Development of environmentally friendly composite matrices from epoxidized cottonseed oil

The continuous rise in oil prices has led to the use of other ways to obtain polymer materials. This paper proposes a methodology to obtain a thermosetting resin from cottonseed oil by epoxidation process. The cottonseed oil contains as most representative fatty acids: 52.5% of linoleic acid (C18: 2), 23.9% of palmitic acid (C16: 0) and 17.6% of oleic acid (C18: 1); the real iodine index, which is indicative of the number of double bonds, has a value of 107. Epoxidized cottonseed oil (ECSO) has been successfully obtained using conventional epoxidation process with hydrogen peroxide, acetic acid and sulfuric acid, maintaining a constant temperature of 70 °C with homogeneous magnetic stirring. Average oxirane oxygen content (OOC) of 5.32% can be obtained by conventional epoxidation process which represents a yield over 83%. The epoxidized oil has been crosslinked with mixtures of two cyclic anhydrides to tailor different properties on final crosslinked thermosetting resins: on the one hand, methyl nadic anhydride (MNA) which is characterized by a rigid molecular structure and on the other hand, dodecenylsuccinic anhydride (DDSA) with a long side chain that can confer flexibility. The crosslinking process has been followed by dynamic differential scanning calorimetry (DSC), ionic mobility and oscillatory rheometry (OR) as well as gel time determination. The effect of the hardener mixture (wt.% DDSA:MNA) on mechanical performance of cured materials has been followed by flexural and impact tests as well as the evolution of the storage modulus (G′) by dynamic mechanical analysis (DMA) in torsion mode. By selecting the appropriate hardener mixture, it is possible to obtain crosslinked materials with different properties ranging from stiff matrices for ECSO crosslinked with MNA to flexible matrices for ECSO cured with DDSA. This has occurred with other thermosetting resins like epoxidized soy bean oil (ESBO) or epoxidized linseed oil (ELO). (C) 2014 Elsevier Ltd. All rights reserved.Authors thank Conselleria d'Educacio, Cultura i Esport (Generalitat Valenciana) Ref: GV/2014/008 for financial support.Carbonell Verdú, A.; Bernardi, L.; García García, D.; Sánchez Nacher, L.; Balart Gimeno, RA. (2015). Development of environmentally friendly composite matrices from epoxidized cottonseed oil. European Polymer Journal. 63:1-10. doi:10.1016/j.eurpolymj.2014.11.043S1106

Improvement of the compatibility between poly(3-hydroxybutyrate) and poly(e-caprolactone) by reactive extrusion with dicumyl peroxide

[EN] Poly(3-hydroxybutyrate) is a biodegradable aliphatic polyester obtained through bacterial fermentation that has gained attention in the last few years; nevertheless, its industrial applications are restricted because of some drawbacks related to its high stiffness and fragility which is associated to its high crystallinity. In this work, poly(3-hydroxybutyrate) (P3HB) was melt blended with poly(e-caprolactone) (PCL) at a constant weight ratio of 75/25 (P3HB/PCL) by reactive extrusion with different contents of dicumyl peroxide (DCP) in the 0 1 wt% range. The effects of the DCP load on mechanical, thermal and morphology of the P3HB/PCL blend were studied. Results showed a positive increase in the elongation at break and the impact-absorbed energy of 91% and 231% respectively with regard the uncompatibilized P3HB/PCL blend by the addition of 1 wt% DCP, being this a clear evidenced of the improved compatibility between these polymers. Moreover, morphology of DCP-compatibilized P3HB/PCL blend obtained by field emission electron microscopy (FESEM) and atomic force microscopy (AFM) showed a remarkable decrease in the particle size of poly(e-caprolactone)-rich domains randomly dispersed in the poly(3-hydroxybutyrate). In addition, both FESEM and AFM also revealed improved interfacial adhesion between P3HB- and PCL-rich phases with a noticeable decrease in the gap between them. Addition of 1 wt% DCP also contributes to lowering the degree of crystallinity of PHB by 14% in the blend and other thermal properties are not highly affected by the reactive extrusion with DCP. ©2016 Elsevier Ltd. All rights reserved.This research was supported by the Ministry of Economy and Competitiveness MINECO through the grant number MAT2014-59242-C2-1-R. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports for the financial support through a FPU grant number FPU13/06011. A. Carbonell-Verdu acknowledges Universitat Politecnica de Valencia for financial support through an FPI grant.García García, D.; Rayón Encinas, E.; Carbonell Verdú, A.; López-Martínez, J.; Balart Gimeno, RA. (2017). Improvement of the compatibility between poly(3-hydroxybutyrate) and poly(e-caprolactone) by reactive extrusion with dicumyl peroxide. European Polymer Journal. 86:41-57. https://doi.org/10.1016/j.eurpolymj.2016.11.018S41578

