polymer mechanism
Post on 13-Jan-2017
1.851 Views
Preview:
TRANSCRIPT
AMITY UNIVERSITY RAJASTHAN
Mechanism of Polymerization
Present BySubhrangsu Sekhar Dey
M.Sc Applied Chemistry
Introduction
Monomers has to be two functionality for polymerization.
Reaction Mechanism
1.Addition or Chain growth
1.1.Radical polymerization
1.2.Cationic polymerization
1.3.Anionic polymerization
2.Condensation or Step growth
Chain-growth Polymerization
Step-growth polymerization
Step Growth V/S Chain Growth
Application
Thermodynamics of Polymerization
Polymerizability of Monomers
Active Intermediates
Substituent Effects V/s Initiator
Free Radical Polymerization
Branching of the Polymer Chain
Application
Cationic Polymerization
the alkene monomerreacts with an electrophile
Application
Anionic Polymerization
Nonterminated chains are called living polymers
The chains remain active until they are killed
Application
Co-ordination Polymerization Ziegler–Natta catalyst
Polymerization of Dienes
Mechanism Of Ziegler Natta Catalysis
Ziegler–Natta catalyst Synthesis of Synthetic Rubber
Ring-Opening Polymerization
Stereochemistry of Polymerization
substituents on the same side
substituents regularly alternate on both sides
General Mechanism of Chain- Growth Polymerization
Progress of a Step-Growth Polymerization
Step Growth Polymerization
Nylon 6,6
Cyclic Ethers
O
O
O
O OO
tertrahydropyrandioxane
polymerization
unreactive
difficult(substituents usually will prevent it)
Cyclic Ethers
A MO
A CH2 CH2 O M
OBuLi
1) Ethylene Oxide
RO
(DMSO)
PEO
Living Polymerization
SCH3
O
H3C
A = HO
R
Cyclic EthersThermo Plastic Elastomer
3,3-bis(azidomethyl)oxetane (BAMO)
O
CH2
CH2 N3
N3
O CH2 C
CH2N3
CH2N3
CH2
3-azidomethyl-3-methyl oxetane (AMMO)
O
CH3
CH2 N3
O CH2 C
CH2N3
CH3
CH2
BAMO AMMO BAMO
Cationic Polymerizationof Cyclic Ethers
OF3C S
O
O
O S CF3
O
O
O
F3C S
O
O
O S CF3
O
O
Difunctional PTMO (initiated by triflic anhydride)
O CH2CH2CH2CH2OF3C S
O
O
S
O
O
CF3
Cyclic AmidesC
N O
H
nCH2
CH2 CH2 N CCH2CH2 CH2
H
O n
CH2 CH2 CCH2CH2 CH2N
O
N
O
H
Na
CH2
CH2
CN
H2C
H2C
H2C
OH
CH2 CH2 CCH2CH2 CH2N
O
N
O
H
H
CH2
CH2
CN
H2C
H2C
H2C
O
+imide dimer: actural initiating species:exo-carbonyl makes it more reactive!Na
CH2
CH2
CN
H2C
H2C
H2C
OH
CH2
CH2
CN
H2C
H2C
H2C
OH
CH2
CH2
CN
H2C
H2C
H2C
O
NaH
Anionic Initiated Polymerization
Siloxanes may be cyclic, linear or cross linked polymer
Cyclosiloxanes
Mechanism of Siloxanes
Ring opening Siloxane
Siloxanes Polymerization
top related