Tarun K. Maji

Chemical modification of rubber wood with styrene in combination with a crosslinker: effect on dimensional stability and strength property

Chemical modification of rubber wood (Hevea Brasiliensis) was carried out by impregnating the wood with styrene and in combination with a crosslinker Glycidyl Methacrylate (GMA). Polymerization was carried out by catalyst heat treatment. The dimensional stability in terms of % volumetric swelling and anti-shrink efficiency was determined and found to be improved on treatment. Water absorption was also found to be decreased considerably for treated wood samples. Mechanical strength of the treated samples in terms of modulus of rupture and modulus of elasticity were also found to be improved. The wood polymer interaction was confirmed by FT-IR spectroscopy. Biodegradability of the wood/polymer composites was determined and found to be improved on treatment with styrene/styrene-GMA.

Chemical modification of simul wood with styrene–acrylonitrile copolymer and organically modified nanoclay

Simul wood (Salmalia malabarica) was chemically modified by treatment with styrene–acrylonitrile copolymer (SAN), glycidyl methacrylate (GMA), and organically modified nanoclay. The physical properties of wood polymer composites (WPC) were improved due to the addition of GMA and nanoclay. XRD analysis indicated a decrease in crystallinity in WPC. FTIR study confirmed the presence of clay in WPC. The presence of clay in cell lumen and cell wall was evidenced by SEM study. WPC containing lower percentage of clay showed better thermal stability compared to WPC loaded with higher percentage of clay.

Preparation and evaluation of gelatin/sodium carboxymethyl cellulose polyelectrolyte complex microparticles for controlled delivery of isoniazid.

The ratio of gelatin to sodium carboxymethyl cellulose (SCMC) at which maximum yield was obtained was optimized. This optimized ratio of gelatin to SCMC along with other parameters was used to prepare microparticles of different sizes. Vegetable oil was used as emulsion medium. Effect of various factors like amount of surfactant, concentration of polymer on the formation, and size of the microparticles was investigated. These microparticles were used as carrier for isoniazid. Among different cross-linkers, glutaraldehyde was found to be the most effective cross-linker at the temperature and pH at which the reaction was carried out. The loading efficiency and release behavior of loaded microparticles were found to be dependent on the amount of cross-linker used, concentration of drug, and time of immersion. Maximum drug loading efficiency was observed at higher immersion time. The release rate of isoniazid was more at higher pH compared to that of at lower pH. The sizes of the microparticles were investigated by scanning electron microscope. In all the cases, the microparticles formed were found spherical in shape except to those at low stirring speed where they were agglomerated. Fourier transform infrared study indicated the successful incorporation of isoniazid into the microparticles. Differential scanning calorimetry study showed a molecular level dispersion of isoniazid in the microparticles. X-ray diffraction study revealed the development of some crystallinity due to the encapsulation of isoniazid.

Microencapsulation of isoniazid in genipin-crosslinked gelatin-A–κ-carrageenan polyelectrolyte complex

Background: Microspheres of gelatin-A and κ-carrageenan were prepared by using genipin, a naturally occurring crosslinker, and sunflower oil as reaction media. Method: The variations in the size of the microspheres formed by varying the amount of surfactant (0.33–1.0 g/g of polymer), polymer (1.5–3.0 g), and crosslinker (0.2–0.8 mmol) were studied by scanning electron microscopy. The encapsulation of isoniazid was carried out by absorption. The isoniazid content in the prepared microspheres was determined. The release characteristic of isoniazid was also studied at pH values 1.2 and 7.4 by using UV-spectrophotometer. Results: Characterization of the isoniazid-loaded microspheres was carried out by using Fourier transform infrared spectrophotometry, differential scanning calorimetry, and X-ray diffractometery.

Study of Complex Coacervation of Gelatin A with Sodium Carboxymethyl Cellulose: Microencapsulation of Neem (Azadirachta indica A. Juss.) Seed Oil (NSO)

The efficiency of complex coacervation of gelatin A with sodium carboxymethyl cellulose (SCMC) was measured by checking viscosity, coacervate yield (%), and turbidity of the mixture. Maximum coacervation occurred at pH 3.5 and SCMC: gelatin ratio of 1.0: 2.33. Encapsulation efficiency, oil content, oil load, and release behavior of the microcapsules were studied. The size and nature of the microcapsules varied with the concentration of polymer and NSO as revealed by scanning electron microscopy study. Fourier transform infrared (FTIR) spectroscopy indicated that there was no significant interaction between the polymer and NSO.

