Search Results (8)

For sustainable development aligned with circular economy principles, the recycling of biopolymers such as polylactic acid (PLA) is of growing interest. In this study, the effect of primary recycling through repeated mechanical reprocessing was investigated. PLA water bottle preforms were subjected to six consecutive extrusion cycles, and changes in its molecular structure and physical properties were evaluated. Structural analysis revealed a progressive degradation, evidenced by a great reduction in the molar mass and increase in the melt flow index, attributed both to the chain scission derived from the thermal degradation and shear stresses of the extrusion process, and hydrolysis at the ester linkage of the polymer. Recycled samples exhibited a darkening of the color and a continuous decrease in thermal stability. After six reprocessing cycles, PLA crystallinity increased from 6.9 to 39.5%, the cold crystallization process disappeared, and molecular weight reduced by up to 40%. Barrier properties were highly affected after reprocessing and by the increase in relative humidity. Biodegradation tests revealed that crystallinity affected considerably the biodegradation rate of PLA. Although the molecular weight was considerably reduced during reprocessing, the biodegradation was slowed down. These findings provide insights into the limitations and potential of mechanically recycled PLA for future material applications. Full article

This study presents the design, fabrication, and experimental validation of a two-finger robotic gripper featuring a 135° V-shaped fingertip profile tailored for lightweight waste collection in laboratory-scale environmental robotics. The gripper was developed with a strong emphasis on cost-effectiveness and manufacturability, utilizing a desktop 3D printer and off-the-shelf servomotors. A four-bar linkage mechanism enables parallel jaw motion and ensures stable surface contact during grasping, achieving a maximum opening range of 71.5 mm to accommodate common cylindrical objects. To validate structural integrity, finite element analysis (FEA) was conducted under a 0.6 kg load, yielding a safety factor of 3.5 and a peak von Mises stress of 12.75 MPa—well below the material yield limit of PLA. Experimental testing demonstrated grasp success rates of up to 80 percent for typical waste items, including bottles, disposable cups, and plastic bags. While the gripper performs reliably with rigid and semi-rigid objects, further improvements are needed for handling highly deformable materials such as thin films or soft bags. The proposed design offers significant advantages in terms of rapid prototyping (a print time of approximately 10 h), modularity, and low manufacturing cost (with an estimated in-house material cost of USD 20 to 40). It provides a practical and accessible solution for small-scale robotic waste-collection tasks and serves as a foundation for future developments in affordable, application-specific grippers. Full article

Bottle gourd (BG) oil (family Cucurbitaceae) has several pharmacological activities including a reduction of the hazard of cardiovascular and atherosclerosis conditions. This work aimed to develop and optimize self-dispersing lipid formulations (SDLFs) of BG oil by applying a full 3² factorial design. The formulation variables (oil concentration and surfactant mixture ratio) showed an obvious impact on the characters of the prepared BG-SDLFs including droplet size (DS), polydispersity index (PDI), emulsification time (ET), and transmission percentage (Tr%). The optimum BG-SDLF composed of 30% oil and Tween 80/Cremophor^® RH40 (1:1) showed good emulsification characteristics and a better drug release profile compared with BG oil. In vivo study in isoproterenol-injected rats showed that BG oil and the optimized BG-SDLF improved cardiac function, by elevating the miRNA-23a gene expression level and decreasing miRNA-21 gene expression. They also caused the inhibition of the plasma B-type natriuretic peptide (BNP), N-terminal proatrial natriuretic peptide (NT-pro-BNP), cystatin c, galectin-3, lipoprotein-associated phospholipase A2 (Lp-PLA2), matrix metallopeptidase 2 (MMP2), cardiac troponin I (cTnI), and cardiac troponin T (cTnT). Our study demonstrated that BG oil and the optimized BG-SDLF provided a cardioprotection against isoproterenol-induced cardiac toxicity with better results in groups treated with the optimized BG-SDLF. Full article

The global demand for plastic is expected to double in the next 20 years. The increasing demand for Single-Use Plastic Products (SUPPs) has become one of the main environmental problems in many developing countries, including Sri Lanka, through direct and indirect means, in the way of excessive consumption and the pollution of the environment through waste generation. In this way, there is a pressing need to accelerate the sustainability evaluation, comparison, impact mitigation and policy recommendation of SUPPs to address the environmental impacts and sustainable development. Therefore, this study aims to quantify and compare the environmental impacts of SUPPs for policy decision making in Sri Lanka using life cycle assessment (LCA) techniques. Accordingly, the most popular and widely used single-use plastic products, which are under consideration for regulation in Sri Lanka, and their possible alternatives, are considered for this LCA study. The results reveal that SUPPs produced using polystyrene (PS), polypropylene (PP), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polyethylene terephthalate (PET) have a significant contribution in all life cycle stages, in terms of global warming potential (GWP) and endpoint impact categories. However, the outcomes of the study reveal that the net GWP impact of SUPPs that have recycling practice at the end of life shows better performance compared to incineration and landfill. In addition, the polylactic acid- (PLA)-based products also show a significant impact on mid- and end-point GWP impact categories. Remarkably, the midpoint analysis of PLA-based products and their alternatives emphasized that PLA production was the most impactful for most of the midpoint impact categories due to PLA resin production, which contributes significantly to all impact categories. In particular, for the pesticide bottles with the preferred end-of-life option of incineration, the HDPE indicates a 7.6% lower GWP compared to PET. For reusable steel cutlery, the largest GWP-associated life cycle stage is the user phase (97.5%), which includes cleaning the cutlery. However, the overall reduction in GWP in the use of steel, considering the best (PS with recycling) and worst (PS with incineration) case scenarios, with single-use items are 0.01 and 0.05 kg CO₂ (eq), respectively. In the case of pesticide bottles, with the preferred end-of-life option being incineration, the HDPE indicates a 7.6% lower GWP compared to PET. the study reveals that conducting LCA will facilitate scientific decision making for policy interventions related to SUPPs and their processes. Notably, the study shows that, at present, the capability of conducting LCA studies to evaluate the sustainability performance of SUPPs in Sri Lanka is limited due to the lack of life cycle inventory (LCI) data availability on SUPPs and relevant waste management practices in Sri Lanka. Full article

