Juan P Fernández-Blázquez

Juan P Fernández-Blázquez
Madrid Institute for Advanced Studies | IMDEA · Multifunctional composites

PhD in Organic Chemistry

About

78
Publications
11,041
Reads
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1,102
Citations
Additional affiliations
January 2009 - November 2011
Max Planck Institute for Polymer Research
Position
  • PostDoc Position
January 2008 - December 2009
Florida State University
Position
  • PostDoc Position
October 2001 - July 2007
Instituto de Ciencia y Tecnología de Polímeros
Position
  • PostDoc Position

Publications

Publications (78)
Article
Construction of fire retardant performance for polymer via protection from intumescent char is an efficient approach. In this work, the mechanical strength and effectiveness of the char barrier to provide fire retardancy towards epoxy resin were investigated. The compression tests under controlled force mode were carried out by dynamic mechanical a...
Article
The feasibility to manufacture scaffolds of poly-lactic acid reinforced with Zn particles by fused filament fabrication is demonstrated for the first time. Filaments of 2.85 mm in diameter of PLA reinforced with different weight fractions of μm-sized Zn - 1 wt. % Mg alloy particles (in the range 3.5 to 17.5 wt. %) were manufactured by a double extr...
Article
Full-text available
Cottonseed protein (CP) was compounded with polycaprolactone (PCL) in different concentrations by melt blending, and then hot-pressed to prepare CP/PCL blend films. A co-continuous phase is formed when the CP/PCL content is 50/50, and the tensile strength, modulus and toughness are 9, 10, and 63 times greater than that of neat CP film. This remarka...
Article
Full-text available
Selective laser sintering (SLS) of polymers has made possible the introduction of lattice-based cells as building blocks of polymer parts, allowing to obtain optimal specific properties. The actual mechanical performance of an SLS part is strongly dependent on the printing direction and part shape. Nevertheless, macroscopic testing is not usually p...
Article
Purpose This paper aims to develop a novel strategy to manufacture poly-lactic acid (PLA) filaments reinforced with Mg particles for fused filament fabrication of porous scaffolds for biomedical applications. Design/methodology/approach The mixture of PLA pellets and Mg particles was extruded twice, the second time using a precision extruder that...
Article
Herein, a novel molecularly imprinted polymer (MIP) based electrochemical sensor for the determination of the receptor-binding domain of SARS-CoV-2-RBD (SARS-CoV-2-RBD) has been developed. For this purpose, first, a macroporous gold screen-printed electrode (MP-Au-SPE) has been fabricated. The MIP was then synthesized on the surface of the MP-Au-SP...
Article
In this work, we investigate gel-polymer electrolytes (GPEs) made of porous PVDF-HFP swollen by concentrated solutions of LiTFSI salt in DMC:FEC mixtures. The porous nature of the polymer matrix allows achieving high values of electrolyte uptake while keeping adequate mechanical stability. As a result, the ionic conductivity values of the different...
Article
Recycled carbon fibres have been employed as a reinforcement material for the synthesis of polypropylene-based thermoplastic matrix composites with different fibre/resin ratios (10, 20 and 30%) by means of injection moulding. A thorough study of their mechanical properties including tensile, impact and bending tests, as well as fibre distribution a...
Article
3D printing of continuous carbon fibre reinforced composites (CCFRC) based on fused filament fabrication (FFF) has a great potential for reproducing robust and complex geometries, generating little waste. However, 3D printed CCFRC present relatively poor interlaminar bonding and high void content in comparison to traditional composites. This work a...
Article
Food packaging for traditional foods mainly serves to isolate foods from external environmental. For this reason, it is a growing interest in developing active packaging materials that can extend foodstuff shelf-life. Also, it could counteract the level of contamination by plastic in the environment using biodegradable polymers. For this purpose, p...