Encapsulation of active ingredients in polysaccharide–protein complex coacervates

Polysaccharide-protein complex coacervates are amongst the leading pair of biopolymer systems that has been used over the past decades for encapsulation of numerous active ingredients. Complex coacervation of polysaccharides and proteins has received increasing research interest for the practical application in encapsulation industry since the pioneering work of complex coacervation by Bungenburg de Jong and co-workers on the system of gelatin-acacia, a protein-polysaccharide system. Because of the versatility and numerous potential applications of these systems essentially in the fields of food, pharmaceutical, cosmetics and agriculture, there has been intense interest in recent years for both fundamental and applied studies. Precisely, the designing of the micronscale and nanoscale capsules for encapsulation and control over their properties for practical applications garners renewed interest. This review discusses on the overview of polysaccharide-protein complex coacervates and their use for the encapsulation of diverse active ingredients, designing and controlling of the capsules for delivery systems and developments in the area.

Preparation and evaluation of the effect of particle size on the properties of chitosan-montmorillonite nanoparticles loaded with isoniazid

In this report, efforts have been made to develop isoniazid loaded chitosan-montmorillonite nanoparticles by ionic gelation of chitosan with pentasodium tripolyphosphate. The nanoparticles have been characterized by FTIR, XRD, SEM and TEM. The effect of surfactant and particle size on chitosan nanoparticles have been assessed with regard to swelling, encapsulation efficiency and release of isoniazid in different mediums. Swelling experiments provide important information on drug diffusion properties, which indicates that the chitosan nanoparticles are highly sensitive to the pH environment. The drug release mechanism has been studied during different time periods using a UV-visible spectrophotometer. Cytotoxicity has been assessed by MTT assay analysis. Mucoadhesion properties have been appraised by an in vitro wash off test and an ex vivo mucoadhesion test. The results imply that chitosan-montmorillonite nanoparticles can be exploited as potential drug carriers for controlled-release applications.

Physical properties of simul (red-silk cotton) wood (Bombax ceiba L.) chemically modified with styrene acrylonitrile co-polymer and nanoclay

Abstract Wood plastic composites have been prepared based on simul wood (Bombax ceiba L.), which was vacuum impregnated with the styrene acrylonitrile (SAN) co-polymer nanoclay (nnc) intercalating system in the presence of glycidyl methacrylate (GMA), a crosslinking agent. The impact of nanoclay was investigated on the mechanical, thermal, dynamic mechanical behavior, and the biodegradability of the resultant wood polymer nanocomposite (WPCnnc) was investigated. The tensile strength, tensile modulus, flexural strength, and flexural modulus of the composite were relatively higher in the presence of 2 phr nanoclay. The limiting oxygen index values showed self-extinguishing behavior of the WPCnnc. Furthermore, the storage moduli (E′) and damping index (tan δ) of these products were high. WPCSAN/GMA/nnc exhibit higher biodegradability compared to WPCSAN/GMA.

In situ polymerized wood polymer composite: effect of additives and nanoclay on the thermal, mechanical properties

This study concerns the preparation and characterization of wood polymer nanocomposites based on impregnation of styrene acrylonitrile co-polymer-nanoclay intercalating system in presence of glycidyl methacrylate (GMA), a cross linking agent, and vinyl trichloro silane (VTCS) as additives into Simul (Bombex ceiba, L.), a soft wood. The effect of nanoclay and VTCS on the properties of the resultant wood polymer nanocomposites (WPNC) has been evaluated. FTIR spectroscopy shows the interaction among wood, polymers, GMA, nanoclay and VTCS. The penetration of polymer and nanoclay into the wood cell wall is supported by SEM study. The distribution of nanoclay in the SAN polymer matrix present within the wood cell wall has been evidenced by TEM study. TGA results show an improvement in the thermostability of the resultant composites. The inclusion of VTCS enhances the self extinguishing behaviour of the WPNC as revealed by limiting oxygen index (LOI) test. Due to treatment, the resultant WPNC exhibits an improvement in all the properties like water repellancy, dimensional stability, hardness, flexural, tensile and thermal stability compared to untreated wood.

Studies of properties of rubber wood with impregnation of polymer

Impregnation of rubber wood has been carried out under different conditions by using styrene as grafting monomer and glycidyl methacrylate (GMA) as crosslinker. Properties such as dimensional stability, water absorption, hardness, tensile strength, flexural strength, etc of the impregnated wood have been checked and found to be improved by incorporation of GMA as the crosslinker with styrene. The polymerimpregnated wood has also been characterized by FTIR spectroscopy and DSC.