Lecture 5: Polyesters and Polycarbonates

0.0(0)
Studied by 0 people
call kaiCall Kai
Locked
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
GameKnowt Play
Card Sorting

1/18

encourage image

There's no tags or description

Looks like no tags are added yet.

Last updated 12:39 PM on 3/8/26
Name
Mastery
Learn
Test
Matching
Spaced
Call with Kai
Chat

No analytics yet

Send a link to your students to track their progress

19 Terms

1
New cards

What are the two main classes of polyesters?

  • Partly aromatic polyesters: PET, PEN, PBT

  • Aliphatic polyesters: PLA, PGA, PCL, PHA.

2
New cards

What is one way to synthesize polyesters?

Step-growth polymerization with diol and dicarboxylic acid.

Ring opening polymerization of Lactones (such as PLA and PCL)

3
New cards

What are important properties of the ester group in polyesters?

  • susceptible to hydrolysis, aminolysis and ester exchange

  • polar

4
New cards

How do aromatic and aliphatic polyesters differ?

  • Aromatic: stiffer, higher Tg and Tm

  • Aliphatic: more flexible and often biodegradable.

5
New cards

What are the key properties of PET?

  • hard, stiff, strong

  • excellent CO₂ barrier

  • high dimensional stability

  • good chemical resistance

  • relatively low impact resistance.

<ul><li><p>hard, stiff, strong</p></li><li><p>excellent CO₂ barrier</p></li><li><p>high dimensional stability</p></li><li><p>good chemical resistance</p></li><li><p>relatively low impact resistance.</p></li></ul><p></p>
6
New cards

What must be considered when processing PET?

  • hygroscopic, so it must be properly dried before processing.

  • slow crystallization

  • mold shrinkage

7
New cards

What additives are commonly used in PET?

  • nucleating agents

  • glass fibers

  • elastomers

8
New cards

What are the main applications of PET?

  • fibers (largest use)

  • bottles

  • food packaging

9
New cards

What are the key properties of PBT?

  • low water absorption

  • High strength and modulus

  • good solvent resistance.

<ul><li><p>low water absorption</p></li><li><p>High strength and modulus</p></li><li><p>good solvent resistance.</p></li></ul><p></p>
10
New cards

Why are many aliphatic polyesters biodegradable?

Many aliphatic polyesters are biodegradable because their ester bonds can be hydrolyzed, and the flexible aliphatic chains allow water and enzymes to break down the polymer more easily compared to a bulky aromatic polyester.

11
New cards

What characterizes PLA?

  • biodegradable

  • produced from renewable resources

  • used in biomedical and packaging applications.

<ul><li><p>biodegradable</p></li><li><p>produced from renewable resources</p></li><li><p>used in biomedical and packaging applications.</p></li></ul><p></p>
12
New cards

What is the difference between Polyesters VS. Polycarbonates?

knowt flashcard image
13
New cards

What monomers are used to synthesize polycarbonate?

  • Bisphenol-A (BPA)

  • Phosgene

<ul><li><p><strong>Bisphenol-A (BPA)</strong></p></li><li><p><strong>Phosgene</strong></p></li></ul><p></p>
14
New cards

Why does polycarbonate have high Tg and toughness?

Because aromatic rings restrict chain mobility

<p>Because <strong>aromatic rings restrict chain mobility</strong></p>
15
New cards

What are the key properties of polycarbonate?

  • amorphous and transparent

  • veeeeeeery high impact resistance

  • good electrical insulation

16
New cards

What are disadvantages of PC?

  • limited resistance to chemicals and UV

  • more expensive than commodity plastics.

17
New cards

Why must polycarbonate be dried before processing?

Because water causes hydrolytic degradation and foamy products.

18
New cards

What additives are commonly used in PC?

  • UV stabilizers

  • antioxidants

19
New cards

What are common applications of polycarbonate?

  • Bullet proof vests

  • automotive components