Synthesis, isomerization, and polymerization of mixed phosphoranimines

White, Michael L.; Matyjaszewski, Krzysztof

doi:10.1002/(sici)1099-0518(19960130)34:2<277::aid-pola14>3.0.co;2-n

Cited by 13 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Despite the formation of cyclic oligomers and the possibility of explosions, phosphorus azides of the type PAB(N 3 ) are potentially interesting intermediates for the synthesis of mixed-substituent phosphazene homopolymers [NPAB] n , starting from the corresponding phosphorus compounds PABCl or PAB(OR), as shown in Scheme 21. Thus, the two-substituent phosphazene homopolymer [PPh(C 6 H 5 -Me-2)] n was obtained together with variable amounts of cyclic trimer and tetramer in the reaction of the phosphazane PPh(C 6 H 5 -Me-2)(OCH 2 CF 3 ) with SiMe 3 (N 3 ), which gives first the azide PPh(C 6 H 5 -Me-2)(N 3 ) [76] and low-molecular-weight polyphosphazenes have been obtained reacting P(OPh) 3Àn (CF 3 CH 2 O) n (n = 0, 1, 2) or P(OPh) 2 (CH 3 OCH 2 CH 2 O) with azidotrimethylsilane [77]. Studying the reactions with SiMe 3 (N 3 ) of trialkyl or triaryl phosphites P(OR) 3 or the mixed derivatives PR(OR) 2 and PR 2 (OR), it was observed that the resulting polyphosphazenes [NP(OR) 2 ] n , [NPR(OR)] n , or [NPR 2 ] n could be formed by two different pathways.…”

Section: Other Less Common Synthetic Methods For Phosphazene Copolymersmentioning

confidence: 99%

Synthesis and Chemical Regularity in Phosphazene Copolymers

Carriedo

2008

Polyphosphazenes for Biomedical Applications

View full text Add to dashboard Cite

Section: Other Less Common Synthetic Methods For Phosphazene Copolymersmentioning

confidence: 99%

Synthesis and Chemical Regularity in Phosphazene Copolymers

Carriedo

2008

Polyphosphazenes for Biomedical Applications

View full text Add to dashboard Cite

“…Lewis acid catalysts function by coordinating to the monomer carbonyl group and are thus needed in higher concentrations (> 10 mol % of initiator). Zinc dihalides, dialkylaluminum halides, tetraalkylaluminoxanes, and more recently lanthanide triflates and Hgl2 have been used in this capacity (85,90,91). Lewis acid catalysts are preferred for acrylate polymerization, as nucleophilic catalysts have been found to give broader molecular weight distributions.…”

Section: Group Transfer Polymerizationmentioning

confidence: 99%

The Organometallic Polymerization of (Meth)acrylates: An Overview

Boffa

2000

ACS Symposium Series

View full text Add to dashboard Cite

Metal-mediated (meth)acrylate polymerizations provide a good example of the versatility and importance of transition metal catalysis in polymer design. This chapter surveys several of these processes with respect to "living" behavior, experimental condition and monomer restrictions, and types of polymer architectures available.In addition to anionic methods, Group Transfer Polymerization (GTP) with silyl enolates or zirconocenes, organolanthanide-and aluminum porphyrin-initiated polymer ization, and Atom Transfer Radical Polymerization (ATRP) are discussed.Polymethacrylate and polyacrylate materials play an important role in our society. Almost two billion pounds of polymer products based on acrylic esters are produced each year for applications such as window plastics, dental materials, paints, contact lenses, fibers, and viscosity modifiers.Polymethacrylates-particularly poly(methyl methacrylate) (PMMA)-possess high strength, high impact resistance, excellent heat and chemical stability, and a highly amorphous nature which results in excellent optical clarity. For these reasons, they are used widely as building plastics (Plexiglas, Lucite). Polyacrylates are less rigid due to their lower glass transition temperatures, and as latex emulsions form the basis for durable automobile and house paints and coatings. Random copolymers of (meth)acrylates with vinylidene chloride (Sarari), acrylonitrile, and ethylene find applications as clothing fibers, tubing, gaskets, disposable gloves, and heat-and oil-resistant automotive elastomers.Despite the commercial utility of polymethacrylates and polyacrylates, refinements in synthetic methodology these macromolecules have lagged behind that of other polymers. The great majority of acrylic ester products in use today are still produced by radical polymerization, which allows little if any control over the fine points of the polymerization process. This is the result of the traditionally illcontrolled nature of acrylate polymerization. While chain termination and transfer side reactions may be largely eliminated for other monomers, such as styrene and dienes, through the use of controlled anionic polymerization, the (meth)acrylate ester

show abstract

“…Numerous numerical and experimental investigations confirmed the fact that the conventional co‐rotating twin screw extruders provide such symmetry in velocity distributions and shear rates, and at the same time independent flow topologies extend downstream towards the exit, i.e., two two‐tip intermeshed screws form three independent topology paths. [ 1–7 ] As far as mixing is concerned, such symmetry prevents melt from further improving mixing because of lack of symmetry break from the point of view of dynamics. To overcome drawbacks originating from such symmetry, a novel kind of dual‐speed Non‐Twin Screw Extruder (NTSE) was proposed.…”

Section: Introductionmentioning

confidence: 99%

Improving Mixing by Changing Topology Through Intermeshed Perturbation Rings in A Co‐Rotating Non‐Twin Screw Channel

Xu,

Liang,

Xiao

et al. 2023

Macro Theory & Simulations

View full text Add to dashboard Cite

A new kind of perturbation ring element (PRE) was first proposed to introduce a repetitive topology of splitting and recombination across the intermeshing zones of a co‐rotating non‐twin screw elements (NTSE) with a speed ratio of 2. A numerical simulation was performed using finite element method (FEM) along with mesh superposition technique (MST). Post‐treatment codes were successfully developed where fourth‐order Runge‐Kutta scheme was used to achieve particle tracking. For the tracer particle groups released initially from the upper and bottom intermeshing regions, mixing was characterized in terms of evolution of tracer particles, mixing variance index and residence time distribution (RTD). The numerical results revealed for a given output, the larger the screw speed, the larger the dividing ratio, and the better distributive mixing is. PRE achieved the best distributive mixing owing to the changing of flow topology. In TSE there are KAM tubes in which the tracer particles are confined to prevent better mixing occurring.This article is protected by copyright. All rights reserved

show abstract

Synthesis, isomerization, and polymerization of mixed phosphoranimines

Cited by 13 publications

References 5 publications

Synthesis and Chemical Regularity in Phosphazene Copolymers

Synthesis and Chemical Regularity in Phosphazene Copolymers

The Organometallic Polymerization of (Meth)acrylates: An Overview

Improving Mixing by Changing Topology Through Intermeshed Perturbation Rings in A Co‐Rotating Non‐Twin Screw Channel

Contact Info

Product

Resources

About