Life Cycle Assessment in a Nutshell-Best Practices and Status Quo for the Plastic Sector.

Life cycle assessment (LCA) is an internationally standardized methodology to evaluate the potential environmental impacts of products and technologies and assists in lowering their negative environmental consequences. So far, extensive knowledge of LCA-their application and interpretation-is restricted to experts. However, the importance of LCA is increasing due to its application in business, environmental, and policy decision-making processes. Therefore, general knowledge of LCA is critically important. The current work provides an introduction to LCA for non-experts discussing important steps and aspects and therefore can be used as a starting point for LCA. In addition, a comprehensive checklist for non-experts with important content and formal aspects of LCA is provided. Specific aspects of LCA for the plastics sector along the value chain are also discussed, including their limitations.

Bacterial diversity of biofilms on polyhydroxybutyrate exposed to marine conditions: Ex-situ vs. in-situ tests.

Biofilms form on any available surface and, depending on the characteristics of the material and the environmental conditions, biodegradation can take place. We compared the bacterial composition of polyhydroxybutyrate (PHB)-related biofilm communities from marine ex-situ and in-situ tests to assess the differences in diversity and abundance between these two biofilms. This comparison will help to better assess the transferability of tank tests to real-life scenarios. The in-situ tests were set up in the Mediterranean Sea on the Island of Elba, Italy where PHB-tensile bars were lodged in the sediments. This created a water-exposed aerobic and mud-planted anaerobic scenario. The ex-situ tests were modeled after in-situ tests and performed in temperature-controlled tanks. The PHB-related biofilms were harvested after 240 days of exposure along with planktonic bacteria, and particle- and sediment-related biofilm. The bacterial composition was elucidated using 16S rDNA sequencing. Biofilms harvested from the in-situ test were more diverse, less even, and contained more rare species compared to biofilms from the ex-situ test. The PHB-related biofilm was characterized by a higher abundance of the bacterial order Desulfobacterales. The composition of PHB-related biofilm varied significantly between the two tests and between aerobic and anaerobic conditions. The composition of PHB-related biofilm was significantly different from planktonic bacteria, particle, and sediment-related biofilm, showing the influence of PHB on the biofilm composition. Thus, the ex-situ tank test for PHB degradation cannot, in terms of bacterial composition, simulate the in-situ conditions to their full extent.

Comparative assessment of environmental impacts of 1st generation (corn feedstock) and 3rd generation (carbon dioxide feedstock) PHA production pathways using life cycle assessment.

Polyhydroxyalkanoates (PHA) are bio-based and biodegradable alternatives to conventional plastic types and have the potential to reduce the environmental impacts along the life cycle. In comparison to already established production routes for PHA (heterotrophic production) based on renewable feedstock like glucose (first generation feedstock), novel production routes, such as the photoautotrophic production of PHA based on CO2 as feedstock (third generation feedstock) could offer new perspectives with regard to the reduction in the environmental impacts. To quantify the environmental impacts of PHA produced via photoautotrophic and heterotrophic production pathways, life cycle assessment (LCA) methodology based on ISO 14040/44 was applied, thus conducting a first of its kind comparative study for PHA based on third generation feedstock. The results show that the photoautotrophic production of PHA has advantages in comparison to heterotrophic PHA based on glucose originating from corn as feedstock in all the assessed environmental impact categories, thus showing the environmental potential of novel production routes for bioplastics. Additionally, the results of the LCA show that the chloroform-based extraction method, commonly used in the downstream processes of both the technologies, has a significant contribution of environmental impacts in the production of PHA. Therefore, the reduction of chloroform loss during the extraction process can reduce its environmental impact. Our results indicate that PHA production from CO2 using the photoautotrophic production route is a promising technology with regard to the environmental impacts when compared to the heterotrophic production based on glucose feedstock.

Thermal and Mechanical Properties of the Recycled and Virgin PET-Part I.

In various countries, polyethylene terephthalate (PET) represents one of the plastics with a very high recycling rate. Since currently there is no analytical method enabling direct distinction between recycled PET (rPET) and virgin PET (vPET), there are various attempts to differentiate these materials indirectly. One of these approaches claims that the recycling of PET leads to polymer chain degradation, which is reflected in changed thermal, mechanical and crystalline properties, and testing of these properties can therefore be used to distinguish rPET and vPET. However, there are many sources leading to changes in the molecular structure and consequently to the changes of the above-mentioned properties of the PET. The purpose of this study is to analyze the glass transition and melting temperature, degree of crystallinity as well as bending and impact properties of 20 different commercially available PET recyclates from 14 suppliers and evaluate the results with respect to the literature values for vPET. The main results of this study show that the range of vPET properties is so broad that all of the corresponding properties of the tested rPET lie within this range.

Publisher Correction: Non-cuttable material created through local resonance and strain rate effects.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Plastics and the Environment-Current Status and Challenges in Germany and Australia.

Polymers and plastics play a very important part in the modern world and contribute to people's wellbeing and comfort. However, products made of them are contributing to land- and marine-based environmental pollution due to littering and other ways of emission, and therefore threaten ecosystems worldwide. However, waste management and responses by governments and the consumer differ strongly from country to country. The current article provides an overview of several important aspects of polymer waste and plastic pollution as well as describes selected strategies to mitigate these using examples from Germany and Australia, and therefore aims to contribute to the resolution of the ever-increasing problem of unsustainable plastic consumption, disposal, and pollution.

Non-cuttable material created through local resonance and strain rate effects.

We have created a new architected material, which is both highly deformable and ultra-resistant to dynamic point loads. The bio-inspired metallic cellular structure (with an internal grid of large ceramic segments) is non-cuttable by an angle grinder and a power drill, and it has only 15% steel density. Our architecture derives its extreme hardness from the local resonance between the embedded ceramics in a flexible cellular matrix and the attacking tool, which produces high-frequency vibrations at the interface. The incomplete consolidation of the ceramic grains during the manufacturing also promoted fragmentation of the ceramic spheres into micron-size particulate matter, which provided an abrasive interface with increasing resistance at higher loading rates. The contrast between the ceramic segments and cellular material was also effective against a waterjet cutter because the convex geometry of the ceramic spheres widened the waterjet and reduced its velocity by two orders of magnitude. Shifting the design paradigm from static resistance to dynamic interactions between the material phases and the applied load could inspire novel, metamorphic materials with pre-programmed mechanisms across different length scales.

Bioplastics.

The number of newly developed bioplastics has increased sharply in recent years and innovative polymer materials are increasingly present on the plastics market. Bioplastics are not, however, a completely new kind of material, but rather a rediscovered class of materials within the familiar group of materials known as plastics. Therefore, existing knowledge from the plastics sector can and should be transferred to bioplastics in order to further increase their performance, material diversity and market penetration.