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Atom radical polymerization

Replacement of Labile Chlorines. When PVC is manufactured, competing reactions to the normal head-to-tail free-radical polymerization can sometimes take place. These side reactions are few ia number yet their presence ia the finished resin can be devastating. These abnormal stmctures have weakened carbon—chlorine bonds and are more susceptible to certain displacement reactions than are the normal PVC carbon—chlorine bonds. Carboxylate and mercaptide salts of certain metals, particularly organotin, zinc, cadmium, and antimony, attack these labile chlorine sites and replace them with a more thermally stable C—O or C—S bound ligand. These electrophilic metal centers can readily coordinate with the electronegative polarized chlorine atoms found at sites similar to stmctures (3—6). [Pg.546]

Allyl alcohol, CH2=CH—CH2OH (2-propen-l-ol) [107-18-6] is the simplest unsaturated alcohol. One hydrogen atom can easily be abstracted from the aHyhc methylene (—CH2—) to form a radical. Since the radical is stabilized by resonance with the C=C double bond, it is very difficult to get high molecular weight polymers by radical polymerization. In spite of the fact that aHyl alcohol has been produced commercially for some years (1), it has not found use as a monomer in large volumes as have other vinyl monomers. [Pg.71]

Photopolymerization reactions are widely used for printing and photoresist appHcations (55). Spectral sensitization of cationic polymerization has utilized electron transfer from heteroaromatics, ketones, or dyes to initiators like iodonium or sulfonium salts (60). However, sensitized free-radical polymerization has been the main technology of choice (55). Spectral sensitizers over the wavelength region 300—700 nm are effective. AcryUc monomer polymerization, for example, is sensitized by xanthene, thiazine, acridine, cyanine, and merocyanine dyes. The required free-radical formation via these dyes may be achieved by hydrogen atom-transfer, electron-transfer, or exciplex formation with other initiator components of the photopolymer system. [Pg.436]

Treatment of 2-methylthiirane with t-butyl hydroperoxide at 150 °C in a sealed vessel gave very low yields of allyl disulfide, 2-propenethiol and thioacetone. The allyl derivatives may be derived from abstraction of a hydrogen atom from the methyl group followed by ring opening to the allylthio radical. Percarbonate derivatives of 2-hydroxymethylthiirane decompose via a free radical pathway to tar. Acrylate esters of 2-hydroxymethylthiirane undergo free radical polymerization through the double bond. [Pg.167]

Studies in the photoinitiation of polymerization by transition metal chelates probably stem from the original observations of Bamford and Ferrar [33]. These workers have shown that Mn(III) tris-(acety]acetonate) (Mn(a-cac)3) and Mn (III) tris-(l,l,l-trifluoroacetyl acetonate) (Mn(facac)3) can photosensitize the free radical polymerization of MMA and styrene (in bulk and in solution) when irradiated with light of A = 365 at 25°C and also abstract hydrogen atom from hydrocarbon solvents in the absence of monomer. The initiation of polymerization is not dependant on the nature of the monomer and the rate of photodecomposition of Mn(acac)3 exceeds the rate of initiation and the initiation species is the acac radical. The mechanism shown in Scheme (14) is proposed according to the kinetics and spectral observations ... [Pg.247]

The facile and reversible reaction of propagating species with transition metal halide complexes to form a polymeric halo-compound is one of the key steps in atom transfer radical polymerization (ATRP, see Section 9.4). [Pg.136]

Traditionally thiols or mercaptans are perhaps the most commonly used transfer agents in radical polymerization. They undergo facile reaction with propagating (and other) radicals with transfer of a hydrogen atom and form a saturated chain end and a thiyl radical (Scheme 6.6). Some typical transfer constants are presented in Table 6.2. The values of the transfer constants depend markedly on the particular monomer and can depend on reaction conditions.4"1 44... [Pg.290]

