What is Polymer: Definition and 109 Discussions

A polymer (; Greek poly-, "many" + -mer, "part")
is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals.
The term "polymer" derives from the Greek word πολύς (polus, meaning "many, much") and μέρος (meros, meaning "part"), and refers to large molecules whose structure is composed of multiple repeating units, from which originates a characteristic of high relative molecular mass and attendant properties. The units composing polymers derive, actually or conceptually, from molecules of low relative molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a definition distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, who spent the next decade finding experimental evidence for this hypothesis.Polymers are studied in the fields of polymer science (which includes polymer chemistry and polymer physics), biophysics and materials science and engineering. Historically, products arising from the linkage of repeating units by covalent chemical bonds have been the primary focus of polymer science. An emerging important area now focuses on supramolecular polymers formed by non-covalent links. Polyisoprene of latex rubber is an example of a natural polymer, and the polystyrene of styrofoam is an example of a synthetic polymer. In biological contexts, essentially all biological macromolecules—i.e., proteins (polyamides), nucleic acids (polynucleotides), and polysaccharides—are purely polymeric, or are composed in large part of polymeric components.

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  1. Y

    Polymer low permeability for balls

    I have 2 interesting questions, I believe, regarding polymer properties. I am designing a ball (pretty much like a basketball in size and appearance) to be used inside pressure vessels for certain corrosive fluids. The ball is inflated with air to a certain pressure in order to cushion extreme...
  2. C

    Charging a 3.7V 110mA Lithium Polymer Battery: Tips and Circuit Guide

    Hi all! I would like to know how to charge a lithium polymber battery of 3.7V, 110mA battery. Anyone has the circuit ? Help! Thank you!
  3. T

    Thin walled polymer balloon deflection

    Hi, I am designing an inflatable balloon (long and thin like those used to make balloon animals) with a purpose to support a force in a manner like a cantilever. I am struggling to find literature/assistance regarding the calculations required to determine balloon deflection under a standard...
  4. S

    Is a tennis ball technically a composite or a polymer?

    Homework Statement Under which class of materials would the following materials be categorized? What are/is the primary bond type(s) in each material/object? a. Tennis Ball Homework Equations The Attempt at a Solution We'll consider a very simple and standard tennis ball...
  5. M

    Polymer with high Coefficient of Friction to Carbon Fiber

    Hey all, I'm trying to design a clamp that has to hold onto a hollow carbon fiber tube, approximately 2.5 inches in diameter. The clamp will be bearing a 15-20lb load. The carbon fiber will be at angles from 20-70 degrees from a vertical axis. I'm curious if there is a polymer that can be...
  6. F

    What is a polymer and when a substance is not a polymer?

    Polymers Polymers are defined as susbtances (natural or artificial) that are composed of smaller units called monomers. These monomers are molecules. Molecules are an aggregation between two or more (similar or different) atoms. That said, why are not all substances polymers? After all...
  7. C

    Designing a polymer coating process

    Hi everybody. My goal is to design a process that, with no automated machinery (I'm using a mechanical pipette), would allow for extremely uniform coverage (that is, with minimal area of multilayers or empty spaces) of a hydrophilic surface with a thin film of polymer solution. I would...
  8. H

    Exploring Polymer Swelling: How Can It Be Controlled?

    can some one discuss this question ? Why does polymer swell ?how can be controoled ? Thanks
  9. C

    Polymer Melt - Learn What It Is and How to Use It

    Hi i wanted to know what are polymer melts. Googling did not help. just had to read this theses which has me pulling my hair over this any help/info/links would be appreciated
  10. R

    Exploring Polymer Blends: Availability and Applications

    I'm looking to get some polymer blend sheets for some tests. Something like PC-ABS or PMMA-PC or something of that nature. Basically a mix of 2 polymers but NOT a co-polymer. Just a simple mix. I looked all over and haven't found anyone selling it. Thanks!
  11. P

    Does Stretching a Polymer Chain Affect Its Energy?

