Lourdes Franco

Lourdes Franco
Universitat Politècnica de Catalunya | UPC · Department of Chemical Engineering (EQ)

PhD in Chemistry

About

133
Publications
21,760
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2,443
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Introduction
Additional affiliations
January 1990 - present
Universitat Politècnica de Catalunya
Position
  • Researcher

Publications

Publications (133)
Article
Full-text available
In the area of coating development, it is extremely difficult to find a substitute for bisphenol A diglycidyl ether (DGEBA), the classical petroleum-based raw material used for the formulation of epoxy thermosets. This epoxy resin offers fast curing reaction with several hardeners and the best thermal and chemical resistance properties for applicat...
Article
Full-text available
Different copolymers incorporating terpene oxide units (e.g., limonene oxide) have been evaluated considering thermal properties, degradability, and biocompatibility. Thus, polycarbonates and polyesters derived from aromatic, monocyclic and bicyclic anhydrides have been considered. Furthermore, ring substitution with myrcene terpene has been evalua...
Article
Full-text available
This article shows a simple and scalable strategy to prepare a series of thermoresponsive polyurethanes synthesized via copolymerization of dicyclohexyl diisocyanate with glycerol ethoxylate in a single one pot system. These polyurethanes exhibit lower critical solution temperatures (LCST) at 57 ºC. The LCST of synthesized polyurethane was determin...
Article
Melt electrospinning of polylactide (PLA) loaded with chloramphenicol (CAM) has been performed and characteristics of fibers, physical properties of scaffolds, CAM release behavior, antibacterial properties and biocompatibility have been evaluated. The interest of CAM loaded samples is nowadays enhanced for biomedical applications since this antibi...
Article
Electrospun scaffolds of the biodegradable and biocompatible poly‐4‐hydroxybutyrate (P4HB) polyester have been prepared using horizontal and vertical set‐up configurations of electrospinning. Specifically, it has been evaluated the influence of solvent, polymer concentration, and processing parameters, such as applied voltage, flow rate, and needle...
Article
Ultrasound micromolding (USM) preparation of hybrid scaffolds based on polylactide (PLA) and hydroxyapatite (HAp) particles has been evaluated. PLA was stable under the applied ultrasound source since a minimum degradation was detected. Porous materials were achieved using polyethylene glycol (PEG) and NaCl salts to the initial PLA and the subseque...
Article
Hydrolytic degradation of poly(4-hydroxybutyrate) (P4HB) films has been studied considering media of different pH values (i.e., 3, 7 and 10) and temperatures (i.e., 37 and 55 °C). Enzymatic degradation has also been evaluated at physiological conditions using two different lipases: Pseudomonas cepacia and Rhizopus oryzae. Different bulk and surface...
Article
The influence of curcumin on the thermal stability and degradation kinetics of poly(glycolic acid) (PGA), poly-ε-caprolactone (PCL) and their blend has been investigated in detail using thermogravimetric analysis. A 50/50 ratio was chosen for the blend and the effect caused by the addition of different percentages of curcumin (CUR) was evaluated. T...
Article
The main aim of the present work was to approach the effect of the addition of an organic acid dopant, dodecylbenzenesulfonic acid (DBSA), in the preparation of poly(4,4-diphenylether-5,5-dibenzimidazole) (OPBI) films, commonly used as proton exchange membranes (PEMs). For this purpose, DBSA was blended with OPBI polymer matrix, at different concen...
Article
Full-text available
Fibers of poly(4-hydroxybutyrate) (P4HB) have been submitted to both hydrolytic and enzymatic degradation media in order to generate samples with different types and degrees of chain breakage. Random chain hydrolysis is clearly enhanced by varying temperatures from 37 to 55 °C and is slightly dependent on the pH of the medium. Enzymatic attack is a...
Article
Development of smart functionalized materials for tissue engineering has attracted significant attention in recent years. In this work we have functionalized a free-standing film isotactic polypropylene (i-PP), a synthetic polymer that is typically used for biomedical applications (e.g. fabrication of implants), for engineering a 3D all-polymer fle...
