http://hdl.handle.net/2117/3607 Sun, 19 May 2013 00:30:39 GMT 2013-05-19T00:30:39Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18630 Title: High Tg bio-based aliphatic polyesters from bicyclic D-mannitol Authors: Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián Abstract: The carbohydrate-based diol 2,4:3,5-di- O -methylene- D -mannitol (Manx) has been used to obtain aliphatic polyesters. Manx is a symmetric bicyclic compound consisting of two fused 1,3-dioxane rings and bearing two primary hydroxyl groups. In terms of sti ff ness, it is comparable to the widely known isosorbide, but it a ff ords the additional advantages of being much more reactive in polycondensation and capable of producing stereoregular polymers with fairly high molecular weights. A fully bio-based homopolyester (PManxS) has been synthesized by polycondensation in the melt from dimethyl succinate and Manx. The high thermal stability of PManxS, its relatively high glass transition temperature ( T g =68 ° C) and elastic modulus, and its enhanced sensitivity to the action of lipases point to PManxS as a polyester of exceptional interest for those applications where biodegradability and molecular sti ff ness are priority requirements. In addition, random copolyesters (PB x Manx y S) covering a broad range of compositions have been obtained using mixtures of Manx and 1,4-butanediol in the reaction with dimethyl succinate. All PB x Manx y S were semicrystalline and displayed T g values from − 29 to +51 ° C steadily increasing with the content in Manx units. The stress − strain behavior of these copolyesters largely depended on their content in Manx and they were enzymatically degraded faster than PBS. Fri, 05 Apr 2013 08:29:59 GMT http://hdl.handle.net/2117/18630 2013-04-05T08:29:59Z Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián no The carbohydrate-based diol 2,4:3,5-di- O -methylene- D -mannitol (Manx) has been used to obtain aliphatic polyesters. Manx is a symmetric bicyclic compound consisting of two fused 1,3-dioxane rings and bearing two primary hydroxyl groups. In terms of sti ff ness, it is comparable to the widely known isosorbide, but it a ff ords the additional advantages of being much more reactive in polycondensation and capable of producing stereoregular polymers with fairly high molecular weights. A fully bio-based homopolyester (PManxS) has been synthesized by polycondensation in the melt from dimethyl succinate and Manx. The high thermal stability of PManxS, its relatively high glass transition temperature ( T g =68 ° C) and elastic modulus, and its enhanced sensitivity to the action of lipases point to PManxS as a polyester of exceptional interest for those applications where biodegradability and molecular sti ff ness are priority requirements. In addition, random copolyesters (PB x Manx y S) covering a broad range of compositions have been obtained using mixtures of Manx and 1,4-butanediol in the reaction with dimethyl succinate. All PB x Manx y S were semicrystalline and displayed T g values from − 29 to +51 ° C steadily increasing with the content in Manx units. The stress − strain behavior of these copolyesters largely depended on their content in Manx and they were enzymatically degraded faster than PBS. http://hdl.handle.net/2117/18374 Title: Copoliésteres alifáticos derivados del ácido galactárico diacetalizado Authors: Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián Mon, 18 Mar 2013 15:25:18 GMT http://hdl.handle.net/2117/18374 2013-03-18T15:25:18Z Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián no http://hdl.handle.net/2117/18366 Title: Comblike Ionic Complexes of Poly(gamma-glutamic acid) and Alkanoylcholines Derived from Fatty Acids Authors: Tolentino, Ainhoa; León, Salvador; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián Abstract: A series of ionic complexes with almost stoichio- metric composition have been “ synthesized ” from bacterial poly( γ - glutamic acid) and alkanoylcholines derived from fatty acids with 12, 14, 16, and 18 carbon atoms. The complexes were stable up to temperatures close to 200 ° C and were non-water-soluble but readily soluble in organic solvents. In the solid state they adopted the biphasic structure typical of comblike systems with the polypeptide chains arranged in sheets and periodically separated by a para ffi nic phase which was partially crystallized for C14, C16, and C18. The window width of the layered structure was estimated by SAXS to be within the 3.6 − 4.5 nm range, and WAXS showed that the alkyl tails were crystallized in a hexagonally packed lattice with a d 100 spacing of 0.41 nm. These complexes displayed reversible melting of the para ffi nic phase in the 40 − 65 ° C range at temperatures with values increasing with the length of the alkanoyl group. A slight expansion of the intersheet distance occurred at melting followed by contraction upon heating at higher temperatures but without signi fi cant alteration of the layered structure. The 13 C CP-MAS NMR analysis revealed the underlying