    A polymer model -- 15.4-3 Homework Statement A rubber band consisting of n polymer chains is stretched from zero length to its full extension (L=Na) at constant temperature T. Does the energy of the system increase or decrease? Calculate the work done on the system and the heat transfer to...
  12. S

    Polymer with low solar radiation resistance, high heat resistance

    I'm an engineer student and I'm trying to build such a solar heating system that it is drum with two layers, inner one is a metal (aluminium alloy I'm thinking) water container and outer layer is made of polymer, with air gap in-between. When suns come out, it radiates through the polymer and on...
  13. T

    Sound Channeling Material? Polymer or Other?

    Hey Guys, Been a while since my last visit, as I've been away for a well earnt break.. But recently I've been set a challenge and its baffling me some what, and i wonder if anyone can help pleaseeee:biggrin: Basically long and short of it, a Car Manufacturer has been struggling in...
  14. W

    Wonderful polymer that has very interesting properties

    Hello colleagues! I’d like to ask your opinion on the following information. I found an article where is talking about wonderful polymer that has very interesting properties to pick up parameters when applied on some surface including human body and to register information and to transfer...
  15. K

    Polymer Engineering question related to Von Mises yield criterion

    It is a proof question. Does anyone can tell me how to do this question?question 22.2 it is the question for extra credit for my final exam. thank you so much.
  16. A

    Temperature increment of polymer due to pressure in ultrasonic welding

    Hi, I want to do a very simplified model to try to modelize the change of temperature in ultrasonic welding of polimers. As a starting point, I only want to simulate the change of temperature of a 1D homogeneous polymer (viscoelastic solid) when I apply a constant pressure and ultrasounds...
  17. L

    How to test the creep deformation of polymer

    Dear all, I am Levy , I am glade to take part into physics Forums, I hope I can share my know with everybody and study from you, Thank You! I test the PET of creep deformation recent days, who has some reference about this aspect. Thank you
  18. A

    Viscosity of a viscoelastic polymer

    Hi all This is my first time here and I'm hoping first that I have reached the right forum for my question and that someone out there can help me! I am trying to model the energy dissipation of what is effectively a mass spring damper where the spring and damper are modelling a polymer. I...
  19. J

    Persistence length: What are the beginning and end point in an polymer?

    Persistence length: What are the beginning and end points in an polymer? Hello, can you tell me where the starting point and the ending point of the (parts of the) persistence length in a polymer are? I thought the persistence length was the greatest length that only just is not bent...
  20. S

    Which PVC to choose for polymer nanocomposite?

    Which PVC to choose for polymer nanocomposite? -------------------------------------------------------------------------------- I’m a final year Mehcanical engineering student. For my individual project, I have to fabricate PVC based nanocomposite using nanosilica. I haven’t been provided...
  21. Y

    Statistical Mechanics - One dimensional Polymer

    Homework Statement Consider a polymer formed by connecting N disc shaped molecules into a one dimensional chain. Each molecule can align along either its long axis (of length 2a) or short axis (of length a ). The Energy of the monomer aligned along its shorter axis is higher by e, that is the...
  22. R

    Help in Finding a Polymer that Satisfies Certain Physical Criteria

    Hello all, I am new to these forums and just registered. I plan to be an active participant on here and reciprocate the generosity I've observed in other threads. Im looking for a certain "material" that can satisfy this list of criteria that I've put together. I'm pretty sure that I am...
  23. J

    In the molten polymer tube model, how do I work out the volume of a tube?

