Papers by Keyword: Biodegradable Polymer

Abstract: This work studied the effect of micro-cellulose fibers prepared from paper pulp on the mechanical and thermal properties of poly(lactic acid) (PLA) and ethylene propylene diene monomer (EPDM) copolymer blends. The FE-SEM shows the micron size of cellulose fibers, and Fourier transform infrared (FTIR) spectroscopy analysis showed that the functional groups of lignin disappeared after passing the synthesis method. An internal mixer prepared the polymer blends and composites, and then samples were molded by compression molding. The results found that the dispersed phase of an EPDM phase was coalescence to droplets on the PLA matrix phase. The micro-cellulose in the polymer was not a homogeneous phase in the polymer matrix. The mechanical properties of polymer blends found that EPDM could improve the strain at break of PLA/EPDM blends when compared with pure PLA and decreased when increasing cellulose fiber content in the polymer matrix. The result of thermal properties found that the cellulose addition affected percent crystallinity but did not affect melting point temperature and glass transition temperature.

Abstract: Starch-based biodegradable films of polybutylene adipate co-terephthalate (PBAT) have been prepared by the solution casting method. The effect of heating at two different temperatures (80 and 110°C) on the mechanical, optical and morphological properties of these films has been evaluated. The two temperatures were selected based on the crystallization and melting temperatures of PBAT. The blend of PBAT with thermoplastic starch has been prepared by melt mixing technique using two roll mills and then the solution casting method has been followed to prepare the films. Apart from curing at room temperature, the films have been cured at 80°C and 110°C. The tensile strength of the films increased by 110% and 252% for films heated to 80°C and 110°C, respectively. As revealed from spectroscopic analysis, the heating of films has no significant effect on the absorption of light by the films in the UV-visible region. The bonding characteristics of the films have been evaluated using Fourier transform infrared (FTIR) spectroscopy. The lowest water absorption and vapour permeability have been obtained in films cured at 80°C.

Abstract: Polyhydroxyalkanoates (PHA) are the biomaterials isolated naturally from bacterial strains. These are present in granules and accumulated intracellularly for storage and energy uptake in stressed conditions. This work was based on the extraction of polyhydroxyalkanoates from haloarchaeal strains isolated from samples of a salt mine and Halocin activity screening of these isolates. For the screening of polyhydroxyalkanoates, Nile Blue and Sudan Black Staining were performed. After confirmation and theoretical determination, polyhydroxyalkanoates extraction was done by sodium hypochlorite digestion and solvent extraction by chloroform method in combination. Polyhydroxyalkanoates production was calculated along with the determination of biomass. Halocin activity of these strains was also screened at different intervals. Isolated strains were identified by 16S RNA gene sequencing. Polyhydroxyalkanoates polymer was produced in form of biofilms and brittle crystals. Halocin activity was exhibited by four strains, among which confirmed halocin activity was shown by strain K7. The remarkable results showed that polyhydroxyalkanoates can replace synthetic plastics which are not environment friendly as they cause environmental pollution – a major threat to Earth rising gradually. Therefore, by switching to the use of biodegradable bioplastics from the use of synthetic plastics, it would be beneficial to the ecosphere.

Abstract: In present work, the structure, absorption and energy gap of films prepared from biodegradable polymer doped ZrO₂-SiC NPs for UV-shielding, biomedical fields and optoelectronics approaches were investigated. The nanocomposites films were fabricated by casting method. The absorption spectra was measured in range (200-800) nm. Results indicated to enhance in absorption and energy gap of biopolymer by adding of ZrO₂-SiC NPs ratios, this behavior make it suitable for various applications like antibacterial films, anti-UV light, diodes, solar cell, transistors and other fields. Keywords: biodegradable polymer, UV-shielding, absorption, energy gap, ZrO₂.

Abstract: This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.

Abstract: One of the challenges in fabricating organic semiconductor thin film is to produce bettermolecular ordering that compromise its electronic properties. Molecular ordering of amorphous thin film can be improved in many ways. Here, high molecular weight polylactic acid (PLA) is introduced as binding matrix to promote 3'''-didodecyl-2,2':5',2'':5'',2'''-quaterthiophene (4T) film’s homogeinity across indium tin oxide (ITO) surface. Molecular ordering of the spin coated biodegradable PLA and 4T blend film processed at ambient atmosphere was studied using two vibrational spectroscopy methods. The complementary analysis of infrared absorption spectrum and Raman spectrum had identified several vibrational modes contributed by thiophene rings and alkyl functional groups. The Raman analysis implied there is a slight change of thiophene ringsʼ molecular orientation due to compressive stress after introduction of polymer. Microscopic characteristics of oligothiophenes especially at the π-π conjugated backbones contained crucial information in order to exploit the oligothiophene as flexible electronics devices.

