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Thermal properties of extrusion and injection grade polylactic acid (PLA) were analysed using high pressure differential scanning calorimetry (HP-DSC) under CO2 pressures of up to 50 MPa. The greatest depression of melting point and degree of crystallinity of the samples occurred at 20-30 MPa (similar to 97-115 degrees C). Batch and semi continuous processes for supercritical foaming and impregnation of PLA with thymol or thyme extract were performed at 30 MPa and 100-110 degrees C to prevent thymol degradation, decrease heating requirements and ease polymer processing. At these conditions, PLA foams containing 5.6% or 1.1% of thymol and 0.7% of thyme extract were obtained using static or dynamic batch impregnation and semi-continuous extraction-impregnation process for 7 h, respectively. DSC and HP-DSC analyses revealed more pronounced effect of scCO(2) plasticizing than foaming on PLA crystallinity. Neat and impregnated PLA foams with pores size of 15-200 pm have potential for food packaging, biomedical and insulation applications.

Solid dispersions production is one of the substantial approaches for improvement of poor drug solubility. Additionally, supercritical fluid assisted method for preparation of solid dispersions can offer many advantages in comparison to the conventional melting or solvent-evaporation methods. Miscibility analysis provides valuable guidance for selection of the most appropriate polymeric carrier for dispersion of the drug of interest. In addition to the increased drug release rate, solid dispersions should have proper mechanical attributes in order to be successfully formulated in the final solid dosage form such as tablet. Therefore, several pharmaceutical grade polymers have been selected for development of BCS Class II drug carvedilol (CARV) solid dispersions. They were compared based on behavior in supercritical CO2 and affinity towards CARV calculated from the miscibility analysis. By utilization of the supercritical CO2 assisted method, solid dispersions of CARV with the selected (co) polymers (polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), Soluplus (R) and Eudragit (R)) were obtained. Properties of the prepared CARV-polymer dispersions were observed by the polarizing and scanning electron microscopy and analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. CARV was additionally characterized by X-ray powder diffraction. Furthermore, in vitro dissolution studies and dynamic compaction analysis were performed on the selected samples of solid dispersions. Among the studied polymers, PVP and HPMC have been identified as polymers with the highest affinity towards CARV, based on the calculated delta(p) values. This has been also confirmed with the highest dissolution efficiency of CARV-PVP and CARV-HPMC solid dispersions. Solid state characterization indicated that CARV was dispersed either molecularly, or in the amorphous form, depending on interactions with each polymer. Determination of CARV-PVP and CARV-HPM

Amorphous, medical grade poly(D,L-lactic acid) (PLA) and poly(D,L-lactic-co-glycolic acid) (PLGA) were used to develop systems for controlled release of a natural bioactive substance - thymol. Supercritical carbon dioxide (scCO(2)) was successfully used both as an impregnation medium for thymol incorporation into the polymer matrix and a foaming agent in a single-step batch process. Impregnation of samples using low to moderate scCO(2) densities (273 kg/m(3) and 630 kg/m(3)) and short processing times (2 h and 4 h) enabled thymol loading of 0.920/0-6.62% and formation of microcellular foams upon system depressurization. Thymol effect on structural and thermal properties on foamed samples was proven by FTIR and DSC. The effect of CO2 under elevated pressure on the neat polymers was analysed by high pressure DSC. Foaming of polymers with lower molecular weight by CO2 of higher density yielded foams with smaller pores. All tested foams released thymol in a controlled manner in phosphate buffered saline (PBS) at 37 degrees C within 3 to 6 weeks. Higher loading and lower cell density favoured thymol release rate, while its concentration in PBS for the tested period depended on foam interaction with the medium. Representative PLGA foam sample with the highest thymol loading (6.62%) showed controlled thymol release within 72 h in mediums having pH values from 1.1 to 7.4.