polymethylene anti -to- gauche conformational conversion that takes place at the thermal transition. An energy-based simulation study of the crystallization process a ff orded a molecular picture of the complex and evidenced the favoring e ff ect of the choline structure on the packing of the alkyl side Mon, 18 Mar 2013 12:26:24 GMT http://hdl.handle.net/2117/18366 2013-03-18T12:26:24Z Tolentino, Ainhoa; León, Salvador; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián no A series of ionic complexes with almost stoichio- metric composition have been “ synthesized ” from bacterial poly( γ - glutamic acid) and alkanoylcholines derived from fatty acids with 12, 14, 16, and 18 carbon atoms. The complexes were stable up to temperatures close to 200 ° C and were non-water-soluble but readily soluble in organic solvents. In the solid state they adopted the biphasic structure typical of comblike systems with the polypeptide chains arranged in sheets and periodically separated by a para ffi nic phase which was partially crystallized for C14, C16, and C18. The window width of the layered structure was estimated by SAXS to be within the 3.6 − 4.5 nm range, and WAXS showed that the alkyl tails were crystallized in a hexagonally packed lattice with a d 100 spacing of 0.41 nm. These complexes displayed reversible melting of the para ffi nic phase in the 40 − 65 ° C range at temperatures with values increasing with the length of the alkanoyl group. A slight expansion of the intersheet distance occurred at melting followed by contraction upon heating at higher temperatures but without signi fi cant alteration of the layered structure. The 13 C CP-MAS NMR analysis revealed the underlying polymethylene anti -to- gauche conformational conversion that takes place at the thermal transition. An energy-based simulation study of the crystallization process a ff orded a molecular picture of the complex and evidenced the favoring e ff ect of the choline structure on the packing of the alkyl side http://hdl.handle.net/2117/18362 Title: Bio-based poly(hexamethylene terephthalate) copolyesters containing cyclic acetalized tartrate units Authors: Japu, Cristina; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; Muñoz Guerra, Sebastián Abstract: A cyclic acetal of dimethyl l-tartrate (dimethyl 2,3-di-O-methylene l-threarate, Thx) was used as comonomer of dimethyl terephthalate (DMT) in the polycondensation with 1,6-hexanediol (HD) in the melt. Random copolyesters PHTxThxy with contents in tartrate units up to 50% were obtained with satisfactory molecular weights (Mw between 20,000 and 50,000) and dispersities slightly above 2, and without apparent discoloration. The copolyesters started to decompose above 300 °C. The Tg of the copolyesters oscillated between +9 and −9 °C with values steadily decreasing with increasing contents in Thx units. All the copolyesters as well as the homopolyester entirely made of tartrate units were semicrystalline with Tm falling from ∼145 °C for PHT to ∼70 °C for PHThx with intermediate values decreasing as the content in Thx increased. Copolyesters containing up to 30% of tartrate units were able to crystallize from the melt at crystallization rates that were delayed by the presence of tartrate units. The PHT70Thx30 copolyester displayed significant hydrodegradability when incubated in aqueous buffer and also certain biodegradability when subjected to the action of porcine pancreas lipases. Mon, 18 Mar 2013 11:26:19 GMT http://hdl.handle.net/2117/18362 2013-03-18T11:26:19Z Japu, Cristina; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; Muñoz Guerra, Sebastián no A cyclic acetal of dimethyl l-tartrate (dimethyl 2,3-di-O-methylene l-threarate, Thx) was used as comonomer of dimethyl terephthalate (DMT) in the polycondensation with 1,6-hexanediol (HD) in the melt. Random copolyesters PHTxThxy with contents in tartrate units up to 50% were obtained with satisfactory molecular weights (Mw between 20,000 and 50,000) and dispersities slightly above 2, and without apparent discoloration. The copolyesters started to decompose above 300 °C. The Tg of the copolyesters oscillated between +9 and −9 °C with values steadily decreasing with increasing contents in Thx units. All the copolyesters as well as the homopolyester entirely made of tartrate units were semicrystalline with Tm falling from ∼145 °C for PHT to ∼70 °C for PHThx with intermediate values decreasing as the content in Thx increased. Copolyesters containing up to 30% of tartrate units were able to crystallize from the melt at crystallization rates that were delayed by the presence of tartrate units. The PHT70Thx30 copolyester displayed significant hydrodegradability when incubated in aqueous buffer and also certain biodegradability when subjected to the action of porcine pancreas lipases. http://hdl.handle.net/2117/17102 Title: Isocyanate toughened pCBT: reactive blending and tensile properties Authors: Abt, Tobias Martin; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Bou Serra, Jordi; Sánchez Soto, Miguel