    I've got this problem where I've got a molten polymer (polyisoprene) in a region where I can imagine a cubic lattice. I am told that it has a density of 910 kg/m^3 and an entanglement molecular weight of 3.7 kg/mol. earlier in the problem I have to figure out the molecular weight of an isoprene...
  24. H

    Looking for a polymer similar to polycarbonate and ABS

    I am doing a science fair experiment testing the effectiveness of polymers commonly used in football helmets. I am planning on using polycarbonate and ABS, because they are commonly used. However, I am looking for one or two other polymers that are similar in strength and price to add more of...
  25. O

    Polymer volume swelling vs weight gain

    Does the volume swell ratio relate to the weight gain when a crosslinked polymer is emersed in a solvent? Is it as simple as calculating (delta V) = (delta w)/density?
  26. T

    Lagrangian for a polymer, with tension and bending modulus given

    Homework Statement http://www.facebook.com/photo.php?fbid=1612917330439&set=a.1250823718325.2039017.1461460506&ref=fbx_album" The Attempt at a Solution I don't want to ask about the full solution for this thing, but only one thing: in that expression, which is the kinetic energy and...
  27. S

    Equation for number of crosslinked polymer strand in rubber

    I am doing an experiment to estimate N, the number of crosslinked polymer strand in a piece of rectangular rubber. To do this, I attached weights to the rubber and measure the extension of the rubber when subject to the force. However, I found two equations that can be used to find N and they...
  28. K

    Whats the max molecular weight for a single polymer strand of styrne

    Few quick questions, too lazy to look up this info my self: 1. Whats the max molecular weight for a single polymer strand of styrne (i.e what's the max number of styrenes you can link up). 2. Anyone know about the industrial process to produce ABS? 3. What is a good solvent for Styrene...
  29. C

    How Can I Separate My Polymer Reaction Product from the THF/Water Mixture?

    Hi chemistry friends, I'm currently working on a reaction to produce the following polymer: Cyclopentadiene functionalized polyketone. I start with polyketone as a reagent and I should end up with the reaction product together with the solvent (THF) and water with NaOH. My question...
  30. J

    What polymer should I use instead of polycarbonate

    The polymer is to be used for rodent housing (cage). I need to find a polymer which has the properties shown below. Polycarbonate Before I go into the specification required, I have researched and have come up with polycarbonate. As it has high impact strength, is 200x stronger than...
  31. M

    Polymerization of 2-Chloro-2-Butene: Solution

    Homework Statement How would the polymer of 2-chloro-2-butene look when formed by addition polymerization Homework Equations The Attempt at a Solution I have attached my solution. Please tell me if i am right/wrong and why if it is wrong.
  32. W

    Adsorption of polymer question

    Dear all, I'm trying to relate the concentration of moisture in an external environment with the concentration of moisture on the surface of a polymer. This is an adsorption and is it right to relate it using Henry's law? What is the explanation for this? On a side note, what happens when...
  33. C

    Sterchable noncombustible polymer

    i need a very strechable, elastic noncombustible polymer. any suggestions?
  34. 3

    Polymer Properties Question

    Tell me what your ideas are for this multiple choice question Compared to semiconductors, metals, and ceramics, polymers: a) have lower melting points b) tend to have lower densities c) deform plastically to a higher extent d) have lower electrical conductivity e) all of the above f)...
  35. M

    Mass attenuation coefficient of silicone polymer

    I'm trying to work out how much energy from sunlight will be absorbed (converted to heat energy) by a silicone polymer. I need the mass attenuation coefficient (from what I can tell at least) so that I can work out the amount of heat energy the water inside a black silicone polymer container...
  36. T

    Continuous fibre reinforced polymer

    Homework Statement For a continuous fibre reinforced polymer, use a diagram to explain how the Young's modulus of the composite varies with fibre orientation and fibre content. Anywhere i could get any of this information? I've been googling with no success for a while
  37. P

    Flory Huggins theory for linear polymer chains

    Hello everyone. I was wondering if anyone could recommend a source for Flory-Huggins theory on linear polymer chains. You see, I've been conducting an undergraduate research project concerning the topic. Every paper I look at, they simply quote an equation, and says that it follows from FH...
  38. R

    Total internal reflexion on a polymer

    Dear Everyone I am facing the following engineering problem. I "inject" light in a flat (6.5mm) Acrylic panel at the edges of it. Due the different refractive index of the Acrylic material (1.4) and air (1) 90% of the "injected light" experiments total internal reflexion. I need to get the...
  39. Z

    Artificial polymer muscles that contract with electronic/magnetic stimulation?

