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Modern Material Science And Engineering 2

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Polymers comprised of two or more different monomer units that attach to the chain in an alternating pattern A-B-A-B...






2. Second- order thermodynamic transition in which the onset of large scale chain mobility occures in polymers. Bellow Tg the polymer is glasslike and brittle. above Tg the polymer becomes rubbery and flexible






3. Arrangement of the largest substituents where the substituets are offset by 120






4. Covalent bonding of the polymer backbone and side groups






5. Polymers that can stretch by 200% or more and still return to their original length when released; polyurethatnes and the aliphatic thermosets(rubbers)






6. Number of repeat/structural units in a polymer chain






7. Specified weight of a polymer that is injected into the mold at the end of the barrel during the injection molding process






8. Softening agents






9. Molecules added to a polymer to enhance or alter specific properties or molecules added to concrete for purposed other than altering a specific property






10. Covalently bonded atoms which are usualy carbon - that comprise the center of the polymer chain.






11. Stiff and extremely inert polymer - low cost - chemical and moisture resistant - outdoor stability






12. Is not asymetric and cannot have multiple configurations






13. Configuration of a polymer in which the sucstituent is located on opposite sides of the molecule in each repeating unit






14. Pigments or dyes that change the way light is absorbed or reflected by a polymer






15. One type of polymer that contains at least 85% of polyacrylonitrile PAN






16. Primary raw material for most polymers






17. Polymers comprised of two or more different monomers that attach to the chain in long runs of one type of monomer - followed by another monomer AAAAAAAAAAAAABBBBBBBBBBBBBBBBBBAAAAAAAA






18. Technique used to make rayon - which involves treating cellulose from wood or cotton with alkali and extruding it through a spinneret






19. Kevlar - Twaron - high tensile strength - lightweight - susceptible to uv degradation - nonconductive - bullet- resistant armor - sports equipment - fire resistance






20. Relative configuration of adjecent asymmetric carbons






21. Double bounded organic molecule used to begin addition polymerization






22. Type of plymer processing similar to extrusion but can be used to develop parts with complex shapes rapidly






23. Peice of the extrusion apparatus that is used as a filter to separate unmelted particles - dirt - and other solid contaminants from the molten polymer






24. Process of pushing polymers through a spinneret and winding the solidified fibers onto a tow - which imposes a shear stress on the fibers upstream as they emerge from the spinneret






25. Process by which chemical cross - linkages can form between adjacent polymer chains - strengthening the material without significantly damaging its elastic properties






26. Small chains of bonded monomers whose properties would be altered by the addition of one more monomer unit






27. Molecule containing a highly reactive unpaired electron






28. Polymer that is made up a single repeat unit






29. Final step in the polymerization process - which causes the elongation of the polymer chain to come to an end






30. Porcess of breaking large organic hydrocarbons into smaller molecules






31. Refers to the spatial geometry of the main chain carbon and substituents that can be changed by rotation and flexural motion






32. Polymers comprised of two or more different monomers - which attach to the polymer chain in no particular order of pattern






33. Coloring agent that is dissolved directly into the polymer - causing the polymer to change color






34. Part of the extrusion apparatus that hols a large quantity of polymer pellets as they are fed into the barrel






35. Term used to describe a polymer that contains significant numbers of both syndiotactic and isotactic dyads






36. Plexiglas - lucite - transparent - shatterproof - biocompatible - hockey rinks - taillights - implants






37. Atoms attached to the polymer backbone.






38. Smallest repeating unit in a polymer. aka repeat unit






39. Polymers that cannot be repeatedly melted and re- formed due to strong covalent bonding between chains






40. On of the two most common reaction schemes used to create polymers - involving three steps: initiaition - propogation - and termination






41. Term associate with blown - film apparatus - which indicated the point at which the molecules develop a more crystalline orientation around the bubble of air






42. High distance- dependent bonding between adjacent polymer chains; usually includes hydrogen bonding - dipoles - and van der waals






43. Broad category of polymers that includes polymers containing urethane linkages






44. Formation of side chains along the backbone; presence of branches disrupts the interactions beween adjacent chains; lowering the tensile strength - melting point - stiffness - crystallinity - and density






45. Occurs when substituent are directly aligned - causing substantial repulsion between the substituents and an unfavorable conformation.






46. Conformation that occurs when the largest substituent in a molecule are offset by 60






47. Term used to represent the average molecular weight of a sample containing a wide range of polymer chain lengths. this term is used to avoid confusion between the number average and the weight molecular average weight






48. Terminating a condensation/step- growth polymerization reaction by adding a material with only one functional group






49. Polymers with low melting poins due to the lack of covalent bonding between adjacent chains. such polymers can be repeatedly melted and re- formed






50. Polymer made up of two of more differenet monomers covalently bonded together