Polyurethane foams modified with borate and urea groups

W pracy omówiono wyniki badań nad stosowaniem hydroksyetylowych pochodnych mocznika estryfikowanych kwasem borowym, jako składników poliolowych do otrzymywania sztywnych spienionych tworzyw poliuretanowych. Uzyskano pianki poliuretanowe o zmniejszonej palności w stosunku do pianek otrzymywanych z udziałem polioli handlowych. Obniżenie palności pianek wynika z obecności boru i zwiększonej zawartości azotu wskutek użycia poliolu z grupami mocznikowymi. Otrzymane pianki są samogasnące i należą do klasy palności HF-1.The work is concerned with an application of hydroxyethyl urea derivatives modified with borate groups as polyol components for a preparation of foamed polyurethane materials. Obtained rigid polyurethane foams are characterized by the reduced combustibility. The reduction of their flammability results from the presence of boron and increased content of nitrogen in polyurethane foams, because of the use of polyol with urea groups. Obtained foams are self-extinguishing and belong to the combustibility class HF-1

Advanced thermal analysis of poly(N-isopropylacrylamide)

W niniejszej pracy otrzymano równowagowe linie bazowe stanu stałego i ciekłego poli(N-izopropyloakryloamidu) (PNIPA) wykorzystując metody analizy termicznej. Linia odniesienia stanu stałego PNIPA została obliczona na podstawie założenia, że w temperaturze poniżej temperatury przejścia szklistego, eksperymentalne ciepło właściwe polimerów wynika tylko z oscylacyjnych ruchów molekularnych. Ponadto obliczono również równowagową linię bazową stanu ciekłego PNIPA. Na podstawie tak wyznaczonych linii odniesienia obliczono zmianę ciepła właściwego w temperaturze przejścia szklistego.In this paper, solid and liquid reference lines of poly(N-isopropylacrylamide) (PNIPA) were received using thermal analysis methods. The baseline of solid PNIPA was calculated based on the assumption that at a temperature below the glass transition temperature, major contribution to the experimental heat capacity have vibrational motions. Furthermore, the baseline of liquid PNIPA was established, too. On the basis of these reference lines of PNIPA, the change of heat capacity at the glass temperature was calculated

Molecular interpretation of low-temperature heat capacity of aliphatic oligo-urethane

The low-temperature heat capacity of semi-crystalline aliphatic oligo-urethane obtained from the reaction between butane-1,4-diol and hexamethylene 1,6-diisocyanate was measured using a Quantum Design PPMS (Physical Property Measurement System) in the temperature range of (2.04–292.38) K. The experimental heat capacity data below the glass transition temperature of 280.2 K (7.05 °C) were interpreted in terms of molecular motion and were linked to the vibrational spectrum of oligo-urethane structure. The presented approach applies the classical Einstein, Debye and Tarasov treatments using the ATHAS Scheme. The low-temperature solid heat capacity was estimated by separately approximating the group and skeletal heat capacities from their vibrational spectra. The group vibrational heat capacity was calculated based on the chemical structure and molecular vibrational motions (Ngr = 90) derived from infrared and Raman spectroscopy. The skeletal vibrational heat capacity contribution was estimated by a general Tarasov equation with thirty skeletal modes (Nsk = 30). The solution of this equation gave the values of characteristic Debye temperatures as: Θ1 = 493.6 K, Θ2 = 133.9 K, and Θ3 = 51.6 K. The result indicates the existence of planer (Θ2) interactions in the oligo-urethane molecules, in addition to linear (Θ1) and special (Θ3) interactions, which are attributed to a possible branched structure mixed with the linear form of the oligomer. The total vibrational heat capacity, being the sum of the group and skeletal heat capacities, was extended to higher temperatures and analysed further. The liquid heat capacity of semi-crystalline aliphatic oligo-urethane was approximated from experimental data by a linear regression and was compared with the estimated linear contributions of polymers that have the same constituent groups and were expressed as Cp(liquid) = 0.406T + 428.5 in J·K−1·mol−1. The solid and liquid heat capacities of oligo-urethane were applied as equilibrium baselines for advanced thermal analysis of the experimental, apparent heat capacity data. Using estimated parameters of transitions and solid and liquid heat capacities at equilibrium, the integral thermodynamic functions of enthalpy, entropy and free enthalpy as functions of temperature were calculated