Abstract: Cyclic butylene terephthalate oligomers (CBT) were reacted in a ring-opening polymerization with three types of isocyanates: a bifunctional aromatic type, a bifunctional aliphatic type and a polymeric aromatic isocyanate. All reactions took place in a batch mixer. The use of 0.5 to 1 wt% isocyanate led to a dramatic increase in elongation at break of polymerized cyclic butylene terephthalate (pCBT), from 8 to above 100%. The stiffness and strength of the modified pCBT, however, were found to slightly decrease. Proton nuclear magnetic resonance (NMR) analysis shows that the formation of thermally stable amide groups is the dominant chain extension reaction mechanism. Gel content measurements suggest a linear structure for samples containing bifunctional isocyanates while pCBT modified with polyfunctional isocyanate exhibited some gel formation at higher isocyanate content. Melting and crystallization temperatures as well as degree of crystallinity were found to decrease with increasing isocyanate content. No phase separation was detected by scanning electron microscopy (SEM) analysis. Moreover, a high degree of polymerization is deduced due to the absence of CBT oligomer crystals. Description: Electronic version of an article published as "Express polymer letters" vol. 7, nº. 2, February 2013, p. 172-185. <http://www.expresspolymlett.com/> Tue, 11 Dec 2012 15:45:30 GMT http://hdl.handle.net/2117/17102 2012-12-11T15:45:30Z Abt, Tobias Martin; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Bou Serra, Jordi; Sánchez Soto, Miguel no Cyclic butylene terephthalate oligomers (CBT) were reacted in a ring-opening polymerization with three types of isocyanates: a bifunctional aromatic type, a bifunctional aliphatic type and a polymeric aromatic isocyanate. All reactions took place in a batch mixer. The use of 0.5 to 1 wt% isocyanate led to a dramatic increase in elongation at break of polymerized cyclic butylene terephthalate (pCBT), from 8 to above 100%. The stiffness and strength of the modified pCBT, however, were found to slightly decrease. Proton nuclear magnetic resonance (NMR) analysis shows that the formation of thermally stable amide groups is the dominant chain extension reaction mechanism. Gel content measurements suggest a linear structure for samples containing bifunctional isocyanates while pCBT modified with polyfunctional isocyanate exhibited some gel formation at higher isocyanate content. Melting and crystallization temperatures as well as degree of crystallinity were found to decrease with increasing isocyanate content. No phase separation was detected by scanning electron microscopy (SEM) analysis. Moreover, a high degree of polymerization is deduced due to the absence of CBT oligomer crystals. http://hdl.handle.net/2117/16855 Title: Modification of microbial polymalic acid with hydrophobic amino acids for drug-releasing nanoparticles Authors: Lanz, Alberto; García Álvarez, Montserrat; Portilla Arias, Jose Antonio; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Holler, Eggehard; Ljubimova, Julia Y.; Muñoz Guerra, Sebastián Abstract: Microbial poly( β , L -malic acid) was modifi ed with either L -leucine ethyl ester (L) or L -phenylalanine methyl ester (F) to produce amphiphylic copolymers. The degradation of these copolymers in aqueous buffer took place under physiological conditions in a few weeks by hydrolysis of the side chain ester group followed by cleavage of the main chain. Spherical nanoparticles with diameters ranging between 70 and 230 nm were prepared from these copolymers by the dialysis-precipitation method. No alteration of the cell viability was observed after incubation of these nanoparticles in different cell lines. Anticancer drugs temozolomide and doxorubicin were encapsulated in the nanoparticles. Temozolomide was released within several hours whereas doxorubicin took several weeks to be completely liberated. Wed, 07 Nov 2012 11:06:30 GMT http://hdl.handle.net/2117/16855 2012-11-07T11:06:30Z Lanz, Alberto; García Álvarez, Montserrat; Portilla Arias, Jose Antonio; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Holler, Eggehard; Ljubimova, Julia Y.; Muñoz Guerra, Sebastián no Microbial poly( β , L -malic acid) was modifi ed with either L -leucine ethyl ester (L) or L -phenylalanine methyl ester (F) to produce amphiphylic copolymers. The degradation of these copolymers in aqueous buffer took place under physiological conditions in a few weeks by hydrolysis of the side chain ester group followed by cleavage of the main chain. Spherical nanoparticles with diameters ranging between 70 and 230 nm were prepared from these copolymers by the dialysis-precipitation method. No alteration of the cell viability was observed after incubation of these nanoparticles in different cell lines. Anticancer drugs temozolomide and doxorubicin were encapsulated in the nanoparticles. Temozolomide was released within several hours whereas doxorubicin took several weeks to be completely liberated. http://hdl.handle.net/2117/16853 Title: Comb-like ionic complexes of hyaluronic acid with alkyltrimethylammonium surfactants Authors: Tolentino, Ainhoa; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián Abstract: Stoichiometric complexes of hyaluronic acid with alkyltrimethylammonium surfactants bearing octadecyl, eicosyl and docosyl groups were prepared by ionic coupling in aqueous solution. The complexes were non soluble in water but soluble in organic solvents. In the solid state they self-assembled in a biphasic layered structure with the alkyl side chains forming a separate phase that melted in the 50–60 °C range. They were stable to heating up to above 200 °C. Wed, 07 Nov 2012 10:52:57 GMT http://hdl.handle.net/2117/16853 2012-11-07T10:52:57Z Tolentino, Ainhoa; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián no Stoichiometric complexes of hyaluronic acid with alkyltrimethylammonium surfactants bearing octadecyl, eicosyl and docosyl groups were prepared by ionic coupling in aqueous solution. The complexes were non soluble in water but soluble in organic solvents. In the solid state they self-assembled in a biphasic layered structure with the alkyl side chains forming a separate phase that melted in the 50–60 °C range. They were stable to heating up to above 200 °C. http://hdl.handle.net/2117/16817 Title: Bio-based poly(butylene terephthalate) copolyesters containing bicyclic diacetalized galactitol and galactaric acid: Influence of composition on properties Authors: Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián Abstract: Copolyesters from 1,4-butanediol, dimethyl terephthalate and either 2,3:4,5-di-O-methylene-galactitol or dimethyl 2,3:4,5-di-O-methylene-galactarate with compositions of 10, 20, 30, 40 and 50% of either galactitol or galactarate units were prepared by melt-polycondensation. The copolyesters had Mw in the 32,000–41,000 g mol−1 range and had a random microstructure. They displayed Tg from 20 to 70 °C with values steadily decreasing with the content in galactarate units but increasing with the content in galactitol units. All the copolyesters were semicrystalline with Tm between 115 and 210 °C and they adopted the crystal structure of PBT. Copolyesters containing up to 20% of galactitol units as well as all galactarate copolyesters were able to crystallize from the melt, at a crystallization rate that decreased with the content in carbohydrate-based units. Stress-strain essays revealed an increment in the tensile strength and elastic modulus with increasing contents in galactitol units whereas these parameters decreased when galactarate units were the replacing ones. Mon, 29 Oct 2012 16:43:22 GMT http://hdl.handle.net/2117/16817 2012-10-29T16:43:22Z Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián no Copolyesters from 1,4-butanediol, dimethyl terephthalate and either 2,3:4,5-di-O-methylene-galactitol or dimethyl 2,3:4,5-di-O-methylene-galactarate with compositions of 10, 20, 30, 40 and 50% of either galactitol or galactarate units were prepared by melt-polycondensation. The copolyesters had Mw in the 32,000–41,000 g mol−1 range and had a random microstructure. They displayed Tg from 20 to 70 °C with values steadily decreasing with the content in galactarate units but increasing with the content in galactitol units. All the copolyesters were semicrystalline with Tm between 115 and 210 °C and they adopted the crystal structure of PBT. Copolyesters containing up to 20% of galactitol units as well as all galactarate copolyesters were able to crystallize from the melt, at a crystallization rate that decreased with the content in carbohydrate-based units. Stress-strain essays revealed an increment in the tensile strength and elastic modulus with increasing contents in galactitol units whereas these parameters decreased when galactarate units were the replacing ones. http://hdl.handle.net/2117/16780 Title: Bio-based aromatic polyesters from a novel bicyclic diol derived from D-mannitol Authors: Lavilla Aguilar, Cristina; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián Abstract: 2,4:3,5-Di-O-methylene-D-mannitol, abbreviated as Manx, is a D-mannitol-derived compound with the secondary hydroxyl groups acetalized with formaldehyde. The bicyclic structure of Manx consists of two fused 1,3-dioxane rings, with two primary hydroxyl groups standing free for reaction. A homopolyester made of Manx and dimethyl terephthalate as well as a set of copolyesters of poly(butylene terephthalate) (PBT) in which 1,4-butanediol was replaced by Manx up to 50% were synthesized and characterized. The polyesters had Mw in the 30 000−52 000 g mol−1 range and a random microstructure and were thermally stable up to nearly 370 °C. They displayed outstanding high Tg with values from 55 to 137 °C which steadily increased with the content in Manx. Copolyesters containing up to 40% of Manx were semicrystalline and adopted the crystal structure of PBT. Their stress− strain parameters were sensitively affected by the presence of carbohydrate-based units with elongation at break decreasing but tensile