Functional Chain Transfer Agent and its Application in Block Polymer Synthesis

2015 ◽  
Vol 799-800 ◽  
pp. 475-478
Author(s):  
Xiao Quan Peng ◽  
Chun Ju He
Keyword(s):  
Block Copolymer ◽  
Triblock Copolymer ◽  
Chain Transfer ◽  
Phase Transfer ◽  
Triblock Copolymers ◽  
Reaction System ◽  
Block Polymer ◽  
First Order ◽  
First Order Kinetics ◽  
Raft Agent

In this report, s-1-dodecyl-s’-(α,α’-dimethyl-α’’-dimethyl-α’’-aceticacid) trithiocarbonate (RAFT-COOH) was successfully synthesized by phase transfer catalyst reaction, which was then amidated with diaminopropyl terminated polydimethylsiloxane (NH2-PDMS-NH2) to synthesize PDMS-based macro-RAFT agent to control the synthesis of tri-block copolymer PDMA-b-PDMS-b-PDMA. The successful synthesis of small and macro chain transfer has been confirmed by techniques of FTIR. Moreover, the polymerization to synthesize tri-block copolymer proceeded with first-order kinetics, which showed the reaction system was a controlled/‘living’ polymerization. The triblock copolymers have also been characterized by FTIR, 1HNMR, and GPC techniques, which confirmed the successful synthesis of triblock copolymer.

A Novel Method for the Synthesis of Amphiphilic Copolymer: PHEMA-b-PDMS-b-PHEMA

2014 ◽  
Vol 789 ◽  
pp. 230-234 ◽  
Author(s):  
Jian Feng Xu ◽  
Xiao Quan Peng ◽  
Chun Ju He
Keyword(s):  
Molecular Weight ◽  
Triblock Copolymer ◽  
Reaction System ◽  
Amphiphilic Copolymer ◽  
Good Thermal Stability ◽  
First Order ◽  
H Nmr ◽  
First Order Kinetics ◽  
Novel Method ◽  
Thermal Stability Of

In this study, a novel amphiphilic copolymer based on the flexible polydimethylsiloxane (PDMS) macroinitiator was successfully prepared by atom transfer radical polymerization (ATRP). First, the high molecular weight bis (hydroxyalkyl)-terminated PDMS was prepared by hydrosilation reaction between hydrogen-terminated PDMS and 2-allyloxyethanol in the presence of Karstedt’s catalyst. The macroinitiator Br-PDMS-Br was prepared by the reaction between different molecular weight bis (hydroxyalkyl)-terminated PDMS and 2-bromoisobutyry bromide. Then the amphiphilic ABA-type block copolymers of poly [dimethylsiloxane-b-(hydroxylethyl methacrylate)] were initiated by bromide end-capped PDMS with HEMA, under an appropriate catalyst/ligand system of CuCl/bpy. The polymerization proceeded with first-order kinetics. It showed that the reaction system was a controlled/‘living’ polymerization. The triblock copolymers were characterized by FTIR, 1H-NMR, TGA and GPC techniques. GPC results showed the tribolck copolymer had narrow polydispersity of Mw/Mn (PDI<1.5). TGA results showed the good thermal stability of the triblock copolymer.

Synthesis of Polystyrene-b-poly(n-butyl acrylate)-b-Polystyrene Triblock Copolymers as Binder for Pigment Dyeing

2012 ◽  
Vol 441 ◽  
pp. 473-477
Author(s):  
Lei Yang ◽  
Cheng Jie Hu ◽  
Hai Yang ◽  
Dong Ming Qi
Keyword(s):  
Mechanical Properties ◽  
Butyl Acrylate ◽  
Triblock Copolymer ◽  
Chain Transfer ◽  
Triblock Copolymers ◽  
Polymerization Process ◽  
Fastness Properties ◽  
Copolymer Films ◽  
Reversible Addition ◽  
Dyed Fabrics

Well-controlled polystyrene-b-poly (n-butyl acrylate)-b-polystyrene (PSt-b-PnBA-b-PSt) triblock copolymers were prepared by RAFT (reversible addition-fragmentation chain transfer) emulsion polymerization process. The mechanical properties of the triblock copolymers were investigated in comparison to the P(nBA-co-St) statistical copolymers. When the PSt content is 20%, the ultimate tensile strength of triblock copolymer is nearly six times the strength of statistical copolymer, while their modulus are all around 3.0×103 Pa. The triblock copolymer films feel smooth and non-tacky as the PSt content is higher than 20%. It indicates that PSt-b-PnBA-b-PSt triblock copolymers can be used as binders in pigment dyeing, providing the dyed fabrics with soft non-tacky handle and good fastness properties.

