Jovan Veličković

The synthesis and characterization of poly(itaconic) acid

SummaryPoly(itaconic acid) (PIA) was obtained indirectly, by the hydrolysis of PIA esters and directly by the polymerization of itaconic acid in water or methanol at 30°C. The first method was not satisfactory but the second gave better results. The elemental composition of the synthetized samples deviated very little from the calculated values. Several crude polymers were fractionated in methanol/isopropanol and the fractions characterized by viscosity and light scattering. The statistically calculated LVN/MW relation, valid for the undissociated polymer, was treated according to the method of Stockmayer and Kurata, to calculate the unperturbed dimensions and to compare them with those of other polymers.

Kinetics of the curing process of alkyd-melamine resin systems

Abstract The aim of this work was to investigate the nature of the curing process of an alkyd-melamine resin mixture, and to determine the kinetic parameters from DSC measurements (Perkin-Euner 2). The experiments were performed using both the dynamic method, with variation of peak exotherm temperature with heating rate, and the isothermal method. A single broad peak was observed in all experiments. Practically no reaction was observed below 350 K. From the dynamic experiments at four heating rates an activation energy of 78.7 kJ mol−1 was obtained. More precise results were obtained from isothermal experiments by scanning the temperature range 415–430 K: a reaction order very close to one, reaction rate constants from 0.76 to 0.85 s−1 and an activation energy of 60.2.

Dilute solution properties of styrene/di-n-alkyl itaconate copolymers

SummarySolution properties of styrene/di-n-butyl itaconate (SDBI), styrene/di-n-hexyl (SDHI) and styrene/di-n-octyl itaconate (SDOI) copolymers from the entire range of copolymer compositions were investigated on series of fractions of uniform composition. Kuhn-Mark-Houwink-Sakurada (KMHS) constants were extrapolated to K⊖ and all results combined with those of styrene/dimethyl itaconate (SDMI) from a previous publication. The σ-parameters describing short range interactions deviate increasingly from the linear summation of parent homopolymer contributions.The excess unperturbed dimensions are correlated with parent homopolymer solubility parameters and discussed in terms of hetero-contacts in the copolymer chain.