Stimuli responsive triblock copolymers by chain-growth polymerization from telechelic macroinitiators prepared via a step-growth polymerization

2014 ◽  
Vol 5 (12) ◽  
pp. 3901-3909 ◽  
Author(s):  
Krishna Dan ◽  
Suhrit Ghosh
Keyword(s):  
Block Copolymers ◽  
Triblock Copolymers ◽  
Chain Growth ◽  
Stimuli Responsive ◽  
Step Growth ◽  
Step Growth Polymerization ◽  
A Chain

The synthesis of stimuli-responsive ABA tri-block copolymers using a step-growth polmerization followed by a chain-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.

Step-growth polymerization—basics and development of new materials

2004 ◽  
Author(s):  
Zhiqun He ◽  
Eric A . Whale
Keyword(s):  
Molecular Weight ◽  
Degree Of Polymerization ◽  
Average Degree ◽  
Chain Growth ◽  
Side Reactions ◽  
Growth Processes ◽  
Molecular Weights ◽  
Reactive Groups ◽  
Step Growth ◽  
Step Growth Polymerization

Step-growth polymerization is often referred to as condensation polymerization, since often—but by no means always—small molecules such as water are released during the formation of the polymer chains. There are a number of differences in the way polymerization occurs in step-growth polymerization compared to chain-growth processes, and these have marked practical implications. The most obvious difference is that, as the name implies, the polymer chain grows in a step-wise fashion; the initial stage of the reaction involves the conversion of monomers to dimers and from these other lower molecular weight oligomers. It is only as the reaction nears completion that significant quantities of higher molecular weight material can be formed. Thus, in order to obtain effective molecular weights, the reaction must proceed almost to completion, indeed the molecular weight (in terms of the number average degree of polymerization xn) of the polymer can be linked to the extent of reaction (p) using eqn (1). Thus, in the simplest case of a difunctional (AB) monomer, when 50% of the available groups have reacted, the number average degree of polymerization is only 2. The consequence of eqn (1) is that high molecular weights in step-growth polymerizations are associated with highly efficient reactions that do not have side-reactions. Notwithstanding this, the types of molecular weights associated with chain-growth processes are not encountered in these processes (except in the case of monomers with more than two reactive groups where hyper-branched or even cross-linked polymers are possible). There is an additional complication, namely the role of cyclization. Kricheldorf has recently shown that under perfect conditions cyclization is the ultimate fate of any polymerization reaction. Thus, under extremely high conversions the prediction given by eqn (1) would overestimate the actual molecular weights produced. Molecules that undergo step-growth polymerization must have at least two reactive functional groups. If the functionality is greater than this, for example, trifunctional, then hyperbranched polymers or even cross-linked systems can be formed. Commonly, this involves the reaction of two different reactive difunctional monomers.

scholarly journals Synthesis and unimolecular micellar behavior of amphiphilic star-shaped block copolymers obtained via the Passerini three component reaction

RSC Advances ◽  
2017 ◽  
Vol 7 (71) ◽  
pp. 45195-45199 ◽  
Author(s):  
S. Oelmann ◽  
M. A. R. Meier
Keyword(s):  
Block Copolymers ◽  
Three Component Reaction ◽  
Step Growth ◽  
Step Growth Polymerization ◽  
Hydrophobic Cores

A series of new amphiphilic star-shaped block copolymers with hydrophobic cores and hydrophilic shells was synthesized, using the Passerini three component step-growth polymerization (Passerini-3CP).

Simultaneous Chain-Growth and Step-Growth Polymerization of Methoxystyrenes by Rare-Earth Catalysts

2016 ◽  
Vol 128 (47) ◽  
pp. 15032-15037 ◽  
Author(s):  
Xiaochao Shi ◽  
Masayoshi Nishiura ◽  
Zhaomin Hou
Keyword(s):  
Rare Earth ◽  
Chain Growth ◽  
Step Growth ◽  
Step Growth Polymerization

scholarly journals Step-growth titanium-catalysed dehydropolymerisation of amine–boranes

2018 ◽  
Vol 9 (13) ◽  
pp. 3360-3366 ◽  
Author(s):  
Titel Jurca ◽  
Theresa Dellermann ◽  
Naomi E. Stubbs ◽  
Diego A. Resendiz-Lara ◽  
George R. Whittell ◽  
...  
Keyword(s):  
Growth Mechanism ◽  
Primary Amine ◽  
Chain Growth ◽  
Step Growth ◽  
A Chain ◽  
Amine Boranes

Titanium-catalysed dehydropolymerisation of primary amine–boranes was found to proceed via a step-growth rather than a chain-growth mechanism.

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