Article
Full-text available
This article describes the design and synthesis of a new series of hydrogel membranes composed of trialkyne derivatives of glycerol ethoxylate and bisphenol A diazide (BA‐diazide) or diazide‐terminated PEG600 monomer via a Cu(I)‐catalyzed photoclick reaction. The water‐swollen hydrogel membranes display thermoresponsive actuation and their lower cr...
Article
Full-text available
In article number 2001683, David Díaz Díaz and co‐workers present a series of strong hydrogel membranes prepared via Cu(I)‐catalyzed photo‐click polymerization using a glycerol ethoxylate core. These materials display thermoresponsive and shape‐memory actuation based on a judicious hydrophilic‐hydrophobic molecular balance, and present a high poten...
Article
Blends with different ratios of polylactide and polyamide 6,10 (PA610) have been prepared by melt-mixing using a Brabender mixer equipment. Previously, a rheologically modified polylactide (PLAREx) was obtained through reactive extrusion using a multifunctional epoxide agent. It was expected that unreacted epoxy groups of PLAREx were able to improv...
Article
Full-text available
Ultrasound micromolding technology has been applied to get microporous polylactide scaffolds from the subsequent leaching of incorporated NaCl salts. A small amount of water-soluble polyethylene glycol (PEG) was required in order to improve the leaching process and get compact pieces with interconnected pores. Distribution of polymers in the proces...
Article
Incorporation of aliphatic units to poly(butylene terephthalate) (PBT) gives rise to biodegradable copolymers with tunable properties (e.g., degradability), depending on the selected comonomer and the specific composition. Specifically, a low molecular weight poly(butylene sebacate-co-terephthalate) (PBSeT) with a high ratio of aliphatic sebacate u...
Article
Full-text available
Chloramphenicol (CAM) has been encapsulated into hydroxyapatite nanoparticles displaying different morphologies and crystallinities. The process was based on typical precipitation of solutions containing phosphate and calcium ions and the addition of CAM once the hydroxyapatite nuclei were formed. This procedure favored a disposition of the drug in...
Article
Poly(l-lactide)s (PLLAs) with different chain structures were prepared by reactive melt processing and using Joncryl ADR as chain extender. Results of gel permeation chromatography (GPC) revealed that chain extended PLLAs had high molecular weights and two differentiated molecular weight distributions. Linear rheology was sensitive to the obtained...
Article
Full-text available
Thermal properties and crystallization kinetics of poly(4-hydroxybutyrate) (P4HB) have been studied. The polymer shows the typical complex melting behavior associated to different lamellar populations. Annealing processes had great repercussions on properties and the morphology of constitutive lamellae as verified by X-ray scattering data. Kinetics...
Article
Full-text available
The non-isothermal crystallization of the biodegradable poly(4-hydroxybutyrate) (P4HB) has been studied by means of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). In the first case, Avrami, Ozawa, Mo, Cazé, and Friedman methodologies were applied. The isoconversional approach developed by Vyazovkin allowed also the...
Article
Full-text available
A technology based on the application of ultrasound as an energy source was applied to get polylactide (PLA) micropieces with minimum degradation and processing time. This requirement could be even shorter than 1.5 s. The ultrasound technology was also demonstrated to be efficient for the incorporation of drugs with a pharmacological activity. Thus...
Article
Cellulose-based supercapacitors display important advantages in comparison with devices fabricated with other materials, regarding environmental friendliness, flexibility, cost and versatility. Recent progress in the field has been mainly focused on the utilization of cellulose fibres as: structural mechanical reinforcement of electrodes; precursor...
Article
Full-text available
Copolyamides derived from even 1,4-butanediamine and different mixtures of odd dicarboxylic acids with a great difference in the number of methylene groups (i.e., glutaric and azelaic acids with 3 and 7 groups, respectively) have been synthesized, characterized and structurally studied. Calorimetric analyses revealed a complex behavior with multipl...
Article
Full-text available
Isothermal and nonisothermal crystallization kinetics of poly(l-lactide) and its nanocomposites with different multiwalled carbon nanotubes (i.e., pristine and functionalized) were investigated. The effects of chain extension and nanofiller content on the crystallization kinetics were also explored. The Avrami analysis was applied as a useful tool...
Article
We employ broadband dielectric spectroscopy to study the relaxation dynamics and crystallization kinetics of a broad-spectrum antibiotic, chloramphenicol, in its supercooled liquid form. Two dynamic processes are observed: the structural α relaxation, which becomes kinetically frozen at Tg = 302 ± 1 K, and an intramolecular secondary relaxation. Un...
