Thermal and mechanical characterization of epoxy resins (ELO and ESO) cured with anhydrides

In this work we have developed polymeric materials from epoxidized vegetable oils in order to obtain materials with excellent mechanical properties for use as green matrix composites. Epoxidized soybean oil (ESO), epoxidized linseed oil (ELO) and different mixtures of the two oils were used to produce the polymers. Phthalic anhydride (17 mol%) and maleic anhydride (83 mol%) which has a eutectic reaction temperature of 48 °C were used as crosslinking agents while benzyl dimethyl amine (BDMA) and ethylene glycol were used as the catalyst and initiator, respectively. The results showed that samples 100ELO and 80ELO20ESO could be used as a matrix in green composites because they demonstrated good mechanical properties. © 2012 AOCS (outside the USA).This work is part of the project IPT-310000-2010-037,''ECOTEXCOMP: Research and development of textile structures useful as reinforcement of composite materials with marked ecological character'' funded by the "Ministerio de Ciencia e Innovacion", with financial aid of 189,540.20 EUR, within the "Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica 2008-2011" and funded by the European Union through FEDER funds, Technology Fund 2007-2013, Operational Programme on R + D + i for and on behalf of the companies.Samper Madrigal, MD.; Fombuena Borrás, V.; Boronat Vitoria, T.; García Sanoguera, D.; Balart Gimeno, RA. (2012). Thermal and mechanical characterization of epoxy resins (ELO and ESO) cured with anhydrides. Journal of the American Oil Chemists' Society. 89(8):1521-1528. https://doi.org/10.1007/s11746-012-2041-yS15211528898Averous L (2004) Biodegradable multiphase systems based on plasticized starch: a review. J Macromol Sci Polym Rev C44:231–274Bledzki AK, Jaszkiewicz A (2010) Mechanical performance of biocomposites based on PLA and PHBV reinforced with natural fibres—a comparative study to PP. Compos Sci Technol 70:1687–1696Raquez JM, Deleglise M, Lacrampe MF, Krawczak P (2010) Thermosetting (bio)materials derived from renewable resources: a critical review. Prog Polym Sci 35:487–509Charlet K, Jernot JP, Gomina M, Bizet L, Breard J (2010) Mechanical properties of flax fibers and of the derived unidirectional composites. J Compos Mater 44:2887–2896Barreto ACH, Esmeraldo MA, Rosa DS, Fechine PBA, Mazzetto SE (2010) Cardanol biocomposites reinforced with jute fiber: microstructure, biodegradability, and mechanical properties. Polym Compos 31:1928–1937Thakur VK, Singha AS (2010) Physico-chemical and mechanical characterization of natural fibre reinforced polymer composites. Iran Polym J 19:3–16Schmitz WR, Wallace JG (1954) Epoxidation of methyl oleate with hydrogen peroxide. J Am Oil Chem Soc 31:363–365La Scala J, Wool RP (2002) Effect of FA composition on epoxidation kinetics of TAG. J Am Oil Chem Soc 79:373–378de Espinosa LM, Ronda JC, Galia M, Cadiz V (2008) A new enone-containing triglyceride derivative as precursor of thermosets from renewable resources. J Polym Sci Pol Chem 46:6843–6850Gerbase AE, Petzhold CL, Costa APO (2002) Dynamic mechanical and thermal behavior of epoxy resins based on soybean oil. J Am Oil Chem Soc 79:797–802Boquillon N, Fringant C (2000) Polymer networks derived from curing of epoxidised linseed oil: influence of different catalysts and anhydride hardeners. Polymer 41:8603–8613Montserrat S, Flaque C, Calafell M, Andreu G, Malek J (1995) Influence of the accelerator concentration on the curing reaction of an epoxy-anhydride system. Thermochim Acta 269:213–229Zacharuk M, Becker D, Coelho LAF, Pezzin SH (2011) Study of the reaction between polyethylene glycol and epoxy resins using N,N-dimethylbenzylamine as catalyst. Polimeros 21:73–77Lozada Z, Suppes GJ, Tu YC, Hsieh FH (2009) Soy-based polyols from oxirane ring opening by alcoholysis reaction. J Appl Polym Sci 113:2552–256

The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends

[EN] In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30 wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6 phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10 °C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility.This research was supported by the Ministry of Economy and Competitiveness-MINECO, Ref: MAT2014-59242-C2-1-R. Authors also thank to "Conselleria d'Educacio, Cultura i Esport"-Generalitat Valenciana, Ref: GV/2014/008 for financial support.Ferri Azor, JM.; García García, D.; Sánchez Nacher, L.; Fenollar Gimeno, OÁ.; Balart Gimeno, RA. (2016). The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends. Carbohydrate Polymers. 147:60-68. https://doi.org/10.1016/j.carbpol.2016.03.082S606814

Degradability of cross-linked polyurethanes based on synthetic polyhydroxybutyrate and modified with polylactide

