Fahmida Parvin

Preparation and Characterization of Starch/PVA Blend for Biodegradable Packaging Material

Polymer films of rice starch/Polyvinyl alcohol (PVA) were prepared by casting method. Different blends were made varying the concentration of rice starch and PVA. Tensile strength (TS) and elongation at break (Eb) of the prepared films were studied. Films made up of rice starch and PVA with a ratio of 2:8 showed highest TS. 10% sugar was added with highest TS giving four composition of Starch/PVA blend in order to increase TS and Eb. Films made up of rice starch and PVA and sugar with a ratio of 1:8:1 showed highest TS and Eb and the recorded value was 14.96MPa and 637% respectively. The physico-mechanical properties of the prepared sugar incorporated films were improved by grafting with acrylic monomer with the aid of UV radiation. A formulation was prepared with monomer, methylmethacrylat in methanol, and a photo initiator. The highest TS of the grafted films were recorded and the value was 16.38 MPa. The water uptake and weight loss in both soil and water of the grafted films are lower than the non-grafted films. The prepared films were further characterized with stereo micrograph and XRD. Finally, the produced film can be used as biodegradable packaging materials for shopping and garbage bags that are very popular and environment friendly.

Preparation and Characterization of Gelatin-Based PVA Film: Effect of Gamma Irradiation

Gelatin-based polyvinyl alcohol (PVA) films were prepared (using a casting process) by mixing aqueous solutions of gelatin and PVA in different ratios. Monomer 1, 4-butanediol diacrylate (BDDA) was dissolved in methanol. Films containing 95% gelatin + 5% PVA were soaked in 3% BDDA monomer (w/w). These films were then irradiated under gamma radiation (60Co) at different doses (50–500 krad) at a dose rate of 350 krad/h. The physico-mechanical and thermal properties of these films were evaluated. It was evident that 5% PVA-containing gelatin blend film exhibited the highest tensile strength (TS) value at 50 krad (51 MPa), which was 46% higher than that of non-irradiated blend films. It was also found that incorporation of PVA significantly reduced the TS value of the blend films compared to the raw film, whereas elongation at break (Eb) value was increased. A significant improvement of the blend films was also confirmed by thermogravimetric analysis (TGA) and thermo-mechanical analysis (TMA) when the acrylate group (from BDDA) was introduced into the film.

Introduction to Manufacturing of Natural Fibre-Reinforced Polymer Composites

In the recent era, different environmental issues have significantly influenced the innovations in material science and technology. The burgeoning demand for clean environment has led the innovation of green materials and utilization of natural materials. Thus, the urge for the production of high-performance engineering products from natural renewable resource is growing day by day. Composites are among those versatile, high-performance materials which combine the unique mechanical and thermal properties that cannot be achieved in a single material. In the recent decade, scientists continued to explore the potential of natural fibres as the reinforcing phase for polymer composites. The important driving force for such emergence of utilizing natural resources is that they are renewable and biodegradable and impose no adverse effects on environment, whereas petroleum-based products are limited and cause environmental problems. This review gives the state-of-the-art overview on currently developed natural fibre-reinforced polymer composites focusing on structure–property relationship of fibres, different polymer matrices used to develop composites, their mechanical performances, different composite fabrication techniques, and the application of such composites in different areas. Critical issues of biocomposites have also been discussed along with their advantages and disadvantages. This article also summarized the critical issues in the manufacturing of natural fibre composites.

Fabrication and Characterization of Jute Fabric-Reinforced PVC-based Composite:

Jute fabrics (hessian cloth) reinforced polyvinyl chloride (PVC) based composites were prepared by compression molding. Jute content varied from 40–60 wt% in the composites. Four layers of jute fabrics were compression molded with five layers of PVC. It was found that the composite containing 40% jute fabrics showed the best performance. The values of tensile strength (TS), bending strength (BS), tensile modulus (TM), and bending modulus (BM) of the composite (40 wt% jute fabrics) were found to be 59.3 MPa, 62.6 MPa, 1.3 GPa, and 3.2 GPa, respectively. The values of TS and BS were improved to 77% and 46%, respectively, compared to the matrix material PVC. Scanning electron microscopic analysis was carried out to investigate the interfacial properties of the composites. Degradation tests of the composites (up to 6 months) were performed in soil medium and showed partial degradation nature.

Thermomechanical, barrier, and morphological properties of chitosan-reinforced starch-based biodegradable composite films

Chitosan-reinforced starch-based biodegradable composite films were prepared by solution casting. The chitosan content in the films was varied from 20% to 80% (w/w). Tensile strength (TS) and tensile modulus (TM) of the starch-based composites were improved significantly with the addition of chitosan. Water vapor permeability (WVP) and oxygen transmission rate (OTR) of chitosan-reinforced starch-based films showed a significant reduction compared to native chitosan film and indicated better barrier properties to water vapor and oxygen. The water uptake of the films pointed out better hydrophobic character due to the incorporation of chitosan in starch-based films. Thermal stability was also found to increase with the addition of chitosan in starch-based films and was confirmed by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Fourier transform infrared (FT-IR) spectroscopy supported the molecular interactions due to the reinforcement of chitosan in starch-based films. Surface and interface morphologies of chitosan film and starch/chitosan composite film were examined by scanning electron microscope (SEM) and suggested sufficient homogenization of starch and chitosan in the biodegradable composite films.