Grape stalk fibers as reinforcing filler for polymer composites with a polystyrene matrix

Abstract

Lignocellulosic fibers have been one of the most used reinforcements for different types of composites. In this context, grape stalks—often discarded in landfills—can be a potential reinforcement for composites. The present study aimed to incorporate in natura and alkali treated grape stalks into the polystyrene (PS) matrix. Initially, the grape stalks were treated with NaOH and 10, 20, and 30 wt % of stalks were added into the PS matrix. The alkaline treatment of the grape stalk fibers promoted the removal of hemicellulose and the partial removal of lignin, thus increasing the surface roughness and crystallinity index of the fibers. An improvement in the mechanical and dynamic‐mechanical properties and an increase in the maximum degradation temperature of the composites were observed. In conclusion, the use of grape stalks is a promising alternative for reinforcing composites, and, in addition, a more proper destination can be given to this type of residue. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47427.

Eco-Conversion of Two Winery Lignocellulosic Wastes into Fillers for Biocomposites: Vine Shoots and Wine Pomaces

“…Very few papers deal with the use of residues stemming from the wine-making process in the preparation of composites. The studies are mainly considering fossil and non-biodegradable polymers as matrices, i.e., polyolefins [ 22 , 23 , 24 , 25 ], epoxy resins [ 26 ], polystyrene ([ 27 ]) or poly(vinyl alcohol) [ 28 ], and to a lesser extent, biosourced and biodegradable matrices such as soy flour [ 28 ], and very recently poly(lactic acid) [ 29 ], poly(butylene succinate) [ 30 ] or poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) [ 31 ]. In particular, PHBV is a bacterial polyester presenting the advantage of being potentially prepared from agro-residues.…”

“…This reduction was attributed to a low aspect ratio of particles, e.g., 1.8 in the case of the ViSh fragments obtained by grinding in a granulator equipped with a 2.5 mm sieve [ 22 ], or to a poor filler/matrix interface [ 22 , 25 , 30 ]. A treatment of lignocellulosic fillers, e.g., an alkaline treatment of grape stalks allowing to increase filler surface roughness and crystallinity [ 27 ], or the addition of compatibilizers, e.g., the use of maleic anhydride in the case of a system based on high-density polyethylene (HDPE) [ 22 , 30 ], could be useful to enlarge the overall performance of composites. As regards barrier properties, it was shown that the introduction of ViSh particles in PHBV allowed increasing water vapor permeability, which could be interesting for some applications, e.g., horticulture or the packaging of respiring products [ 31 ].…”

Effect of Thermal and Alkali Treatment on Morphological Analysis of Natural Bamboo Fibre

“…This procedure uses an aqueous solution of sodium hydroxide (NaOH) to influence the structure and chemical build of plant fibres. Depending on the properties of the fibres and how they are utilized, the concentration, temperature, and period of action will change [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The removal of surface impurities and the prevention of fibrillation are both made possible by this treatment, which results in a fibrous material with a larger surface area and a smaller diameter, increasing the tensile strength of the fibres and the mechanical properties of the resulting composite [43].…”

Natural oils as coupling agents in recycled polypropylene wood flour composites: Mechanical, thermal and morphological properties

“…During the last few years, both ecological and economic interests have resulted in a more intensive utilization of recycled and natural materials for the development of new composites. 1 -4 In addition, issues such as recyclability, renewability and environmental safety have become increasingly important for the introduction of new materials and products in several markets. 3,5 So, the recycled wastes and by-products can be made into specific useful products.…”