week 7

Question 1

what is elastic

Answer 1

a material that is able to stretch and be reformed back to its original shape or size

Question 2

what is plastic

Answer 2

a material soft enough to be shaped into diffrent forms

Question 3

what is a polymer

Answer 3

this is a material made of large molecules which have many repeated units.

Question 4

how can polymers be reproduced

Answer 4

by a chemcial reaction called polymerization

Question 5

what are 4 natrual polymers

Answer 5

wool, cotton, leather and silk

Question 6

what is a cellulose

Answer 6

a molecule which has hundreds of hydrogen, oxygen and carbon

Question 7

what are most polymers made out of

Answer 7

hydro and carbon

Question 8

what type of bonding do hydro and carbon have

Answer 8

covalent bonding

Question 9

how many electrons does a carbon and hydrogen atom have

Answer 9

both have 2 in the first circle inside

hydrogen has 1 outer and carbon has 4 outer electrons

Question 10

what is the nomenclature for polymer

Answer 10

high morelcure weight, made up of repeat unit (a-a-a-a-a-a-a-a-a-a-a-a-a)

Question 11

what is the nomenclature for monomer

Answer 11

low moleculer weight, which connect to form a polymer

Question 12

what is the nomenclature for oligomer

Answer 12

short chain polymer

Question 13

what is the nomenclature for copolymer

Answer 13

made up of 2 more more monomers

Question 14

what is the nomenclature for alternating copolymer

Answer 14

a-b-a-b-a-b-a-b-a-b-a-b-a-b-a-b-a-b-a-b-a-b-a-b-a-b

Question 15

what is the nomenclature for block copolymer

Answer 15

a-a-a-a-a-a-a-a-a-a-a-a-a-a-b-b-b-b-b-b-b-b-b-b-b

Question 16

what is a addition polymer

Answer 16

formed by an adidtion reacton. monomers bond togther via rearrangments of bondss without loss of atom or moreclue

Question 17

What is a condensation polymer

Answer 17

formed by a condensation reaction, water is lost during the reaction

Question 18

mechanical properties of polymers (4 things)

Answer 18

molecule size and weight
chain configuration
degree if polymerisation
crystallinity

Question 19

do polymers have fixed structures and chain lengths

Answer 19

no, they are not fixed for both.

Question 20

how is the molecule weight determined

Answer 20

by the sum of the atomic weight of each element by the number of atoms in the molecule formula
eg (12 + 4(1)

Question 21

whats a negative about long chains

Answer 21

they exhibit a higher degree of entanglement

Question 22

what is the strength of a polymer correlated to

Answer 22

its correlated to the microstructure, of its chain configuration

Question 23

how is the length of a linear polymer represented

Answer 23

by the degree of polymerisation (the number of (‘mers’) in the chain

Question 24

what 2 things increase when crystallinity increases

Answer 24

tensile strength and youngs modulus

Question 25

what can cause crystalline regions to grow

Answer 25

annealing

Question 26

what to categories do polymers fall into

Answer 26

thermoplastics and thermosets

Question 27

what is a thermoplastic

Answer 27

a polymer that melts when heated and freezes to a glassy state when cooled

Question 28

what is a thermoset

Answer 28

a polymer that decomposes chemically when heated

Question 29

which one tends to be stronger, thermosets or thermoplastic

Answer 29

thermosets

Question 30

thermosets properties (3 things)

Answer 30

large cross-linking hard and brittle does not soften upon heating

Question 31

thermoplastic properties (3 things)

Answer 31

little cross-linking ductile softens upon heating

Question 32

what is a elastomers

Answer 32

a rubber, which can be a thermoset or thermoplastic. featuring excellent flexibility, strength and durability

Question 33

need to see page for extra information

Answer 33

extra info