Synthesis, self-assembly and self-healing properties of organic–inorganic ABA triblock copolymers with poly(POSS acrylate) endblocks

2019 ◽  
Vol 10 (19) ◽  
pp. 2424-2435 ◽  
Author(s):  
Bingjie Zhao ◽  
Sen Xu ◽  
Sixun Zheng
Keyword(s):  
Self Assembly ◽  
Triblock Copolymer ◽  
Chain Transfer ◽  
Triblock Copolymers ◽  
Raft Polymerization ◽  
Self Healing ◽  
Reversible Addition ◽  
Aba Triblock Copolymer

A novel organic–inorganic ABA triblock copolymer with a poly(acrylate amide) (PAA) midblock and poly(POSS acrylate) [P(POSS)] endblocks was synthesized via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization.

An amphiphilic block copolymer conjugated with carborane and a NIR fluorescent probe for potential imaging-guided BNCT therapy

2016 ◽  
Vol 7 (26) ◽  
pp. 4411-4418 ◽  
Author(s):  
Zheng Ruan ◽  
Le Liu ◽  
Liyi Fu ◽  
Tao Xing ◽  
Lifeng Yan
Keyword(s):  
Block Copolymer ◽  
Fluorescent Probe ◽  
Triblock Copolymer ◽  
Near Infrared ◽  
Chain Transfer ◽  
Fluorescence Probe ◽  
Reversible Addition ◽  
Nir Fluorescence ◽  
Ring Open ◽  
Nir Dye

A carborane-containing triblock copolymer conjugated with a near infrared (NIR) fluorescence probe has been synthesized via reversible addition fragmentation chain transfer (RAFT), ring open polymerization (ROP), and conjugations of a cyanine NIR dye.

Phase Behavior of Triblock Copolymers upon Incorporation of Non-Parent, Midblock-Associating Additives

1996 ◽  
Vol 461 ◽  
Author(s):  
J. H. Laurer ◽  
J. F. Mulling ◽  
R. Bukovnik ◽  
R. J. Spontak
Keyword(s):  
Molecular Weight ◽  
Block Copolymer ◽  
Phase Behavior ◽  
Triblock Copolymer ◽  
Triblock Copolymers ◽  
Thermoplastic Elastomer ◽  
Low Molecular Weight ◽  
Repulsive Interactions

ABSTRACTAddition of a block-selective homopolymer to a microphase-ordered block copolymer is known to result in preferential swelling of the chemically compatible microdomain. In this work, we examine the miscibility between a triblock copolymer and a relatively low-molecular-weight, chemically dissimilar, midblock-associating homopolymer and demonstrate that the homopolymer molecules residing in the swollen midblock matrix self-assemble to avoid repulsive interactions with neighboring microdomains. We extend this investigation to include systems composed of a very low-molecular-weight, midblock-associating additive (an oil). At high oil concentrations, the glassy copolymer endblocks micellize, resulting in the formation of a thermoplastic elastomer gel.

A New Approach in Kinetic Modeling Using Thermodynamic Framework for Chemically Reacting Systems and Oxidative Ageing in Polymer Composites

2013 ◽  
Author(s):  
K. V. Mohankumar ◽  
K. Kannan
Keyword(s):  
Polymer Composites ◽  
Reaction System ◽  
Gibbs Potential ◽  
New Approach ◽  
First Order ◽  
First Order Kinetics ◽  
Chemically Reacting Systems ◽  
Chemically Reacting ◽  
Reacting Systems ◽  
Single Reaction

A thermodynamic framework for chemically reacting systems is put to use in kinetic modeling of any chemical system with N species undergoing M reactions. A new approach of deriving kinetic models from a Gibbs potential, of multivariate polynomial function, is demonstrated with an example of single reaction system involving three species. Also, the usual first order kinetics is deduced as a special case in the example. The distinct advantages of the new approach lies in obtaining the evolution of concentrations of species, their individual chemical potentials and the specific Gibbs potential and is demonstrated for a single reaction system as an example. Oxidation in polymer composites is studied with a coupled reaction-diffusion model obtained using first order kinetics and is solved for a boundary value problem that predicts the concentration of species over space and time. Concentration of oxidized products is correlated with modulus of aged sample and degradation effects is calculated in case of simple torsion.

scholarly journals Synthesis of Poly(methyl methacrylate) Grafted Multiwalled Carbon Nanotubes via a Combination of RAFT and Alkyne-Azide Click Reaction

2019 ◽  
Vol 9 (3) ◽  
pp. 603 ◽  
Author(s):  
Wenzhong Ma ◽  
Yuchen Zhao ◽  
Zhiwei Zhu ◽  
Lingxiang Guo ◽  
Zheng Cao ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Chain Transfer ◽  
Click Reaction ◽  
Multiwalled Carbon ◽  
Poly Methyl Methacrylate ◽  
First Order ◽  
Pristine Mwcnts ◽  
First Order Kinetics ◽  
Molecular Weight Dependence ◽  
Reversible Addition

