In this paper, we report on the physicochemical characterization of hydrogels recently obtained b... more In this paper, we report on the physicochemical characterization of hydrogels recently obtained by crosslinking poly (vinylalcohol), PVA, with telechelic PVA (telPVA, bearing terminal aldehydic groups) via acetalization in aqueous solution. These gels were studied by equilibrium swelling, compression modulus measurements, and proton relaxometry experiments. Swelling and compression modulus data allow to estimate the average molecular weight of PVA chain between crosslinks, the average mesh size of the networks, and the polymer-solvent interaction parameter 1 . The average mesh size of PVA-telPVA compares well with domain dimensions of diffusionally confined water as detected by NMR relaxometry. Proton relaxometry also showed different network domains in which water is compartmentalized, indicating a complex heterogeneity. The study of the temperature behavior of the nuclear spin-spin relaxation times of the confined water was also considered.
ABSTRACT The approach for calculating the adsorption free energy and adsorption energy distributi... more ABSTRACT The approach for calculating the adsorption free energy and adsorption energy distributions for a heterogeneous solid surface as the sum of two uniform functions directly from co-ordinates of the tail of the probe’s chromatographic peak is presented and discussed. Distribution functions are derived from data collected for the series of test adsorbates (n-alkanes C5—C10 and five polar organic compounds) by means of inverse gas chromatography at finite concentrations. Average dispersive components of surface free energy and the donor/acceptor components of the adsorption energy in the monolayer region for the parent and mixed Si and Al pyrogenic oxides are also determined and discussed.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Mar 1, 2019
The objective of the study is to obtain the modified zeolite powders and to apply these materials... more The objective of the study is to obtain the modified zeolite powders and to apply these materials as an active fillers in the dental composites with the remineralizing potential. Three different synthesis pathways were applied to receive LTA-type (Linde A-type) zeolites. All zeolites were subjected to the ion exchange process and mineralization of surface with hydroxyapatite (HA) layer. As a result a calcium form and surface modified form of these materials were prepared. The effectiveness of each modification process was confirmed by X-ray Difractometry, Infrared and Raman Spectroscopy. Materials were also characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy and nitrogen adsorption/desorption measurements. The remineralizing potential was specified as an ability to release calcium ions during the incubation in saline with the use of Inductively Coupled Plasma-Mass Spectrometry. The obtained zeolite fillers were placed in the organic matrix to create a photopolymerizable composites with potential dental applications. The homogeneity of the filler distribution in polymeric matrix was checked by the Raman spectra mapping. Composites containing calcium form of zeolites as well as zeolites with the HA layer proved to have the ability to release calcium ions during incubation in saline in the amount comparable to calcium phosphates-filled composites or even higher than dental glass-filled composites. The ability to release calcium ions, together with good mechanical properties and mass stability testify the suitability of prepared composites in potential dental applications.
Sorbents that potentially can be used for separation of the products of biotechnological conversi... more Sorbents that potentially can be used for separation of the products of biotechnological conversion of glycerol were examined. Properties of Zeolite 5A, resins: Amberlite, Diaion and their samples impregnated with an aqueous solutions of 1,2,3-propanetriol, 1,3-propanediol, 2,3-butanediol, acetic acid, succinic acid and model fermentation broth were investigated. Because surface properties will probably depend on the ambient humidity the IGC experiments were carried out under different conditions of relative humidity RH = 0, 40 and 80%. Activity of the sorbents surface was expressed by the value of the dispersive component of the free surface energy. Inverse gas chromatography was also used to express acid-base properties of materials described by K A and K D parameters. The changes in the activity of investigated sorbents significantly varied depending on the type of impregnating agent. Moreover, the obtained results demonstrate that humidity can strongly influence, in some cases, the dispersive component of the free surface energy and the ability to specific interactions (K A and K D ).
One of the most important stages during production of abrasive tools is their hardening. The degr... more One of the most important stages during production of abrasive tools is their hardening. The degree of hardening is very important and influence toughness of the final product. During hardening process the cross-linking of the phenolic resins, used as a binder, occurs. Nowadays, there is no standard, accurate and simple method for the estimation of the hardening degree of abrasive tools. The procedure of the determination of hardening degree of the binder (phenolic resins) by means of inverse gas chromatography (IGC) was presented in this paper. Results obtained by use of IGC derived method was verified by Soxhlet extraction and by FTIR method. Good agreement was found for results from IGC and Soxhlet extraction whereas those from FTIR were much lower. FTIR method supplies data concerning bulk properties not the surface as in case of IGC and Soxhlet methods. These results indicate that resins are more cross-linked on the surface than inside the material.