Green composites based on polypropylene matrix and hydrophobized spend coffee ground (SCG) powder

Green composites were prepared with polypropylene matrix and 20 wt.% spent coffee ground (SCG) powder for uses as a wood plastic composite (WPC). The effects of hydrophobic treatment with palmitoyl chloride on SCG powder is compared with conventional surface treatment based on silanization with (3-glycidyloxypropyl) trimethoxysilane and the use of a maleated copolymer compatibilizer (polypropylene-graft-maleic anhydride, PP-g-MA) in terms of mechanical properties, morphology, thermal properties and water uptake. Composites were previously mixed in a twin-screw co-rotating extruder and subsequently subjected to injection moulding. The comparative effect of the different surface treatments and or compatibilizers on mechanical performance was studied by flexural, impact tests and dynamic mechanical thermal analysis (DMTA-torsion); in addition, the stabilizing effect of SCG was revealed by differential scanning calorimetry (DSC) and thermogravymetric analysis (TGA). As one of the main drawbacks of wood plastic composites and natural fibre reinforced plastics is the moisture gain, water uptake tests were carried out in order to quantify the effectiveness of the hydrophobization process with palmitoyl chloride. Results show a slight increase in flexural modulus for composites with both untreated and treated/compatibilized SCG powder (20 wt.%). As expected, thermal stability is improved as indicated by an increase of more than 8% in the onset degradation temperature by DSC if compared to unfilled polypropylene. Fracture analysis by scanning electron microscopy (SEM) shows better particle dispersion for PP-SCG composites with hydrophobized SCG with palmitoyl chloride treatment; in addition a remarkable decrease in water uptake is observed for composites with hydrophobized SCG. ©2015 Elsevier Ltd. All rights reserved.García García, D.; Carbonell Verdú, A.; Samper Madrigal, MD.; García Sanoguera, D.; Balart Gimeno, RA. (2015). Green composites based on polypropylene matrix and hydrophobized spend coffee ground (SCG) powder. Composites Part B: Engineering. 78:256-265. doi:10.1016/j.compositesb.2015.03.0802562657

Optimización de las condiciones de epoxidación y curado de resinas basadas en aceite de semilla de algodón

En esta investigación se propone una metodología para obtener una resina termoestable a partir de aceite de semilla de algodón (ASA) mediante el proceso de epoxidación. La influencia del ratio de peróxido y tiempo de epoxidación, han sido seguidos mediante el índice de yodo y oxígeno. Se ha conseguido un rendimiento de más del 83%, frente a los valores teóricos, durante la epoxidación llevada a cabo con el mayor ratio de peróxido. El proceso de reticulación, de la mezcla en estado líquido del aceite epoxidado con mezclas de dos endurecedores (DDSA : MNA), ha sido seguido mediante el tiempo de gel y reometría oscilatoria para las temperaturas de 110 y 120ºC.Este trabajo ha sido financiado por la Conselleria d'Educació, Cultura i Esport (Generalitat Valenciana) Ref: GV/2014/008.Carbonell Verdú, A.; Montañés Muñoz, N.; Fombuena Borrás, V.; Sánchez Nacher, L.; Balart Gimeno, RA. (2015). Optimización de las condiciones de epoxidación y curado de resinas basadas en aceite de semilla de algodón. Compobell, S.L. http://hdl.handle.net/10251/73479

Desarrollo y caracterización de "wood plastic composites" con fibras de plumero de la pampa

