Hanyang Univ. Spring 2008 Chap 12. Zieglar-Natta Catalyst - Before Z-N Catalyst invention, PP...
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Hanyang Univ. Hanyang Univ. Spring 2008 Chap 12. Zieglar-Natta Catalyst Before Z-N Catalyst invention, PP composites were only atactic form After that, isotactic PP composites of extraordinary MW(>10 6 ) is synthesized LDPE = HPPE HDPE PP This has less hardness, stiffness and strength compared to HDPE, but better ductility, Free radical 10 billion lb/yr Use chromium compounds. Zieglar-Natta process is recent application. A few number of branches AlR3, AlHR2 Natta 4 billion lb/yr Characteristic conditions for PP PP and solid catalysts are put together at 50℃ to 90℃ below 5atm. After stopping of reaction, it is washed with H2O or ROH to remove the catalysts. MW is on the control of chain transfer agent E.g.) CO 2 , O 2 , H 2 , H 2 O, … Zieglar-Natta Catalyst
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Transcript of Hanyang Univ. Spring 2008 Chap 12. Zieglar-Natta Catalyst - Before Z-N Catalyst invention, PP...
Hanyang Univ.Hanyang Univ.
Spring 2008
Chap 12. Zieglar-Natta Catalyst
- Before Z-N Catalyst invention, PP composites were only atactic form - After that, isotactic PP composites of extraordinary MW(>106) is synthesized
LDPE = HPPE HDPE PP
This has less hardness, stiffness and strength compared to HDPE, but better ductility, Free radical
10 billion lb/yr
Use chromium compounds.
Zieglar-Natta process is recent application.
A few number of branches
AlR3, AlHR2
Natta
4 billion lb/yr
Characteristic conditions for PP
PP and solid catalysts are put together at 50 to 90 below 5atm.℃ ℃After stopping of reaction, it is washed with H2O or ROH to remove the catalysts.MW is on the control of chain transfer agent
E.g.) CO2, O2, H2, H2O, …
Zieglar-Natta Catalyst
Hanyang Univ.Hanyang Univ.
Spring 2008
Dr. Ziegler and Dr. Natta
Hanyang Univ.Hanyang Univ.
Spring 2008
Assumption: equal site reactivity
TiCl
Cl
ClCl
*
CH2
CH2=CHCH3+ TiCl
Cl
ClCl
*
CH2
CHCH3
CH2
TiCl
Cl
ClCl
*
CH2
HC CH3
Ti
CH2 CHCH3
CH2Ti
*
CH2CHCH3
CH2
open
isotactic syndio
migration
- Monometallic Corsee mechanism
TiCl
Cl
Cl Cl*
open
CH2=CHCH3
MonometallicBimetallic mechanism
Zieglar-Natta Catalyst
Hanyang Univ.Hanyang Univ.
Spring 2008
Ti
CH2
AlR
CHCH3CH2
Ti AlR
CH2
CHCH3
H2C
Ti AlR
CH2
CHCH3
H2C
TiCH
AlR
CHCH3
CH2
β-TiCl3
1 vacancy site => isotactic
2 vacancy sites => atactic 1 vacancy site => isotactic
Bimetallic
TiCl
Zieglar-Natta Catalyst
α-TiCl3
Hanyang Univ.Hanyang Univ.
Spring 2008
Zieglar-Natta Catalyst
This image shows the mechanism by which the Ziegler Natta catalyst polymerizes 1-propene. The image was created by Christine Ann.
Hanyang Univ.Hanyang Univ.
Spring 2008
Polymerization rate
Time
Types of rate curves observed in Ziegler-Natta polymerization: (A) constant; (B) decaying; and (C) decaying to constant
A
B
C
Hanyang Univ.Hanyang Univ.
Spring 2008
A
B
CD
E
Hanyang Univ.Hanyang Univ.
Spring 2008
Chap 13. Polymerization Processes
Homogeneous polymerization
Heterogeneous polymerization
Bulk polymerization
Solution Polymerization
Suspension polymerization
Emulsion polymerization
Hanyang Univ.Hanyang Univ.
Spring 2008
Bulk polymerization
Hanyang Univ.Hanyang Univ.
Spring 2008
Solution Polymerization
Hanyang Univ.Hanyang Univ.
Spring 2008
Suspension polymerization
Hanyang Univ.Hanyang Univ.
Spring 2008
Emulsion polymerization
Hanyang Univ.Hanyang Univ.
Spring 2008
Stages in Emulsion Polymerization
![The structure of Isotactic Polypropylene Crystallized from ... · During the crystallization of isotactic polypropylene, Varga [4] found that, two types of spherulites α-and β-modification.](https://static.fdocuments.in/doc/165x107/5f728cad3c16086d9a751103/the-structure-of-isotactic-polypropylene-crystallized-from-during-the-crystallization.jpg)
![Preparation of Atactic Polypropylene Elastomers With a Cpticl2n[Si(Ch3)3]2mao Catalyst Metallocene](https://static.fdocuments.in/doc/165x107/56d6bf7f1a28ab301696773a/preparation-of-atactic-polypropylene-elastomers-with-a-cpticl2nsich332mao.jpg)
