M. Asim

Laccase application in medium density fibreboard to prepare a bio-composite

Laccase efficacy as a biological tool for the removal of lignin in pulp industries is evident and has scope for a wider application. In this research study, rubber wood (Hevea brasiliensis) fibres were treated with laccase enzyme to study its effect on the fibre surface and the enzyme hydrolysis lignin (EHL) was collected as a byproduct. Collected EHL was concentrated (con) until the solution reached a 3% solid content. Fibre surface modification was studied by FESEM, FTIR and XRD. A distinct fibre surface with an improved crystallinity index was observed. EHL and Con-EHL were analyzed on a viscometer, FTIR, DSC, and TGA. Con-EHL exhibits a lower stretching energy at the benzene range compared to EHL and a curing pattern similar to UF was reported. To evaluate the capability of modified fibre and Con-EHL, 6 mm medium density fibreboard (MDF) of 810 kg m−3 were prepared by using 10% Con-EHL solution (by weight of fibre). The MDF boards exhibit higher mechanical strength and have passed the ASTM D1037 standard for internal bonding and modulus of rupture.

Recent Advances in Nanoclay/Natural Fibers Hybrid Composites

The growing demand for continual improvement in the engineering applications of thermoplastic and thermoset polymer materials compared with metals in various applications led to the emergence of hybrid nanocomposites by the addition of different nano fillers, with advanced properties. Nano fillers such as carbon black, pyrogenic silica, nano oxides and metal particles are being used as additives in polymers from decades. However, the increasing stringent environmental legislation and consumer awareness highlights the importance of natural, low cost and abundant clay materials such as nanoclays. The hybridization of natural fiber with nanoclay is interestingly positive due to the tendency of nanoclay to upsurge both flexibility and rigidity of the natural fiber in one step. The most promising nanoclay involved in the modification of polymers and natural fibers reinforced polymer composite are montmorillonite, organoclay, saponite and halloysite nanotubes. Nanoclay/natural fibers hybrid nanocomposites have engrossed great attention since their discovery due to their wide variety of properties in food packaging, biomedical devices, automotive industries and other consumer applications with better thermal, physical, mechanical, optical and barrier properties. Present article designed to be a comprehensive source of recent literature and study on nanoclay fillers, its different classes, modification of polymers by nanoclay and their varied applications. This article also intended to covers the recent advances in natural fiber/nanoclay hybrid polymer nanocomposites research study, including their different commercial applications.

Effect of pineapple leaf fibre and kenaf fibre treatment on mechanical performance of phenolic hybrid composites

In this work, hybrid composites were fabricated by hand layup method to hybridize treated Pineapple leaf fibre (PALF) and kenaf fibre (KF) in order to achieve superior mechanical properties on untreated hybrid composites. Silane treated PALF/KF phenolic hybrid composites were prepared on various fibre fraction to investigate mechanical properties and compared with untreated PALF/KF phenolic hybrid composites. The effects of silane treatment on hybrid composites were investigated by fourier transform infrared spectroscopy (FTIR) and found very effective peaks. Effects of treated hybrid composites were morphologically investigated by using scanning electron microscopy images and analysed the tensile results. Treated PALF/KF phenolic hybrid composites enhanced the flexural strength, modulus, impact strength and energy absorption while tensile strength and modulus decreased. The overall performances of 70 % PALF 30 % Kenaf hybrid composites were improved after silane treatment. Silane treatment of fibres improved the mechanical performance of hybrid composites and it can be utilized to produce components for building structure, materials and automobile applications.

The Effect of Silane Treated Fibre Loading on Mechanical Properties of Pineapple Leaf/Kenaf Fibre Filler Phenolic Composites

The aim of the present study is to investigate mechanical and morphological properties of pineapple leaf fibres (PALF) reinforced phenolic composites and its comparison with kenaf fibre (KF)/phenolic composites. Mechanical properties (tensile, flexural and impact) of untreated and treated PALF phenolic composites at different fibre loading were investigated. Tensile, flexural and impact properties of PALF and kenaf/phenolic composites were analyzed as per ASTM standard. Morphological analysis of tensile fracture samples of composites was carried out by scanning electron microscopy. Obtained results indicated that treated PALF/phenolic composites at 50% PALF loading exhibited better tensile, flexural and impact properties as compared to other untreated PALF/phenolic composites. Treated kenaf/phenolic composites at 50% fibre loading showed better tensile, flexural and impact properties than untreated kenaf/phenolic composite. It is concluded that treated 50% fibre loading kenaf and PALF/phenolic composites showed better mechanical properties than untreated kenaf and PALF/phenolic composites due to good fibre/matrix interfacial bonding. Results obtained in this study will be used for the further study on hybridization of PALF and KF based phenolic composites.