strength and elastic moduli steadily increasing with the degree of replacement. Tue, 23 Oct 2012 10:19:45 GMT http://hdl.handle.net/2117/16780 2012-10-23T10:19:45Z Lavilla Aguilar, Cristina; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián no 2,4:3,5-Di-O-methylene-D-mannitol, abbreviated as Manx, is a D-mannitol-derived compound with the secondary hydroxyl groups acetalized with formaldehyde. The bicyclic structure of Manx consists of two fused 1,3-dioxane rings, with two primary hydroxyl groups standing free for reaction. A homopolyester made of Manx and dimethyl terephthalate as well as a set of copolyesters of poly(butylene terephthalate) (PBT) in which 1,4-butanediol was replaced by Manx up to 50% were synthesized and characterized. The polyesters had Mw in the 30 000−52 000 g mol−1 range and a random microstructure and were thermally stable up to nearly 370 °C. They displayed outstanding high Tg with values from 55 to 137 °C which steadily increased with the content in Manx. Copolyesters containing up to 40% of Manx were semicrystalline and adopted the crystal structure of PBT. Their stress− strain parameters were sensitively affected by the presence of carbohydrate-based units with elongation at break decreasing but tensile strength and elastic moduli steadily increasing with the degree of replacement. http://hdl.handle.net/2117/16756 Title: Poly(gamma-glutamic acid) esters with reactive functional groups suitable for orthogonal conjugation strategies Authors: Pacini, Aurora; Caricato, Marco; Ferrari, Stefania; Capsoni, Doretta; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián; Pasini, Dario Abstract: We report on a series of novel poly(c-glutamic acid) (PGGA) esters, in which the chemical structure and composition, and the molecular weight are systematically changed. Modification of PGGA of microbial origin, used either as the sodium salt or in the free acid form, by means of alkylation with highly reactive bromides under SN2 conditions, affords copolymers with an essentially random microstructure. These reaction conditions are applied iteratively to achieve full esterification, obtaining allyl or propargyl ester functionalities within the polymer backbone, diluted with inert functional groups, such as benzyl, ethyl, or hexyl ester functionalities. The copolymers have been characterized regarding their chemical structure and thermal and bulk properties using nuclear magnetic resonance, thermogravimetry, differential scanning calorimetry, and X-ray diffraction techniques. We demonstrate that allyl and propargyl ester groups can be efficiently transformed using click chemistries, such as thiol-ene or copper(I)- catalyzed azide–alkyne cycloaddition reactions; such efficient conjugation strategies will be required to transformthe native bacterial biopolymer into a material with tailored properties for bulk scale or biomedical applications. Fri, 19 Oct 2012 08:37:43 GMT http://hdl.handle.net/2117/16756 2012-10-19T08:37:43Z Pacini, Aurora; Caricato, Marco; Ferrari, Stefania; Capsoni, Doretta; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián; Pasini, Dario no We report on a series of novel poly(c-glutamic acid) (PGGA) esters, in which the chemical structure and composition, and the molecular weight are systematically changed. Modification of PGGA of microbial origin, used either as the sodium salt or in the free acid form, by means of alkylation with highly reactive bromides under SN2 conditions, affords copolymers with an essentially random microstructure. These reaction conditions are applied iteratively to achieve full esterification, obtaining allyl or propargyl ester functionalities within the polymer backbone, diluted with inert functional groups, such as benzyl, ethyl, or hexyl ester functionalities. The copolymers have been characterized regarding their chemical structure and thermal and bulk properties using nuclear magnetic resonance, thermogravimetry, differential scanning calorimetry, and X-ray diffraction techniques. We demonstrate that allyl and propargyl ester groups can be efficiently transformed using click chemistries, such as thiol-ene or copper(I)- catalyzed azide–alkyne cycloaddition reactions; such efficient conjugation strategies will be required to transformthe native bacterial biopolymer into a material with tailored properties for bulk scale or biomedical applications. http://hdl.handle.net/2117/16666 Title: Study of molecular structure and vibrational spectra of poly (ß,-1-malic acid) [PMLA] using DFT approach Authors: Chaturvedi, D.; Mishra, S.; Tandon, P.; Portilla Arias, Jose Antonio; Muñoz Guerra, Sebastián Abstract: Poly (β-L-malic acid) (PMLA) is a biodegradable polymer and it has various important applications in the biomedical field. In the present work the structural and spectral characteristics of PMLA have been studied by methods of infrared, Raman spectroscopy and quantum chemistry. Electrostatic potential surface, optimized geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by density functional theory (DFT) using oligomeric approach employing B3LYP with complete relaxation in the potential energy surface using 6-311++G (d, p) basis set. Based on results, we have discussed the correlation between the vibrational modes and the structure of the PMLA. A complete analysis of the experimental infrared and Raman spectra has been reported on the basis of wavenumber of the vibrational bands and potential energy distribution. The calculated HOMO and LUMO energies shows that charge transfer occur within the molecule. The calculated infrared and the Raman spectra of the polymer based on DFT calculations show reasonable agreement with the experimental results. Mon, 08 Oct 2012 10:02:50 GMT http://hdl.handle.net/2117/16666 2012-10-08T10:02:50Z Chaturvedi, D.; Mishra, S.; Tandon, P.; Portilla Arias, Jose Antonio; Muñoz Guerra, Sebastián no IR- Raman spectroscopy, Oligomer, PMLA Poly (β-L-malic acid) (PMLA) is a biodegradable polymer and it has various important applications in the biomedical field. In the present work the structural and spectral characteristics of PMLA have been studied by methods of infrared, Raman spectroscopy and quantum chemistry. Electrostatic potential surface, optimized geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by density functional theory (DFT) using oligomeric approach employing B3LYP with complete relaxation in the potential energy surface using 6-311++G (d, p) basis set. Based on results, we have discussed the correlation between the vibrational modes and the structure of the PMLA. A complete analysis of the experimental infrared and Raman spectra has been reported on the basis of wavenumber of the vibrational bands and potential energy distribution. The calculated HOMO and LUMO energies shows that charge transfer occur within the molecule. The calculated infrared and the Raman spectra of the polymer based on DFT calculations show reasonable agreement with the experimental results. http://hdl.handle.net/2117/16502 Title: Carbohydrate-based polyamides and polyesters: an overview illustrated with two selected examples Authors: Muñoz Guerra, Sebastián Abstract: An overview on the synthesis, structure and properties of polyamides and aromatic copolyesters produced by using monomers derived from carbohydrates is provided. Two examples are selected for illustration: (a) aliphatic polyamides prepared from aldaric acids and (b) aromatic copolyesters containing alditols units. Polycondensation in solution of n-alkanediamines (n taking even values from 6 to 12) with activated pentaric (L-arabino and xylo) and hexaric (galacto and D-manno) acids bearing the secondary hydroxyl groups protected as methyl ether, afforded linear polyaldaramides PA-nSu with Mw oscillating between 25 000 and 150 000 g mol 1. They are stable above 300 C and are semicrystalline even so only PA-nMn are stereoregular. Melting temperatures of PA-nSu range between 140 and 230 C and most of them are able to crystallize from the melt at a rate that increases with the length of the polymethylene segment. Both melting and glass transition temperatures decrease with the content in sugar units. Spherulitic films, oriented fibers and lamellar single crystals could be obtained from PA-nSu. All these polyamides seem to adopt a common crystal structure made of hydrogen-bonded sheets with the sugar residue skewed to attain an efficient side-by-side packing of the polymer chains. Aromatic homopolyesters and copolyesters derived from terephthalic acid and mixtures of butylene glycol and O-methylated alditols were prepared by polycondensation in the melt with Mw in the 20 000–50 000 g mol 1 range and a random microstructure. The thermal properties of PBT containing alditols units are very depending on the sugar constitution and copolyester composition. In general they are thermally stable above 300 C and display crystallinity for contents in alditols up to 30%. Melting temperatures decrease with the content in alditols whereas an opposite trend is observed for glass transition temperatures. The crystalline structure of PBT is preserved in the crystalline copolyesters whereas a different crystal lattice is adopted by homopolyesters entirely made of alditol units. In general, polyamides and polyesters containing sugar derived units are widely soluble in organic solvents, markedly hydrophilic and more susceptible to hydrolysis than their parent polymers. Mon, 17 Sep 2012 08:07:40 GMT http://hdl.handle.net/2117/16502 2012-09-17T08:07:40Z Muñoz Guerra, Sebastián no Alditols, Aromatic copolyesters, Butylene glycol, Copolyesters, Crystalline structure, Crystallinities, Homopolyesters, Hydroxyl groups, Methyl ethers, Parent polymers, Polymer chains, Polymethylene, Random microstructure, Selected examples, Semicrystallines, Stereoregular, Structure and properties, Sugar residues, Sugar units, Terephthalic acids, Thermally stable An overview on the synthesis, structure and properties of polyamides and aromatic copolyesters produced by using monomers derived from carbohydrates is provided. Two examples are