Polymers Flashcards
Chemical compounds with large molecules bonded together in long, repeating chains.
Polymers
Sequentially bonding repeating units in polymers.
Monomers
Polymers offer physical properties such as _____ and _____ that can be desirable in a wide range of uses.
Strength, Elasticity
Polymers properties can be _____ or _____ to a greater degree (compared to metals or other classes of materials).
Controlled, Tailored
Interactions between chains of a polymer lead elements of _____ to the structure of polymers.
Order
Stretching the polymer chains as they form can _____ the amount of order, leading to a degree of crystallinity of the polymer.
Increase
_____ the polymer chains lead to a degree of crystallinity of the polymer.
Stretching
Different degree of _____ can lead to polymers of the same substance that have very different physical properties.
Crystallinity
Chemically bonding chains of polymers to each other can _____ and _____ the substance.
Stiffen, Strengthen
The average number of repeating units in the polymer chain.
Degree of Polymerization
Product of the degree of polymerization and the molecular weight of the repeating unit.
Molecular Weight of a Polymer
Polymers in which the chains fold and make lamellar structure arranged in the regular manner.
Crystalline Polymers
Polymers in which the chains are in the irregular manner.
Amorphous Polymers
A state when the amorphous region of the polymer is at lower temperature.
Glassy State
When a polymer is in glassy state, it is
_____ , _____ , and ______.
Brittle, Hard, Rigid
A state when the polymer is heated.
Rubbery State
When a polymer is in rubbery state, it becomes _____ and _____.
Soft, Flexible
Temperature at which glassy state makes a transition to rubbery state.
Glass Transition Temperature (Tg)
Glass Transition Temperature (Tg) is a property of the _____ materials, or the amorphous region of a ______ materials.
Amorphous, Semicrystalline
Amount of stress required to break the sample.
Strength
Measures the percentage change in the length of the material before fracture.
Percent Elongation to Break (Ultimate Elongation)
Measures the stiffness of the material.
Young’s Modulus (Modulus of Elasticity or Tensile Modulus)
_____ polymers are polymers that occur naturally and exists in living things in nature.
Natural
_____ polymers are man-made polymers made in laboratory through chemical processes.
Synthetic
The types of polymer (based on the structure of their monomer chain) are _____ , _____ , and _____.
Linear, Branched, Cross-Linked
The types of polymers are _____ , _____ , and _____.
Thermoplastics, Thermosetting Polymers, Elastomers
Polymers that melt or deform on heating. (can be repeatedly soften by heating and then solidifies by cooling)
Thermoplastics
Molecules in a thermoplastic are held together by relatively _____ intermolecular forces.
Weak
Polymers that offer increased strength upon heating, and will retain their form and stay solid even under heat.
Thermosetting Polymers
Polymers that can be stretched easily to several times their length and which rapidly return to their original dimensions when the applied stress is released.
Elastomers
The process of creating synthetic polymers by combining small monomer molecules into chains held together by covalent bonds.
Polymerization
In _____ polymerization, small monomer units joined to form a giant polymer.
Addition
Addition polymerization begins with the generation of a _____ , which is normally accomplished by heating a molecule.
Free Radical
In addition polymerization, the free radical repeatedly attacks the _____ bond in a monomer molecule, forming a new radical that now includes one monomer unit.
Double
In _____ polymerization, it involves the elimination of a small molecule, usually water, as each monomer is added to the growing chain.
Condensation
In condensation polymerization, there must be two _____ groups on the monomer, which can react together to form small molecules.
Functional
Condensation polymers are made by joining two subunits through a reaction in which a smaller molecule (often water) is also formed as a by-product. These are also called _____.
Copolymers
_____ copolymers are arranged in a regular,
alternating series.
Alternating
_____ copolymers has regions in the material where a single monomer unit is repeated,
interspersed with other regions where a different monomer is the repeating unit.
Block
In block copolymers, some regions are relatively _____ , whereas others are _____.
Stiff, Flexible
_____ copolymers involve side chains of one polymer attached to a backbone of a different polymer.
Graft
In graft copolymers, both _____ and _____ are attached to a _____ backbone.
Butadiene, Acrylonitrile, Polystyrene
A thermoplastic made from monomer ethylene. It is soft, flexible and melts at a low temperature.
Low-Density Polyethylene (LDPE)
A thermoplastic made from petroleum. It has a higher chemical resistance and can withstand higher temperature.
High-Density Polyethylene
(HDPE)
Thermoplastic polymer used in various applications due to its good chemical resistance.
Polypropylene (PP)
The third-most widely produced plastic that is cheaper and stronger than traditional alternatives such as copper or ductile iron.
Polyvinyl Chloride (PVC)
An aromatic polymer made from the monomer styrene, it has very slow biodegradation
Polystyrene (PS)
A family of synthetic polymers known
genetically as polyamides.
Nylon, Nylon 6, Nylon 66
The amide backbone present in nylon causes
it to be more _____ unlike hydrocarbon polymers.
Hydrophilic
Synthetic fluoropolymer of tetrafluoroethylene.
Teflon (Polytetrafluoroethylene)
Thermoplastic elastomer consisting of linear segmented block copolymers.
Thermoplastic Polyurethanes (TPU)
Plastic with the lowest coefficient of friction.
Teflon (Polytetrafluoroethylene)