Article
Full-text available
Polyetheretherketone (PEEK)/polyetherimide (PEI) blends (50/50, v/v) keeping the crystal phase of PEEK have been manufactured by alternate PEEK/PEI layer stacking. This strategy avoided the complete miscibility of both polymers, keeping layers of PEEK and PEI unmixed along the sample thickness, as well as promoting the formation of a smooth interfa...
Article
Full-text available
An approach of largely improving the properties of protein-based biopolymers is reported. Cottonseed protein concentrate (CPC) purified from cottonseed protein powder waste, with a protein content of >70% and a plasticizing efficiency of 4.2, was used to produce bioplastic polymer. A prepreg consisting of relatively oriented sisal fiber (SF) was tr...
Article
Full-text available
A novel halogen-free flame retardant containing sulfonamide, 1,3,5,7-tetrakis (phenyl-4-sulfonamide) adamantane (FRSN) was synthesized and used for improving the flame retardancy of largely used polycarbonate (PC). The flame-retardant properties of the composites with incorporation of varied amounts of FRSN were analyzed by techniques including lim...
Article
This research provides a thorough study of the mechanical response of PCL scaffolds and determines their deformation micromechanisms at different scales by a combination of experimental techniques (mechanical tests, scanning electron microscopy, wide angle X-ray diffraction and small-angle X-ray scattering). Scaffolds with different fibre orientati...
Article
Graphene has recently become one of the preferred conductive materials for smart textiles. The most widely employed strategy to integrate graphene into textiles consists of coating the surface of the target substrate. However, this approach presents limitations related to the preparation of the coating material and its performance during work. Here...
Article
This work presents a new family of bio-hybrid light-emitting diodes (Bio-HLEDs) using all-bio color down-converting coatings that combine silk fibroin (SF) as a packaging matrix and fluorescent proteins (FPs) as emitters. The thermal, mechanical, optical, and luminescent features of the FP–SF bio-phosphors were optimized with respect to the blend c...
Article
Full-text available
The state-of-the-art process for additive manufacturing of continuous-fibre reinforced polymers is fused filament fabrication (FFF), which has potential for reproducing robust and complex geometries. However, at the present, the mechanical performance of the resulting parts is affected by the low adhesion between layers and the high concentration o...
Article
Full-text available
Current studies on nanocomposites have focused on their multifunctional properties and their industrial production. In this work, polyetheretherketone (PEEK)/graphene nanoplate (GNP) composites were produced by a direct semi-industrial process. Different percentages of untreated GNP (1, 5, and 10 wt.%) were added to PEEK by employing melt-compoundi...
Article
Full-text available
Bio-hybrid light-emitting diodes (Bio-HLEDs) based on color down-converting filters with fluorescent proteins (FPs) have achieved moderate efficiencies (50 lm/W) and stabilities (300 h) due to both thermal- and photo-degradation. Here, we present a significant enhancement in efficiency (~130 lm/W) and stability (>150 days) using a zero-thermal-quen...
Article
Three microporous organic frameworks (hereafter denoted as MPOF-Ads) based on a rigid adamantane core have been successfully synthesized via Sonogashira-Hagihara polycondensation coupling in high yields, 83.7-94.6%. The obtained amorphous MPOF-Ads networks have high BET surface areas (up to 737.3 m2 g-1), narrow pore size distribution (0.95-1.06 nm...
Article
Full-text available
Color down‐converting filters with fluorescent proteins (FPs) embedded in a polymer matrix have led to new bio‐hybrid light‐emitting diodes (Bio‐HLEDs), featuring stabilities of 100 h and <1 min at low and high applied currents, respectively. Herein, the FP deactivation mechanism in Bio‐HLEDs at high driving currents is deciphered. Primarily, the n...
Article
Full-text available
The directed assembly of conjugated polymers into macroscopic organization with controlled orientation and placement is pivotal in improving device performance. Here, the supramolecular assembly of oriented spherulitic crystals of poly(3‐butylthiophene) surrounding a single carbon nanotube fiber under controlled solvent evaporation of solution‐cast...