Article
Three isomeric ionene polymers containing 1,4-diazabicyclo[2.2.2]octane (DABCO) and N,N’-(x-phenylene)dibezamide (x= ortho- / meta- / para-) linkages have been used as dopant agents to produce n-doped poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes by reducing already dedoped conducting polymer (CP) films. This work focuses on the influence of...
Article
Full-text available
Crystalline morphology and structure of nylon 4 9 have been studied by means of optical and transmission electron microscopies, and X-ray diffraction. Rhombic crystals were characteristic of crystallization from glycerin dilute solutions, although the final morphology was dependent on the crystallization temperature. In any case, a single electron...
Article
Frontispiece: Poly(ε-caprolactone) matrices reinforced with well distributed nanofibers of a polyglycolide rich copolymer have been prepared by molding multilayered assemblies of alternate PCL films and electrospun scaffolds. Efficient encapsulation of chlorhexidine and short and long term tunable release were achieved. This is reported by Yolanda...
Article
Electrospun scaffolds constituted by different mixtures of two biodegradable polyesters are prepared. Specifically, materials with well differentiated properties can be derived from the blending of hydrophilic polyglycolide (PGA) and hydrophobic poly(ε‐caprolactone) (PCL), which are also two of the most applied polymers for biomedical uses. Electro...
Article
Electrospinning of a segmented copolymer having polyglycolide hard segments is successfully performed from 1,1,1,3,3,3-hexafluoroisopropanol solutions. During the process, a bactericidal agent, i.e., chlorhexidine (CHX), is effectively loaded, which results in nanofibers with a smaller diameter because of the change in solution conductivity. New fa...
Article
Full-text available
Poly(ε-caprolactone) (PCL) films reinforced with polylactide (PLA) microfibers were prepared by two methodologies: a) melt pressing of an electrospun PLA mat between two PCL films, and b) melt pressing of a co-electrospun mat composed of PLA microfibers and PCL nanofibers. Electrospinning conditions were selected for each polymer to obtain films lo...
Article
Random copolyesters having 1,4-butanediol units were synthesized from a transesterification process between homopolymers constituted by aliphatic dicarboxylates (i.e. succinate, adipate or sebacate) and the aromatic therephthalate derivative, as verified by NMR spectroscopy. Biodegradability of resulting copolyesters was studied via enzymatic hydro...
Article
Full-text available
Ultrasound micro-molding technology was successfully applied to prepare nanocomposites based on a poly(ε-caprolactone) (PCL) matrix and multi-walled carbon nanotubes (MWCNTs). Optimization of processing parameters (i.e., amplitude, force and time) was crucial to obtain nanocomposites without any evidence of degradation, high material saving and sho...
Article
Incorporation of chloramphenicol and captopril into coated and uncoated monofilament sutures was evaluated, as well as the derived bactericide and wound healing effects. To this end, a commercially available suture and an amorphous random copolymer constituted by trimethylene carbonate and lactide units were considered. The suture had a segmented a...
Article
Thermal stability and degradation kinetics have been studied for a series of aliphatic-aromatic copolyesters where the terephthalate content was varied between 30 mol-% and 70 mol-%. Succinate, adipate and sebacate were considered as the aliphatic dicarboxylate unit. All copolyesters were synthesized with a perfect random distribution by a thermal...
Article
The encapsulation of amino acids (AAs) and their correct preservation before they are ingested are challenging tasks. Nonpolar (l-alanine and l-phenylalanine), polar (l-cysteine hydrochloride and l-asparagine), and charged (l-lysine hydrochloride and l-aspartic acid) AAs were loaded into biodegradable and nontoxic poly(tetramethylene succinate) (PE...
Article
Polyalkylene dicarboxylates derived from 1,9-nonanediol and mixtures with different ratios of pimelic acid and azelaic acid were synthesized by thermal polycondensation. All samples had a high degree of crystallinity although it was found to decrease with the comonomer content. Crystallization kinetics of the two homopolymers and the copolymer with...
