Polymers I

Question 1

What are polymers?

Answer 1

Large, sometimes complex, molecules of repeat units of the same structure linked together by covalent bonds.

Question 2

Polymers are long-chain molecules frequently composed of thousands of repeat units called?

Answer 2

Monomers.

Question 3

How are polymers structurally represented?

Answer 3

Parentheses around the monomer unit, with degree of monomerization indicated by the subscript to the right.

Question 4

Polymers are sold as different grades and employ a numerical designator that reflects?

Answer 4

The average molecular weight of the polymer chains or a physical property related to the molecular weight.

Question 5

What is a true crystalline solid?

Answer 5

A highly ordered molecular structure characterized by densely packed, folded, and aligned segments.

Question 6

Why do we refer to polymers as semi-crystalline?

Answer 6

They are too big to easily arrange into repeat patterns and overlap in in periodically organized regions, while other portions are amorphous and randomly organized.

Question 7

What do polymers grow as?

Answer 7

Sphearilite, consisting of organized, folded polymers separated by entangled, connecting links having no discernable order.

Question 8

Highly irregular, branched polymers are _____________ prohibited from forming the periodic organization needed to consider them crystalline.

Answer 8

Thermodynamically.

Question 9

What reflects how polymers will be used in pharmacy?

Answer 9

The degree of crystallinity.

Question 10

Amorphous solid API are less physically ________ and tend to recrystallize and revert to the less soluble form.

Answer 10

Stable.

Question 11

Why does an API dissolve faster in its solidified, amorphous form?

Answer 11

There are fewer non-covalent bonds to be broken between molecules to send API into solution.

Question 12

What prevents the recrystallization of the API and increases its solubility profile?

Answer 12

An amorphous solid dispersion that incorporates API molecules into the amorphous region of a water-soluble polymer.

Question 13

Polymers that consist of only one type of monomers are called?

Answer 13

Homopolymers.

Question 14

What does a co-polymer combine?

Answer 14

Different monomers together in a process called co-polymerization.

Question 15

What are random co-polymers?

Answer 15

When different monomers add to the chain randomly.

Question 16

What are alternate co-polymers?

Answer 16

Monomers are added to the chain in an alternating fashion.

Question 17

What are graft co-polymers?

Answer 17

A block polymer is added to a homopolymer backbone.

Question 18

What are block co-polymers?

Answer 18

Two or more chemically distinct polymer blocks covalently bonded together.

Question 19

The glass transition temperature is an indicator of what?

Answer 19

Molecular mobility.

Question 20

At low temperature, the mobility of the polymer is very low and the polymer is termed?

Answer 20

Glassy or brittle.

Question 21

At higher temperatures, the mobility of the polymer chains is higher, making the molecules more flexible. What is this region called?

Answer 21

The rubbery region.

Question 22

What does the glass transition temperature represent?

Answer 22

The transition between the glassy and rubbery regions.

Question 23

The glass transition temperature is important to a class of excipients known as?

Answer 23

Plasticizers.

Question 24

Without plasticizers, what would polymers be constrained to?

Answer 24

The “brittle region” at room temperature.

Question 25

Hydrophilic polymers can be used as _________ to set the rheological properties at a specific value.

Answer 25

Viscosifiers.

Question 26

When added to an aqueous solution, what part of the polymer becomes hydrated?

Answer 26

Hydrophilic functional groups.

Question 27

What does hydration of a polymer result in?

Answer 27

A viscous, thick mixture characterized by resistance to flow.

Question 28

What describes the movement of a solute through a specific medium occurring at a specific rate?

Answer 28

Einstein's random walk theory.