

    I have been assigned by my tutor to design a hydraulic guillotine (rubber bale cutter). After designing its features of the hydraulic, cutting blade etc. I tried to calculate the force needed of cutting a piece of Rubber bale (Natural as reference) having an ultimate tensile strength of 30 MPa...
  28. S

    Why does a rubber band's tension grow when stretched?

    My very beginner level understanding is that the rubber band's tension stems from it's particles being held together by it's electric bonds: Atoms and molecules are bound together by their electric charges. And so, When I stretch a rubber band, I am presumably pulling it's particles away from...
  29. R

    Force Required to Stretch a Rubber Band to a Certain Diameter

    Summary: Looking of someone to double check my work on this design issue. I am posting this here because I am no longer a student, but it is similar to a simple homework problem Problem: I am designing a rubber-band like product for a client. He wants to take a durable rubber band and stretch...
  30. jeffinbath

    I Gravity and balls on rubber sheets

    I have never felt comfortable about trying to explain gravitational attraction to children by using heavy balls running around elastic rubber sheets. After all, it is using gravity to explain gravity. It would be so much better to explain it more like it really is, thanks to that originally...
  31. G

    I What's wrong with this approach to the ant on a rubber rope problem?

    Hi. An ant walks with 1 cm/s along a rubber rope with initial length 10 cm that is stretched uniformly with 10 cm/s. Find its velocity at time ##t##. This is a a well-known problem, but I'd like to know what's wrong with the following alternative approach: At time ##t>0##, any point ##x_0## on...
  32. F

    Rubber soled slippers generating static electricity

    I started having this problem with wearing slippers (or any shoes with rubber soles) in the house because the rubber, rubs the carpet and charges me up. Anything metal that I touch gives me a mild-nasty shock depending on how charged up I am. I tried different kinds of slippers and socks, I...
  33. A

    Solving Exercise: Find Thickness of Rubber Insulation for Copper Wire

    Good day all, I tried to solve the following exercise, I would be glad to get feedback for my attempt ( indeed I was puzzled by the numerical solution I got just need to check it for any mistake: A copper wire , 2mm in diameter and 100 m in length has an electrical resistance of 0,5 mΩ/m, the...
  34. G

    Tire rubber durometer rating -- stability

    Hello; I import karting tires from Taiwan , while reviewing a sample tire sent for inspection for our order, I noticed a change in spec. of Duro rating . We spec. them at 65-75D ,this sample came in at 60-65D ..here is the factory response= Hi Gus, The tire factory explained that the tire...
  35. K

    Can you stop rubber from bouncing?

    Is there anyway to stop rubber from bouncing? My class is doing an experiment on material absorption. I have been given the task to stop a rubber ball from bouncing. I was given a rubber ball that weighs 5 and a half ounces and has a circumference of 8 in. My material can't be over an inch...
  36. Muhammad Danish

    B Lead Bullet or Rubber Bullet?

    Which bullet of same momentum is more effective in knocking a bear down? Lead bullet or rubber bullet?
  37. R

    How Natural Rubber (NR) reacts with sulfur?

    Hello My name is ron and i am a mechanical engineering in pump factory. In some project i work on, i have fluent that contains sulfur (less then 10 %). my question is how natural rubber react with sulfur? and if its currect to use natural rubber? thanks
  38. P

    Rubber Properties for Scaffolding Tube Clamping

    I have to make a part that clamps into the inside of the end of a scaffolding tube. I’m thinking of two disk of metal with a disk of rubber sandwiched between and when inside the tube you tighten the bolts pulling the two disks together and squeezing/expanding the rubber so it wedges it’s self...
  39. H

    Rubber strings pulled and realeased -- find the max height

    Homework Statement Homework EquationsThe Attempt at a Solution I tried to find constant k f = k ##\Delta##x 1/2 * 9,8 = k * 0,1 k = 49 N/m is rubber string the same as spring? Ep + EK at 0,1 meter = Ek + EP at 0,3 m 1/2 k x^2 + 0 = 1/2 k x^2 + 1/2 mv^2 v^2 = 2*49(0,08) v = 7*0,4 = 2,8...
  40. J

    Rubber Band Car- Wheel Placement and Center of Gravity?

    I have an odd question after making a rubber band car. I'm wondering if placement of my pairs of wheels has any affect on how fast or how far my car goes. It seems to be a very impractical design, but I do want to know the science behind it. My question is if I move two wheels all the way to...
  41. M

    Rubber Pad Design: Selection & Considerations

    Hello All, Very new to design , especially in material selection and rubber stuff. I have requirement where piston/shaft reciprocates to housing at high speeds. In order to reduce noise and for safety reasons, I must add rubber pads on both. Application as below: Red part is the...
  42. S

    How to determine the force that stretches a rubber band

    Homework Statement Let's put a ball in an empty space with a mass of 280 kg and a radius of 6 meters. Imagine that there is a rubber band around this ball. The initial radial extent of the rubber band is 2 meters. How can I determine the force that stretches the rubber band? And can i say that...
  43. K

    B Ant on a rubber rope problem confusion

    I was reading this wikipedia article: https://en.wikipedia.org/wiki/Ant_on_a_rubber_rope In the analytic solution section, it says that, at time ##t##, a point at ##x=X##, i.e. initially at a distance ##X## from the starting fixed point on a uniformly expanding rope moves with a speed...
  44. Toby_phys

    Adiabatic stretching 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. Prove that: (b) adiabatic stretching of the band results in an increase in temperature; (c) the band will...
  45. B

    Automotive NVH Test for rubber mounts on firewall

    Hello gang! I am dealing with a new issue at work and I though you might give me some much useful insight. Im trying to fix a component to a plate and using 4 screws and rubber bushings to attach said plate to the firewall. The component is around 5-6 kgs and needs to held in place firmly but...
  46. H

    Low damping rubber materials

    Cross posted this in the materials forum but i received nothing so I'm posting it here. << Mentor Note -- OP has been reminded not to cross-post at the PF >> So the application is in a pedal set for a racing simulator cockpit. The brake pedal has a high resolution pressure transducer that...
  47. A
  48. Z

    I How does the physics of a rubber band plane affect its flight?

    Hi all, I am working on a rubber band plane (something like this: http://www.instructables.com/id/Rubber-Band-Powered-Aeroplane/) and I got a question regarding to the physics on these plane. As there is only one propeller and one rubber band, when the rubber band untwist, why doesn’t it rotate...
  49. D

    Why does stretching a rubber band increase its temperature?

    I was reading the Feynman lectures and in one of the chapters on thermodynamics it is stated that stretching a rubber band makes its temperature rise. I feel like I understand the thermodynamics of the rubber band and yet this statement is puzzling me. I believe that when you stretch a rubber...
  50. R

    Potential energy of rubber bands

    <Mentor's note: moved from a general forum and therefore no template> This is the equation of potential energy in rubber bands, however, I don't know how to calculate the inertia of the arm of catapults or get the k constant. And what does n mean? Basically, i don't understand the whole...
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