Solid dispersions production is one of the substantial approaches for improvement of poor drug solubility. Additionally, supercritical fluid assisted method for preparation of solid dispersions can offer many advantages in comparison to the conventional melting or solvent-evaporation methods. Miscibility analysis provides valuable guidance for selection of the most appropriate polymeric carrier for dispersion of the drug of interest. In addition to the increased drug release rate, solid dispersions should have proper mechanical attributes in order to be successfully formulated in the final solid dosage form such as tablet. Therefore, several pharmaceutical grade polymers have been selected for development of BCS Class II drug carvedilol (CARV) solid dispersions. They were compared based on behavior in supercritical CO2 and affinity towards CARV calculated from the miscibility analysis. By utilization of the supercritical CO2 assisted method, solid dispersions of CARV with the selected (co) polymers (polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), Soluplus (R) and Eudragit (R)) were obtained. Properties of the prepared CARV-polymer dispersions were observed by the polarizing and scanning electron microscopy and analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. CARV was additionally characterized by X-ray powder diffraction. Furthermore, in vitro dissolution studies and dynamic compaction analysis were performed on the selected samples of solid dispersions. Among the studied polymers, PVP and HPMC have been identified as polymers with the highest affinity towards CARV, based on the calculated delta(p) values. This has been also confirmed with the highest dissolution efficiency of CARV-PVP and CARV-HPMC solid dispersions. Solid state characterization indicated that CARV was dispersed either molecularly, or in the amorphous form, depending on interactions with each polymer. Determination of CARV-PVP and CARV-HPM

Thermal properties of extrusion and injection grade polylactic acid (PLA) were analysed using high pressure differential scanning calorimetry (HP-DSC) under CO2 pressures of up to 50 MPa. The greatest depression of melting point and degree of crystallinity of the samples occurred at 20-30 MPa (similar to 97-115 degrees C). Batch and semi continuous processes for supercritical foaming and impregnation of PLA with thymol or thyme extract were performed at 30 MPa and 100-110 degrees C to prevent thymol degradation, decrease heating requirements and ease polymer processing. At these conditions, PLA foams containing 5.6% or 1.1% of thymol and 0.7% of thyme extract were obtained using static or dynamic batch impregnation and semi-continuous extraction-impregnation process for 7 h, respectively. DSC and HP-DSC analyses revealed more pronounced effect of scCO(2) plasticizing than foaming on PLA crystallinity. Neat and impregnated PLA foams with pores size of 15-200 pm have potential for food packaging, biomedical and insulation applications.

Amorphous, medical grade poly(D,L-lactic acid) (PLA) and poly(D,L-lactic-co-glycolic acid) (PLGA) were used to develop systems for controlled release of a natural bioactive substance - thymol. Supercritical carbon dioxide (scCO(2)) was successfully used both as an impregnation medium for thymol incorporation into the polymer matrix and a foaming agent in a single-step batch process. Impregnation of samples using low to moderate scCO(2) densities (273 kg/m(3) and 630 kg/m(3)) and short processing times (2 h and 4 h) enabled thymol loading of 0.920/0-6.62% and formation of microcellular foams upon system depressurization. Thymol effect on structural and thermal properties on foamed samples was proven by FTIR and DSC. The effect of CO2 under elevated pressure on the neat polymers was analysed by high pressure DSC. Foaming of polymers with lower molecular weight by CO2 of higher density yielded foams with smaller pores. All tested foams released thymol in a controlled manner in phosphate buffered saline (PBS) at 37 degrees C within 3 to 6 weeks. Higher loading and lower cell density favoured thymol release rate, while its concentration in PBS for the tested period depended on foam interaction with the medium. Representative PLGA foam sample with the highest thymol loading (6.62%) showed controlled thymol release within 72 h in mediums having pH values from 1.1 to 7.4.

Solid dispersions production is one of the substantial approaches for improvement of poor drug solubility. Additionally, supercritical fluid assisted method for preparation of solid dispersions can offer many advantages in comparison to the conventional melting or solvent-evaporation methods. Miscibility analysis provides valuable guidance for selection of the most appropriate polymeric carrier for dispersion of the drug of interest. In addition to the increased drug release rate, solid dispersions should have proper mechanical attributes in order to be successfully formulated in the final solid dosage form such as tablet. Therefore, several pharmaceutical grade polymers have been selected for development of BCS Class II drug carvedilol (CARV) solid dispersions. They were compared based on behavior in supercritical CO2 and affinity towards CARV calculated from the miscibility analysis. By utilization of the supercritical CO2 assisted method, solid dispersions of CARV with the selected (co) polymers (polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), Soluplus (R) and Eudragit (R)) were obtained. Properties of the prepared CARV-polymer dispersions were observed by the polarizing and scanning electron microscopy and analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. CARV was additionally characterized by X-ray powder diffraction. Furthermore, in vitro dissolution studies and dynamic compaction analysis were performed on the selected samples of solid dispersions. Among the studied polymers, PVP and HPMC have been identified as polymers with the highest affinity towards CARV, based on the calculated delta(p) values. This has been also confirmed with the highest dissolution efficiency of CARV-PVP and CARV-HPMC solid dispersions. Solid state characterization indicated that CARV was dispersed either molecularly, or in the amorphous form, depending on interactions with each polymer. Determination of CARV-PVP and CARV-HPM