Article
In the present study poly (butylene sebacate-co-terephthalate)s having different compositions were synthesized with a high yield and a random distribution by thermal transesterification of poly (butylene sebacate) and poly (butylene terephthalate) homopolymers. The copolymer with the highest comonomer ratio was the least crystalline sample, althoug...
Article
A new biodegradable coating was developed for bioabsorbable monofilament sutures. Specifically, a random copolymer having 35 wt-% and 65 wt-% of lactide and trimethylene carbonate units showed appropriate flexibility, stickiness and degradation rate, as well as capability to produce a complete and uniform coating. Monofilament sutures of polyglycol...
Article
Non-isothermal crystallization kinetics of polydioxanone (PDO), a polymer with well-established applications as bioabsorbable monofilar suture, was investigated by Avrami, Mo, and isoconversional methodologies. Results showed Avrami exponents appearing in a relatively narrow range (i.e., between 3.76 and 2.77), which suggested a three-dimensional s...
Article
Structural transitions of nylons 8 9 and 12 9 heating and cooling processes were investigated using calorimetric, spectroscopic during and real time X‐ray diffraction data. These even‐odd nylons had three polymorphic forms related to structures where hydrogen bonds were established in two planar directions. Heating processes showed a first structur...
Article
Full-text available
Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The seco...
Article
Increasing interest for the application of polypeptide-based smart systems in the biomedical field has developed due to the advantages given by the peptidic sequence. This is due to characteristics of these systems, which include: biocompatibility, potential control of degradation, capability to provide a rich repertoire of biologically specific in...
Article
Full-text available
Development of materials with an antimicrobial activity is fundamental for different sectors, including medicine and health care, water and air treatment, and food packaging. Electrospinning is a versatile and economic technique that allows the incorporation of different natural, industrial, and clinical agents into a wide variety of polymers and b...
Article
Crystallization of a biodegradable segmented copolymer constituted by polyglycolide hard segments and a middle soft segment constituted by a random disposition of glycolyl, e-caproyl and trimethylene carbonyl units has been studied bymeans of optical microscopy, atomic force microscopy and time resolved X-ray diffraction techniques. This Poly(GL)-b...
Article
Full-text available
Hydrolytic degradation in media having a continuous variation of pH from 2 to 12 was studied for a copolymer having two polyglycolide hard blocks and a middle soft segment constituted by glycolide, trimethylene carbonate, and ɛ-caprolactone units. The last units were susceptible to cross-linking reactions by γ irradiation that led to an increase of...
Article
Spherulitic morphologies of nylon 6 9 as an example of an even-odd nylon were studied by optical microscopy. A well-defined dependence on crystallization temperature was found. In particular, positively birefringent spherulites were characteristic for temperatures higher than 232 °C, low birefringence spherulites developed between 232 and 225 °C, p...
Article
Crystallization of multiarm star systems constituted by a core of poly(ethyleneimine) (PEI) and arms of poly(e-caprolactone) (PCL) was studied by transmission electron microscopy, calorimetry and optical microscopy techniques. Three systems differing on the degree of polymerization of PCL were studied as well as binary mixtures constituted by syste...
Article
Ultrasound micro-molding technology has been tested as a new method to get polymer/clay nanocomposites. Biodegradable polylactide (PLA) and poly (nona-methylene azelate) (PE99) have been used as polymer matrices, whereas different silicate clays have been assayed. The new technology is able to get specimens without evidences of degradation during p...
Conference Paper
Even-odd nylons constitute a peculiar group of polyamides because hydrogen-bonding intermolecular interactions cannot be established between molecular chains having an all-trans conformation. Nevertheless, characteristic spacings associated to this crystalline structure can be detected depending on the crystalli-zation process. Furthermore, even-od...
Article
Lactide and trimethylene carbonate copolymers were successfully grafted with polyethylene glycol via previous functionalization with maleic anhydride and using N,N'-diisopropylcarbodiimide as condensing agent. Maleinization led to moderate polymer degradation. Specifically, the weight average molecular weight decreased from 36,200 to 30,200g/mol fo...
Article
Kinetics of isothermal and non-isothermal crystallization studies of a biodegradable monofilament suture constituted by polyglycolide hard blocks and soft segments derived from glycolide, epsilon-caprolactone and trimethylene carbonate have been undertaken by means of calorimetric methods. This segmented polymer was semicrystalline with melting and...