    Artificial polymer "muscles" that contract with electronic/magnetic stimulation? Hi everyone! First post-- hope this is the right place for it! And just to let you know, I'm not an engineering professional. I'm asking this question based on a speculative industrial design contest for which...
  40. R

    Polymer random walk question

    I understand the mean square end-to-end distance of a polymer of stepsize b and number of units N is given by \left\langle R^{2}\right\rangle = \sum_{i,j=1}^{N} \left\langle r_{i} r_{j}\right\rangle + \left\langle \sum_{i \neq j}^{N} r_{i} r_{j}\right\rangle And that the cross terms drop...
  41. D

    Which UV Radiation Is Most Effective in Polymer Degradation?

    Hi there, does anyone know which type of UV radiation would be most effective in polymer degradation or more importantly jet ink fading. Personally I think it should be UVC as it has the highest energy per photon but I could't find much about it so please help, it's very important as I'm behind...
  42. P

    Polymer: Draw Structural Formula 1,3-Butadiene Z

    Homework Statement Draw the structural formula for a three-monomer segment of poly(1,3-butadiene) in which addition is 1,2 for the middle unit and 1,4 for the outer units, with double bonds Z. Homework Equations Markovnikov's rule: H goes to the Carbon with the most H's The Attempt at a...
  43. G

    Does Simulating 3-D Structures Enhance Polymer Solar Cell Efficiency?

    Is it useful simulating a 3-D structure of a polymer solar cell? Is there a particular internal structure for a polymer solar cell which is most efficient?
  44. E

    Polymer Modelling for Carbon, Nitrogen, Oxygen

    Hi PF,I'm working on a semi-classical model for a group of rather strange polymers based on carbon, nitrogen, and oxygen. In this treatment, I'm approximating the bond length and bond angle to be more or less classical (ie. ball and stick). But I would also like to treat the dihedral angles...
  45. J

    Replacing a lead acid 12 volt battery with a Lithium ion Polymer battery

    I got this idea that I could maybe replace the heavy lead acid battery on my motorcycle with a lithium ion polymer battery. I found that you can buy batteries for RC cars that match the power requirements. The lead acid battery is 12 volts, 6Ah. It seams that L.I.P. batteries for RC cars are...
  46. M

    Entropy of a One Dimensional Polymer

    Homework Statement Polymers are made of very long molecules, usually tangled up in a configuration that has lots of entropy. As a very crude model of a rubber band, consider a chain of N links, each of length l. Imagine that each link has only two possible states, pointing either left or...
  47. S

    Bitumen Polymer: Is it a Polymer?

    Hey I am trying to find out if bitumen is a polymer, and if it is please direct me to resources where I could see its structure.Thanks
  48. K

    Schools Exploring US Universities for Materials Science & Polymer Chemistry

    Hello! I am a junior in a high school. Currently, I am exploring different different colleges and universities, only in the United States and America. Right now, materials science and polymer chemistry is really interests me and I want to know if anyone here can recommend a university...
  49. A

    Hydrophilic polymer that sublimes in vacuum

    I am trying to find a hydrophilic polymer that sublimes in vacuum (~ 10-7 torr). Can anyone help me or tell me where i could find one?
  50. B

    Calculate Polymer Melt Structure Factor - Help Needed

    I'm trying to calculate the structure factor for a polymer melt: S(q)=\sum_{k}\sum_{j}\epsilon^{i*<q>*<r_{kj}>}, but I don't know how to deal with the imaginary exponent...(the rest of the variable don't really matter, because I'm confused about how to deal with the exponent, but q is the...
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