An efficient synthesis route was developed for the preparation of multiwalled carbon nanotube (MWCNT) nanohybrids using azide-terminated poly(methyl methacrylate) (PMMA) via a combination of reversible addition fragmentation chain transfer (RAFT) and the click reaction. A novel azido-functionalized chain transfer agent (DMP-N3) was prepared and subsequently employed to mediate the RAFT polymerizations of methyl methacrylate (MMA). The RAFT polymerizations exhibited first-order kinetics and a linear molecular weight dependence with the conversion. The kinetic results show that the grafting percentage of PMMA on the MWCNTs surface grows along with the increase of the reaction time. Even at 50 °C, the grafting rate of azide-terminated PMMA is comparatively fast in the course of the click reaction, with the alkyne groups adhered to MWCNTs in less than 24 h. The successful functionalization of PMMA onto MWCNT was proved by FTIR, while TGA was employed to calculate the grafting degree of PMMA chains (the highest GP = 21.9%). Compared with the pristine MWCNTs, a thicker diameter of the MWCNTs-g-PMMA was observed by TEM, which confirmed the grafted PMMA chain to the surface of nanotubes. Therefore, the MWCNTs-g-PMMA could be dispersed and stably suspended in water.

THE KINETICS OF THE INHIBITED AUTOXIDATION OF TETRALIN

1964 ◽  
Vol 42 (10) ◽  
pp. 2324-2333 ◽  
Author(s):  
J. A. Howard ◽  
K. U. Ingold
Keyword(s):  
Isotope Effect ◽  
Chain Transfer ◽  
Square Root ◽  
Deuterium Isotope Effect ◽  
First Order ◽  
Oxidation Rates ◽  
First Order Kinetics ◽  
A Value ◽  
Root Relation ◽  
Kinetics Of

The kinetics of the inhibition of the autoxidation of tetralin by 2,6-di-t-butyl-4-methylphenol, phenol, and 4-methoxyphenol have been investigated at 65 °C. The highly hindered 2,6-di-t-butyl-4-methylphenol follows simple first order kinetics and exhibits a normal deuterium isotope effect (kH/kD = 10). The kinetics with phenol are complicated by the fact that the phenoxy radical can abstract a hydrogen atom from both tetralin and its hydroperoxide. This leads to oxidation rates which are inversely proportional to the square root of the phenol concentration. The deuterium isotope effect has about the value to be expected in view of this square root relation. The kinetics with 4-methoxyphenol result from chain transfer and from chain termination by the coupling of 4-methoxyphenoxy radicals. The isotope effect varies between zero and a value that approaches the upper limit of about 10 at low inhibitor concentrations.

Preparation of Thermo-Sensitive Supramolecular Hydrogels Formed from MPEG-b-PNIPAM-b-MPEG Triblock Copolymer with α-Cyclodextrin

2014 ◽  
Vol 934 ◽  
pp. 75-79 ◽  
Author(s):  
Xiao Feng Ye ◽  
Mi Zhou ◽  
Jing Ying Hu ◽  
Xin Qian
Keyword(s):  
Triblock Copolymer ◽  
Chain Transfer ◽  
Triblock Copolymers ◽  
Raft Polymerization ◽  
Inclusion Complexation ◽  
Gel Permeation Chromatography ◽  
H Nmr ◽  
Reversible Addition ◽  
Response Interval ◽  
Gel Permeation

To develop a new drug delivery matrix with the suitable responsive interval, a well-defined triblock copolymer MPEG-b-PNIPAM-b-MPEG was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. Then, the supramolecular hydrogels were fabricated via inclusion complexation with α-cyclodextrin (α-CD) and the triblock copolymers in aqueous solutions. The triblock copolymers were characterized by 1H NMR and gel permeation chromatography (GPC), and the supramolecular structures of hydrogels was confirmed by DSC. The resultant hydrogels was found to be thermo-sensitive, and the response interval could be modulated by controlling the content of PNIPAM.

scholarly journals The kinetics of a novel cyclic reaction system and its use in the assay of polynucleotide phosphorylase or adenosine diphosphate plus adenosine triphosphate

1968 ◽  
Vol 106 (4) ◽  
pp. 887-895 ◽  
Author(s):  
R. J. H. Wilson ◽  
M. D. Lilly
Keyword(s):  
Specific Activity ◽  
Reaction System ◽  
Adenosine Diphosphate ◽  
Polynucleotide Phosphorylase ◽  
Quick Method ◽  
First Order ◽  
First Order Kinetics ◽  
Cyclic Reaction ◽  
Optical Assay ◽  
Kinetics Of

1. A sensitive new method is described for the rapid optical assay of polynucleotide phosphorylase in crude bacterial extracts of low specific activity. 2. The assay is non-linear with time and a quick method for determining the approximate activity by using a nomograph is given. 3. The dependence of the assay on Mg2+ concentration was investigated and the conditions that gave first-order kinetics were determined. 4. The theoretical behaviour of the system was examined mathematically and shown to tend to a simple dynamic steady state, under certain conditions. 5. The potential uses of such cyclic systems are discussed.

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