Basic polymer science

Question 1

When picking a polymer you consider which three things and what aspect of the polymer dictates these things?

Answer 1

Performance, Manufacture, cost.

Chemical structure

Question 2

What are the two major groups of polymers and what are the basic steps in making them?

Answer 2

Thermoset: resin + catalyst, mixed together, a cure reaction resulting in a solidified thermoset
Thermoplastic: solid stocks/granules, heated, reshapen, mixed etc into a finished product

Question 3

Are polymers organic or inorganic compounds?

Answer 3

organic

Question 4

In which 4 ways are the chemical structure of polymers usually represented?

Answer 4

1)schematic solid ball model, 2)stick and ball model, 3)2-d simplification of stick and ball model, 4)simple structure model

Question 5

Poymers form large molecules made from multitudes of what?

Answer 5

small repeating units (mers)

Question 6

What is the process between a monomer and polymer?

Answer 6

bonds on a monomer breaks forming an intermediate or mer group which makes up a polymer

Question 7

What are two main fundamental groups of polymers?

Answer 7

Thermoplastics, and thermosets

Question 8

what is the alternative name for thermoplastic?

Answer 8

linear polymer

Question 9

what is the alternative name for a thermoset polymer?

Answer 9

network polymer

Question 10

In order of highest to lowest influence, which 3 length scales are important with regards to the mobility of a polymer

Answer 10

Intramer(structure of the mer groups), Intramolecular(the way the mers form polymer chains), Intermolecular (how different polymer chains interact

Question 11

What aspects of a monomer with regards to its chemical structure, dictate how they bind to form Polymer molecules?

Answer 11

the elements present, the type of covalent bonds that can be formed between mers (single/double etc)

Question 12

How will the presence of double bonds and bulky side groups in a monomer affect its polymer?

Answer 12

they result in an inflexible and bulky polymer molecule, the resulting reduction of molecular flexibility results in increased stiffness of the solid and viscosity of its melt

Question 13

Describe three possible intramolecular structures for a polymer chain

Answer 13

isotactic;side groups all on one side
syndiotactic;side groups on alternating sides
atactic;random sides for side groups

Question 14

with regards to intramolecular structure, increasing entanglement results in what?

Answer 14

inhibited mobility of molecules, increased stiffnes and melt viscosity

Question 15

How does the number of “ends” in a solution affect polymers properties? why?

Answer 15

it doesn’t as there are very few

Question 16

the typical number of mers making up a chain is measured by what?

Answer 16

molecular weight (Mw)

Question 17

How does the average molecular weight of a polymer affect its propeerties?

Answer 17

increased Mw stiffness and viscosity also increase

Question 18

what type of bonds are formed between polymer molecules?

Answer 18

secondary bonds ( van der waals, hydrogen, dipole-dipole)

Question 19

If you had a polymer melt (held above it Tm) how would you cool the melt to obtain a semicrystalline polymer and an Amorphous polymer? describe the make up of the polymer chains

Answer 19

Semicrystalline: slow cooling, chains are in a regular crystalline formation with close packing of molecules (higher density)
amorphous: quench, results in a random arrangements of polymer chains (tangled)