Papers by Keyword: Biodegradation

Abstract: The effectiveness of the use of structures made of wood-polymer composites lies in ensuring their stability and durability both under wide temperature and humidity fluctuations and under biological action. Therefore, the object of research was the change in the properties of wood-polymer composites under biological influence and its protection when using synthetic resins capable of penetration by microorganisms. It has been established that in the process of biological action, the process of stability of wood-polymer composite consists in the use of materials with low biodegradation. Experimental studies on the determination of the biological stability of wood-polymer composites show that the maximum mass loss in the case of biodegradation of samples of wood-polymer composites based on starch was up to 15% and refers to biodegradation. The mass loss of samples of wood-polymer composites based on PVA glue did not exceed 5%, made from sawdust and synthetic resin was less than 1.5%, which refers them to bioresistant materials. The study of the compressive strength after biodegradation showed that the product from wood-polymer composite on starch and PVA glues is brittle. So, the lowest compressive strength was shown by the sample on starch with an average value of 0.1 MPa, a slightly better value was shown by the sample on PVA glue D3 – 0.98 MPa and the sample on PVA glue D4 – 1.92 MPa. However, for samples based on synthetic resins, the compressive strength is much higher and is: for wood-polymer composite based on epoxy resin, the average value is 3.1 MPa and polyester resin – 2.4 MPa.

Abstract: This study explored eggshells as an eco-friendly and cost-effective material for synthesizing hydroxyapatite. The phase compositions and morphological structure of polylactic acid composite with and without co-doped hydroxyapatite addition via a melt blending approach were evaluated. Furthermore, the biodegradation profile of the polylactic acid composite in phosphate buffer solution was studied. The concentrations of PLA/HAp, PLA/7.5MgO-7.5ZnO, and PLA/12.5MgO-2.5ZnO samples, respectively, were examined in this study. The results of morphological evaluation showed a well-distributed irregular spherical phase of hydroxyapatite. Meanwhile, the co-doped hydroxyapatite phases have variations in sizes and shapes. The polylactic acid composites showed fractured, rough, and honeycomb surfaces with interconnected pores suitable for cell propagation and enhancement, and the elemental composition proved precipitation of apatite formation. Characteristics of absorption bands of the hydroxyapatite, magnesium, zinc, and polylactic acid were present, respectively. The XRD spectra confirmed the presence of crystalline and semi-crystalline structures with percent crystallinity of 48.57%, 56.64%, and 60.08%, respectively. Meanwhile, the addition of the co-doped hydroxyapatite results in shifts in the 2θ angles of the crystal phases. The biodegradation study revealed the beneficial role of reinforcing polylactic acid composite with biogenic hydroxyapatite and hybrid doped hydroxyapatite as fillers and their synergetic effect with the pH of 7.08±0.21, 6.63±0.46, & 7.28±0.44, the porosity of 52.26±7.29, 48.57±6.74, & 43.72±5.07 %, and the degradation rate (weight loss) of 51.83±7.03, 48.16±6.85, & 43.66±5.46, respectively. Findings revealed that the current study aligns with the sustainable biodegradable composite used in bone tissue repair and hence contributed towards sustainable material without polluting the environment.

Abstract: Growing interest in utilizing and processing natural fibres (NF) to create biodegradable and sustainable composites as environmental concerns upsurge globally. Date palm trees (DPT) account for more than 4.5 million tons of waste annually worldwide, making it one of the most abundant agricultural biomass waste in the MENA region. This study evaluated the biological resistance of thermoplastic composites developed from polylactic acid (PLA) and recycled polyvinyl chloride (RPVC) reinforced with date palm fibre (DPF) at different contents (10, 20, 30, 40 wt.%) and fibre size (250 – 500 µm and ≥1,000 µm). Composites where exposed to the brown-rot fungus; Irpex lacteus, and white-rot fungus; Tyromyces palustris, to evaluate its resistance to biodegradation. Results showed that composites developed using PLA had higher weight loss (%) when compared to the same samples but reinforced with RPVC. Composites with higher DPF content showed high rates of decay when used with different polymer matrix. Also, DPF length had a significant effect on the disintegration of the composites. DPF/PLA reinforced with 40 wt.% DPF showed the highest weight loss (WL%) reaching 5.61% and 5.46% when exposed to Tyromyces palustris and Irpex lacteus respectively. On the other hand, the biodegradation had a direct impact on the disintegration of the composites developed where the WL%, of PLA composites developed with 40 wt.% DPF showed 61.40%.

Abstract: The development of bioplastics is currently increasing, because bioplastics are an effort to reduce landfill waste. One of the bioplastics that has good degradation ability is cornstarch. The addition of nanoparticles was carried out to improve the properties of bioplastic packaging. One example of the application of nanotechnology in food packaging is silver nanoparticles (AgNP), known as antimicrobial substances. This research was conducted to determine the effect of adding AgNP (0%, 1%, and 2%) on the antimicrobial and biodegradation of cornstarch bioplastics. Bioplastics are made by casting method. AgNP was used from the synthesis of silver nitrate (AgNO₃) and trisodium citrate dihydrate (C₆H₅Na₃O₇.2H₂O) as a reducing agent and stabilizer by chemical reduction method, which was then analyzed by FTIR. The results obtained showed that cornstarch bioplastic AgNP 1% has the ability to estimate the fastest degradation time among other concentrations with an addition of 103 days. Cornstarch bioplastic AgNP 2% had the best ability to inhibit bacterial growth, with antibacterial inhibition zone diameters of 11.03 mm (Staphylococcus aureus) and 10.61 mm (Escherichia coli). However, AgNP could not inhibit the mold growth of Aspergillus niger. The addition of AgNP to cornstarch bioplastics can increase the degradation capabilities and antibacterial activity of bioplastics.

