Search results for "Mono"
showing 10 items of 6843 documents
N,N-Diallylglycidylamine: A Key Monomer for Amino-Functional Poly(ethylene glycol) Architectures
2012
The first application of N,N-diallylglycidylamine (DAGA) as a monomer for anionic ring-opening polymerization is presented. The monomer is obtained in a one-step procedure using epichlorohydrin and N,N-diallylamine. Both random and block copolymers consisting of poly(ethylene glycol) and poly(N,N-diallylglycidylamine) with adjusted DAGA ratios from 2.5 to 24% have been prepared, yielding well-defined materials with low polydispersities (Mw/Mn) in the range 1.04–1.19. Molecular weights ranged between 2600 and 10 300 g mol–1. Isomerization of allylamine to enamine structures during polymerization depending on time, temperature, and counterion has been realized. The kinetics of the formation o…
4-Vinylphthalic anhydride
1994
4-Vinylphthalic anhydride can be prepared from phthalic acid via bromination and subsequent olefination (Heck-reaction). Homo- and copolymerization with styrene was accomplished using AIBN as initiator. The copolymer compositions were determined by infrared-spectroscopy. The copolymerization parameters are rs=0,15 and rVPA=3,09, the corresponding Q, e values of 4-vinylphthalic anhydride are estimated as Q=3,34 and e=0.09.
Electrically conductive TCNQ complexes of aromatic ionenes
1995
New types of complex salts of 7,7',8,8'-tetracyanoquinodimethane with aromatic ionenes and their model compounds were prepared. The electrical conductivity and the activation energy were measured and discussed in relation to their structure. The effects of the nature of the aromatic unit, and the flexibility and rigidity of the polymer backbone were compared with the corresponding model compounds. The effects of frequency and temperature are discussed in terms of the molecular structure of the complex. The electroconductivity at room temperature of the 1 :1 polymer complex salts was found to be between 2 x 10 -4 and 7 x 10 -5 S/cm, while that of the model complex salts was between 1.3 x 10 …
The anionic copolymerization of 5-(N,N-diisopropylamino)isoprene with styrene
1995
The anionic copolymerization of 5-(N,N-diisopropylamino)isoprene (N,N-diisopropyl-2-vinylallylamine) and styrene initiated with alkyllithium compounds is studied. Copolymers obtained from different compositions are characterized by size-exclusion chromatography (SEC), differential scanning calorimetry and by 1 H NMR and 13 C NMR spectroscopy. Under these conditions the dialkylaminoisoprene, similar to butadiene and isoprene, is more reactive than styrene and is incorporated faster into the polymer backbone. The incomplete conversion of the monomers has been attributed to the formation of intra-or intermolecular complexes between the Li + counterion at the chain end and amino groups. Because…
ABA Triblock Copolymers Based on Linear Poly(oxymethylene) and Hyperbranched Poly(glycerol): Combining Polyacetals and Polyethers
2013
The synthesis of hyperbranched-linear-hyperbranched ABA triblock copolymers based on a linear poly(oxymethylene) (POM) block and hyperbranched poly(glycerol) (hbPG) blocks is described. The polymers containing a polyacetal polyether structure were prepared from linear bishydroxy-functional POM macroinitiators, obtained by cationic ring-opening polymerization of trioxane and 1,3-dioxolane as a comonomer with formic acid as a transfer agent and subsequent hydrolysis of the formate group. Partial deprotonation of the resulting hydroxyl groups permitted “hypergrafting” of glycidol by anionic ring-opening multibranching polymerization (ROMBP). With respect to the hyperbranched blocks, the obtain…
Epifluorescence microscopy studies of fatty acid monolayers: Domain formation induced by polymeric gegenions
1991
The monolayer behavior of long-chain fatty acids at the air/water interface on a poly(ethyleneimine) containing subphase was investigated. The interaction of the polymeric gegenions in the subphase leads to expanded states and permits the visualization of the aggregation behavior of different long-chain fatty acids via fluorescence microscopy. The monolayer morphologies and their variability were intensively studied by fluorescence microscopy. In addition, the transfer of the complexed fatty acid monolayers to solid substrates has been investigated.
Novel polyolefin materials via catalysis and reactive processing
1998
Recent advances in transition metal catalyzed olefin polymerization and melt processing stimulate the production of new polymers derived from old monomers Modern polyolefin processes do not require polymer purification and give excellent control of molecular and supermolecular polyolefin architectures. Progress in catalyst design and preparation of tailor-made homo-and copolymers is highlighted for isotactic, syndiotactic, atactic and stereoblock polypropylene (PP), novel 1-olefin copolymers, and ethylene copolymers with polar monomers, e.g., CO and acrylics Today polyethylene short-and long-chain-branching is controlled either by uniform ethylene copolymerization with 1-olefins using singl…
Interfaces in immiscible polymer blends: A Monte Carlo simulation approach on the CRAY T3E
1999
Polymeric materials pose a challenge for Monte Carlo simulations because of the widely spread length and time scales involved. Using large scale computer simulations we investigate the interfacial structure in a partially compatible polymer mixture. The problem is studied in the framework of a coarse grained lattice model - the bond fluctuation model on the simple cubic lattice, choosing N = 32 and lattice linear dimensions L × L × D up to 512 × 512 × 64. We employ a two dimensional geometric decomposition scheme to implement this algorithm on the CRAY T3E. The algorithm scales very well with the number of processors. The structure of polymer coils near interfaces between coexisting phases …
Structure and dynamics of grafted polymer layers: A Monte Carlo simulation
1991
The bond fluctuation model of polymer chains on lattices is used to study layers of polymers anchored with one end at a hard wall, assuming good solvent conditions and repulsive interactions between the monomers and the wall. Chain lengths from N=10 to N=80 and grafting densities σ from 0.025 to 0.20 are considered, both for the ‘‘quenched’’ case, where the anchor points are kept fixed at randomly chosen surface sites, and the ‘‘annealed’’ case, where lateral diffusion of the anchored ends at the wall is considered. Profiles of monomer density and free end density, chain linear dimensions parallel and perpendicular to the wall, as well as corresponding mean square displacements of inner and…
Translocation dynamics of a short polymer driven by an oscillating force
2013
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