selected for illustration: (a) aliphatic polyamides prepared from aldaric acids and (b) aromatic copolyesters containing alditols units. Polycondensation in solution of n-alkanediamines (n taking even values from 6 to 12) with activated pentaric (L-arabino and xylo) and hexaric (galacto and D-manno) acids bearing the secondary hydroxyl groups protected as methyl ether, afforded linear polyaldaramides PA-nSu with Mw oscillating between 25 000 and 150 000 g mol 1. They are stable above 300 C and are semicrystalline even so only PA-nMn are stereoregular. Melting temperatures of PA-nSu range between 140 and 230 C and most of them are able to crystallize from the melt at a rate that increases with the length of the polymethylene segment. Both melting and glass transition temperatures decrease with the content in sugar units. Spherulitic films, oriented fibers and lamellar single crystals could be obtained from PA-nSu. All these polyamides seem to adopt a common crystal structure made of hydrogen-bonded sheets with the sugar residue skewed to attain an efficient side-by-side packing of the polymer chains. Aromatic homopolyesters and copolyesters derived from terephthalic acid and mixtures of butylene glycol and O-methylated alditols were prepared by polycondensation in the melt with Mw in the 20 000–50 000 g mol 1 range and a random microstructure. The thermal properties of PBT containing alditols units are very depending on the sugar constitution and copolyester composition. In general they are thermally stable above 300 C and display crystallinity for contents in alditols up to 30%. Melting temperatures decrease with the content in alditols whereas an opposite trend is observed for glass transition temperatures. The crystalline structure of PBT is preserved in the crystalline copolyesters whereas a different crystal lattice is adopted by homopolyesters entirely made of alditol units. In general, polyamides and polyesters containing sugar derived units are widely soluble in organic solvents, markedly hydrophilic and more susceptible to hydrolysis than their parent polymers. http://hdl.handle.net/2117/16205 Title: Biodegradable aromatic copolyesters made from bicyclic acetalized galactaric acid Authors: Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián Abstract: Random poly(hexamethylene terephthalate-co-galactarate) s and poly(dodecamethylene terephthalate-co-galactarate) s copolyesters covering the whole range of compositions were obtained with weight-average molecular weights of 30,000–50,000 g mol 1 by melt polycondensation. They were thermally stable above 300 C, and displayed Tg in the þ20 to 20 C range with values steadily decreasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 50 and 150 C and those made from dodecanediol were able to crystallize from the melt at a crystallization rate depending on composition. Copolyesters containing up to 50% of galactaric units retained the crystal structure of their respective polyterephthalate homopolyesters, whereas they adopted the structure of the respective polygalactarates when the content in Galx units reached 70%. Stress-strain essays revealed decay in the mechanical parameters as the aromatic units were replaced by Galx. Incubation in aqueous buffer revealed that hydrolysis of the polyesters were largely enhanced by copolymerization and evidenced the capacity of the Galx unit for making aromatic polyesters susceptible to biodegradation. A detailed NMR analysis complemented by SEM observations indicated that hydrolysis took place by preferred splitting of galactarate ester bonds with releasing of alkanediol and Galx-diacid. Mon, 09 Jul 2012 11:11:15 GMT http://hdl.handle.net/2117/16205 2012-07-09T11:11:15Z Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián no Random poly(hexamethylene terephthalate-co-galactarate) s and poly(dodecamethylene terephthalate-co-galactarate) s copolyesters covering the whole range of compositions were obtained with weight-average molecular weights of 30,000–50,000 g mol 1 by melt polycondensation. They were thermally stable above 300 C, and displayed Tg in the þ20 to 20 C range with values steadily decreasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 50 and 150 C and those made from dodecanediol were able to crystallize from the melt at a crystallization rate depending on composition. Copolyesters containing up to 50% of galactaric units retained the crystal structure of their respective polyterephthalate homopolyesters, whereas they adopted the structure of the respective polygalactarates when the content in Galx units reached 70%. Stress-strain essays revealed decay in the mechanical parameters as the aromatic units were replaced by Galx. Incubation in aqueous buffer revealed that hydrolysis of the polyesters were largely enhanced by copolymerization and evidenced the capacity of the Galx unit for making aromatic polyesters susceptible to biodegradation. A detailed NMR analysis complemented by SEM observations indicated that hydrolysis took place by preferred splitting