Amorphous, medical grade poly(D,L-lactic acid) (PLA) and poly(D,L-lactic-co-glycolic acid) (PLGA) were used to develop systems for controlled release of a natural bioactive substance - thymol. Supercritical carbon dioxide (scCO(2)) was successfully used both as an impregnation medium for thymol incorporation into the polymer matrix and a foaming agent in a single-step batch process. Impregnation of samples using low to moderate scCO(2) densities (273 kg/m(3) and 630 kg/m(3)) and short processing times (2 h and 4 h) enabled thymol loading of 0.920/0-6.62% and formation of microcellular foams upon system depressurization. Thymol effect on structural and thermal properties on foamed samples was proven by FTIR and DSC. The effect of CO2 under elevated pressure on the neat polymers was analysed by high pressure DSC. Foaming of polymers with lower molecular weight by CO2 of higher density yielded foams with smaller pores. All tested foams released thymol in a controlled manner in phosphate buffered saline (PBS) at 37 degrees C within 3 to 6 weeks. Higher loading and lower cell density favoured thymol release rate, while its concentration in PBS for the tested period depended on foam interaction with the medium. Representative PLGA foam sample with the highest thymol loading (6.62%) showed controlled thymol release within 72 h in mediums having pH values from 1.1 to 7.4.

Biodegradable polymers with antibacterial properties are highly desirable materials for active food packaging applications. Thymol, a dietary monoterpene phenol with a strong antibacterial activity is abundant in plants belonging to the genus Thymus. This study presents two approaches for supercritical CO2 impregnation of poly (lactic acid)(PLA)/poly(epsilon-caprolactone)(PCL) blended films to induce antibacterial properties of the material: (i) a batch impregnation process for loading pure thymol, and (ii) an integrated supercritical extraction-impregnation process for isolation of thyme extract and its incorporation into the films, operated in both batch or semi-continuous modes with supercritical solution circulation. The PCL content in films, impregnation time and CO2 flow regime were varied to maximize loading of the films with thymol or thyme extract with preserving films' structure and thermal stability. Representative film samples impregnated with thymol and thyme extract were tested against Gram ( - ) (Escherichia col) and Gram( + ) (Bacillus subtilis) model strains, by measuring their metabolic activity and re-cultivation after exposure to the films. The film containing thymol (35.8 wt%) showed a strong antibacterial activity leading to a total reduction of bacterial cell viability. Proposed processes enable fast, controlled and organic solvent-free fabrication of the PLA/PCL films containing natural antibacterial substances at moderately low temperature, with a compact structure and a good thermal stability, for potential use as active food packaging materials.

This study discusses utilization of supercritical carbon dioxide for impregnation of cellulose acetate films with thymol in order to produce material with anti-biofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus. Analysis of anti-biofilm activity of cellulose acetate beads impregnated with thymol suggested that optimal thymol loading was in the range from 26% to 30% for efficient reduction of biofilm formation and eradication of pre-formed biofilms. Polymer films were fabricated by the solvent casting method from polymer solutions of different contents, and loaded with thymol using supercritical carbon dioxide at 15.5 MPa and 35 degrees C. The film containing 30% of thymol (F1 30%) exhibited substantial anti-adhesion properties inhibiting biofilm formation on its surface and considerably reduced formation of biofilms on the surrounding surfaces (up to 80%) by all tested strains including antibiotic resistant P. aeruginosa DM50 and methicillin-resistant S. aureus.