Zeolites are well-known as very good adsorbents used, e.g. for water purification, gas drying and... more Zeolites are well-known as very good adsorbents used, e.g. for water purification, gas drying and removal of harmful compounds. They are also used as molecular sieves for separation of mixtures of different compounds. Zeolites may also serve as fragrance carriers. This paper presents surface properties of natural and synthetic zeolites and influence of these properties on the ability to adsorb several fragrance compounds: citral, p-cymene, geraniol, menthol. The enthalpy, entropy and energy of adsorption of these compounds on the surface of studied zeolites were estimated using of inverse gas chromatography (IGC). Activity of the zeolites surface was expressed by the value of the dispersive component of the free surface energy c D S . c D S parameter was determined by means of inverse gas chromatography at 35 °C and various humidity. Zeolite structure was determined by XRD and nitrogen sorption. IGC derived experimental data concerning adsorption of fragrance on zeolites have been discussed using structural and affinity QSAR characteristics obtained by from DFT and Hyperchem procedures. Obtained results prove that both studied zeolites can be successfully applied as fragrance carrier.
Insufficient mechanical properties of hydroxyapatite-based composites prompted the search for new... more Insufficient mechanical properties of hydroxyapatite-based composites prompted the search for new and effective solutions for dental applications. To improve the mechanical properties without losing the remineralization potential, the use of hybrid fillers was proposed. The first of them was based on the formation of hydroxyapatite (HA) layer on the surface of SYLOID®244 silica. The second of the investigated fillers was created by simultaneous synthesis of nanoparticles from precursors of HA and silica. The obtained fillers were extensively characterized by spectral methods including X-ray Diffractometry (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), and X-ray fluorescence (XRF), as well as by Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS). Tests using probiotic microorganisms were an important part of the analysis, indicating that there was no potential interaction of the materials with microflora. The tests of degree of conversion, depth of cure, opacity, sorption, solubility, flexural and compressive strength, and the remineralizing potential also showed that the composites with nano-sized silica/HA showed better mechanical properties than the composites with HA alone or commercial silica and at the same time the remineralization remained at the desired level. Thus, the proposed composite has a high application potential in the creation of implants and dental materials.
become more porous and hence the number of places vulnerable to denture plaque and calculus accum... more become more porous and hence the number of places vulnerable to denture plaque and calculus accumulation increases which favours adhesion of the Candida fungi-the main pathogens responsible for the development of prosthetic stomatopathies . The roughness and microporosity of the surfaces of elastic materials increase the risk of infection in spite of frequent and regular hygiene practices applied by the patient. The observed phenomena of diffusion, elution, and leaching of compounds from the elastic materials may Abstract The use of elastic materials favours degradation of their surface. The period of their clinical usefulness is then shortened, and their further utilisation in the oral cavity may have the reverse effect. The surface properties of such material as well as the influence of the humidity on their surface are very important as they determine the prosthetic materials behavior in the mouth. The surface of such material should be resistant to water. Inverse gas chromatography is an accurate, sensitive technique for studying surface properties. Thanks to using a unique equipment specially designed for IGC technique, Surface Energy Analyzer, it was possible to characterize the surface at 0 and 80% of humidity. Our results show that increased humidity does not affect surface properties of studied prosthetic materials. Their ability to dispersive and specific interactions change in very limited degree. IGC experiment was also applied for the estimation of Hansen solubility parameters that indicate ability of a material to dispersive, polar, and hydrogen-bonding interactions. Relation between the surface characteristics and practical use of soft lining materials with implications for their clinical usefulness is also discussed.
The surface properties of aluminosilicates (perlites and zeolites)-potential fillers in abrasive ... more The surface properties of aluminosilicates (perlites and zeolites)-potential fillers in abrasive articles-have been examined by inverse gas chromatography. The dispersive component of the surface free energy (c D S ) and K A and K D describing the acidity and basicity, respectively, of the fillers were used to express the surface activity of examined materials. The Flory-Huggins parameter, v 0 23 ; characterized the interactions between polymer and filler, i.e., interactions between phenolic resin and filler. Zeolites were found to be materials with an active surface layer and relatively high ability to participate in filler-resin interactions. Therefore, they might be considered as potential ''replacement material'' for standard fillers. The IGC-derived values mentioned above provided useful information about the behavior of fillers during the manufacture and use of abrasive articles.
