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Muro del Alcoy, Spain

Samper M.D.,Polytechnic University of Valencia | Fages E.,Textile Research Institute AITEX | Fenollar O.,Polytechnic University of Valencia | Boronat T.,Polytechnic University of Valencia | Balart R.,Polytechnic University of Valencia
Journal of Applied Polymer Science

This article presents a study on the stabilization of polypropylene against thermo-oxidation and UV radiation by using natural phenolic compounds derived from the structures of flavonoids: a flavone (chrysin), a flavanol (quercetin), two flavanone glycosides (hesperidin and naringin), and flavanoligand (silibinin). Thermal stabilization has been assessed in an oxidizing atmosphere by means of differential scanning calorimetry both in isothermal and in dynamic conditions. In addition, the effectiveness of these phenolic compounds as thermal stabilizers at high temperature has been quantified with the use of thermogravimetric analysis. Stabilization against UV radiation has been estimated by studying the morphology changes of the exposed surfaces by scanning electron microscope (SEM); also, surface chemical changes have been followed by infrared spectroscopy. Global results show that flavonoid compounds of type flavonols (quercetin and silibinin) provide the best results in stabilizing both against oxidation and against the action of UV radiation. © 2012 Wiley Periodicals, Inc. Source

Ferrero B.,Textile Research Institute AITEX | Fombuena V.,Polytechnic University of Valencia | Fenollar O.,Polytechnic University of Valencia | Boronat T.,Polytechnic University of Valencia | Balart R.,Polytechnic University of Valencia
Polymer Composites

In the present study the valorization of wastes from Posidonia oceanica (PO) has been carried out in order to obtain a fully biobased composite material in combination with a biobased polyethylene obtained from sugar cane as matrix. Morphological analysis by scanning electron microscopy (SEM) of the fractured surfaces from impact tests has revealed a homogenous distribution of particles of PO, as a consequence, good balanced properties have been obtained for composites with PO contents in the 5-40 wt%. Thermal properties of composites have been studied through differential scanning calorimetry (DSC) and thermogravymetric analysis (TGA); the obtained results show an improvement on the thermal degradation. With regard to thermomechanical properties, dynamic mechanical analysis (DMA) results have shown a much enhanced storage modulus (G′) as the Posidonia oceanica content increases. Tensile tests have shown a remarkable increase in stiffness with tensile modulus values about 60% higher for composites with 40 wt% with regard to unfilled material. In a similar way, the flexural modulus is more than twice with regard the unloaded polyethylene. Shore D hardness confirms this improvement on mechanical properties and Charpy impact test shows values very similar to sample without PO, so that the intrinsic high impact energy absorption of HDPE is maintained in HDPE-PO composites. The water uptake test determines that the water absorption percent does not exceed 8%, which is relatively low for a high immersion time (5 months), which guarantees a dimensional stability in lifetime for these composites. © 2014 Society of Plastics Engineers. Source

Lopez R.,Polytechnic University of Valencia | Pascual M.,Polytechnic University of Valencia | Garcia-Sanoguera D.,Textile Research Institute AITEX | Sanchez-Nacher L.,Textile Research Institute AITEX | Balart R.,Textile Research Institute AITEX
Fibers and Polymers

The use of nonwoven textile substrates for filtration and absorption purposes is generalized due to the high surface area they can provide. Many of these applications require good wetting properties to increase efficiency. In this work, low pressure plasma treatment with a CH4-O2 mixture gas has been used to increase surface wettability and subsequent absorption properties on nonwoven polypropylene substrates. CH4 plasma treatment leads to a plasma polymerization process which results in hydrophobic surface finishing, but in combination with O2, it is possible to form a functionalized plasmapolymerized layer thus improving wetting properties. Changes in wetting properties have been studied by contact angle measurements showing that optimum wetting properties are obtained with exposure times to plasma treatment of about 10 min, and no significant changes are obtained for longer exposure times. Absorption efficiency has been followed by determining three different parameters by the guidelines of the UNE-EN-ISO 9073-6 standard: wetting time, liquid absorption capacity (LAC) and liquid propagation rate or absorption speed. All these properties are remarkably improved as the exposure time to CH4-O2 plasma increases; this improvement is remarkably high for relatively short exposure times (5-10 min) and no significant changes are obtained for long exposure times so that, it is possible to conclude that previous plasma treatment with exposure times in the 5-10 min range is an efficient method to improve overall absorption properties of nonwoven polypropylene substrates. © 2012 The Korean Fiber Society and Springer Science+Business Media Dordrecht. Source

Lopeza R.,Textile Research Institute AITEX | Boronatb T.,Polytechnic University of Valencia | Pascuala M.,Textile Research Institute AITEX | Calvoa O.,Textile Research Institute AITEX | Balartb R.,Polytechnic University of Valencia
AIP Conference Proceedings

In this work we have used low-pressure plasma with a gas based on methane and oxygen mixture to improve wettability and durability of a PP nonwoven fabrics. The obtained results show good durability with the use of methaneoxygen plasma mixture gas. The effects of the plasma are similar to a plasmapolymerization process but in this case we obtain hydrophilic properties with high durability. The surface does not suffer important changes and the roughness of the material remains constant. © 2010 American Institute of Physics. Source

Espana J.M.,Polytechnic University of Valencia | Fages E.,Textile Research Institute AITEX | Moriana R.,Textile Research Institute AITEX | Boronat T.,Polytechnic University of Valencia | Balart R.,Polytechnic University of Valencia
Polymer Composites

The aim of this study is to establish the thermal performance of a biocomposite (Arbofill kokos®), stabilized with different natural phenolic additives, to check the antioxidant capacity of the resulting compounds. Different phenolic compounds (thymol, carvacrol, α-tocopherol, and tannic acid) were used as biobased additives and the concentrations ranged between 0.5 wt% and 2 wt%. The results obtained were compared with formulations containing a typical industrial petroleum-based antioxidant agent (octadecyl-3-(3,5-di-tert- butyl-4-hydroxyphenyl) propionate). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to characterize the antioxidant performance of the selected natural additives. The antimicrobial effect of these natural phenolic compounds was also studied by analyzing the growth of bacterial colonies. The comparison between the natural phenolic compounds and the petroleum-based antioxidant compound showed good antioxidant action for natural phenolic compounds; in all the mixtures of biocomposite and antioxidant agent the oxidation onset temperature (OOT) increased in a remarkable way, but the highest stabilization effect was achieved with α-tocopherol with provides a % increase on OOT of about 45%. With regard to antibacterial activity of the different natural phenolic compounds, thymol, and carvacrol showed interesting antibacterial properties against Staphylococcus aureus. Copyright © 2012 Society of Plastics Engineers. Source

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