Some of the more remarkable examples of this form of topologically controlled radical polymerization were reported by Percec et cii.231 234 Dendron maeromonomers were observed to self-assemble at a concentration above 0.20 mol/L in benzene to form spherical micellar aggregates where the polymerizable double bonds are concentrated inside. The polymerization of the aggregates initiated by AIBN showed some living characteristics. Diversities were narrow and molecular weights were dictated by the size of the aggregate. The shape of the resultant macroniolecules, as observed by atomic force microscopy (ATM), was found to depend on Xn. With A, <20, the polymer remained spherical. On the other hand, with X>20, the polymer became cylindrical.231,232... [Pg.443]

The first reports of ATRP (Atom Transfer Radical Polymerization), which clearly displayed the characteristics of living polymerization, appeared in 1995 from the Laboratories of Sawamoto,2 Matyjaszewski266 and Percec.267 The literature on ATRP is now so vast that a comprehensive review cannot be... [Pg.486]

ORl OX w di-Miutyl peroxyoxalalc deactivation by reversible chain transfer and bioinolecular aclivaiion 456 atom transfer radical polymerization 7, 250, 456,457, 458,461.486-98 deactivation by reversible coupling and untmolecular activation 455-6, 457-86 carbon-centered radical-mediated poly nierizaiion 467-70 initiators, inferlers and iriiters 457-8 metal complex-mediated radical polymerization 484... [Pg.605]

Polystyrene-Woc -polysulfone-/ /oc -polystyrene and poly(butyl acrylate)-Woc -polysulfone-/ /oc -poly(butyl acrylate) triblock copolymers were prepared using a macroinitiator.214 The hydroxyl-terminated polysulfone was allowed to react with 2-bromopropionyl bromide, an atomic transfer radical polymerization (ATRP) initiator, in the presence of pyridine. The modified macroinitiator could initiate die styrene polymerization under controlled conditions. [Pg.359]

Cobalt porphyrin complexes are involved in the chain transfer catalysis of the free-radical polymerization of acrylates. Chain transfer catalysis occurs by abstraction of a hydrogen atom from a grow ing polymer radical, in this case by Co(Por) to form Co(Por)H. The hydrogen atom is then transferred to a new monomer, which then initiates a new propagating polymer chain. The reaction steps are shown in Eqs. 12 (where R is the polymer chain. X is CN), (13), and (14)." ... [Pg.290]

Brzezinska KR, Deming TJ (2004) Synthesis of AB diblock copolymers by atom-transfer radical polymerization (ATRP) and living polymerization of alpha-amino acid-N-carboxyan-hydrides. Macromol Biosci 4 566—569... [Pg.25]

In 2003, the van Hest group produced elastin-based side-chain polymers [123]. This research was motivated by the demonstration of the occurrence of an inverse temperature transition in a single repeat of VPGVG [124]. A methacrylate-functionalized VPGVG was synthesized and used as a monomer to perform atom transfer radical polymerization (ATRP) to produce homopolymers (Fig. 16b) or... [Pg.92]

Star polymers are a class of polymers with interesting rheological and physical properties. The tetra-functionalized adamantane cores (adamantyls) have been employed as initiators in the atom transfer radical polymerization (ATRP) method applied to styrene and various acrylate monomers (see Fig. 21). [Pg.229]

Figure 21. Atom transfer radical polymerization (ATRP) synthetic route to tetrafunctional initiators of a star polymer with adamantyl (adamantane core). Taken from Ref. [91] with permission. Figure 21. Atom transfer radical polymerization (ATRP) synthetic route to tetrafunctional initiators of a star polymer with adamantyl (adamantane core). Taken from Ref. [91] with permission.
Polyalkenes form by linking carbon atoms in a free radical polymerization. The polymer structure is constructed by connecting monomer units. The polymerization process converts the bonds of the monomers to a bonds between polymer repeat units. [Pg.901]


