International Journal of Materials and Chemistry 2015, 5(4): 96-100 DOI: 10.5923/j.ijmc.20150504.03 Preparation and Characterization of Nylon 6 and Lignin Coated Carbon Nanotube Composite Ayesha Kausar Nanosciences and Catalysis Division, National Centre For Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan Abstract Novel lignin modified carbon nanotube (L-CNT) were prepared as reinforcement of nylon 6 composites. The carbon nanotube was coated with lignin using dioxane solvent. The filler was loaded in polyamide-6 composites through in-situ polymerization. Two parameters were varied i.e. (i) sonication time during in-situ reaction and (ii) L-CNT content. The effect of L-CNT on molecular weight (M n and M w ), glass transition temperature (T g ) and tensile modulus of the composites was studied. The molecular weight of in-situ polymerized PA6 was decreased with the addition of L-CNT content. The same effect was observed with the increase in sonication time due to hindrance in chain growth by L-CNT. Significant increase in the mechanical properties was observed up to the sonication time of 0.5 h. The tensile modulus of the composites was increased to 5.9 GPa in PA 6/L-CNT 10 nanocomposite. However there was 61% increase in the tensile modulus with 10 wt. % nanofiller addition compared with 1 wt. % L-CNT. The glass transition temperature for PA 6/L-CNT 1, PA 6/L-CNT 3, PA 6/L-CNT 5, and PA 6/L-CNT 10 was found as 80, 82, 84, and 101°C at 0.5 h sonication time. Hence there was 21% increase in the T g upon the addition of 10 wt. % filler compared with 1 wt. % L-CNT addition. Keywords Polyamide, Lignin, in-situ polymerization, Nanocomposite, T g , Tensile modulus 1. Introduction Over the past years, discovery of carbon nanotube (CNT) have concerned huge interest owing to their remarkable electrical, physical, and mechanical properties, which make them ideal candidates for various applications in the fields of electronics, nanomechanics, and sensor development [1, 2]. CNT have been categorized into two different categories, i.e. single-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT). The difference between single-walled and multi-walled carbon nanotube is that SWCNT show single-layer of graphene sheet with simple geometry (diameter ranges from 0.3-0.4 nm) whereas MWCNT consist of several layers of graphene sheets. Due to their outstanding characteristic features, CNT can also be used in several fields including mechanical, chemical, and electrical relevance. The CNT-based composites are even more fascinating materials since properties of their constituents are often changed and tuned by a synergistic effect. The polymer/CNT composites are the most representative examples of such hybrid materials [3]. The term lignin is used to illustrate both naturally occurring binding cellulose fibers, biopolymers together in plant cells, and a byproduct from paper/pulp industry, which in fact is a * Corresponding author: asheesgreat@yahoo.com (Ayesha Kausar) Published online at http://journal.sapub.org/ijmc Copyright © 2015 Scientific & Academic Publishing. All Rights Reserved diversity of chemical derivatives characterized by lower molecular weight, changed chemical structure and solubility in aqueous and/or organic phases. From the chemical point of view, the parent lignin is an amorphous polyphenolic material arising from an enzyme mediated dehydrogenative polymerization of three phenylpropanoid monomers, coniferyl, coumaryl, and sinapyl alcohol [4, 5]. Next to cellulose, lignin is the second most abundant renewable natural resource which is highly-branched, three-dimensional biopolymer. It comprises of three phenylpropanoid units such as guaiacyl (G), p-hydroxyphenyl (H) and syringyl (S) (Fig. 1). The distinctive network structure as well as the presence of numerous chemical substituents offer special functional features to lignin such as UV-absorption, stabilizing effect [6], biodegradability, reinforcing effect, anti-fungal, and antibiotic activity [7-9]. However, the prospective of lignin is not clearly valued; because it is principally achieved as byproducts in pulp manufacture thus is mainly used as fuel. Fortunately, incorporating into polymeric materials will be a value-added relevance for lignin [10-12]. Lignins demonstrate a strong potential toward adsorption on organic substrates [13, 14]. In fact, extensive work has been conducted regarding the investigation of the properties of polymer/lignin/carbon filler composites [15, 16]. They are also employed in strengthening, electrostatic discharge, and sorption materials [17, 18]. Especially in rubber-based materials as compared to carbon black, lignin is less dense, non-conducting, and being lighter in color. For the