This study discusses utilization of supercritical carbon dioxide for impregnation of cellulose acetate films with thymol in order to produce material with anti-biofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus. Analysis of anti-biofilm activity of cellulose acetate beads impregnated with thymol suggested that optimal thymol loading was in the range from 26% to 30% for efficient reduction of biofilm formation and eradication of pre-formed biofilms. Polymer films were fabricated by the solvent casting method from polymer solutions of different contents, and loaded with thymol using supercritical carbon dioxide at 15.5 MPa and 35 degrees C. The film containing 30% of thymol (F1 30%) exhibited substantial anti-adhesion properties inhibiting biofilm formation on its surface and considerably reduced formation of biofilms on the surrounding surfaces (up to 80%) by all tested strains including antibiotic resistant P. aeruginosa DM50 and methicillin-resistant S. aureus.

This study discusses utilization of supercritical carbon dioxide for impregnation of cellulose acetate films with thymol in order to produce material with anti-biofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus. Analysis of anti-biofilm activity of cellulose acetate beads impregnated with thymol suggested that optimal thymol loading was in the range from 26% to 30% for efficient reduction of biofilm formation and eradication of pre-formed biofilms. Polymer films were fabricated by the solvent casting method from polymer solutions of different contents, and loaded with thymol using supercritical carbon dioxide at 15.5 MPa and 35 degrees C. The film containing 30% of thymol (F1 30%) exhibited substantial anti-adhesion properties inhibiting biofilm formation on its surface and considerably reduced formation of biofilms on the surrounding surfaces (up to 80%) by all tested strains including antibiotic resistant P. aeruginosa DM50 and methicillin-resistant S. aureus.

This study discusses utilization of supercritical carbon dioxide for impregnation of cellulose acetate films with thymol in order to produce material with anti-biofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus. Analysis of anti-biofilm activity of cellulose acetate beads impregnated with thymol suggested that optimal thymol loading was in the range from 26% to 30% for efficient reduction of biofilm formation and eradication of pre-formed biofilms. Polymer films were fabricated by the solvent casting method from polymer solutions of different contents, and loaded with thymol using supercritical carbon dioxide at 15.5 MPa and 35 degrees C. The film containing 30% of thymol (F1 30%) exhibited substantial anti-adhesion properties inhibiting biofilm formation on its surface and considerably reduced formation of biofilms on the surrounding surfaces (up to 80%) by all tested strains including antibiotic resistant P. aeruginosa DM50 and methicillin-resistant S. aureus.

This study discusses utilization of supercritical carbon dioxide for impregnation of cellulose acetate films with thymol in order to produce material with anti-biofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus. Analysis of anti-biofilm activity of cellulose acetate beads impregnated with thymol suggested that optimal thymol loading was in the range from 26% to 30% for efficient reduction of biofilm formation and eradication of pre-formed biofilms. Polymer films were fabricated by the solvent casting method from polymer solutions of different contents, and loaded with thymol using supercritical carbon dioxide at 15.5 MPa and 35 degrees C. The film containing 30% of thymol (F1 30%) exhibited substantial anti-adhesion properties inhibiting biofilm formation on its surface and considerably reduced formation of biofilms on the surrounding surfaces (up to 80%) by all tested strains including antibiotic resistant P. aeruginosa DM50 and methicillin-resistant S. aureus.

This study discusses utilization of supercritical carbon dioxide for impregnation of cellulose acetate films with thymol in order to produce material with anti-biofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus. Analysis of anti-biofilm activity of cellulose acetate beads impregnated with thymol suggested that optimal thymol loading was in the range from 26% to 30% for efficient reduction of biofilm formation and eradication of pre-formed biofilms. Polymer films were fabricated by the solvent casting method from polymer solutions of different contents, and loaded with thymol using supercritical carbon dioxide at 15.5 MPa and 35 degrees C. The film containing 30% of thymol (F1 30%) exhibited substantial anti-adhesion properties inhibiting biofilm formation on its surface and considerably reduced formation of biofilms on the surrounding surfaces (up to 80%) by all tested strains including antibiotic resistant P. aeruginosa DM50 and methicillin-resistant S. aureus.