See other pages where Atom radical polymerization is mentioned: [Pg.115]    [Pg.32]    [Pg.128]    [Pg.115]    [Pg.32]    [Pg.128]    [Pg.367]    [Pg.103]    [Pg.538]    [Pg.487]    [Pg.500]    [Pg.999]    [Pg.330]    [Pg.331]    [Pg.165]    [Pg.7]    [Pg.185]    [Pg.423]    [Pg.456]    [Pg.486]    [Pg.587]    [Pg.616]    [Pg.616]    [Pg.626]    [Pg.628]    [Pg.637]    [Pg.665]    [Pg.55]    [Pg.136]    [Pg.139]    [Pg.109]    [Pg.2]    [Pg.5]    [Pg.8]   
See also in sourсe #XX -- [ Pg.16 , Pg.115 ]




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Addition polymerization atom transfer radical

Atom Transfer Radical Polymerization (ATRP) Approach to Polymer-grafted CNTs

Atom Transfer Radical Polymerization (ATRP) Process

Atom Transfer Radical Polymerization of Styrenes

Atom transfer radical emulsion polymerization

Atom transfer radical polymerization

Atom transfer radical polymerization (ATRP surface initiated

Atom transfer radical polymerization ATRP)

Atom transfer radical polymerization activation rate constants

Atom transfer radical polymerization active copper complexes

Atom transfer radical polymerization analysis

Atom transfer radical polymerization block copolymers

Atom transfer radical polymerization carbon—halogen bond

Atom transfer radical polymerization chain

Atom transfer radical polymerization chain length dependence

Atom transfer radical polymerization controlled chain lengths

Atom transfer radical polymerization copolymers

Atom transfer radical polymerization crosslinking

Atom transfer radical polymerization deactivation rate constants

Atom transfer radical polymerization dendrimers

Atom transfer radical polymerization disulfide groups

Atom transfer radical polymerization effect

Atom transfer radical polymerization equilibrium

Atom transfer radical polymerization experimental

Atom transfer radical polymerization functional group tolerance

Atom transfer radical polymerization grafting

Atom transfer radical polymerization initiation techniques

Atom transfer radical polymerization materials

Atom transfer radical polymerization mechanism

Atom transfer radical polymerization methacrylate

Atom transfer radical polymerization methacrylate) -based

Atom transfer radical polymerization miniemulsion

Atom transfer radical polymerization parameters

Atom transfer radical polymerization precursors

Atom transfer radical polymerization reactions

Atom transfer radical polymerization regeneration

Atom transfer radical polymerization reverse

Atom transfer radical polymerization ring-opening polymerizations

Atom transfer radical polymerization styrene

Atom transfer radical polymerization synthesis

Atom transfer radical polymerization synthesized

Atom transfer radical polymerization thermodynamics

Atom transfer radical polymerization understanding

Atom-Transfer Radical Addition (ATRA) and Polymerization Reactions (ATRP)

Atom-transfer radical living polymerization

Atom-transfer radical polymerization ATRP) continued)

Atom-transfer radical polymerization inorganic nanoparticles

Atom-transfer radical polymerization methacrylate) synthesis

Atom-transfer radical polymerization modification

Atom-transfer radical polymerization polymers

Atom-transfer radical polymerization star-shaped polymers

Atomic transfer radical polymerization

Biomaterial atom transfer radical polymerization

General Features of Atom Transfer Radical Polymerization (ATRP)

Hyperbranched polymers, atom transfer radical polymerization

Initiators for atom transfer radical polymerization

Macromonomers Obtained by Atom Transfer Radical Polymerization

Methylmethacrylate , atom-transfer radical polymerization

Photoinitiated atom transfer radical polymerization

Polymer Clay Nanocomposites by In-situ Atom Transfer Radical Polymerization

Ring-opening polymerizations atom transfer radical

See atom transfer radical polymerization

Solvent effects, atom transfer radical polymerization

Star polymers, atom transfer radical polymerization

Surface-initiated atom transfer radical polymerization

Surface-initiated atom transfer radical polymerization method

Synthesis of Block Copolymers by Atom Transfer Radical Polymerization, ATRP

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