Competitive Chain Transfer by .beta.-Hydrogen and .beta.-Methyl Elimination for a Model Ziegler-Natta Olefin Polymerization System [Me2Si(.eta.5-C5Me4)2]Sc{CH2CH(CH3)2}(PMe3)

1994 ◽  
Vol 13 (4) ◽  
pp. 1147-1154 ◽  
Author(s):  
Sharad Hajela ◽  
John E. Bercaw
Keyword(s):  
Chain Transfer ◽  
Olefin Polymerization ◽  
Polymerization System

scholarly journals Visible Light-Controlled Living Cationic Polymerization of Methoxystyrene

2021 ◽  
Author(s):  
Lei Wang ◽  
Shaodong Zhang ◽  
Yongfeng Zhou ◽  
Yupo Xu ◽  
Quan Zuo ◽  
...  
Keyword(s):  
Visible Light ◽  
Cationic Polymerization ◽  
Molar Mass ◽  
Chain Transfer ◽  
Polymerization Reaction ◽  
Great Success ◽  
Living Cationic Polymerization ◽  
Green Led ◽  
Polymerization System ◽  
Lytic System

Photo-controlled living polymerization has received great attention in recent years. However, despite the great success therein, the report on photo-controlled living cationic polymerization has been greatly limited. We demonstrate here a novel decolorable, metal-free and visible light-controlled living cationic polymerization system by using tris(2,4-dimethoxyphenyl)methylium tetrafluoroborate as the photocatalyst and phosphate as the chain transfer agent (CTA) for polymerization of 4-methoxystyrene. This polymerization reaction under green LED light irradiation shows clear living characteristics including predictable molar mass, narrow molar-mass dispersity (Đ = 1.25), and sequential polymerization capability. In addition, the photocata-lytic system exits excellent “on-off” photo switchability and shows the longest “off period” of 36 h up to now for photo-controlled cationic polymerization. Furthermore, the residual photo-catalyst is easily deactivated and decolored with addition of a base after the polymerization.

Suppression of Chain Transfer via Restricted Rotation Effect of Dibenzosuberyl Substituents in Polymerization Catalysis

2021 ◽  
Author(s):  
Shengyu Dai ◽  
Gen Li ◽  
Weiqing Lu ◽  
Yudan Liao ◽  
Weigang Fan
Keyword(s):  
Chain Transfer ◽  
Olefin Polymerization ◽  
Effective Strategy ◽  
Rotation Effect ◽  
Restricted Rotation ◽  
Polymerization Catalysis

The introduction of bulky ortho-steric substituents into α-diimine Ni(II) and Pd(II) species has been often used as an effective strategy to retard the chain transfer in olefin polymerization. In this...

An Exploration of the Effects of Reversibility in Chain Transfer to Metal in Olefin Polymerization

2008 ◽  
Vol 41 (12) ◽  
pp. 4081-4089 ◽  
Author(s):  
Phillip D. Hustad ◽  
Roger L. Kuhlman ◽  
Edmund M. Carnahan ◽  
Timothy T. Wenzel ◽  
Daniel J. Arriola
Keyword(s):  
Chain Transfer ◽  
Olefin Polymerization
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