The concept of the solubility parameter has been used in many industries for explanation of the d... more The concept of the solubility parameter has been used in many industries for explanation of the different properties of the components of a formulation. Knowledge of solubility-parameter data for different species is important for predicting the magnitude of interactions between the components of the formulation and for predicting the stability of the product. Determination of Hansen solubility parameters (HSP) for solid materials is extremely complicated. Inverse gas-solid chromatography has been found useful for determination of the HSP of solid polymers and other materials. Use of this technique for characterization of modified and unmodified nanomaterials is presented and discussed. S γ ) properties of the surface layers of
The sorption and wettability properties for mucoadhesive polymers were determined. The contac... more The sorption and wettability properties for mucoadhesive polymers were determined. The contact angle measurements for powders were performed according to the Washburn method. The surface properties of polymers were assessed by the IGC technique. Three types of experimental investigation were applied for determination of surface energy of powders.
The surface properties of the fillers have a significant effect on the mechanical properties of t... more The surface properties of the fillers have a significant effect on the mechanical properties of the composites. Despite many uses of diazonium interface chemistry, it has rarely been used in the modification of fillers, although it has much to offer. In this work zeolite surface was modified by 4-(dimethylamino)benzenediazonium cation to obtain an active filler having dimethylamino groups for potential further applications. Modification effectiveness was determined by means of scanning-electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. All applied methods confirmed the presence of an organic layer on the surface of modified zeolite, thereby the success of modification. A modified material was applied as an active filler in a methacrylic-resin-based photocurable composites which are mainly used in many dental applications. To verify the active properties of a zeolite filler some mechanical properties, as well as crosslinking ability were examined. All conducted tests proved that the addition of some amount of modified filler is beneficial for the final composite.
The dependence of the depth of cure (DOC) and degree of conversion (DC) on the depth of experimen... more The dependence of the depth of cure (DOC) and degree of conversion (DC) on the depth of experimental and commercial materials were determined according to ISO 4049 procedure and with the use of Raman spectroscopy, respectively. Moreover, an attempt was made to find the correlation between the DOC and DC and the depth of the material. The hypothesis was that curing time recommended by the manufacturers is appropriate for curing both commercial and experimental materials to achieve comparable values of the examined properties. The impact of the filler characteristic was clearly observed. The longer curing time provides a deeper curing (DOC values) and higher reaction rate (DC); however, the dependence between the DC values and DOC values was not visible. Instead, a logarithmic trend in the relation of the DOC and curing time was clearly observed. The results of this study suggest that the experimental materials give some hope for potential clinical applications and should be further investigated.
In this paper, we report on the physicochemical characterization of hydrogels recently obtained b... more In this paper, we report on the physicochemical characterization of hydrogels recently obtained by crosslinking poly (vinylalcohol), PVA, with telechelic PVA (telPVA, bearing terminal aldehydic groups) via acetalization in aqueous solution. These gels were studied by equilibrium swelling, compression modulus measurements, and proton relaxometry experiments. Swelling and compression modulus data allow to estimate the average molecular weight of PVA chain between crosslinks, the average mesh size of the networks, and the polymer-solvent interaction parameter 1 . The average mesh size of PVA-telPVA compares well with domain dimensions of diffusionally confined water as detected by NMR relaxometry. Proton relaxometry also showed different network domains in which water is compartmentalized, indicating a complex heterogeneity. The study of the temperature behavior of the nuclear spin-spin relaxation times of the confined water was also considered.
ABSTRACT The approach for calculating the adsorption free energy and adsorption energy distributi... more ABSTRACT The approach for calculating the adsorption free energy and adsorption energy distributions for a heterogeneous solid surface as the sum of two uniform functions directly from co-ordinates of the tail of the probe’s chromatographic peak is presented and discussed. Distribution functions are derived from data collected for the series of test adsorbates (n-alkanes C5—C10 and five polar organic compounds) by means of inverse gas chromatography at finite concentrations. Average dispersive components of surface free energy and the donor/acceptor components of the adsorption energy in the monolayer region for the parent and mixed Si and Al pyrogenic oxides are also determined and discussed.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Mar 1, 2019
The objective of the study is to obtain the modified zeolite powders and to apply these materials... more The objective of the study is to obtain the modified zeolite powders and to apply these materials as an active fillers in the dental composites with the remineralizing potential. Three different synthesis pathways were applied to receive LTA-type (Linde A-type) zeolites. All zeolites were subjected to the ion exchange process and mineralization of surface with hydroxyapatite (HA) layer. As a result a calcium form and surface modified form of these materials were prepared. The effectiveness of each modification process was confirmed by X-ray Difractometry, Infrared and Raman Spectroscopy. Materials were also characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy and nitrogen adsorption/desorption measurements. The remineralizing potential was specified as an ability to release calcium ions during the incubation in saline with the use of Inductively Coupled Plasma-Mass Spectrometry. The obtained zeolite fillers were placed in the organic matrix to create a photopolymerizable composites with potential dental applications. The homogeneity of the filler distribution in polymeric matrix was checked by the Raman spectra mapping. Composites containing calcium form of zeolites as well as zeolites with the HA layer proved to have the ability to release calcium ions during incubation in saline in the amount comparable to calcium phosphates-filled composites or even higher than dental glass-filled composites. The ability to release calcium ions, together with good mechanical properties and mass stability testify the suitability of prepared composites in potential dental applications.
