Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour

[EN] Green composites made of polylactide (PLA) filled with almond shell flour (ASF) at a constant weight content of 25¿wt.-% were manufactured by injection molding. In order to increase the interfacial adhesion between the biopolymer and the lignocellulosic fillers, three different compatibilizers were tested, namely multi-functional epoxy-based styrene-acrylic oligomer (ESAO), aromatic carbodiimide (AC), and maleinized linseed oil (MLO). The effect of each compatibilizer on the thermal, mechanical, and thermomechanical properties and water uptake of the injection-molded PLA/ASF pieces was analyzed. The obtained results indicated that all the here-studied compatibilizers had a positive influence on both the thermal stability and the mechanical and thermomechanical performance of the green composite pieces but low impact on their water uptake profile. In addition, the morphological analysis performed at the fracture surfaces of the green composite pieces revealed that the filler¿matrix gap was substantially reduced. Among the tested compatibilizers, ESAO and MLO yielded the highest performance in terms of mechanical strength and ductility, respectively. In the case of MLO, it also offers the advantage of being a plant-derived additive so that its application in green composites positively contributes to the development of sustainable polymer technologies.This research was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) program number MAT2014-59242-C2-1-R and AGL2015-63855-C2-1-R and Generalitat Valenciana (GV) program number GV/2014/008. A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia (UPV) for his FPI grant. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports (MECD) for his FPU grant (FPU13/06011). L. Quiles-Carrillo also wants to thank GV for his FPI grant (ACT/2016/182) and the MECD for his FPU grant (FPU15/03812).Quiles-Carrillo, L.; Montanes, N.; Garcia-Garcia, D.; Carbonell-Verdu, A.; Balart, R.; Torres-Giner, S. (2018). Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour. Composites Part B Engineering. 147:76-85. https://doi.org/10.1016/j.compositesb.2018.04.017S768514

Biopolyamide matrix composites with walnut shell flour surface-modified by silver nanoparticles

Biokompozyty poliamidu 10,10 z 10%wag. i 30%wag. mączki łupin orzecha charakteryzowano pod kątem zastosowań konstrukcyjnych i medycznych. Dokonano wstępnych prób pokrycia powierzchni wytworzonych próbek nanocząstkami srebra. W celach porównawczych wytworzono i badano kompozytu poliamidu 10,10 z 30%wag. włókna szklanego. Określono właściwości mechaniczne, przeprowadzono analizy z zastosowaniem skaningowego mikroskopu elektronowego. Zmierzono parametry chropowatości powierzchni. Określono chłonność wody i jej wpływ na właściwości mechaniczne po 7 dniach moczenia. Biokompozyty wykazały wzrost modułu sprężystości, niską gęstość, wyższe właściwości plastyczne i lepszą jakość powierzchni niż kompozyty z włóknem szklanym. Modyfikację powierzchniową nanocząstkami srebra wskazano jako interesujące rozwiązanie, szczególnie dla sprzętu medycznego, jednak same techniki nanoszenia wymagają dopracowania.In the study, biocomposites of polyamide 10,10 with 10%wt. and 30%wt. of walnut shell flour were characterized in respect to structural and extracorporeal medical applications. Preliminary attempts were made to cover the composites with silver nanoparticles. For comparison purposes, specimens of PA 10.10 with 30%wt. glass fibers were also manufactured and tested. Mechanical properties were tested and the composite structure was observed using scanning electron microscope. Surface roughness parameters were measured. Water absorption and its influence on mechanical properties was assessed after 7 days of soaking. The biocomposites showed an increase in modulus of elasticity, higher ductile properties and better surface quality than composites with glass fibers. Surface modification with silver nanoparticles was indicated as an interesting solution, especially for medical equipment, however the techniques of application should be refined

Structure and function of sensory organs

Mudskippers have many morphological adaptations that enable them to cope with the different conditions encountered in and between aquatic and terrestrial habitats. This is challenging especially for fishes with a body plan suitable for the aquatic medium. In addition to essential processes such as osmoregulation, excretion, respiration, thermal balance, and locomotion, basic functioning senses such as photoreception, chemoreception, and mechanoreception must now accommodate both habitats (Sayer 2005).At a position usually directly on or close to the body surface, receptor cells can readily receive impulses from the surrounding environment but at the same time, expose these receptors to external conditions. The adaptations to these demanding environments have made mudskippers a frequently studied fish group and make them possible extant models for the Paleozoic evolution of vertebrate transition from water to land (Graham and Lee 2004)

Structure and function of sensory organs

Mudskippers have many morphological adaptations that enable them to cope with the different conditions encountered in and between aquatic and terrestrial habitats. This is challenging especially for fishes with a body plan suitable for the aquatic medium. In addition to essential processes such as osmoregulation, excretion, respiration, thermal balance, and locomotion, basic functioning senses such as photoreception, chemoreception, and mechanoreception must now accommodate both habitats (Sayer 2005).At a position usually directly on or close to the body surface, receptor cells can readily receive impulses from the surrounding environment but at the same time, expose these receptors to external conditions. The adaptations to these demanding environments have made mudskippers a frequently studied fish group and make them possible extant models for the Paleozoic evolution of vertebrate transition from water to land (Graham and Lee 2004)