In many areas of application of conventional non-degradable cross-linked polyurethanes (PUR), there is a need for their degradation under the influence of specific environmental factors. It is practiced by incorporation of sensitive to degradation compounds (usually of natural origin) into the polyurethane structure, or by mixing them with polyurethanes. Cross-linked polyurethanes (with 10 and 30%wt amount of synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments) and their physical blends with poly([d,l]-lactide) (PDLLA) were investigated and then degraded under hydrolytic (phosphate buffer solution) and oxidative (CoCl2/H2O2) conditions. The rate of degradation was monitored by changes of samples mass, morphology of surface and their thermal properties. Despite the small weight losses of samples, the changes of thermal properties of polymers and topography of their surface indicated that they were susceptible to gradual degradation under oxidative and hydrolytic conditions. Blends of PDLLA and polyurethane with 30 wt% of R,S-PHB in soft segments and PUR/PDLLA blends absorbed more water and degraded faster than polyurethane with low amount of R,S-PHB

Phenanthroline-functionalized MWCNTs as versatile platform for lanthanides complexation

A multiwalled carbon nanotube (MWCNT) scaffold was covalently functionalized with phenanthroline moieties capable to chelate tris Eu(III) complexes, such as Eu(III) tris-(2-theonyl)-trifluoroacetonate ([EuL 3]), yielding a brightly luminescent hybrid (MWCNTs- Phen•[EuL3]). The material was thoroughly characterized by means of TGA, XPS, TEM and steady-state UV-Vis absorption and emission investigations. These studies demonstrated both the integrity of the luminescent Eu(III)-based complex in the hybrid, as well as its high loading. The versatility of the coordinating properties of phenanthroline allowed the anchoring of other lanthanides like Gd(III), producing functional hybrids with potential applicability as magnetic resonance agents. Finally, the developed hybrid revealed to be highly dispersible in biodegradable polymer matrices such as Poly(l-lactide) (PLLA), making it a promising luminophore for applications in biomaterial science. © 2013 Elsevier Ltd. All rights reserved

Self-nucleation and crystallization kinetics of double crystalline poly(p-dioxanone)-b-poly(epsilon-caprolactone) diblock copolymers

The crystallization kinetics of each constituent of poly(p-dioxanone)-b-poly(epsilon-caprolactone) diblock copolymers (PPDX-b-PCL) has been determined in a wide composition range by differential scanning calorimetry and compared to that of the equivalent homopolymers. Spherulitic growth rates were also measured by polarized optical microscopy while atomic force microscopy was employed to reveal the morphology of one selected diblock copolymer. It was found that crystallization drives structure formation and both components form lamellae within mixed spherulitic superstructures. The overall isothermal crystallization kinetics of the PPDX block at high temperatures, where the PCL is molten, was determined by accelerating the kinetics through a previous self-nucleation procedure. The application of the Lauritzen and Ho. man theory to overall growth rate data yielded successful results for PPDX and the diblock copolymers. The theory was applied to isothermal overall crystallization of previously self-nucleated PPDX ( where growth should be the dominant factor if self-nucleation was effective) and the energetic parameters obtained were perfectly matched with those obtained from spherulitic growth rate data of neat PPDX. A quantitative estimate of the increase in the energy barrier for crystallization of the PPDX block, caused by the covalently bonded molten PCL as compared to homo-PPDX, was thus determined. This energy increase can dramatically reduce the crystallization rate of the PPDX block as compared to homo-PPDX. In the case of the PCL block, both the crystallization kinetics and the self-nucleation results indicate that the PPDX is able to nucleate the PCL within the copolymers and heterogeneous nucleation is always present regardless of composition. Finally, preliminary results on hydrolytic degradation showed that the presence of relatively small amounts of PCL within PPDX-bPCL copolymers substantially retards hydrolytic degradation of the material in comparison to homo-PPDX. This increased resistance to hydrolysis is a complex function of composition and its knowledge may allow future prediction of the lifetime of the material for biomedical applications

Interplay between poly(ethylene oxide) and poly(L-lactide) blocks during diblock copolymer crystallization

The influence of composition and crystallization conditions on the behavior of double crystalline poly (ethylene oxide-b-l-lactide) (PEO-b-PLLA) diblock copolymers is investigated. Poly(l-lactide) contents in the synthesized copolymers vary from 50 to 91%, and the molecular weight of the PLLA block ranges from 2 to 20 kg mol-1, while that of the PEO block is kept constant at 2 kg mol-1. In bulk samples, DSC results show a synergistic interaction between the crystallization processes of the two blocks. The PEO block provides heterogeneities and exerts a plasticizing action which favors the crystallization of the PLLA block with a nucleation efficiency of 30%. In contrast, the subsequent crystallization of the PEO block is subject to two opposing effects: (a) the nucleating action of PLLA crystals and (b) the topological and geometrical constraints imposed by PLLA crystals, especially when the PEO content is 20 wt% or less. In the case of ultra thin films, block copolymers with PEO contents equal or smaller than 20 wt% form distorted PLLA single crystals when crystallized from the melt. However, upon increasing the PEO content in the system to 33 wt% (by blending or copolymerization), the distortions disappear and the angle between the {110} growth faces changes from 140° to 121°, since the PEO block acts as a solvent or plasticizer for the PLLA block during the crystallization process. PEO incorporation can therefore tailor the rate and morphology of PLLA block crystallization. TEM and AFM studies allowed direct observation of the PEO block dendritic crystals on the surface of lozenge-shaped PLLA crystals previously formed during cooling from the melt.SCOPUS: ar.jinfo:eu-repo/semantics/publishe