Abstract: In this research, the biodegradable film of poly (butylene adipate-co-terephthalate) (PBAT) would be used as the polymer matrix. The influence of zeolite (as the filler) type and content were investigated on the mechanical and barrier properties of film packaging. Zeolite was treated with (3-aminopropyl) trimethoxy silane. Films were produced by cast film extruder. Effects of different types of zeolite (5A and 13X) as well as zeolite loading (1-5 wt%) on mechanical properties and permeability of gases (oxygen, carbon dioxide and water vapor) of PBAT composites films have been extensively studied. Tensile properties of PBAT incorporated with zelolite 5A are higher than the one with zeolite 13X. In addition, increasing zeolite content into PBAT film is likely to improve Young’s modulus with the sacrifices of both tensile strength and percentage of elongation at break of PBAT film. For barrier properties, PBAT/zeolite 5A possessed lower permeation both of oxygen and carbon dioxide gases than PBAT/zeolite 13X. The effect of zeolite content plays a major role on oxygen and carbon dioxide permeability of composite films. PBAT/zeolite composite film could certainly extend the ripening period of Homthong bananas for approximately longer than one week.

Abstract: The objective of this work was to characterize the stereocomplex film properties prepared from different ratios of PLLA-PEG-PLLA/PDLA-PEG-PDLA. All ratios used were homogeneous in texture with a small size of pores which increased as the PDLA-PEG-PDLA ratio was increased. The PDLA-PEG-PDLA supported the increase of stereocomplexation of the film's texture. With tetracycline, the increasing of pores on the film surfaces were observed, but not interfered stereocomplexation of the films. However, the drug helped to enhance the homo-crystalline formation. The stereocomplex structure of films both with and without tetracycline have completely formed when the ratios of PLLA-PEG-PLLA/PDLA-PEG-PDLA used were 60/40 and 70/30, respectively. The rate of drug release trends to decrease when the ratio of PDLA-PEG-PDLA increased. This indicated that the different ratios of PLLA-PEG-PLLA/PDLA-PEG-PDLA might be affected by the properties of film as well as the drug release pattern. The obtained results might be applied for designing film for specific proposing, especially as a hydrophobic drug carrier for drug controlled-release.

Abstract: From the last few decades, biodegradable composites have become best alternatives over the petro based polymer because these degrade in the simple compound in the natural environments. Among the available biodegradable polymers, polylactic acid (PLA) is more popular due to its biocompatibility and mechanical properties, that can be used in the biomedical application, such as sutures, bone and ligament fixation screws etc. In this study, synthesis of PLA was performed by ring opening polymerization and Calcium phosphate/Polylactic acid (PLA) bio-composites were prepared by melt mixing technique. Tensile properties of these composites are investigated to assess its feasibility in biomedical and food packaging application.

Abstract: Bioplastics are biodegradable polymers which can be produced by bacteria. The production occurs when the bacteria grow in a medium containing a minimum amount of key nutrients, such as nitrogen, magnesium, and phosphorus but is rich of carbon source. It is known that some bacteria from the genus Halomonas can produce bioplastics compound such as polyhydroxybutyrate (PHB). This study focused to evaluate the potential of Halomonas elongata BK-AB8 in producing PHB. The bacteria were grown on a medium containing nile red. The grown bacterial colony exhibited orange luminescence when exposed under UV light indicating that the bacteria was able to produce bioplastics. The bioplastic production was conducted by growing the bacteria in the modified growth medium at 37 °C for 22 hours with aeration rate of 150 rpm. The resulting bioplastic was extracted using a mixture of chloroform−NaOCl (1:1), and subsequently precipitated in methanol. The highest efficiency of bioplastics production by Halomonas elongata BK-AB8 was around 24.7% using glucose as the main carbon resource. ¹H-NMR, ¹³C-NMR, and FTIR characterizations of the resulting bioplastic showed high similarities to the corresponding profiles of PHB, which is likely in the form of poly-(R)-hydroxybutyrate. Thermogravimetry Analysis (TGA) showed that the resulting PHB sample started to degrade at 210 °C. Further characterization by Differential Scanning Calorimetry (DSC) showed a melting temperature of PHB at 164 °C with a degree of crystallinity around 14.2%, which strongly indicates that PHB was successfully produced from Halomonas elongata BK-AB8.