Article
Nanomembranes have been prepared by spin-coating mixtures of a polythiophene (P3TMA) derivative and thermoplastic polyurethane (TPU) using 20:80, 40:60 and 60:40 TPU:P3TMA weight ratios. After structural, topographical, electrochemical and thermal characterization, properties typically related with biomedical applications have been investigated: sw...
Article
The synthesis of a series of poly(ester amide)s constituted by glycolic acid, adipic acid, and different ratios of 1,3-pentanediamine and 1,5-pentanediamine units was studied and the derived copolymers were characterized. Thermal polycondensation between the potassium adipate salt and the appropriate ratio of N,N′-bis(chloroacetyl)-1,3-pentanediami...
Article
Poly(butylene azelate-co-butylene succinate) samples with different azelate/succinate ratios were synthesized and characterized. Calorimetric data indicate a semicrystalline character for all copolyesters studied and a melting point depression that could be interpreted on the basis of complete exclusion of comonomers from well organized lamellae. C...
Article
Ultrasound technology was proved as an efficient processing technique to obtain micro-molded specimens of polylactide (PLA) and polybutylene succinate (PBS), which were selected as examples of biodegradable polyesters widely employed in commodity and specialty applications. Operational parameters such as amplitude, molding force and processing time...
Article
The hydrolytic degradation of Monosyn (TM), a segmented copolymer derived from glycolide, trimethylene carbonate and epsilon-caprolactone, has been evaluated in buffered aqueous media at different pH and temperature. Degradation processes have been followed by considering mass loss and molecular weight profiles as well as the changes on H-1 NMR and...
Article
Random copolymers derived from 1,4-butanediol and two dicarboxylic units differing in the parity of the number of methylene groups and length of the polymethylene sequence (i.e. succinic and azelaic acids) were studied in terms of thermal properties, crystalline structure and morphology, crystallization kinetics and biodegradability. All samples we...
Article
Basic diffraction data on nylon 47 pointed out a peculiar structure of hydrogen bonds along two directions. Nylon 47 showed reversible polymorphic transitions during heating/cooling processes that were analyzed by real time synchrotron WAXD experiments. Results indicated that nylon 47 had a first structural transition at low temperature, followed b...
Article
Full-text available
Free-standing and supported nanomembranes have been prepared by spin-coating mixtures of a semiconducting polythiophene (P3TMA) derivative and thermoplastic polyurethane (TPU). Thermal studies of TPU:P3TMA blends with 60 : 40, 50 : 50, 40 : 60 and 20 : 80 weight ratios indicate a partial miscibility of the two components. Analysis of the glass tran...
Article
Hydrolytic degradation of a series of copolymers synthesized by ring opening polymerization of trimethylene carbonate and glycolide was studied by following the weight loss and changes in molecular weight, polydispersity index and mechanical properties. Analyses of 1H NMR and FTIR spectra taken during exposure to a pH 7.4 phosphate buffered solutio...
Article
The thermal stability and degradation kinetics of poly(trimethylene carbonate) (PTMC) blends with different ratios of polylactide (PLA) and alternatively polycaprolactone (PCL) were investigated by thermogravimetric analysis under a nitrogen atmosphere. These studies were extended to the single components (i.e. PCL and PLA). In all cases, the deriv...
Article
The polymerization kinetics of potassium chloroacetate (MGL), potassium N-chloroacetyl-6-aminohexanoate (MEA), and their mixtures was studied by Fourier transform infrared spectroscopy. The bulk polycondensation reaction was faster for MEA than for MGL but kinetic differences in the selected temperature range (110–130°C) were not large enough to ma...
Article
In this study we prepared blends of polystyrene (PS) and high-impact polystyrene (HIPS) with poly(styrene-ethylene-butylene) (SEBS) triblock copolymer. After sulfonation, blends were used to fabricate ion-exchange membranes by solvent-casting and subsequent thermal treatment to obtain homogeneous packing densities. The morphology and structure of t...
Article
Copolymers of glycolide and trimethylene carbonate with different compositions and microstructures (i.e. random, blocky and segmented) were synthesized by two-step ring opening polymerization.NMR analyses revealed that transesterification reactions took place during the first step, which corresponded to the synthesis of soft segments, and mainly wh...