Article
The effects of high loading of carbon nanotube (CNT) fibers on the morphological, thermal, and crystallization properties of polylactic acid (PLA) in PLA‐CNT fiber composites are investigated. The fabrication methods ensure full impregnation of the fiber by PLA and formation of a large fiber/polymer interface, resulting in an oriented transcrystall...
Preprint
We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentati...
Article
Full-text available
Reported tensile mechanical properties of many natural plant fibres vary to a large extent due to very often inappropriate measurement of the fibre’s cross-sectional area by diameter estimation. Using natural ramie filament as a model testing elementary fibre, a more realistic stereological determination is presented, including microscopic imaging...
Article
The current work reports the preparation of nanocomposites of polysulfone (PSU) reinforced with reduced graphene oxide (rGO) by a solvent-free extrusion-injection method. In order to improve nanofiller dispersation, rGO was covalently grafted with PSU brushes via click chemistry. Several rGO/PSU nanocomposites with concentrations up to 3% (by weigh...
Article
Full-text available
The effect of the graphene nanoplateletets (GNP), at concentration of 1, 5 and 10 wt %, in Poly ether ether ketone (PEEK) composite crystallization from melt and during cold crystallization were investigated by differential scanning calorimetry (DSC) and real time X-ray diffraction experiments. DSC results revealed a double effect of GNP: (a) nucle...
Article
The local mechanical properties of hierarchically reinforced laminates of graphene-isotactic polypropylene (iPP) and carbon fibres are investigated by nanoindentation. Carbon fibre fabrics are alternated with films of iPP reinforced with different graphene contents and types (pristine and modified with iPP brushes). The distribution of the mechanic...
Article
Macroscopic fibres of carbon nanotubes are hierarchical structures combining long building blocks preferentially oriented along the fibre axis and a large porosity arising from the imperfect packing of bundles. Synchrotron small-angle X-ray scattering SAXS measurements show that such structure is a surface fractal with fractal dimension (Ds) of 2.5...
Article
Full-text available
Development of biomass-derived materials using sustainable practices has been one of the major scientific aims over the last few decades. A new class of bio-derived nanocomposite derived from epoxidised linseed oil, a bio-derived crosslinker and a starch based carbonaceous mesoporous material (Starbon®) has been developed. The use of Starbons® tech...
Article
To overcome the flammability of epoxy resins, novel nitrogen (CNx) and oxygen (COx) doped CNT were synthesized via CVD method and epoxy nanocomposites at 2 wt.%. constant loading were prepared by three roll milling and cured. The structures of the nanotubes were confirmed by XRD, XPS, SEM and Raman and it was found a very high aspect ratio especial...
Article
This article presents the preparation of a smectic liquid-crystalline elastomer from a main-chain polybibenzoate with cross-linkable methacrylate groups incorporated at the ends of the polymeric chains. The advantage of this functionalization is that it can be thermally cross-linked in the bulk state without initiator. Rheological experiments have...
Article
In this work we study the reinforcement of polymers by mechanically interlocked derivatives of single-walled carbon nanotubes (SWNTs). We compare the mechanical properties of fibers made of polymers and of composites with pristine single-walled carbon nanotubes (SWNTs), mechanically interlocked derivatives of SWNTs (MINTs) and the corresponding sup...
Article
The role played by mesophases in the ordering of polymers, namely if they are either competitors with the more stable crystal structures, or they act as precursors of subsequent crystallization, has been analyzed in two kinds of systems: a) isotactic polypropylene and copolymers with 1-pentene, as representative of forming solid mesophases, and b)...
Chapter
Semiflexible polyesters prepared by an alternating arrangement of biphenyl mesogenic units and aliphatic spacers represent an ideal model for studying the behavior of main-chain liquid crystalline polymers (MCLCP). The transition temperatures, type of mesophase and rate of mesophase–crystal transformation can be tailored by the utilization of a sui...