Yogurt is a diverse dairy product category. It is available in different packaging designs made of different materials. To identify potential for improvement for these packagings, a better understanding about used materials and packaging efficiencies is necessary. For this study, 150 dairy products and some yogurt relevant desserts were bought from various supermarkets, street markets and discounters in the Munich region (Germany) in spring 2022. Commercial types of packaging are cups, buckets, pouches, bottles, glass packagings and bricks. The filling ratio of most packagings is above 70%, the rest of the volume is headspace. Poly(1-methylethylene) (PP) and poly(1-phenylethene) (PS) dominate as main materials for the different types of packaging. For bottle packagings, poly(ethylene terephthalate) (PET) and polyethene high-density (PE-HD) are used. Interestingly, poly(lactic acid) (PLA) is not found. Closures (caps) are responsible for 5 to 30% of the total packaging weight. Typical filling efficiencies are 20 to 40 g food product packaged in one gram of packaging material. For glass packagings, the values are 1.5 to 2 g food product packaged in one gram of packaging material. Therefore, plastic packaging results in an at least ten-times lower packaging use per unit of food, at single use packagings. With increasing product weights, we observe a tendency towards higher packaging efficiencies. By using paper/carton wrapping at cups, plastic use is reduced for the whole packaging. Full article

The aim of the present study is to assess the use of polylactic acid (PLA) bottles as an alternative to polyethylene terephthalate (PET) ones for high-pressure processing (HPP) of apple juice. The treatment of PLA bottles at 600 MPa for 3 min did not cause alterations in the packaging shape and content, confirming the suitability of PLA bottles to withstand HPP conditions as well as PET bottles. Quantification of total mesophilic bacterial and fungal load suggested HPP treatment can be effectively applied as an alternative to pasteurization for apple juice packed in PLA bottles since it guarantees microbial stability during at least 28 days of refrigerated storage. The headspace gas level did not change significantly during 28 days of refrigerated storage, irrespective of the bottle material. Color parameters (L*, a*, and b*) of the HPP-treated juice were similar to those of the fresh juice. Irrespective of the packaging type, the total color variation significantly changed during storage, showing an exponential increase in the first 14 days, followed by a steady state until the end of observations. Overall, PLA bottles proved to offer comparable performances to PET both in terms of mechanical resistance and quality maintenance. Full article

Using environmentally friendly materials in the technological process of bottle production fits perfectly into the idea of sustainable development. The use of natural raw materials as well as conscious energy consumption are strategic aspects that should be considered in order to improve the effectiveness of the bottle moulding process. This paper presents a new and structured approach to the analysis of uncertainty and sensitivity in life cycle assessment, one developed in order to support the design process of environmentally friendly food packaging materials. With regard to this “probabilistic” approach to life cycle assessment, results are expressed as ranges of environmental impacts, and alternative solutions are developed while offering the concept of input uncertainty and the effect thereof on the final result. This approach includes: (1) the evaluation of the quality of inputs (represented by the origin matrix); (2) the reliability of results and (3) the uncertainty of results (the Monte Carlo method). The use of the methodology is illustrated based on an experiment conducted with real data from the technological process of bottle production. The results provide insight into the uncertainty of life cycle assessment indicators regarding global warming, acidification and the use of arable fields and farmland. Full article

In recent years, there has been a significant increase in the consumption of single-use packaging. Their material diversity is a significant barrier to recycling, causing overloading of landfills. Increasing negative environmental aspects have highlighted the need to develop solutions to achieve a relatively high efficiency of the bottle shaping process with the lowest possible energy consumption. The aim of the project is to try to describe the impact of this process on the state, transformation and development of the natural environment. The work concerns current issues of the impact of packaging on the natural environment. The main goal was to conduct a life cycle analysis (LCA) of beverage bottles made of polylactide. The functional unit comprised a total of 1000 pieces of PLA bottles with a capacity of 1 L. The boundary of the adopted system included the steps from the delivery of the preforms to the production plant to their correct formation in the process of forming beverage bottles. Further stages of the production process were excluded from the system, such as beverage bottling, labeling, and storage and distribution. Processes related to transport and storage of raw material were also excluded. The LCA analysis was performed using the program of the Dutch company Pre Consultants called SimaPro 8.4.0. The ReCiPe 2016 method was chosen for the interpretation of the quantity of emitted substances into the natural environment. The test results were presented graphically on bar charts and subjected to verification and interpretation. Full article