Biodegradable polymers with antibacterial properties are highly desirable materials for active food packaging applications. Thymol, a dietary monoterpene phenol with a strong antibacterial activity is abundant in plants belonging to the genus Thymus. This study presents two approaches for supercritical CO2 impregnation of poly (lactic acid)(PLA)/poly(epsilon-caprolactone)(PCL) blended films to induce antibacterial properties of the material: (i) a batch impregnation process for loading pure thymol, and (ii) an integrated supercritical extraction-impregnation process for isolation of thyme extract and its incorporation into the films, operated in both batch or semi-continuous modes with supercritical solution circulation. The PCL content in films, impregnation time and CO2 flow regime were varied to maximize loading of the films with thymol or thyme extract with preserving films' structure and thermal stability. Representative film samples impregnated with thymol and thyme extract were tested against Gram ( - ) (Escherichia col) and Gram( + ) (Bacillus subtilis) model strains, by measuring their metabolic activity and re-cultivation after exposure to the films. The film containing thymol (35.8 wt%) showed a strong antibacterial activity leading to a total reduction of bacterial cell viability. Proposed processes enable fast, controlled and organic solvent-free fabrication of the PLA/PCL films containing natural antibacterial substances at moderately low temperature, with a compact structure and a good thermal stability, for potential use as active food packaging materials.

Biodegradable polymers with antibacterial properties are highly desirable materials for active food packaging applications. Thymol, a dietary monoterpene phenol with a strong antibacterial activity is abundant in plants belonging to the genus Thymus. This study presents two approaches for supercritical CO2 impregnation of poly (lactic acid)(PLA)/poly(epsilon-caprolactone)(PCL) blended films to induce antibacterial properties of the material: (i) a batch impregnation process for loading pure thymol, and (ii) an integrated supercritical extraction-impregnation process for isolation of thyme extract and its incorporation into the films, operated in both batch or semi-continuous modes with supercritical solution circulation. The PCL content in films, impregnation time and CO2 flow regime were varied to maximize loading of the films with thymol or thyme extract with preserving films' structure and thermal stability. Representative film samples impregnated with thymol and thyme extract were tested against Gram ( - ) (Escherichia col) and Gram( + ) (Bacillus subtilis) model strains, by measuring their metabolic activity and re-cultivation after exposure to the films. The film containing thymol (35.8 wt%) showed a strong antibacterial activity leading to a total reduction of bacterial cell viability. Proposed processes enable fast, controlled and organic solvent-free fabrication of the PLA/PCL films containing natural antibacterial substances at moderately low temperature, with a compact structure and a good thermal stability, for potential use as active food packaging materials.

The chemical composition, antimicrobial and antioxidant activity of Thymus praecox extracts obtained by fractional supercritical fluid extraction (SFE) with carbon dioxide were investigated. Properties of supercritical extracts and extracts obtained by Soxhiet extraction were compared. The chemical composition of extracts was determined using GC-FID and GC-MS analytical methods. The antimicrobial activity of extracts was evaluated against 16 pathogenic microorganisms using microdilution method. Antioxidant potential of extracts to neutralize DPPH radicals was also investigated. Investigated supercritical extracts showed better antimicrobial activity than commercial antibiotics (streptomycin and ampicillin) and commercial fungicides (bifonazol and ketoconazole) against all tested strains. For bacteria MIC and MBC were 38-200 mu g/m1 and 75-300 mu g/ml, respectively, while for fungi MIC and MFC were 17-150 mu g/ml and 35-300 mu g/ml, respectively.

The chemical composition, antimicrobial and antioxidant activity of Thymus praecox extracts obtained by fractional supercritical fluid extraction (SFE) with carbon dioxide were investigated. Properties of supercritical extracts and extracts obtained by Soxhiet extraction were compared. The chemical composition of extracts was determined using GC-FID and GC-MS analytical methods. The antimicrobial activity of extracts was evaluated against 16 pathogenic microorganisms using microdilution method. Antioxidant potential of extracts to neutralize DPPH radicals was also investigated. Investigated supercritical extracts showed better antimicrobial activity than commercial antibiotics (streptomycin and ampicillin) and commercial fungicides (bifonazol and ketoconazole) against all tested strains. For bacteria MIC and MBC were 38-200 mu g/m1 and 75-300 mu g/ml, respectively, while for fungi MIC and MFC were 17-150 mu g/ml and 35-300 mu g/ml, respectively.

