Surface properties of silica gel samples modified by selected proteins

The adsorption of a polar (water) and a non-polar (n-octane) liquid on silica gels, modified by adsorption of proteins, has been studied by thermal analysis. Silica gels with physically adsorbed BSA and ovalbumin layers were used. Thermodesorption energies were determined from Q-TG and Q-DTG curves recorded under quasi-equilibrium conditions. Significant differences in liquid desorption were observed from the surfaces due to heterogeneous changes (energetic and geometrical) as a result of modification. These results are compared with those obtained for the samples heated at 160°C for 1 h.     

Studies of sorption properties of porous copolymers of 1-vinyl-2-pyrrolidone

Sorption of water, n-butanol and n-heptane into different porous copolymers of 1-vinyl-2-pyrrolidone was studied by thermogravimetry. It was shown that differences in interactions of these adsorbates with copolymers of different surface area and polarity can be monitored by this technique. The relative thermodesorption plot was introduced and used to analyze thermogravimetric data.     

Crystal structure of olanzapine and its solvates. Part 3. Two and three-component solvates with water, ethanol, butan-2-ol and dichloromethane

Crystalline solvates of olanzapine (1), 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5]benzodiazepine, have been characterized by an X-ray analysis and thermal (DSC) data. Crystallization of 1 from ethanol gives a solid containing both water and ethanol molecules; the solvate 1 · H₂O · EtOH (2:2:1) is monoclinic with the space group P2₁/c and the unit-cell volume V = 3752.8(12) Å³. Butan-2-ol forms with 1 solvate which is also a three-component phase, 1 · H₂O · BuOH, but its stoichiometry is different (1:1:1). The space group for this crystal is P2₁/c and the unit-cell volume V = 2216.5(7) Å³. Crystalline olanzapine dichloromethane solvate (2:1), 1 · CH₂Cl₂, is triclinic with the space group .The characteristic feature of all crystal structures is presence of a pair of olanzapine molecules which form dimer stabilized by multiple weak C–Hπ interactions between the N-methylpiperazine fragment and the phenyl / thiophene systems. Theoretical calculations have been performed indicating that the total C–Hπ binding energy is about 8 kcal mol⁻¹. In the crystal structure, the self-assembled olanzapine molecular dimers are arranged into parallel crystal planes. Packing of the layers proceeds in two ways in which structural motives are replicated by (i) perpendicular translation forming columns, and (ii) rotation around the twofold screw axis (parallel to the layer).     

Studies of thermal properties of di(methacryloyloxymethyl)naphthalene–divinylbenzene (DMN–DVB) copolymer and its alkyl-bonded derivatives

This paper presents the thermal properties of highly crosslinked di(methacryloyloxymethyl)naphthalene–divinylbenzene (DMN–DVB) copolymeric microspheres containing polar groups in the structure and their alkyl-bonded derivatives. C₈ and C₁₈ alkyl chains were introduced into the aromatic rings of the DMN–DVB porous copolymer by means of the Friedel–Crafts reaction. As a source of C₈ and C₁₈ alkyl chains, octyl and octadecyl chlorides were used. It was necessary to check whether the introduction of alkyl chains into the structure of polymeric packing had an impact on its thermal properties. The studies were carried out by thermogravimetry coupled online with FTIR spectroscopy and differential scanning calorimetry in inert atmosphere (helium). It was stated that the modified materials showed 20 and 50% mass losses at higher temperatures than the non-modified one while 1% mass loss was observed at lower temperatures. Moreover, an analysis of volatile decomposition products was performed.

     

Sorption on porous copolymers of 1-vinyl-2-pyrrolidone-divinylbenzene

Sorption properties of porous copolymers 1-vinyl-2-pyrrolidone-divinylbenzene (VP-DVB) were investigated by thermogravimetry. Water, n-butanol and n-heptane were used as sorptives. The current studies were performed for VP-DVB copolymers which were synthesized under different condition and vary in terms of porous structure. Additionally, VP-DVB 5 sample has more polar character comparing with other samples. It was demonstrated that porous structure of the adsorbent has the fundamental impact on the adsorption process but not only the value of specific surface area but also the pore diameter plays important role. Sorption of water is enhanced by the presence of micropores and polar character of the adsorbent.     

TG/DSC studies of modified 1–vinyl-2-pyrrolidone–divinylbenzene copolymers

In this paper, the synthesis and characterization of porous copolymers of 1-vinyl-2-pyrrolidone with divinylbenzene are presented. They were obtained by suspension polymerization as pure polymers or composite materials with different inorganic fillers. The influence of the type of filler on the textural and thermal properties was investigated in detail. It was found that the value of the porous surface area and the degree of double bonds’ conversion of composites are much lower than in the case of pure copolymers. Thermal properties of the obtained materials were investigated by the means of thermogravimetry and differential scanning calorimetry.