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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. 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






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






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






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






5. Sylon - transparent - shatter proof - biocompatible - hockey rinks - taillights - implants






6. Type of polyamide in which less that 85% of the amide groups are bonded to the aromatic rings






7. Polymer in which more than 85% of the amide groups are bonded to two aromatic rings






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






9. Long chain polymers that contain at least 85% of an ester of a substituted aromatic carboxylic acid. these fibers are strong and can dyed or made transpared






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






11. Additives that cause swelling - which allows the polymer chains to slide past one another more easily - making the polymer softer and more pliable. also used to decrease the viscosity of cement paste to make it easier to flow






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






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






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






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






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






17. One of the two different types of termination in the polymerization process. during this type of termination - the free radicals from two different polymer chains join to end the propogation process






18. 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






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






20. Number of bonds a molecule has formed






21. An acid and an alcohol






22. Large spool that is used to wind solidified polymer fibers after they have been pushed through the spinneret






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






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






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






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






27. Is not asymetric and cannot have multiple configurations






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






29. 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






30. Form of the molecular weight of a sample of polymer chains determined by dividing the mass of the specimen by total number of mols present; always less than weight average molecular weight; all molecules regardless of size correlate well with Mn






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






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






33. Atoms attached to the polymer backbone.






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






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






36. Polymer that is made up a single repeat unit






37. Spatial arrangement of substituents around the main chain carbon atom that can be altered only by the breaking of bonds






38. Formation of a polymer that occurs when two potentially reactive end groups on a polymer react to form a new covalent bond between the polymer chain. this reaction also forms a byproduct - which is typically water






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






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






41. Additives that improve a polymer's resistance to variable that cause bonds to rupture - such as heat and light






42. Second stage of polymerization process during which the polymer chain begins to go as monomers are added to the chain






43. Device used in the processing of polymers that melts polymer pellets and feeds them continuously through a shaping device






44. Conformation in which the largest substituents are offset by 180






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






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






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






48. Two substituents found at both ends of a polymer chain - which have little to no effect on mechanical properties






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






50. First step in the process of polymerization - during which a free radical is formed