Fibers and Polymers 2013, Vol.14, No.3, 423-427 423 Effect of Alkali and Silane Treatments on Mechanical and Thermal Behavior of Phormium tenax Fibers Debora Puglia, Marco Monti, Carlo Santulli 1 * , Fabrizio Sarasini 1 , Igor Maria De Rosa 2 , and Josè Maria Kenny Civil and Environmental Engineering Department, UdR INSTM, Università di Perugia, 05100 Terni, Italy 1 Department of Chemical Engineering, Materials and Environment, Sapienza-Università di Roma, 00184 Rome, Italy 2 Department Materials Science, University of California Los Angeles, Los Angeles, CA 90095, USA (Received January 13, 2012; Revised July 27, 2012; Accepted August 16, 2012) Abstract: The effect of different treatments on the mechanical (tensile), thermal behavior (TGA), FTIR, and morphology of Phormium tenax fibers has been studied with the aim to investigate methods to improve their compatibility with polymer matrices. Applied treatments included sodium hydroxide (NaOH), silane (APTES, 3-aminopropyltriethoxysilane), and the combined application of silane treatment after NaOH. The effectiveness of the treatments in the removal of non-structural matter from the fibers was confirmed by FTIR investigation and TGA measurements, suggesting also that the alkali treatment has a strong effect on their thermal behavior. The study of tensile properties of the fibers performed using Weibull statistics indicates that the tensile properties are somewhat reduced by chemical treatment. The morphological investigation of treated fibers through scanning electron microscopy indicates that silane treatments, both on raw fibers and on alkalized ones, result in limited fiber degradation. Keywords: New Zealand flax (Phormium tenax), Treatments, Tensile properties, Thermal analysis, Morphology Introduction The ever-growing environmental awareness requires the development of the next generation of materials and processes to be inspired by principles of sustainability, ecoefficiency, and green chemistry. The depletion of petroleum resources coupled with the disposition of stricter environmental regulations are acting synergistically to create a strong stimulus for new materials and products, whose use would produce the lowest ‘carbon footprint’. In this regard, ‘green’ composites made of renewable agricultural and forestry feedstock can represent a suitable alternative to glass fiber reinforced composites, providing potential value-added source of income to the agricultural community [1]. In this context, together with the more traditional plant fibers increasingly used as reinforcement for polymer composites such as jute, flax, hemp, sisal, and coir, other fibers may generate some interest, in view of their potential for this application [2]. In particular, New Zealand flax, more correctly referred to as Phormium, is a monocotyledon plant belonging to the Agavaceae family indigenous to New Zealand and Norfolk Island. There are two distinct species of New Zealand flax: Phormium tenax (also known as harakeke) and Phormium cookianum (also known as wharariki), the key difference being the way their seedpods grow. Phormium represented an important resource in Maori life. Phormium leaves are traditionally used in the Maori culture for making plaiting mats and containers, while the extracted fibers have been used for making fishing nets, ropes, baskets, and cloaks [3]. During the last few years, several papers have been published concerning the use of Phormium tenax fibers as potential reinforcement in both thermoplastic and thermosetting matrices [4-8], but only a few studies regarding the tensile behavior of technical fibers can be found [9,10]. In general, the properties of plant fiber composites can be improved in terms of interfacial adhesion and resistance to moisture absorption using suitable chemical treatment [11]. However, the mechanical and thermal effect of treatment on fiber modification is still quite poorly known, especially on leaf-extracted fibers, which have been less used in products for the textile industry, from which the procedures most commonly applied on plant fibers, such as sodium hydroxide treatment, originate. A substantial difference is recognized between primary treatments (e.g., alkali), and secondary treatments, such as the application of organosilanes [12]. While the former are mostly devoted to the removal of non- structural matter from the fibers, the latter appear capable of providing protective coating to the fibers, furthermore improving their adhesion to the polymer matrix. On phormium fibers, deacetylation by means of alkali treatment has been tried, which resulted in the additional removal of some of the xylans by applying 5 % of sodium hydroxide for 4 h, considerably reducing the water uptake of the composites with no detectable effect on mechanical properties [13]. In this work, alkali and organosilane treatment, and a combination of them have been applied on phormium fibers in preparation for their introduction in a polymer matrix with the aim of contributing to the definition of an optimized chemical treatment for these fibers. *Corresponding author: carlosantulli141@gmail.com DOI 10.1007/s12221-013-0423-x