of galactarate ester bonds with releasing of alkanediol and Galx-diacid. http://hdl.handle.net/2117/16184 Title: Carbohydrate-based copolyesters made from bicyclic acetalized galactaric acid Authors: Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián Abstract: Mixtures of the dimethyl esters of adipic acid and 2,3:4,5-di-O-methylene-galactaric acid (Galx) were made to react in the melt with either 1,6-hexanediol or 1,12-dodecanediol to produce linear polycyclic copolyesters with aldarate unit contents varying from 10 up to 90 mole %. The copolyesters had weight–average molecular weights in the ∼35,000–45,000 g mol−1 range and a random microstructure, and were thermally stable up to nearly 300 °C. They displayed Tg in the -50 to -7 °C range with values largely increasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 20 and 90 °C but only those made from 1,12-dodecanediol were able to crystallize from the melt at a crystallization rate that decreased as the contents in the two comonomers approached each other. Copolyesters containing minor amounts of galactarate units adopted the crystal structure characteristic of aliphatic polyesters but a new crystal polymorph was formed when the cyclic sugar units became the majority. Stress–strain parameters were sensitively affected by composition of the copolyesters with the mechanical behavior changing from flexible/ductile to stiff/brittle with the replacement of adipate units by the galactarate units. Thu, 05 Jul 2012 09:51:55 GMT http://hdl.handle.net/2117/16184 2012-07-05T09:51:55Z Lavilla Aguilar, Cristina; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Benito, Elena; García Martín, Maria de Gracia; Galbis Pérez, Juan Antonio; Muñoz Guerra, Sebastián no Mixtures of the dimethyl esters of adipic acid and 2,3:4,5-di-O-methylene-galactaric acid (Galx) were made to react in the melt with either 1,6-hexanediol or 1,12-dodecanediol to produce linear polycyclic copolyesters with aldarate unit contents varying from 10 up to 90 mole %. The copolyesters had weight–average molecular weights in the ∼35,000–45,000 g mol−1 range and a random microstructure, and were thermally stable up to nearly 300 °C. They displayed Tg in the -50 to -7 °C range with values largely increasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 20 and 90 °C but only those made from 1,12-dodecanediol were able to crystallize from the melt at a crystallization rate that decreased as the contents in the two comonomers approached each other. Copolyesters containing minor amounts of galactarate units adopted the crystal structure characteristic of aliphatic polyesters but a new crystal polymorph was formed when the cyclic sugar units became the majority. Stress–strain parameters were sensitively affected by composition of the copolyesters with the mechanical behavior changing from flexible/ductile to stiff/brittle with the replacement of adipate units by the galactarate units. http://hdl.handle.net/2117/15764 Title: Poly(ethylene terephthalate) terpolyesters containing 1,4-cyclohexanedimethanol and isosorbide Authors: Quintana Vicente, Robert; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; Muñoz Guerra, Sebastián Abstract: A series of poly(ethylene terephthalate) terpolyesters containing varying amounts of both 1,4-cyclohexylenedimethylene and isosorbide units were prepared by melt phase polycondensation. These terpolymers were obtained with high molecular weights and polydispersities around 2.0–2.5. The nuclear magnetic resonance data revealed that they were all random terpolymers and that small amounts of isosorbide were lost during the polycondensation reaction. Thermal data showed that terpolymers with 90 mol% of ethylene units were crystalline, whereas the two other series containing 80 and 70 mol% were unable to crystallize from the melt. For the three series studied, it was observed that the glass transition temperature increased steadily with the content of isosorbide units, and that they had similar thermal stability. Thu, 26 Apr 2012 09:59:32 GMT http://hdl.handle.net/2117/15764 2012-04-26T09:59:32Z Quintana Vicente, Robert; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Alla Bedahnane, Abdelilah; Muñoz Guerra, Sebastián no A series of poly(ethylene terephthalate) terpolyesters containing varying amounts of both 1,4-cyclohexylenedimethylene and isosorbide units were prepared by melt phase polycondensation. These terpolymers were obtained with high molecular weights and polydispersities around 2.0–2.5. The nuclear magnetic resonance data revealed that they were all random terpolymers and that small amounts of isosorbide were lost during the polycondensation reaction. Thermal data showed that terpolymers with 90 mol% of ethylene units were crystalline, whereas the two other series containing 80 and 70 mol% were unable to crystallize from the melt. For the three series studied, it was observed that the glass transition temperature increased steadily with the content of isosorbide units, and that they had similar thermal stability.