Apresentacao efetuada no "PolyChar 23 - 23rd World Forum on Advanced Materials", em Lin... more Apresentacao efetuada no "PolyChar 23 - 23rd World Forum on Advanced Materials", em Lincoln, Nebraska, U.S.A., 2015
SUNNY-ESF, Department of Chemistry Seminar, em 2017Molecular imprinting involves polymerization o... more SUNNY-ESF, Department of Chemistry Seminar, em 2017Molecular imprinting involves polymerization of a functional monomer in the presence of a target analyte that acts as a template. The monomer initially forms a complex with the template. After polymerization and subsequent removal of the template, imprinted sites remain upon the polymer surface. They are complementary in size and shape to the analyte molecules. In that way, a memory effect is introduced into the polymer, which is now capable to recognize and “capture” the analyte. Molecular imprinting can be used in biosensors and in any analytic techniques requiring selective absorption. The main idea of this work was to combine the molecular imprinting with microencapsulation aiming at the preparation of smart biodegradable microparticles susceptible to external magnetic fields and bearing recognition sites sensitive to protein templates As functional monomer 2-pyrrolidone (PD) was used and as a template – bovine serum albumin (BSA). The polymer forming process was anionic ring-opening polymerization carried out at 40ºC in the presence of Fe or Fe2O3 nanoparticles. The molecularly imprinted particles were characterized by microscopy, spectral and thermal techniques. Their absorption capacity toward BSA was increased by 25-140% depending on the pH, concentration and type of the magnetic particles.TSSiPRO—NORTE-01-0145-FEDER-000015, by NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development FundStrategic projects UID/CTM/50025/2013 and LA25/2013-2014info:eu-repo/semantics/publishedVersio
In this work, dynamic mechanical analysis (DMA) was used to investigate the solid state rheologic... more In this work, dynamic mechanical analysis (DMA) was used to investigate the solid state rheological properties of amorphous poly(ethylene terephthalate) (PET), poly(ethylene 2,6-dicarboxylate) (PEN) and the corresponding blend (1:1 by wt). The DMA results obtained with the pure materials were used to predict the expected viscoelastic behaviour of the blend assuming a complete phase separation. The modelling showed more separated tan … peaks, as compared to those experimentally found in the real PET/PEN blend. These results suggested that some degree of compatibilization is present in the blend. This effect was attributed to the fine homogenisation of the phases during the preparation of the blend, as well as to the occurrence of interchange chemical reactions (transesterification) taking place between the PET and PEN components.(undefined
The structure of polyamide 6-montmorillonite hybrid (PA6-MMT) composites prepared in-situ by mean... more The structure of polyamide 6-montmorillonite hybrid (PA6-MMT) composites prepared in-situ by means of activated anionic polymerization (AAP) of caprolactam (CL) was studied by various methods. It was established by WAXS that the predominant PA6 polymorph in the MMT hybrids obtained by AAP is the α-PA6 form, contrary to the conventional hybrids produced by melt intercalation with hydrolytic PA6 where almost pure γ-PA6 was observed. The gradual transition of ε-CL into α-PA6 as the AAP advances, as well as the polymorphic changes of the resulting hybrids as a function of temperature were observed for the first time by in-beam AAP during a WAXS measurement in synchrotron beamline (Figure 1, a). It can be seen that the two crystalline reflections of the α-polymorph are abruptly formed after 10 min of polymerization at 165oC. Until the end of AAP one observes disappearance of CL crystalline reflections whereby amorphous PA6 material is apparently formed. Heating of anionic PA6 to 200oC (b...
A.M.S.C and S.G.C. acknowledge financial support from Fundacao para a Ciencia e Tecnologia (FCT) ... more A.M.S.C and S.G.C. acknowledge financial support from Fundacao para a Ciencia e Tecnologia (FCT) through the grants SFRH/BD/101748/2014 and SFRH/BPD/96797/2013. N.V.D. is grateful for the FCT support through nSTEP project NORTE-07-0124-FEDER-000039.
