Renata Lubczak

Copolymerization of hydroxyalkyl methacrylates with acrylamide and methacrylamide. I. Determination of reactivity ratios

The free-radical copolymerization of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 3-chloro-2-hydroxypropyl methacrylate with acrylamide and methacrylamide was investigated. The reactivity ratios of the monomers were determined by the Fineman-Ross and Kelen-Tudos methods.

Novel Phenol-Formaldehyde Resins, 1. Novolaks

New possibilities of preparing phenol-for-maldehyde resins not in direct reactions of the substrates, but in reactions of phenol with multihydroxyl derivatives of some ketones obtained by reacting the latter with excess of formaldehyde are presented. The properties of the new type of products, such as softening point, flow index at 200°C, and time of curing with hexamine wer evaluated. The resins contained in their structure fragments of multihydroxyl derivatives of ketones that made them slightly more flexible than classical novolaks.

Polyurethane Foams with Carbazole Ring

The oligoetherols obtained from carbazole, glycidol and oxiranes or alkylene carbonates were suitable substrates to obtain polyurethane foams. The foams were characterized by measuring their apparent density, water uptake, linear dimension changes and heat conductance. It has been found that polyurethane foams have a more enhanced thermal resistance than polyurethane foams obtained from oligoetherols synthesized from melamine and cyanuric acid and alkylene carbonates.

A study of the reaction of adenine with ethylene oxide or with ethylene carbonate

Abstract A study on the reaction of adenine with ethylene oxide or with ethylene carbonate at different molar ratios of reagents is described. For both pairs of reagents, nominally, the same products were obtained. At first, N (9)-2-hydroxyethyl derivative of adenine was obtained, and then, polyetherols containing purine rings. The main difference between the reactions carried out using the oxide and carbonate was the resulting substitution degree of amine group. The course of both types of reactions was followed using 1 H NMR spectroscopy to determine the contents of amine, hydroxyl, and methylene groups in the products of reactions.

Kinetics and mechanism of reaction between acrylic acid or methacrylic acid and some oxiranes in the presence of N, N‐dimethylaniline catalyst

The reactions of acrylic and methacrylic acids in ethylene oxide, propylene oxide, or glycerin epichlorohydrin were carried out in DMF in the presence of N, N-dimethylaniline catalyst. The kinetic equations describing these equations have been devised and activation parameters ΔH#, ΔS#, and ΔG# calculated. The mechanism of the reaction has been proposed and verified by using kinetic and instrumental methods

Thermally resistant polyurethane foams with reduced flammability

Thermally resistant polyurethane foams containing 1,3,5-triazine ring were modified with additive flame retardants. It has been found that addition of melamine, melamine polyphosphate, or isocyanurate at the foaming step resulted in reduction of foam flammability. The physical properties of flame-retardant modified foams were compared with those of non-modified foams. The obtained modified foams showed oxygen index 22.2–24.2 and were highly thermally resistant even at long lasting 200℃ temperature exposure.

Multifunctional oligoetherols and polyurethane foams with carbazole ring

Abstract A new method of preparation of multifunctional oligoetherols containing carbazole ring is presented. The oligoetherols were obtained in the reaction of 9-(2,3-epoxypropyl)carbazole with sorbitol and oxiranes like ethylene and propylene oxide. The structure of obtained oligoetherols was determined by IR, H-NMR and MALDI-ToF spectroscopies. Physical properties of the products render them good candidates for preparing polyurethane foams. The foams were obtained and their properties were examined. It has been found that the foams are rigid at room temperature and their apparent density was 50–70 kg/m3. The water uptake was low, maximum to 6.5 mass%. Obtained foams have high thermal resistance. Dynamic thermal analysis of these foams showed that 5% mass loss was initiated at 250–300°C, while temperature of 50% mass loss was 370–404°C. Concomitantly the increase of compression strength was observed.

Hydroxyalkylation of Cyclic Imides with Oxiranes Part III. Mechanism of the Reaction in Presence of Sodium Hydroxide Catalyst

The kinetics of reaction between cyclic monoimides (succinimide, phtalimide, and glutarimide) with ethylene and propylene oxides in presence of sodium hydroxide was studied. The effect of substrate and catalyst concentrations on the course of the reaction was investigated. Kinetics of reaction was studied by dilatometry, i.e. by measuring volume contraction of reaction mixture. The kinetic law describing the reaction of imides with oxiranes is: . where ccat, cAH and cB are concentrations of catalyst, imide, and oxirane, respectively. The relative reactivity of imides and oxiranes was: GI > PI ≥ SI and EO > PO. The reaction mechanism was proposed based upon experimentally determined rate law for the reaction of cyclic monoimides and oxiranes as well as analytical and instrumental analysis of products. The elementary reaction between oxirane and imide anion is rate determining step. The imide anion is formed by hydrogen cation transfer into catalytic hydroxide anion from dissociated NaOH. In the consecutive elemental reaction an imidate anion attack on the oxirane molecule occurs. It is the slowest stage of the reaction, limiting the entire process. All the studied reactions obey the same mechanism as can be concluded from isokinetic relationship of studied systems)

Copolymerization of hydroxyalkyl methacrylates with acrylamide and methacrylamide. II. Properties of the copolymers

Copolymers of 2-hydroxyethyl–methacrylate, 2-hydroxypropyl–methacrylate, or 3-chloro-2-hydroxypropyl methacrylate with acrylamide or methacrylamide having different compositions were synthesized by free radical bulk polymerization. Some of their properties, for example, density, polymerization shrinkage, Vicats softening point, glass transition temperature, hardness, and thermal and chemical stability were measured. The effect of the content of acrylamide or methacrylamide units on the properties of copolymers is discussed.