Synthesis of lignocellulosic polymer with improved chemical resistance through free radical polymerization

Abstract

Rising environmental awareness has resulted in a renewed interest in biological macromolecules obtained from renewable resources. So in view of technological significance of natural lignocellulosic polymers in numerous applications, the present study is an attempt to synthesize lignocellulosic polymers based graft copolymers using free radical polymerization. Different reaction conditions have been studied to synthesize the lignocellulosic graft copolymers. The graft copolymers have been characterized with scanning electron micrography (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The grafted samples have also been screened against different physico-chemical conditions to assess their applicability in different applications.

Introduction

Recently, rising environmental awareness has resulted in a renewed interest in green materials obtained from renewable resources [1], [2], [3]. Commercial interest in manufacturing these products is driven by the derivation of the polymers from renewable sources as well as by their specific properties including biodegradability [4], [5], [6], [7], [8]. Indeed there has been rapid growth in the area of cellulosic polymers, facilitated by novel technologies, which has resulted in a more urgent focus on developing potential green materials more effectively and efficiently [9], [10], [11]. Natural cellulosic polymers e.g. natural fibers offer a number of advantages which include biodegradability, easy availability, eco-friendliness, toxicologically harmless, enhanced energy recovery, low cost etc. as compared to the traditional synthetic materials such as glass fibers, carbon fibers, aramid fibers [12], [13], [14], [15]. Last few years have seen a resurgence of natural cellulosic materials as potential reinforcement in green composites as well as in toxic metal ion removal, packaging and biomedical applications [16], [17], [18], [19], [20]. In conventional synthetic polymer composites none of the component belongs to natural polymers and thus affects the environment directly or indirectly. On the other hand composite materials which contain natural cellulosic fibers as one of the component normally exhibit enhanced eco-friendly properties because of the partial replacement of the synthetic filler materials with low cost economic green reinforcing material [21], [22], [23], [24]. Natural fibers polymer composites have been the subject of intense research efforts all around the globe since last few years. A number of practical applications of natural fibers reinforced composites are now emerging in different field such as in interior decorating, automotive components and biomedical applications [24], [25], [26], [27]. However the natural fibers reinforced composites suffers from few drawbacks such as these are inferior to harsh environmental conditions as the cellulose fibers are of hydrophilic nature. In order to improve the properties of natural cellulosic polymers a number of surface modification techniques have been used such as mercerization, benzoylation, acetylation and graft copolymerization [27], [28], [29], [30], [31]. Among these graft copolymerization is most facile to induce desired functionalities into the cellulosic polymers. The aim of this study is to improve the existence properties such as poor physico-chemical resistance, hydrophilic nature and thermal stability of natural lignocellulosic polymer: Eulaliopsis binata through graft copolymerization of ethyl acrylate monomer. These grass fibers species are traditional in a number of countries and so far have been the unexplored materials in spite of their wide potential. The present communication for the first time describes in detail the effect of different reaction conditions on the percentage of grafting onto these lignocellulosic polymers. The grafted lignocellulosic polymers were subjected to different physico-chemical studies and have been found to exhibit better properties after graft copolymerization is accomplished.