NOVEL HYBRID COMPOSITES FROM HIGH DENSITY POLYETHYLENE REINFORCED BY NANOCLAY-FILLED POLYAMIDE 6 FIBRILS

Abstract Polyamide 6 filled with nanosized, montmorillonite (o-MMT/PA6) is nowadays one of the most common polymer nanocomposites with plate-like reinforcement in industrial applications. This work reports on the preparation and characterization of a new type of hybrid composite materials as an attempt to avoid the disadvantages of o-MMT/PA6 and MFCs

Simultaneous crystalline-amorphous phase evolution during crystallization of polymer systems

Despite the fact that polymer crystallization has been the object of intense research, this process is far from being fully understood. Traditional polymer crystallization studies using X-ray scattering techniques mainly provide information about the ordered regions. To obtain a more complete information about the time evolution of both the crystalline and the amorphous phase during polymer crystallization, we have developed a technique which allows one to obtain information about both the crystalline and the amorphous phase simultaneously. We report here simultaneous information about three key aspects of the isothermal polymer crystallization process: i) polymer chain ordering, through Wide-Angle X-ray Scattering; ii) lamellar crystals arrangement, through Small-Angle X-ray Scattering; iii) amorphous phase evolution through dielectric spectroscopy. Our results probe that during primary crystallization the average mobility of the amorphous phase is not notably affected. Upon passing through the crossover time, marking the transition from primary to secondary crystallization, the restriction to the mobility of the amorphous phase mainly occurs in the regions between the lamellar stacks regions and not in the amorphous regions within the lamellar stacks. We hypothesize that molecular mobility in the amorphous regions located between consecutive crystals become strongly arrested as soon as the lamellar stack is formed. © EDP SciencesMCYT (grants FPA2001-2139, BMF2000-1474), Spain. MEC “Científicos y Tecnólogos Extranjeros” program. IHP-Contract HPRI-CT-1999-00040 of the European Commission (EC(ERBFMGEDT 950059) and II-00-015 EC).Peer Reviewe

Bovine serum albumin-imprinted magnetic poly(2-pyrrolidone) microparticles for protein recognition

This study reports on the synthesis and adsorption properties of molecularly imprinted porous magnetic microparticles (MIP) based on the biodegradable and sustainable poly(2-pyrrolidone) (PPD or PA4). These new PPD MIP materials were obtained via activated anionic ring-opening polymerization of 2-pyrroldone carried out at 40 °C, in the presence of iron fillers and bovine serum albumin (BSA) as a template. Neither solvent, nor additional crosslinking or porogen agents were used in the PPD MIP synthesis. Analogously, PPD particles without BSA imprinting (NIP) were also produced. Depending on the microparticles composition, their yields were in the 55–70 wt% range, the average size varying between 8 and 25 μm. After characterization of the surface topography of all samples, their adsorption capacity toward the BSA target was assessed as a function of the adsorption time, protein concentration and pH of the medium. All three PPD MIP samples displayed adsorption capacity toward BSA being up to one order of magnitude higher as compared to other BSA-imprinted polymer systems. It was found that the rebinding of BSA on MIP is best described by the Langmuir isotherm, whereas for rebinding on NIP the Freundlich isotherm was the more adequate model. On this basis, the nature of the adsorption on MIP and NIP was discussed. The adsorption toward two other proteins, namely Ovalbumin and Cytochrome C was also tested. The newly synthesized BSA-imprinted PPD MIP displayed selective adsorption for the BSA target being dependent on the pH values of the medium. The easy recovery of the Fe-containing MIP and the capacity of all MIP samples for multiple sorption/desorption cycles was demonstrated.The authors gratefully acknowledge the financial support of the project TSSiPRO NORTE-01-0145-FEDER-000015, supported by the regional operation program NORTE2020, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund, as well as the support by National Funds through Fundação para a Ciência e Tecnologia (FCT), project UID/CTM/50025/2019. N. Dencheva is also grateful for the financial support of FCT in the frames of the strategic project UID/CTM/50025/2013 and the personal pro gram-contract CTTI-51/18-IP

Procedimiento de preparación mediante molido criogénico de mezclas de poliésteres aromáticos con control del grado de transesterificación

Referencia OEPM: P200002257.-- Fecha de solicitud: 15/09/2000.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Procedimiento de preparación mediante molido criogénico de mezclas de poliésteres aromáticos con control del grado de transesterificación. Se presenta un procedimiento para la preparación de mezclas de polímeros de policondensación como: poliésteres, poliamidas, policarbonatos, poliuretanos, poliimidas, polietercetonas y polímeros similares que son capaces de desarrollar reacciones de intercambio tendentes a formar copolímeros mediante transesterificación, transamidación, intercambio ester-amida u otro tipo de reacción de intercambio. El procedimiento permite la obtención de mezclas con un grado controlado de transesterificación, o de la reacción de intercambio relacionada, y consiste en: 1) Premezcla de los granulados iniciales de los polímeros de interés. 2) Molido criogénico de la premezcla. 3) Termomoldeo a presión en un molde deseado del polvo obtenido por molido criogénico y ulterior enfriamiento rápido para obtener un material amorfo.Peer reviewe