Structural Composition of Butadiene–Styrene Copolymers,According to 1Н and 13С NMR Data

Russian Journal of Applied Chemistry - Commercial samples of butadiene–styrene copolymers were studied by NMR spectroscopy in a magnetic field of 16.4 T (protons Larmor frequency 700 MHz). A...     

Determination of the molecular weight of polyoxypropylenepolyols by <Superscript>1</Superscript>H NMR spectroscopy

Commercial and laboratory samples of polyoxypropylenepolyols were studied by ¹H NMR spectroscopy at operating frequencies of 100 and 500 MHz. Various methods depending on the solvent used were suggested for determining the equivalent weight (molecular weight of the polyether per terminal hydroxy group). The ¹H NMR data are compared to the data obtained by chemical methods and gel permeation chromatography.     

Microstructure of Products of Isoprene Polymerization on Titanium–Magnesium Catalysts: an NMR Study

Russian Journal of Applied Chemistry - Polyisoprenes synthesized on titanium–magnesium catalysts were studied by 1H and 13C NMR spectroscopy (Larmor’s frequency for protons 700 MHz)....     

Kuhn–Mark–Houwink–Sakurada Coefficients for Determination of Molecular Parameters of cis-Polybutadiene Rubbers by Gel Permeation Chromatography

Industrial samples of polybutadiene rubbers with a high (95% or more) content of cis-1,4-units obtained on the neodymium-containing catalysts are studied by GPC and NMR spectroscopy (600 MHz). The GPC data obtained under different experimental conditions are analyzed taking into account the molecular weight calculated from NMR data. As a result, the coefficients of the Kuhn–Mark–Houwink–Sakurada equation for the solutions of cis-polybutadiene rubbers in toluene and tetrahydrofuran are refined.     

Glass-transition temperature and microstructure of polybutadienes

DSC and NMR are employed to determine the glass-transition temperatures and the structural features of polybutadienes with widely varying configuration isomeric compositions. The dependences of the glass-transition temperature on the contents of cis-1,4-, trans-1,4, and 1,2-units in polybutadiene chains are plotted and discussed. An analysis of the experimental results and the published data suggests that, in the study of the glass-transition-structure relationship, simplified approaches are inapplicable and it is necessary to consider the configurational and conformational geometry of polybutadiene chains.     

The structure of chain segments and <Superscript>1</Superscript>H NMR spectra of polychloroprene

The ¹H NMR spectra (working frequencies of 500 and 600 MHz) of polychloroprenes are studied. The spin systems of protons for monomer units of different configurations (1,2, 3,4, 1,4-cis-and 1,4- trans- units), as well as for dyad and triad combinations of 1,4 units, are classified. A high working frequency, the method of double resonance, and the calculation of chemical shifts by empirical increments make it possible to refine the assignment of ¹H NMR signals.     

Determination of the microstructure of polychloroprenes from 1H and 13C NMR data

Commercial samples of chloroprene rubbers were studied by high-resolution NMR spectroscopy (600 MHz). ¹H and ¹³C NMR proved to be efficient in quantitative analysis of the microstructure of polychloroprenes.     

Structure of polyoxypropylene polyols synthesized with basic and dimetal cyanide catalytic systems according to 13C NMR spectroscopic data

¹³C NMR spectroscopy was used to make a comparative characterization of the distribution of polyoxypropylene polyols synthesized on basic (KOH) and dimetal cyanide catalysts over the type of functionality, regioregularity, and stereotacticity.