MS&E #14+15 Polymers

57 flashcards · Physics · by Kristóf Nagy

1. Graft copolymer

   A copolymer with branches of one kind of repeat unit grafted onto a main chain of a different kind of repeat unit.

2. Chain-folded model

   Model describing how polymer chains fold back and forth in a lamellar crystallite.

3. Isotactic configuration

   Configuration of a polymer chain with side groups all on the same side of the backbone.

4. Block copolymer

   A copolymer containing long sequences of one repeat unit separated by shorter sequences of another repeat unit.

5. Molecular structure

   Three-dimensional arrangement of atoms constituting a molecule.

6. Copolymer

   Polymer comprised of two or more types of repeat units.

7. Thermoplastic polymer

   Polymer that becomes softer and flows readily when heated, allowing it to be processed and recycled.

8. Thermosetting polymer

   Polymer that undergoes a chemical change when heated, becoming irreversibly hard and infusible.

9. Saturated

   Describing a compound without double or triple bonds between carbon atoms.

10. Crosslinked polymer

    Polymer with covalent bonds linking individual polymer chains, enhancing rigidity and resistance to melting.

11. Network polymer

    Highly crosslinked polymer with significant three-dimensional connectivity.

12. Molecular weight

    Total mass of a molecule divided by Avogadro's number, indicating the number of atoms or subunits making up the molecule.

13. Functionality

    Number of functional groups available for reaction in a molecule.

14. Trifunctional

    Having three functional groups capable of reacting in a polymerization process.

15. Crystallinity (polymer)

    Presence of ordered, structured regions in a polymer, reflecting tight packing of polymer chains.

16. Isomerism

    Occurrence of multiple structures with the same molecular formula due to different arrangements of constituent atoms or groups.

17. Bifunctional

    Having two functional groups capable of reacting in a polymerization process.

18. Crystallite

    Small, localized domain of tightly packed, ordered polymer chains in a semi-crystalline polymer.

19. Monomer

    Simple molecule serving as the starting material for polymerization, combining to create the polymer chain.

20. Cis (structure)

    Geometric isomer with two identical groups on the same side of a double bond.

21. Unsaturated

    Containing one or more double or triple bonds between carbon atoms.

22. Syndiotactic configuration

    Configuration of a polymer chain with side groups alternating regularly on opposite sides of the backbone.

23. Degree of polymerization

    Extent of polymerization, defined as the ratio of the number of repeat units in a polymer chain to the average number of repeat units per chain.

24. Polymer

    Long, chain-like molecule consisting of repeating subunits known as repeat units.

25. Macromolecule

    Large molecule with a high molecular weight, typically built from repetitive subunits.

26. Stereoisomerism

    Form of isomerism arising from different spatial arrangements of identical atoms or groups in a molecule.

27. Repeat unit

    Basic building block of a polymer chain, representing the smallest recurring unit in the chain's structure.

28. Random copolymer

    A copolymer with a random sequence of two different repeat units distributed along the chain.

29. Atactic configuration

    Configuration of a polymer chain with side groups arranged randomly on both sides of the backbone.

30. Linear polymer

    A polymer with a uniform, unbranched chain.

31. Spherulite

    A semi-crystalline polymer morphology featuring a radial arrangement of folded polymer chains around a central nucleus.

32. Homopolymer

    A polymer consisting of identical repeat units.

33. Branched polymer

    A polymer with side chains branching off the main chain.

34. Alternating copolymer

    A copolymer consisting of alternating sequences of two different repeat units.

35. drawing

    A process involving the permanent mechanical elongation of a fiber in the direction of its axis. Drawing aligns molecular chains and enhances the stiffness and strength of the material.

36. vulcanization

    A chemical reaction in which a polymer is crosslinked by adding sulfur or other crosslinking agents. Improves the mechanical properties and durability of the polymer.

37. viscoelasticity

    A property of materials that exhibits both viscous and elastic behavior when subjected to a stress. Time-dependent strain is observed.

38. ultra-high-molecular-weight polyethylene (UHMWPE)

    A polyethylene with a high molecular weight (>1 million g/mol) and high crystallinity. Has excellent wear resistance and impact strength.

39. thermoplastic elastomer (TPE)

    A polymer blend or block copolymer that behaves as an elastomer at room temperature and as a thermoplastic at elevated temperatures. Can be processed like a thermoplastic but has the elastic recovery of an elastomer.

40. addition polymerization

    A process by which monomers are linked together one at a time in chainlike fashion to form a linear molecule.

41. adhesive

    A substance used to bond together the surfaces of two solid materials (adherends).

42. colorant

    A material added to impart a specific color to a polymer. May be added in the form of dyestuffs or pigments.

43. condensation polymerization

    A process involving stepwise intermolecular chemical reactions that may include more than a single molecular species. Small molecular weight by-products such as water are eliminated.

44. elastomer

    A polymer that can be deformed to large strains and then recover its original shape when the stress is released. Exhibits rubberlike elasticity.

45. fiber

    A material having a high aspect ratio (ratio of length to width) and exceptional strength and stiffness. Used in textiles and composites.

46. filler

    A solid inert material added to a polymer matrix to improve certain properties such as stiffness, impact strength, and dimensional stability.

47. flame retardant

    A material added to a polymer to inhibit ignition and reduce the tendency of the material to burn.

48. foam

    A cellular solid material comprised of cells filled with a gas. Has low density and is used for insulation and buoyancy.

49. glass transition temperature (Tg)

    The temperature at which a polymer transitions from a rigid state to a more flexible state. The glass transition separates the glassy and rubbery regions of the polymer.

50. liquid crystal polymer (LCP)

    A polymer that exhibits mesomorphic properties - i.e., a partially ordered state. Can be used for display screens.

51. melting temperature (Tm)

    The temperature at which a semi-crystalline polymer transitions from a solid state to a liquid state.

52. molding

    A process in which a polymer is shaped by applying heat and pressure to a mold. Examples include injection molding, blow molding, and compression molding.

53. plastic

    A polymeric material that can be shaped by the application of heat and pressure. Generally refers to thermoplastics.

54. plasticizer

    A material added to a polymer to increase its flexibility and workability. Reduces the glass transition temperature of the polymer.

55. relaxation modulus

    A measure of a polymer's stiffness as a function of time. Decreases as the polymer ages and relaxes.

56. spinning

    A process in which a polymer is drawn out into fine threads or fibers. Includes melt spinning, gel spinning, and electrospinning.

57. stabilizer

    A material added to a polymer to prevent degradation due to heat, light, or oxygen. Slows down the aging process of the polymer.