Article
Full-text available
In the presence of macroscopic fibres of carbon nanotubes (CNT), various semicrystalline polymers are shown to present accelerated crystallisation through the formation of a transcrystalline (TC) layer perpendicular to the fibre axis. From differential scanning calorimetry, polarized optical microscopy and X-ray diffraction we establish this to be...
Article
From a mechanical perspective, graphene and its derivatives, such as graphite nanoplates, graphite oxide, carbon nanofibers, or nanotubes, are envisioned as ideal nanofillers for polymer composites. Thus, tremendous research effort has been invested to determine the reinforcing mechanism of these nanofillers in the matrix: crack bridging, crystalli...
Article
Thermomechanical relaxation events and different water states in cottonseed protein bioplastics are presented whilst investigating the effects of aldehyde cross-linking agents. Thermomechanical relaxation of cottonseed protein bioplastics associated with protein denaturation, moisture absorption and broad glass transitions (Tg) were observed from D...
Article
Full-text available
A photo-healable rubber composite based on effective and fast thiol-alkyne click chemistry as a self-healing agent prestored in glass capillaries is reported. The click reaction and its effect on the mechanical properties of the composite are monitored in real time by dynamic mechanical analysis, showing that the successful bleeding of healing agen...
Conference Paper
Full-text available
This work shows results on the addition of conducting nanoparticles (e.g. CNTs, GO) to epoxy resins to obtain conductive adhesives which can be cured by Joule heating and used for composite repair. Importantly, the small amount of conductive nanofillers required for this process produces only a moderate increase in matrix viscosity, but still at a...
Article
In order to improve the thermal properties of a polymeric matrix, hollow glass microspheres (HGM) and carbon nanotubes-hollow glass microspheres hybrids (CNT-HGM) were added. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and infrared thermal imaging were performed. Dynamic mechanical analysis shows an improvement of 50% in sto...
Article
Degradation kinetics and the thermal stability of Invar 36 powder injection moulding feedstocks (PIM) based on cellulose acetate butyrate (CAB) and polyethylene glycol (PEG) binders were investigated using simultaneous thermogravimetric analysis (STA) and differential scanning calorimetry (DSC). The initial decomposition temperature (IDT) and the i...
Article
A method for reinforcing the strength of the interface between a polymer fiber and a polymer matrix is described. PET fibers were etched in an oxidative plasma to generate a surface nanopattern. Depending on the plasma treatment time, lamellae patterns with different geometries were obtained. The interfacial shear strength (IFSS) between the fiber...
Article
Gecko-inspired arrays of micropillars made of a liquid crystalline elastomer display thermoswitchable adhesive behavior as a consequence of elongation changes caused by reorientation of the mesogens at the nematic-isotropic (N-I) phase transition.
Article
Directional dry etching of polymer films under oxygen plasmas combined with a controlled crystallization and mechanical pretreatment of the polymer sample was exploited for obtaining surface nanopatterns. Fibrillar and lamellae surface nanopatterns of different dimensions, either randomly distributed or aligned in a particular direction, were obtai...
Article
The surface topography of different polymer films (polyterephthalates, polyolefins, polyethers) after oxidative plasma treatment has been studied. Distinct surface nanopatterns were observed depending on the polymer type and were characterized by SEM. Their geometry and dimensions at low etching degrees (0.5-1 [small mu ]m etching depth) could be c...
Article
This manuscript studies the formation of nanopatterns onto PET films under different experimental conditions. Homogeneous patterns with randomly distributed bumps or nano-fibrils were observed depending on the plasma parameters. The influence of the power, oxygen pressure and electrode charge in the etching rate and final nanotopography is studied...
Article
Two different types of regularity bands are identified in a real time FTIR crystallization of a series of random propylene 1-hexene copolymers. The first is akin to the bands observed in the homopolymer, those associated with 3(1) helices of isotactic sequences of different n length (n, number of monomer units). The second type corresponds to vibra...