Sorbents that potentially can be used for separation of the products of biotechnological conversi... more Sorbents that potentially can be used for separation of the products of biotechnological conversion of glycerol were examined. Properties of Zeolite 5A, resins: Amberlite, Diaion and their samples impregnated with an aqueous solutions of 1,2,3-propanetriol, 1,3-propanediol, 2,3-butanediol, acetic acid, succinic acid and model fermentation broth were investigated. Because surface properties will probably depend on the ambient humidity the IGC experiments were carried out under different conditions of relative humidity RH = 0, 40 and 80%. Activity of the sorbents surface was expressed by the value of the dispersive component of the free surface energy. Inverse gas chromatography was also used to express acid-base properties of materials described by K A and K D parameters. The changes in the activity of investigated sorbents significantly varied depending on the type of impregnating agent. Moreover, the obtained results demonstrate that humidity can strongly influence, in some cases, the dispersive component of the free surface energy and the ability to specific interactions (K A and K D ).
One of the most important stages during production of abrasive tools is their hardening. The degr... more One of the most important stages during production of abrasive tools is their hardening. The degree of hardening is very important and influence toughness of the final product. During hardening process the cross-linking of the phenolic resins, used as a binder, occurs. Nowadays, there is no standard, accurate and simple method for the estimation of the hardening degree of abrasive tools. The procedure of the determination of hardening degree of the binder (phenolic resins) by means of inverse gas chromatography (IGC) was presented in this paper. Results obtained by use of IGC derived method was verified by Soxhlet extraction and by FTIR method. Good agreement was found for results from IGC and Soxhlet extraction whereas those from FTIR were much lower. FTIR method supplies data concerning bulk properties not the surface as in case of IGC and Soxhlet methods. These results indicate that resins are more cross-linked on the surface than inside the material.
Zeolites are well-known as very good adsorbents used, e.g. for water purification, gas drying and... more Zeolites are well-known as very good adsorbents used, e.g. for water purification, gas drying and removal of harmful compounds. They are also used as molecular sieves for separation of mixtures of different compounds. Zeolites may also serve as fragrance carriers. This paper presents surface properties of natural and synthetic zeolites and influence of these properties on the ability to adsorb several fragrance compounds: citral, p-cymene, geraniol, menthol. The enthalpy, entropy and energy of adsorption of these compounds on the surface of studied zeolites were estimated using of inverse gas chromatography (IGC). Activity of the zeolites surface was expressed by the value of the dispersive component of the free surface energy c D S . c D S parameter was determined by means of inverse gas chromatography at 35 °C and various humidity. Zeolite structure was determined by XRD and nitrogen sorption. IGC derived experimental data concerning adsorption of fragrance on zeolites have been discussed using structural and affinity QSAR characteristics obtained by from DFT and Hyperchem procedures. Obtained results prove that both studied zeolites can be successfully applied as fragrance carrier.
Insufficient mechanical properties of hydroxyapatite-based composites prompted the search for new... more Insufficient mechanical properties of hydroxyapatite-based composites prompted the search for new and effective solutions for dental applications. To improve the mechanical properties without losing the remineralization potential, the use of hybrid fillers was proposed. The first of them was based on the formation of hydroxyapatite (HA) layer on the surface of SYLOID®244 silica. The second of the investigated fillers was created by simultaneous synthesis of nanoparticles from precursors of HA and silica. The obtained fillers were extensively characterized by spectral methods including X-ray Diffractometry (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), and X-ray fluorescence (XRF), as well as by Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS). Tests using probiotic microorganisms were an important part of the analysis, indicating that there was no potential interaction of the materials with microflora. The tests of degree of conversion, depth of cure, opacity, sorption, solubility, flexural and compressive strength, and the remineralizing potential also showed that the composites with nano-sized silica/HA showed better mechanical properties than the composites with HA alone or commercial silica and at the same time the remineralization remained at the desired level. Thus, the proposed composite has a high application potential in the creation of implants and dental materials.