This study discusses the possibility of impregnation of polypropylene (PP) and corona modified PP non-woven material with thymol in supercritical solvent in order to fabricate eco-friendly antimicrobial textile material. Carbon dioxide was used as a working fluid. The morphological changes on the PP fiber surface induced by corona treatment at atmospheric pressure as well as the presence of thymol on the fiber surface after impregnation were confirmed by FESEM analysis. Chemical changes were assessed by FTIR analysis. Antimicrobial activity of the modified PP non-woven material was tested against Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli and fungus Candida albicans. Although both PP non-woven material impregnated with thymol and corona activated PP impregnated with thymol provided maximum microbial reduction, corona pre-treated material was much faster wetted, which could be an advantage in wound healing.

Present work was aimed to investigate supercritical solvent impregnation of thymol into cellulose acetate in order to explore the possibility of developing a new functionalized solvent-free material with antimicrobial properties. Impregnation experiments were carried out with supercritical carbon dioxide at 10, 15 and 20 MPa, and at 35 and 50 degrees C. The time of impregnation was varied from 2 to 44h. Samples of impregnated cellulose acetate were tested against selected microorganisms. Thymol release kinetic studies were performed and obtained results were correlated. The impregnation yield varied from 4.51% to 72.26% depending on the operating conditions and impregnation time. Morphology of the samples changed significantly with the high impregnation yields, implying the impact of thymol on the cellulose acetate. The rate of impregnation was dependent on the impregnation conditions. Strong antimicrobial effect of impregnated samples against Escherichia colt, Staphylococcus aureus and Candida albicans strains with microbial reduction up to 99.9% was observed. Depending on the impregnation yield, samples of impregnated cellulose acetate have continuously released thymol in period from 2 to 21 days.

This study discusses the possibility of impregnation of polypropylene (PP) and corona modified PP non-woven material with thymol in supercritical solvent in order to fabricate eco-friendly antimicrobial textile material. Carbon dioxide was used as a working fluid. The morphological changes on the PP fiber surface induced by corona treatment at atmospheric pressure as well as the presence of thymol on the fiber surface after impregnation were confirmed by FESEM analysis. Chemical changes were assessed by FTIR analysis. Antimicrobial activity of the modified PP non-woven material was tested against Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli and fungus Candida albicans. Although both PP non-woven material impregnated with thymol and corona activated PP impregnated with thymol provided maximum microbial reduction, corona pre-treated material was much faster wetted, which could be an advantage in wound healing.

Present work was aimed to investigate supercritical solvent impregnation of thymol into cellulose acetate in order to explore the possibility of developing a new functionalized solvent-free material with antimicrobial properties. Impregnation experiments were carried out with supercritical carbon dioxide at 10, 15 and 20 MPa, and at 35 and 50 degrees C. The time of impregnation was varied from 2 to 44h. Samples of impregnated cellulose acetate were tested against selected microorganisms. Thymol release kinetic studies were performed and obtained results were correlated. The impregnation yield varied from 4.51% to 72.26% depending on the operating conditions and impregnation time. Morphology of the samples changed significantly with the high impregnation yields, implying the impact of thymol on the cellulose acetate. The rate of impregnation was dependent on the impregnation conditions. Strong antimicrobial effect of impregnated samples against Escherichia colt, Staphylococcus aureus and Candida albicans strains with microbial reduction up to 99.9% was observed. Depending on the impregnation yield, samples of impregnated cellulose acetate have continuously released thymol in period from 2 to 21 days.

Present work was aimed to investigate supercritical solvent impregnation of thymol into cellulose acetate in order to explore the possibility of developing a new functionalized solvent-free material with antimicrobial properties. Impregnation experiments were carried out with supercritical carbon dioxide at 10, 15 and 20 MPa, and at 35 and 50 degrees C. The time of impregnation was varied from 2 to 44h. Samples of impregnated cellulose acetate were tested against selected microorganisms. Thymol release kinetic studies were performed and obtained results were correlated. The impregnation yield varied from 4.51% to 72.26% depending on the operating conditions and impregnation time. Morphology of the samples changed significantly with the high impregnation yields, implying the impact of thymol on the cellulose acetate. The rate of impregnation was dependent on the impregnation conditions. Strong antimicrobial effect of impregnated samples against Escherichia colt, Staphylococcus aureus and Candida albicans strains with microbial reduction up to 99.9% was observed. Depending on the impregnation yield, samples of impregnated cellulose acetate have continuously released thymol in period from 2 to 21 days.