Article
Using two living nickel α-diimine complexes (rac-1 and rac-4) activated with methylaluminoxane (MAO), isotactic polypropylene (iPP) samples containing five types of regiodefects were synthesized. Both isolated and successive groups of (2,1) and (3,1) enchainments were identified by solution-state 13C NMR spectroscopy. The extended monomer and bulky...
Article
This manuscript explores the possibility of exploiting polymer morphology (thermal or flow-induced) as materials inherent template, and domain-selective plasma etching as pattern developer, to obtain nanopatterned surfaces with different and controlled geometries, with a particular focus on nanofibrillar patterns. Oxidative plasma treatment of PET...
Article
The deformation process of a semi‐crystalline ethylene–(vinyl alcohol) copolymer (with a vinyl alcohol content of 68 mol%) has been evaluated using simultaneously real‐time synchrotron X‐ray diffraction and stress‐strain experiments at 150 °C. Small changes are observed during the initial elastic region in monoclinic crystallites. However, signific...
Article
Polypropylenes synthesized with a chiral diimine Ni(II) catalyst and MAO produce isotactic poly(propylenes) with random 1,3 enchainments and offer the opportunity to study the effect of this defect on iPP crystallization in reference to the effect given by 1-alkene comonomers. The type and content of 1,3 insertions was obtained from high resolution...
Article
The real-time evolution of IR regularity bands during isothermal crystallization of random propylene copolymers confirm the beginning of crystallization at a critical helical sequence length (n*) of about 12 isotactic units, corresponding to a vibrational frequency of 841 cm-1. The evolution with time of concentration of helical sequences below and...
Chapter
Liquid crystalline polymers are an important class of materials in which the existence of mesophases may control dramatically the physical properties. The phase behavior of liquid crystalline polymers is usually rather complicated, and many of these materials exhibit polymorphism and/or polymesomorphism. A combination of differential scanning calor...
Article
Small concentrations of long chain branching (LCB) added via copolymerization with a diene to a linear poly(propylene) chain have a dramatic effect on crystallization. LCB iPPs with diene levels between 100 and 400 ppm show greatly enhanced nucleation density, increasing with diene content. The increased nucleation observed in optical micrographs,...
Article
Ethyl 4 '-n-undecyloxybiphenyl-4-carboxylate, 2(11)OBC, and 4 '-n-undecyloxybiphenyl-4-carboxylic acid, (11)OBC, are smectic liquid crystals precursors of low molecular weight premesogens, and of potential liquid crystal macromolecules. The single-crystal X-ray study of 2(11)OBC showed that it crystallizes in a non-centrosymmetric space group with...
Article
The effect of molecular weight on the uniaxial orientation process has been analyzed in two samples of thermotropic poly(diethylene glycol p,p'-bibenzoate), evaluating the influence of that parameter on the type of orientation obtained. Several strain rates and deformation temperatures have been tested in order to map out the conditions for obtaini...
Article
The synthesis and phase behaviour of PB32 is reported. The results indicate that PB32 develops a low-ordered smectic mesophase of the type SmC alt. The slow formation of such a mesophase allows the quenching of the isotropic melt into an amorphous state so that both amorphous glass and smectic glass can be obtained, which exhibit different glass-tr...
Article
The analysis of the structural relaxation in specimens of a thermotropic polymer that are either in the glassy amorphous or in the liquid crystalline state (or in a mixture of them) has been carried out. The results indicate that the two phases behave independently, exhibiting two independent (and well different) glass transitions and with their ow...
Article
The thermotropic phase behavior of a liquid-crystalline poly(ether ester) derived from 4′-hydroxybiphenyl-4-carboxylic acid and two different spacer diols (2-methyl-1,3-propanediol and R-1,3-butanediol) has been analyzed by differential scanning calorimetry, real time synchrotron X-ray diffraction and solid-state 13C NMR. It has been found that the...