become more porous and hence the number of places vulnerable to denture plaque and calculus accum... more become more porous and hence the number of places vulnerable to denture plaque and calculus accumulation increases which favours adhesion of the Candida fungi-the main pathogens responsible for the development of prosthetic stomatopathies . The roughness and microporosity of the surfaces of elastic materials increase the risk of infection in spite of frequent and regular hygiene practices applied by the patient. The observed phenomena of diffusion, elution, and leaching of compounds from the elastic materials may Abstract The use of elastic materials favours degradation of their surface. The period of their clinical usefulness is then shortened, and their further utilisation in the oral cavity may have the reverse effect. The surface properties of such material as well as the influence of the humidity on their surface are very important as they determine the prosthetic materials behavior in the mouth. The surface of such material should be resistant to water. Inverse gas chromatography is an accurate, sensitive technique for studying surface properties. Thanks to using a unique equipment specially designed for IGC technique, Surface Energy Analyzer, it was possible to characterize the surface at 0 and 80% of humidity. Our results show that increased humidity does not affect surface properties of studied prosthetic materials. Their ability to dispersive and specific interactions change in very limited degree. IGC experiment was also applied for the estimation of Hansen solubility parameters that indicate ability of a material to dispersive, polar, and hydrogen-bonding interactions. Relation between the surface characteristics and practical use of soft lining materials with implications for their clinical usefulness is also discussed.
The surface properties of aluminosilicates (perlites and zeolites)-potential fillers in abrasive ... more The surface properties of aluminosilicates (perlites and zeolites)-potential fillers in abrasive articles-have been examined by inverse gas chromatography. The dispersive component of the surface free energy (c D S ) and K A and K D describing the acidity and basicity, respectively, of the fillers were used to express the surface activity of examined materials. The Flory-Huggins parameter, v 0 23 ; characterized the interactions between polymer and filler, i.e., interactions between phenolic resin and filler. Zeolites were found to be materials with an active surface layer and relatively high ability to participate in filler-resin interactions. Therefore, they might be considered as potential ''replacement material'' for standard fillers. The IGC-derived values mentioned above provided useful information about the behavior of fillers during the manufacture and use of abrasive articles.
The concept of the solubility parameter has been used in many industries for explanation of the d... more The concept of the solubility parameter has been used in many industries for explanation of the different properties of the components of a formulation. Knowledge of solubility-parameter data for different species is important for predicting the magnitude of interactions between the components of the formulation and for predicting the stability of the product. Determination of Hansen solubility parameters (HSP) for solid materials is extremely complicated. Inverse gas-solid chromatography has been found useful for determination of the HSP of solid polymers and other materials. Use of this technique for characterization of modified and unmodified nanomaterials is presented and discussed. S γ ) properties of the surface layers of
The sorption and wettability properties for mucoadhesive polymers were determined. The contac... more The sorption and wettability properties for mucoadhesive polymers were determined. The contact angle measurements for powders were performed according to the Washburn method. The surface properties of polymers were assessed by the IGC technique. Three types of experimental investigation were applied for determination of surface energy of powders.
The surface properties of the fillers have a significant effect on the mechanical properties of t... more The surface properties of the fillers have a significant effect on the mechanical properties of the composites. Despite many uses of diazonium interface chemistry, it has rarely been used in the modification of fillers, although it has much to offer. In this work zeolite surface was modified by 4-(dimethylamino)benzenediazonium cation to obtain an active filler having dimethylamino groups for potential further applications. Modification effectiveness was determined by means of scanning-electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. All applied methods confirmed the presence of an organic layer on the surface of modified zeolite, thereby the success of modification. A modified material was applied as an active filler in a methacrylic-resin-based photocurable composites which are mainly used in many dental applications. To verify the active properties of a zeolite filler some mechanical properties, as well as crosslinking ability were examined. All conducted tests proved that the addition of some amount of modified filler is beneficial for the final composite.
The dependence of the depth of cure (DOC) and degree of conversion (DC) on the depth of experimen... more The dependence of the depth of cure (DOC) and degree of conversion (DC) on the depth of experimental and commercial materials were determined according to ISO 4049 procedure and with the use of Raman spectroscopy, respectively. Moreover, an attempt was made to find the correlation between the DOC and DC and the depth of the material. The hypothesis was that curing time recommended by the manufacturers is appropriate for curing both commercial and experimental materials to achieve comparable values of the examined properties. The impact of the filler characteristic was clearly observed. The longer curing time provides a deeper curing (DOC values) and higher reaction rate (DC); however, the dependence between the DC values and DOC values was not visible. Instead, a logarithmic trend in the relation of the DOC and curing time was clearly observed. The results of this study suggest that the experimental materials give some hope for potential clinical applications and should be further investigated.
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Papers by Adam Voelkel