Concept of Polymers

Question 1

is a molecular compound distinguished by a very high molar mass, ranging into thousands and millions of grams, and is made up of many repeating units

Answer 1

polymer

Question 2

a chemical reaction in which two or more molecules combine to form larger molecules that contain repeating structural units

Answer 2

polymerization

Question 3

polymers can be very resistant to

Answer 3

chemicals

Question 4

polymers can be both

Answer 4

thermal and electrical insulators

Question 5

polymers are very

Answer 5

light in weight with significant degrees of strength

Question 6

plastic is melted in a heating chamber and then forced by a plunger into cold molds to set

Answer 6

injection molding

Question 7

melted polymer is extruded through a die in continuous form to be cut into lengths or coiled

Answer 7

extrusions

Question 8

polymers are materials with a

Answer 8

limitless range of characteristics and colors

Question 9

polymers can be used to make

Answer 9

items that have no alternative from other materials

Question 10

are derived from petroleum oil, and made by scientists and engineers

Answer 10

synthetic polymers

Question 11

occur in nature and can be extracted. They are often water-based

Answer 11

natural polymers

Question 12

are mostly derived from naturally occurring polymers by chemical modifications

Answer 12

semi-synthetic polymers

Question 13

same monomer is repeated throughout the chain of polymer

Answer 13

homopolymer

Question 14

this is also known as heteropolymer as they are composed of two or more different kinds of monomers

Answer 14

copolymer

Question 15

simplest polymer; have linear long polymeric chain of same types of monomer units or simply a chain in which all of the carbon-carbon bonds exist in a single straight line

Answer 15

linear polymers

Question 16

these branches are known as side chains and can also be very long groups of repeating structures.

Answer 16

branched polymers

Question 17

are mostly linear molecules that pack closely together and can assume fairly ordered crystalline structure. It’s rigid and has good tensile strength.

Answer 17

high-density polyethylenes

Question 18

have plenty of side chains branching off polymer molecules. It’s waxy, bendable plastics that are lower melting than HDPE

Answer 18

low-density polyethylene

Question 19

they form long chains, either branched or linear, that can form covalent bonds between the polymer molecules

Answer 19

cross linked and network polymers

Question 20

is a process where the rubber is heated so the sulfur molecules in the rubber polymer chains form covalent bonds with each other

Answer 20

vulcanization

Question 21

who discovered vulcanization?

Answer 21

Charles Goodyear in 1839

Question 22

are also known as heteropolymer as they are composed of two or more different kinds of monomers

Answer 22

copolymers

Question 23

are the condensation of carboxylic acid and amine monomers

Answer 23

polyamides

Question 24

are the condensation of carbocyclic acid and alcohol monomers

Answer 24

polyesters

Question 25

the monomers are arranged in any order such as AABAAABBBBAB

Answer 25

random copolymer

Question 26

two blocks of homopolymers are joined together. It can be represented as AAAAAAABBBBBBB

Answer 26

block copolymer

Question 27

the two monomers are arranged in an alternative way and can be represented as ABABABABAB

Answer 27

alternating copolymer

Question 28

composition of the main chain is a preformed macromolecule and is compositionally or configurationally different from the side
chains or branches w/ repeat units

Answer 28

graft copolymer

Question 29

is an extended application of Nylon; can replace steel ropes and cables

Answer 29

kevlar

Question 30

polymers become soft on the application of heat and thus can be molded in the desired shape

Answer 30

thermoplastics

Question 31

polymers have individual chain bonded covalently during polymerization by application of heat or chemical treatment. The shape cannot be changed and resist subsequent mechanical deformation or heat softening or solvent attack

Answer 31

thermosets

Question 32

is the gradual and reversible transition in amorphous materials from a hard and relatively brittle “glassy” state into a viscous or rubbery state as the temperature is increased.

Answer 32

glass transition

Question 33

are polymers with considerable extensions which are reversible, examples are natural and synthetic rubbers

Answer 33

elastomers

Question 34

are linear macromolecules that are usually suitable for making man-made fibers

Answer 34

fiber-forming polymers

Question 35

two types of polymerization

Answer 35

chain-reaction (addition) and step-reaction (condensation)