Chain growth polymerization mechanism in polyurethane-forming reactions

RSC Advances ◽  
2015 ◽  
Vol 5 (84) ◽  
pp. 68361-68368 ◽  
Author(s):  
R. Ghoreishi ◽  
G. J. Suppes
Keyword(s):  
Chain Growth ◽  
Growth Mechanisms ◽  
New Approach ◽  
Polymerization Mechanism ◽  
Step Growth ◽  
Catalytic Mechanisms

A new approach simulates alcohol–isocyanate reactions in polyurethane systems: catalytic mechanisms dominate the kinetics and chain growth mechanisms overwhelm step growth.

Polymer Chemistry

2004 ◽  
Keyword(s):  
Conducting Polymers ◽  
Liquid Crystalline ◽  
Polymer Chemistry ◽  
Chain Growth ◽  
Crystalline Polymers ◽  
Wide Range ◽  
Cyclic Oligomers ◽  
Step Growth

Polymer Chemistry: A Practical Approach in Chemistry has been designed for both chemists working in and new to the area of polymer synthesis. It contains detailed instructions for preparation of a wide-range of polymers by a wide variety of different techniques, and describes how this synthetic methodology can be applied to the development of new materials. It includes details of well-established techniques, e.g. chain-growth or step-growth processes together with more up-to-date examples using methods such as atom-transfer radical polymerization. Less well-known procedures are also included, e.g. electrochemical synthesis of conducting polymers and the preparation of liquid crystalline elastomers with highly ordered structures. Other topics covered include general polymerization methodology, controlled/"living" polymerization methods, the formation of cyclic oligomers during step-growth polymerization, the synthesis of conducting polymers based on heterocyclic compounds, dendrimers, the preparation of imprinted polymers and liquid crystalline polymers. The main bulk of the text is preceded by an introductory chapter detailing some of the techniques available to the scientist for the characterization of polymers, both in terms of their chemical composition and in terms of their properties as materials. The book is intended not only for the specialist in polymer chemistry, but also for the organic chemist with little experience who requires a practical introduction to the field.

General procedures in chain-growth polymerization

2004 ◽  
Author(s):  
Najib Aragrag ◽  
Dario C. Castiglione
Keyword(s):  
Free Radical ◽  
Ring Opening ◽  
Point Of View ◽  
Polymerization Process ◽  
Undergraduate Teaching ◽  
Chain Growth ◽  
Reaction Conditions ◽  
Growth Processes ◽  
Reagent Purity ◽  
Step Growth

This chapter is intended to provide a general introduction to the laboratory techniques used in polymer synthesis, by focusing on some relatively well-known polymerizations that occur by chain-growth processes. In this way some of the more commonly used procedures in polymer chemistry are described. Due to the nature of the intermediates produced, such as free radicals, carbanions, carbocations, together with a range of organometallic species, the techniques often involve handling compounds in the complete absence of oxygen and moisture. Because of this the best results may require quite sophisticated equipment and glassware; however, it is our intention to show that the general procedures are accessible to any reasonably equipped laboratory, and indeed some of the techniques are suitable for use in an undergraduate teaching laboratory. Chain-growth polymerization involves the sequential step-wise addition of monomer to a growing chain. Usually, the monomer is unsaturated, almost always a derivative of ethene, and most commonly vinylic, that is, a monosubstituted ethane, 1 particularly where the growing chain is a free radical. For such monomers, the polymerization process is classified by the way in which polymerization is initiated and thus the nature of the propagating chain, namely anionic, cationic, or free radical; polymerization by coordination catalyst is generally considered separately as the nature of the growing chain-end may be less clear and coordination may bring about a substantial level of control not possible with other methods. Ring-opening polymerizations exhibit many of the features of chain-growth polymerization, but may also show some of the features expected from stepgrowth polymerizations. However, it is probably fair to say that from a practical point of view the techniques involved are rather similar or the same as those used in chain-growth processes and consequently some examples of ring-opening processes are provided here. It is particularly instructive to consider the requirements of chain-growth compared to step-growth processes in terms of the demands for reagent purity and reaction conditions.

Synthesis of Thermal Degradable Poly(alkoxyamine) through a Novel Nitroxide Radical Coupling Step Growth Polymerization Mechanism

2014 ◽  
Vol 47 (22) ◽  
pp. 7812-7822 ◽  
Author(s):  
Xuepu Wang ◽  
Jian Huang ◽  
Lingdi Chen ◽  
Yujie Liu ◽  
Guowei Wang
Keyword(s):  
Nitroxide Radical ◽  
Polymerization Mechanism ◽  
Radical Coupling ◽  
Step Growth ◽  
Step Growth Polymerization

Amphiphilic poly(disulfide) micelles and a remarkable impact of the core hydrophobicity on redox responsive disassembly

2015 ◽  
Vol 6 (36) ◽  
pp. 6465-6474 ◽  
Author(s):  
Dipankar Basak ◽  
Raju Bej ◽  
Suhrit Ghosh
Keyword(s):  
Triblock Copolymers ◽  
Triethylene Glycol ◽  
Monomethyl Ether ◽  
Chain Growth ◽  
Glycol Monomethyl Ether ◽  
The Core ◽  
Redox Responsive ◽  
Step Growth

Redox-responsive amphiphilic triblock copolymers based on poly(triethylene glycol monomethyl ether)methacrylate-b-poly(disulfide)-b-poly(triethylene glycol monomethyl ether)methacrylate (PTEGMA-b-PDS-b-PTEGMA) with different hydrophobicities of the PDS block were synthesized by step-growth followed by chain-growth polymerization.

Simultaneous step-growth and chain-growth cationic polymerization of styrenic monomers bearing carbazolyl groups

Polymer ◽  
2017 ◽  
Vol 129 ◽  
pp. 83-91 ◽  
Author(s):  
Irina V. Vasilenko ◽  
Aliaksei A. Vaitusionak ◽  
Jurgita Sutaite ◽  
Ausra Tomkeviciene ◽  
Jolita Ostrauskaite ◽  
...  
Keyword(s):  
Cationic Polymerization ◽  
Chain Growth ◽  
Step Growth
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