Influence Of Monomer Structure Research Articles

Light induced polymer and polymerization reactions, 35. Influence of monomer structure and binder composition on the photoinduced polymerization of multifunctional acrylic esters

AbstractPhotocalorimetry, differential scanning calorimetry and ESR‐spectroscopy were used to analyse the photoinduced polymerization of multifunctional acrylic esters in various polymeric binders. Limiting conversion, maximal polymerization rate, inhibition time, and the time necessary to reach the maximum of the polymerization reaction rate were used to compare the reactivity of the photopolymer systems investigated in this work. Significant correlations exist between the limiting conversion and chemical structure of the acrylic esters used. A relation was also found between the glass transition temperature and oxygen permeability of the binder and the limiting conversion measured calorimetrically. A good correlation does not exist for the other reactivity parameters, because other factors such as phase change and changing diffusion conditions can have a complex influence on those values.

Coordination polymerization of chlorophenyl glycidyl ethers

AbstractResults of investigations on the polymerization of chloropheyl glycidyl ethers containing from one up to five chlorine atoms in the benzene ring, carried out in the presence of coordination initiators Al(OiPr)3/ZnCl2, AlEt3/H2O, AlEt2(OiPr)/H2O and ZnEt2/H2O are presented. Some new isotactic polymers were obtained in this way. The influence of monomer structure and initiator type on the properties of the polymer obtained and on its chain microstructure is discussed.

Copolymers with Pendant Electron-Donor and Electron-Acceptor Groups

Abstract This paper is concerned with charge transfer complex properties of copolymers with pendant electron-donor and electron-acceptor groups obtained by radical copolymerization. The complexing groups were carbazolyl, anthryl, phenothiazinyl, and p-dimethyl-aminobenzyl as electron-donor groups, and picryl, dinitrophenyl, dinitrobenzoyl, and trinitrofluorenyl as electron-acceptor groups. The microstructure of such copolymers, including the tendency to alternating and coisotactic addition, together with the influence of monomer structure and reaction conditions, is discussed. Intramolecular complexation interactions are analyzed. These properties were measured by means of 1H-NMR and electronic absorption spectra. Finally, some physical properties, e.g., color, solubility, density, and photoconductivity, are presented to illustrate the intramolecular and intermolecular complexation interactions. It is concluded that such copolymers are weak charge transfer complexes of the π-π type. They are of theoretical interest for study of the correlation between synthesis, structure, and properties, and of practical interest due to their optoelectric properties.

The influence of monomer structure on polypropylene modification in emulsion

Oxidized isotactic polypropylene powder is chemically modified by monomers of widely differing structure, the reaction being carried out at 30 °C in aqueous emulsion in the presence of a ferrous chelate as an activator. Apart from the polymer bonded to the polypropylene carrier also some homopolymer is formed simultaneously during this heterogeneous polymerization initiated by polypropylene peroxides. The mutual proportion and amount of the resulting polymers may be considerably influenced by the properties of the monomer used, such as by its partial or total solubility in water, its polarity and reactivity as well as by the substituent size. Moreover, the chelate and emulsifier type as well as the presence of organic liquid phase in the system play also an important role. The mechanistic discussion is focused to the early initiation stage of the polymerization. This period, together with the active participation of the monomer, is decisive for the formation of both polymer types produced in the system. The results obtained are in accordance with the observed heterogeneous distribution of -O-O- groups in oxidized polypropylene.

Solid‐state polymerization of acrylamide and its derivatives complexed with some lewis acids. II. Radiation‐induced in‐source polymerization

AbstractRadiation‐induced solid‐state polymerizations of complexes of N‐tert‐butylacrylamide, N‐tert‐amylacrylamide, and N‐tert‐hexylacrylamide with zinc chloride and zinc bromide have been studied. An accelerating effect of temperature and an inhibiting effect of oxygen on the polymerization process were observed. The activation energies have been established. The influence of monomer structure as well as the halide used on the polymerization rate have been discussed and some regularities have been pointed out. The polymers obtained show good solubilities in common solvents, which proves that they are not crosslinked.

Mehrparameterkorrelationen zur Quantifizierung der kationischen Copolymerisation von Styrol und p-substituierten Styrolen

For cationic copolymerization of styrene and p-substituted styrenes the experimental aim values, ratio of monomer reactivity ratios (log(r1/r2)) and average degrees of polymerization (log P), can be connected by linear multiparameter equations with parameters characterizing the influence of monomer structure (Δσp), solvent (ET), the reaction temperature (T) and the catalyst activity (χkat.; eGlas/Kat.). The equations allow qualitative and partially quantitative predictions for the selectivity of the cross-propagation reaction in the copolymerization (log(r1/r2)).

13C NMR sequence analysis, 10. Synthesis and spectroscopic characterization of sequence polypeptides containing taurine, γ‐aminopropanesulfonic acid, and sulfanilic acid

AbstractStarting with benzyloxycarbonyltauryl chloride (1) and benzyloxycarbonylsulfanilyl chloride as well as with glycine ethyl ester and β‐alanine methyl ester several Z‐tripeptides (3a–c, 7a–d) were synthesized. The sulfanilyl peptides 7a–d were converted to the 4‐(isothiocyanato)benzenesulfonyl dipeptides 9a–d, which were condensed to the sequence polymers 10a–d at 140–170°C. From the Z‐tauryl peptides 3a–c the free tripeptides 5a–c were prepared and condensed to the ternary sequence polypeptides 16a–c using the phosphorus triazolides 13 and 14 as condensing reagents. Starting with dipeptides 4a–d and 6a–d the binary sequence polymers 15a–d and 17a–d were obtained in like fashion. The 1H NMR spectra of these oligo‐ and poly‐peptides were recorded in trifluoroacetic acid and 13C NMR spectra of the polypeptides in dimethyl sulfoxide and trifluoroacetic acid. Both 1H NMR and 13C NMR spectra allow characterization of and clear distinction between isomeric oligopeptides, i.e. Z‐Sulf‐Gly‐β‐Ala/Z‐Sulf‐β‐Ala‐Gly, and isomeric polypeptides, i.e. poly(Tau‐γ‐Abu)/poly(γ‐Aps‐β‐Ala) or poly(Tau‐Gly‐β‐Ala)/poly(Tau‐β‐Ala‐Gly). A change of the solvent from dimethyl sulfoxide to trifluoroacetic acid results in a downfield shift of the 13C‐carbonyl signals of the sequence polypeptides by about 10ppm, whereas the other C‐signals show only small effects (<2ppm). The influence of monomer structure, sequence, and solvent on chemical shift is discussed.

Determination of coisotacticities of some alternating styrene–acrylic copolymers by NMR spectra

AbstractCoisotacticities σ for some alternating copolymers were determined through the analyses of their CH3O, CH3 and CH2 proton NMR spectra; styrene–methyl methacrylate (σ = 0.56), styrene‐methyl acrylate (σ = 0.53), styrene–methyl α‐chloroacrylate (σ = 0.69), styrene–methacrylonitrile (σ = 0.19), styrene–methacrylamide (σ = 0.16), α‐methylstyrene–methyl methacrylate (σ = 0.21), and α‐methylstyrene–methyl acrylate (σ = 0.53) were studied. It was found that a terminal model or Bernoullian trial prevails in these complexed copolymerizations with diethylaluminum chloride. The influence of monomer structure on σ values is discussed.