Natural Fiber Improvement by Laccase; Optimization, Characterization and Application in Medium Density Fiberboard

ABSTRACT Crystallinity of cellulosic fiber directly affects the physical and chemical behavior of the individual fiber and ultimately the product made from. In a controlled condition, if the natural fiber is exposed to enzymatic hydrolysis, its crystallinity improves without affecting the cellulose component of the fiber. In this work, four basic factors for enzymatic reaction, i.e., temperature, time, pH, and enzyme amount, were optimized using response surface methodology (RSM). The response was taken as the fiber crystallinity index, measured by X-ray diffraction method. The optimum treated fiber was further analyzed for the field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA) and results were compared with untreated fiber. Medium density fiberboards (MDF) were manufactured from optimum treated fiber and its tensile properties and water resistance properties were compared with MDF made from untreated fiber. The observation revealed a maximum of up to 14% increment in fiber crystallinity index (CrI) as compared to untreated fiber. The MDF prepared from optimum treated fiber exhibits improved tensile property and lower water absorption property as compared to MDF prepared from untreated fibers.

Dimensional stability of pineapple leaf fibre reinforced phenolic composites

In this research, pineapple leaves fibre (PALF)/phenolic resin (PF) composites were fabricated by hand lay-up method. The aim of this work is to investigate the physical properties (water absorption and thickness swelling) of PALF reinforced phenolic resin composites. Long-term water absorption (WA) and thickness swelling (TS) behaviours of the PALF/PF composites were investigated at several water immersion times. The effects of different fibre loading on WA and TS of PALF/PF composites were also analyzed. Obtained results indicated that the WA and TS of PALF/PF composites vary with fibres content and water immersion time before reaching to equilibrium. WA and TS of PALF/PF composites were increased by increasing fibre loading. Results obtained in this study will be used for further study on hybridization of PALF and Kenaf fibre based phenolic composites.In this research, pineapple leaves fibre (PALF)/phenolic resin (PF) composites were fabricated by hand lay-up method. The aim of this work is to investigate the physical properties (water absorption and thickness swelling) of PALF reinforced phenolic resin composites. Long-term water absorption (WA) and thickness swelling (TS) behaviours of the PALF/PF composites were investigated at several water immersion times. The effects of different fibre loading on WA and TS of PALF/PF composites were also analyzed. Obtained results indicated that the WA and TS of PALF/PF composites vary with fibres content and water immersion time before reaching to equilibrium. WA and TS of PALF/PF composites were increased by increasing fibre loading. Results obtained in this study will be used for further study on hybridization of PALF and Kenaf fibre based phenolic composites.

Nanocellulose: Preparation methods and applications

Abstract Cellulose is a multilevel, complex molecular structure built from superfine fibrils having diameters in the nanoscale. These nanofibrils contain highly ordered nanocrystallites and low-ordered whiskers in nanodomains. The cellulose in nanosize can be recovered from the cellulosic biomass by the top-down technique involving various physical and chemical processes followed by refining technique. At present, nanocellulose synthesis is an entirely established technique; however, it involves harsh chemical treatments that are perpetually hazardous to humans and the environment. Various green techniques for nanocellulose synthesis have been proposed such as enzymatic hydrolysis, ionic liquid, and so forth. Although nanocellulose is derived from cellulose, it possesses completely diverse characteristics from original materials. It shows enhanced crystallinity, high surface area, rheological properties, alignment and orientation, biodegradability, biocompatibility, low toxicity, and so on. Nanocellulose has gained much attention for various biochemical applications due to its remarkable physical properties, exceptional surface chemistry and superb biological properties. Its biomedical applications include wound dressings, drug conveyance, medicinal inserts, tissue building, nourishment, and beautifying agents. Whereas its composite materials applications include preparation of biodegradable plastics, aqueous coating, and materials creation.