Debido a los altos costes económicos y a los riesgos ambientales de los productos derivados del petróleo en los últimos años hay una creciente tendencia en la investigación, desarrollo y fabricación de biocomposites. Los biocomposites son aquellos materiales en los que al menos uno de los componentes, ya sea la matriz o el refuerzo, proviene de origen renovable. En este estudio se ha utilizado como matriz un biopolímero de polietileno verde obtenido a partir de etanol de caña de azúcar y, como material de refuerzo se ha utilizado fibra de plumero de la pampa. Las propiedades mecánicas de los materiales compuestos se evaluaron mediante ensayos estandarizados de flexión y tracción. El comportamiento térmico del mismo mediante Calorimetría Diferencial de Barrido (DSC). Para justificar el comportamiento mecánico se estudió la morfología de las muestras por microscopía electrónica de barrido (SEM).Carbonell Verdú, A.; García García, D.; García Sanoguera, D.; Boronat Vitoria, T.; Montañés Muñoz, N.; Balart Gimeno, RA. (2014). Desarrollo y caracterización de "wood plastic composites" con fibras de plumero de la pampa. Compobell, S.L. http://hdl.handle.net/10251/70654

Circulating Tumor DNA in Stage III Colorectal Cancer, beyond Minimal Residual Disease Detection, toward Assessment of Adjuvant Therapy Efficacy and Clinical Behavior of Recurrences

PURPOSE: Sensitive methods for risk stratification, monitoring therapeutic efficacy, and early relapse detection may have a major impact on treatment decisions and patient management for stage III colorectal cancer patients. Beyond assessing the predictive power of postoperative ctDNA detection, we explored the added benefits of serial analysis: assessing adjuvant chemotherapy (ACT) efficacy, early relapse detection, and ctDNA growth rates. EXPERIMENTAL DESIGN: We recruited 168 patients with stage III colorectal cancer treated with curative intent at Danish and Spanish hospitals between 2014 and 2019. To quantify ctDNA in plasma samples (n = 1,204), 16 patient-specific somatic single-nucleotide variants were profiled using multiplex-PCR, next-generation sequencing. RESULTS: Detection of ctDNA was a strong recurrence predictor postoperatively [HR = 7.0; 95% confidence interval (CI), 3.7–13.5; P < 0.001] and directly after ACT (HR = 50.76; 95% CI, 15.4–167; P < 0.001). The recurrence rate of postoperative ctDNA-positive patients treated with ACT was 80% (16/20). Only patients who cleared ctDNA permanently during ACT did not relapse. Serial ctDNA assessment after the end of treatment was similarly predictive of recurrence (HR = 50.80; 95% CI, 14.9–172; P < 0.001), and revealed two distinct rates of exponential ctDNA growth, slow (25% ctDNA-increase/month) and fast (143% ctDNA-increase/month; P < 0.001). The ctDNA growth rate was prognostic of survival (HR = 2.7; 95% CI, 1.1–6.7; P = 0.039). Serial ctDNA analysis every 3 months detected recurrence with a median lead-time of 9.8 months compared with standard-of-care computed tomography. CONCLUSIONS: Serial postoperative ctDNA analysis has a strong prognostic value and enables tumor growth rate assessment. The novel combination of ctDNA detection and growth rate assessment provides unique opportunities for guiding decision-making. See related commentary by Morris and George, p. 43

Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure

A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of “extra-target” RAS suggests the need for RAS screening in all three DAA target regions

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Revisores de este número

Eva Bálmont Rica Antonio Carbonell Gimeno Ángel Casado Castro Salvador Tarek Cruz TabaresSilvia Gálvez Salamanca Antonio Carlos García Ruiz Lourdes Lara Romero Mª Eugenia Prieto Gómez Sara Ramos Millán Inmaculada Sicilia Rubio Juan Vallejo Lesme

‘Dans les pierres, il ne peut y avoir de fiction’ ?

International audienceRodrigo Caro (1573-1647) has long been considered an unreliable witness of the epigraphic tradition, first and foremost by E. Hübner (CIL II). This article reconsiders his role in the transmission of the Conventus Hispalensis' falsae vel incertae, after a careful analysis of Caro's Antigüedades de Sevilla (1634). Within this work, the Sevillian humanist overall appears to be scrupulous: it is only his duty to superior interests, such as those of the archbishopric of Seville, which forces him (as in his defense of the pseudo-Dexter) to reluctantly retain certain falsae included in the Antigüedades