Structure property relationship in polymer

1. Structure Property Relationship of Polymer
Course Title: Advanced Polymer Engineering
Course No: ACCE 503
RASHIDUL ISLAM
ID: 20121107007
Applied Chemistry and Chemical Engineering.
BSMRSTU, Gopalganj.

2. 1. Solubility
• Solubility is the ability of a polymer to dissolve in a solvent.
• Solubility change with change in polymer structure.
– Increases with short branch
– Decreases with long branch
– Decreases with crosslinking
Crosslinked polymer

3. 2. Glass Transition Temperature (Tg)
• The temperature at which a polymer transitions from a hard,
glassy material to a soft, rubbery material.

4. Tg decreases with Chain Flexibility
• Tg depends on the ability of a chain to undergo internal
rotations.
• Higher the freedom of rotation, the more flexible are the
chains.
• Linear polymers with single bonds have high degree of
rotation.
• The presence of aromatics, cyclic structures in backbone
hinder this rotation.

5. Tg decreases with big bulky side groups
• Big bulky side groups can lower the Tg
• The big side groups limit how closely the polymer chains can
pack together. The further they are from each other, the more
easily they can move around.
• We can see this with a series of methacrylate polymers

6. Tg increase with Cross-linking
• cross-linking increases Tg since
• The presence of covalent bonding between chains reduces
molecular freedom
Tg = -93 °C
Tg= 50 °C

7. Tg decreases with Plasticizer
• Plasticizers are small molecules which occupy position
between polymer chains
• To increase flexibility, elongation and to reduce hardness

8. 3. Thermal stability
• Thermal stability is the stability of a polymer at high temperatures.
• Aromatic cyclic chains are more stable than aliphatic carbon
chains at elevated temperatures.
• Polyvinyl fluoride and PVDF are more stable to elevated
temperatures than the corresponding chloride polymers.
polytetrafluoroethylene (PTFE) is highly stable.
• < < <
• Presence of an oxygen or a sulfur atom in the backbones such as
polyphenylene oxide (PPO), polyphenylene sulfide (PPS), and
polyphenylene sulfone are highly stable at elevated temperatures.

9. 4. Tensile strength
• The tensile strength of a polymer quantifies how much stress
the polymer will endure before failing.
• Tensile strength changes with change in polymer structure.
• Branched< Linear< Crosslinked

10. References
• Raymond B. Seymour & Charles E. Carraher, Jr; Structure-
Property Relationships in Polymers
• http://www.socoolglasses.com/definition-of-glass-transition-
temperature/
• http://pslc.ws/macrog/tg.htm
• http://chemistry.tutorvista.com/analyticalchemistry/homopol
ymer.html