This study discusses the possibility of impregnation of polypropylene (PP) and corona modified PP non-woven material with thymol in supercritical solvent in order to fabricate eco-friendly antimicrobial textile material. Carbon dioxide was used as a working fluid. The morphological changes on the PP fiber surface induced by corona treatment at atmospheric pressure as well as the presence of thymol on the fiber surface after impregnation were confirmed by FESEM analysis. Chemical changes were assessed by FTIR analysis. Antimicrobial activity of the modified PP non-woven material was tested against Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli and fungus Candida albicans. Although both PP non-woven material impregnated with thymol and corona activated PP impregnated with thymol provided maximum microbial reduction, corona pre-treated material was much faster wetted, which could be an advantage in wound healing.

Through this study, an attempt has been made to evaluate the solubility of thymol in supercritical carbon dioxide as well to investigate a prospect of its impregnation on cotton gauze on laboratory scale. Solubility of thymol in supercritical carbon dioxide was determined at temperatures of 35 degrees C, 40 degrees C and 50 degrees C, and pressures ranging from 7.8 to 25 MPa (CO2 density range 335.89-849.60 kg/m(3)) using a static method. The solubility data were correlated using semi-empirical equations introduced by Chrastil, Adachi and Lu and del Valle and Aguilera. Taking into account obtained results, temperature of 35 degrees C and pressure of 15.5 MPa were selected as operating conditions for the impregnation process. Impregnation of cotton gauze with thymol was performed in a cell using carbon dioxide as a solvent. Kinetics of the process was determined and modeled. Masses of thymol on cotton gauzes after 2 h and 24 h of impregnation were 11% and 19.6%, respectively. FT-IR analysis confirmed the presence of thymol on the surface of the cotton fibers. The impregnated gauze provided strong antimicrobial activity against tested strains of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis and Candida albicans.

Through this study, an attempt has been made to evaluate the solubility of thymol in supercritical carbon dioxide as well to investigate a prospect of its impregnation on cotton gauze on laboratory scale. Solubility of thymol in supercritical carbon dioxide was determined at temperatures of 35 degrees C, 40 degrees C and 50 degrees C, and pressures ranging from 7.8 to 25 MPa (CO2 density range 335.89-849.60 kg/m(3)) using a static method. The solubility data were correlated using semi-empirical equations introduced by Chrastil, Adachi and Lu and del Valle and Aguilera. Taking into account obtained results, temperature of 35 degrees C and pressure of 15.5 MPa were selected as operating conditions for the impregnation process. Impregnation of cotton gauze with thymol was performed in a cell using carbon dioxide as a solvent. Kinetics of the process was determined and modeled. Masses of thymol on cotton gauzes after 2 h and 24 h of impregnation were 11% and 19.6%, respectively. FT-IR analysis confirmed the presence of thymol on the surface of the cotton fibers. The impregnated gauze provided strong antimicrobial activity against tested strains of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis and Candida albicans.

Through this study, an attempt has been made to evaluate the solubility of thymol in supercritical carbon dioxide as well to investigate a prospect of its impregnation on cotton gauze on laboratory scale. Solubility of thymol in supercritical carbon dioxide was determined at temperatures of 35 degrees C, 40 degrees C and 50 degrees C, and pressures ranging from 7.8 to 25 MPa (CO2 density range 335.89-849.60 kg/m(3)) using a static method. The solubility data were correlated using semi-empirical equations introduced by Chrastil, Adachi and Lu and del Valle and Aguilera. Taking into account obtained results, temperature of 35 degrees C and pressure of 15.5 MPa were selected as operating conditions for the impregnation process. Impregnation of cotton gauze with thymol was performed in a cell using carbon dioxide as a solvent. Kinetics of the process was determined and modeled. Masses of thymol on cotton gauzes after 2 h and 24 h of impregnation were 11% and 19.6%, respectively. FT-IR analysis confirmed the presence of thymol on the surface of the cotton fibers. The impregnated gauze provided strong antimicrobial activity against tested strains of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis and Candida albicans.