Abstract: The introduction of plastic materials has revolutionised our society. However, excessive use of traditional, non-biodegradable plastic materials, especially for packaging applications, has created many environmental issues. During the past few decades, many biodegradable polymers, bio-based and petroleum-based, have been developed to address the above problem. Several research has been carried out on various biodegradable polymer blends and composites. However, their widespread application is still limited. This paper gives an overview and progress made on biodegradable polymers for flexible packaging applications, a critical analysis of their performance characteristics and recommendations on priority areas for further research. This Paper shows that, among the polyesters, though PHAs is most attractive concerning biodegradability, its low elongation at break, narrow processing temperature and high production cost limit their use for flexible packaging application. For flexible packaging applications, PBS (Polybutylene succinate) is better than PLA (Polylactic acid) and PHAs (Polyhydroxyalkonates), considering thermal characteristics and tensile elongation. In addition, PBS is biodegradable in compost, soil, lake and seawater, though its rate of biodegradation is reported to be slower compared to PHAs.

Abstract: Amount of packaging waste is constantly increasing, resulting in different environmental problems. Packaging waste, mainly plastic and paper based, comprises about one-third of all municipal solid waste. Anaerobic degradation is common method of the waste management for the organic based materials. In this study, biodegradability potential of UV curable thermochromic ink, as most common sample od smart packaging, was studied. The used ink is based on polyurethane acrylate.. Results indicated that by the proper selection of materials the biodegradability aspect of printed samples can be varied. Moreover, the results point to heterogeneous degradation of prints surface. This can be confirmed by the determination of the prints’ total colour difference, which was relatively high in all cases pointing to print deterioration. Biodegradation of UV TC ink, based on polyurethane acrylate results in breaking down of the ester linkages i.e. due to the hydrolysis of the ester bonds. Within the used printing substrates, TC print on wood free uncoated paper shows the highest rate of biodegradation over 150 days of incubation, around 40%, followed by print on 100% recycled paper and wood free coated paper. The present study shows that TC prints in studied environment, are ultimately biodegradable.

Abstract: Today, biodegradable polymers are used to obtain various functional materials, including for the needs of agriculture. The article describes the current state of the production of polymeric materials, the problems of their operation, as well as the prospects for the creation of new polymeric biodegradable materials for agriculture. It is found that, depending on the method of obtaining a biopolymer-based material, its ability to diffuse water and water absorption is different – non-woven materials have higher performance than film materials. After seed germination, the thermophysical characteristics of the polylactide-based material change, the degree of crystallinity decreases by 7-10%, which indicates the destruction of the crystalline phase.

Abstract: The recovery of a fractured femur using the plate and screw internal fixation. The plate internal fixation is made of metal has good mechanical strength, but causes allergic reactions, secondary surgery, stress shielding and high costs. Evaluation of the lack of metal, now developed biodegradable polymers use Polylactide (PLA) and Poly ɛ-caprolactone (PCL). The advantages of PLA and PCL materi-als can control the rate of degradation and increase mechanical strength. Manufac-turing processes of the plate fixation internal using cold isotactic pressing. Inde-pendent variable on the PLA/PCL blends from 90/10, 80/20, 70/30, and 60/40 wt% and tested for FTIR, XRD, SEM, density and porosity. Result from adding PCL make the degree of crystallinity is decreased significantly. The formation of semi-crystalline the with peak width smaller and the crystal size bigger in the 60PLA sample. PLA/PCL blends largely formed bonding and some immiscibility in the form of small flakes and cavities after the addition of PCL content. Large cavities reduce density and increase porosity which can affect mechanical proper-ties. 90PLA sample has high density and low porosity of 1,186 g/cm3 and 4% porosity, respectively.

Abstract: Plastic waste is an ever-growing concern, causing harm to many ecological and human health aspects, one of the major contributors to this problem being packaging. Mycelium composites (MC) are ecologically safe materials, well suited for the short-life usage as packaging materials. In our study we made MC using fine and coarse granulometry hemp shives applying them in 3 substrate variants – with added bran, with added bran and birch bark, and as the sole substrate. We assessed material's water absorption and mechanical properties, chemical decomposition, biodegradability, mold resistance and fungal biomass. Granulometric effect was observed only when using shives as the sole substrate, where larger particle size gave poorer results. Bran did not significantly improve mechanical properties or water uptake. Bark reduced water uptake by ~200 %, but lowered mechanical properties, and provided no benefits to mold resistance which was low for all specimens. Overall, hemp MC showed complete biodegradability after 12 weeks, mechanical properties up to 0,235 MPa, compatible with expanded polystyrene, but very high water uptake of up to 1000 %. Future studies are needed to reduce water absorption and improve mold resistance, as well as invent consensus methodology for better cross-study comparison.

Abstract: Developing Mg based implants for temporary applications based on their biodegradation in the physiological environment is a potential research area in the biomedical engineering. Assessing the bio-corrosion in simulated conditions helps to reduce the complexity of research studies associated with in-vivo experiments and can be used to assess the true behavior of the Mg implant in artificial solutions. On the other hand, assessing the corrosion behavior by using 3.5% NaCl solution is a standard ASTM protocol widely used in the industries. Hence, in the present work, degradation of pure Mg due to bio-corrosion in two different solutions i.e simulated body fluids (SBF) and 3.5% NaCl solution has been investigated. From the results, the weight loss measurements indicated higher degradation during the initial 24 h in SBF solution. However, with the increased immersion time to 72 h, due to the deposition of mineral phases from SBF as confirmed from the electron microscopy and X-Ray diffraction study, the degradation was observed as decreased in SBF compared with NaCl solution. Hence, the results demonstrate that the evaluation of degradation behavior of Mg based materials in simulated physiological environments is appropriate compared with the standard NaCl environment.