Apresentacao efetuada no "PolyChar 23 - 23rd World Forum on Advanced Materials", em Lin... more Apresentacao efetuada no "PolyChar 23 - 23rd World Forum on Advanced Materials", em Lincoln, Nebraska, U.S.A., 2015
SUNNY-ESF, Department of Chemistry Seminar, em 2017Molecular imprinting involves polymerization o... more SUNNY-ESF, Department of Chemistry Seminar, em 2017Molecular imprinting involves polymerization of a functional monomer in the presence of a target analyte that acts as a template. The monomer initially forms a complex with the template. After polymerization and subsequent removal of the template, imprinted sites remain upon the polymer surface. They are complementary in size and shape to the analyte molecules. In that way, a memory effect is introduced into the polymer, which is now capable to recognize and “capture” the analyte. Molecular imprinting can be used in biosensors and in any analytic techniques requiring selective absorption. The main idea of this work was to combine the molecular imprinting with microencapsulation aiming at the preparation of smart biodegradable microparticles susceptible to external magnetic fields and bearing recognition sites sensitive to protein templates As functional monomer 2-pyrrolidone (PD) was used and as a template – bovine serum albumin (BSA). The polymer forming process was anionic ring-opening polymerization carried out at 40ºC in the presence of Fe or Fe2O3 nanoparticles. The molecularly imprinted particles were characterized by microscopy, spectral and thermal techniques. Their absorption capacity toward BSA was increased by 25-140% depending on the pH, concentration and type of the magnetic particles.TSSiPRO—NORTE-01-0145-FEDER-000015, by NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development FundStrategic projects UID/CTM/50025/2013 and LA25/2013-2014info:eu-repo/semantics/publishedVersio
In this work, dynamic mechanical analysis (DMA) was used to investigate the solid state rheologic... more In this work, dynamic mechanical analysis (DMA) was used to investigate the solid state rheological properties of amorphous poly(ethylene terephthalate) (PET), poly(ethylene 2,6-dicarboxylate) (PEN) and the corresponding blend (1:1 by wt). The DMA results obtained with the pure materials were used to predict the expected viscoelastic behaviour of the blend assuming a complete phase separation. The modelling showed more separated tan … peaks, as compared to those experimentally found in the real PET/PEN blend. These results suggested that some degree of compatibilization is present in the blend. This effect was attributed to the fine homogenisation of the phases during the preparation of the blend, as well as to the occurrence of interchange chemical reactions (transesterification) taking place between the PET and PEN components.(undefined
The structure of polyamide 6-montmorillonite hybrid (PA6-MMT) composites prepared in-situ by mean... more The structure of polyamide 6-montmorillonite hybrid (PA6-MMT) composites prepared in-situ by means of activated anionic polymerization (AAP) of caprolactam (CL) was studied by various methods. It was established by WAXS that the predominant PA6 polymorph in the MMT hybrids obtained by AAP is the α-PA6 form, contrary to the conventional hybrids produced by melt intercalation with hydrolytic PA6 where almost pure γ-PA6 was observed. The gradual transition of ε-CL into α-PA6 as the AAP advances, as well as the polymorphic changes of the resulting hybrids as a function of temperature were observed for the first time by in-beam AAP during a WAXS measurement in synchrotron beamline (Figure 1, a). It can be seen that the two crystalline reflections of the α-polymorph are abruptly formed after 10 min of polymerization at 165oC. Until the end of AAP one observes disappearance of CL crystalline reflections whereby amorphous PA6 material is apparently formed. Heating of anionic PA6 to 200oC (b...
A.M.S.C and S.G.C. acknowledge financial support from Fundacao para a Ciencia e Tecnologia (FCT) ... more A.M.S.C and S.G.C. acknowledge financial support from Fundacao para a Ciencia e Tecnologia (FCT) through the grants SFRH/BD/101748/2014 and SFRH/BPD/96797/2013. N.V.D. is grateful for the FCT support through nSTEP project NORTE-07-0124-FEDER-000039.
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