Organometallic compounds as reversible spin scavengers and chain growth regulators in free-radical polymerization processes

2008 ◽  
Vol 50 (3) ◽  
pp. 221-242 ◽  
Author(s):  
D. F. Grishin
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Growth Regulators ◽  
Free Radical Polymerization ◽  
Organometallic Compounds ◽  
Chain Growth

Modelling the Complete Molecular Weight Distribution in Chain Growth Polymerizations

2016 ◽  
Vol 1819 ◽  
Author(s):  
Ramiro Infante-Martínez ◽  
Enrique Saldívar-Guerra ◽  
Odilia Pérez-Camacho ◽  
Maricela García-Zamora ◽  
Víctor Comparán-Padilla
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Radical Polymerization ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Chain Transfer ◽  
Free Radical Polymerization ◽  
Experimental Program ◽  
Chain Growth ◽  
Coordination Polymerization

ABSTRACTThis work shows the development of several models for chain-growth polymerizations that admit the direct calculation of the complete molecular weight distribution of the polymer. The direct and complete calculation implies that no statistical mean values are employed as in the moments method neither numerical approximations like in the minimum-squared based methods. The free radical polymerization of ethylene (LDPE) and the coordination via metallocenes polymerization of ethylene (HDPE) are taken as examples for analysis.In the free radical polymerization case, the conventional scheme for chain-growth polymerization is adopted, with steps for initiation, propagation, chain transfer to small species and the additional step of chain transfer to dead chains [1]. The kinetic parameter are obtained from the open literature. Two kind of reactors were modelled: batch and continuous stirred tank reactor. For this last case, a simulation strategy was considered in which the run started from an initial known population of dead chains. Results show that typical non-linear polymerization profiles for the molecular weight distribution are obtained. For the coordination polymerization of ethylene via metalocenes, the standard coordination model was employed [2]. A two-site catalyst was considered and kinetic parameters reported in the open literature were used. For this study an experimental program in a lab-scale reactor was undertaken in order to obtain modelling data [3]. Results show that the standard model adequately reproduces the experimental data in the kinetic and molecular attributes of the polymer.

scholarly journals Insights on the Atmospheric-Pressure Plasma-Induced Free-Radical Polymerization of Allyl Ether Cyclic Carbonate Liquid Layers

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2856
Author(s):  
Edyta M. Niemczyk ◽  
Alvaro Gomez-Lopez ◽  
Jean R. N. Haler ◽  
Gilles Frache ◽  
Haritz Sardon ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Atmospheric Pressure ◽  
High Resolution Mass Spectrometry ◽  
Free Radical Polymerization ◽  
Monomer Conversion ◽  
Cyclic Carbonate ◽  
Allyl Ether ◽  
Chain Growth ◽  
Plasma Exposure

Plasma-induced free-radical polymerizations rely on the formation of radical species to initiate polymerization, leading to some extent of monomer fragmentation. In this work, the plasma-induced polymerization of an allyl ether-substituted six-membered cyclic carbonate (A6CC) is demonstrated and emphasizes the retention of the cyclic carbonate moieties. Taking advantage of the low polymerization tendency of allyl monomers, the characterization of the oligomeric species is studied to obtain insights into the effect of plasma exposure on inducing free-radical polymerization. In less than 5 min of plasma exposure, a monomer conversion close to 90% is obtained. The molecular analysis of the oligomers by gel permeation chromatography coupled with high-resolution mass spectrometry (GPC-HRMS) further confirms the high preservation of the cyclic structure and, based on the detected end groups, points to hydrogen abstraction as the main contributor to the initiation and termination of polymer chain growth. These results demonstrate that the elaboration of surfaces functionalized with cyclic carbonates could be readily elaborated by atmospheric-pressure plasmas, for instance, by copolymerization.

Non-isothermal Kinetics of Free Radical Polymerization of 2-Phenylethyl (Meth)acrylate

2018 ◽  
Vol 8 (3) ◽  
pp. 585-594
Author(s):  
Khdbudin Mulani ◽  
Ravindra Ghorpade ◽  
Surendra Ponrathnam ◽  
Nayaku Chavan ◽  
Kamini Donde
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Isothermal Kinetics ◽  
Kinetics Of

Oxygen-Initiated Free-Radical Polymerization of Alkyl Acrylates at High Temperatures

2021 ◽  
Author(s):  
Shi Liu ◽  
Lauren Chua ◽  
Ahmad Arabi Shamsabadi ◽  
Patrick Corcoran ◽  
Abhirup Patra ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
High Temperatures ◽  
Free Radical Polymerization ◽  
Alkyl Acrylates
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