Optimization of the processing of bio based polymer sustainable products

Polylactic Acid (PLA) is processed by injection moulding technology. The main aim of this study is to provide guidelines for mould and part design, namely to cope with the shrinkage effect and the ejection forces related to the use of bio based polymers. Furthermore optimization of the overall process will be investigated as well as the influence of different parameters to the process and product properties. Draft angle, mould temperature and holding pressure will be related to the ejection forces and the level of shrinkage that occurs

Circular economy initiatives are no guarantee for increased plastic circularity:A framework for the systematic comparison of initiatives

Plastic plays a prominent role within circular economy, with many stakeholders promoting initiatives to increase plastic circularity during the manufacturing, use and end-of-life phases. Despite well-meant intentions, many initiatives are characterized by a lack of compliance with basic circular economy principles, implementation barriers, and limited effects on the intended long-term plastic circularity. This study provides a systematic evaluation framework for comparison of plastic initiatives, based on 17 criteria addressing key aspects of plastic circularity. A three-level likelihood ranking approach is applied to analyse the impact of 54 initiatives targeting plastic circularity in a European context. It was found that relatively few of these initiatives were readily implementable without considerable investments, e.g. in new waste management and recycling technologies, and changes in plastic production and product design. The results clearly suggest that current suggestions for circular economy initiatives targeting plastic may have limited effect and not lead to the intended impacts without the support of new regulations and change in plastic demand and consumption. The study stresses the importance of synergies and cooperation between stakeholders across the value chain to reach plastic circularity. The framework offers a consistent basis for decision-makers to identify critical barriers and enablers in relation to plastic circularity characteristics, but the approach may also be applied to other topic areas

Corrigendum to Circular economy initiatives are no guarantee for increased plastic circularity:A framework for the systematic comparison of initiatives

The authors regret to inform you about a minor error that has been identified in Fig. 1, on the basis of an error in the Supplementary Materials. We discovered a lack of consistency in the rounding scoring of the third pillar (Long-term Circularity Contributions), corresponding to the size of the bubbles, for 8 of the 52 initiatives. In the Supplementary Materials, Table SM3 and Table SM4.2 have been corrected to be consistent. A corrected version of Fig. 1, which accurately represents the intended information and aligns with the article's content, has been made to rectify this error. The only change is the size of the bubble for the 8 updated initiatives. The changes performed do not affect the underlying discussion in the article. The authors would like to apologise for any inconvenience caused

Macromolecular Insights into the Altered Mechanical Deformation Mechanisms of Non-Polyolefin Contaminated Polyolefins

Current recycling technologies rarely achieve 100% pure plastic fractions from a single polymer type. Often, sorted bales marked as containing a single polymer type in fact contain small amounts of other polymers as contaminants. Inevitably, this will affect the properties of the recycled plastic. This work focuses on understanding the changes in tensile deformation mechanism and the related mechanical properties of the four dominant types of polyolefin (PO) (linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP)), contaminated with three different non-polyolefin (NPO) polymers (polyamide-6 (PA-6), polyethylene terephthalate (PET), and polystyrene (PS)). Under the locally elevated stress state induced by the NPO phase, the weak interfacial adhesion typically provokes decohesion. The resulting microvoids, in turn, initiate shear yielding of the PO matrix. LLDPE, due to the linear structure and intercrystalline links, is well able to maintain high ductility when contaminated. LDPE shows deformation similar to the pure material, but with decreasing ductility as the amount of NPO increases. Addition of 20 wt% PA-6, PET, and PS causes a drop in strain at break of 79%, 63%, and 84%, respectively. The typical ductile necking of the high-crystalline HDPE and PP is strongly disturbed by the NPO phase, with a transition even to full brittle failure at high NPO concentration

Technical functionality as a basis for developing substitution coefficients in waste management Life Cycle Assessment studies

Life Cycle Assessment (LCA) is a widespread tool used to guide decision-makers towards optimal strategic choices for sustainable growth. A key aspect of LCA studies of waste management systems where recycling activities are present is to account for resource recovery and the related substitution effects. Although multiple scientific papers assume a 1:1 substitution ratio between similar materials/products, this is often incorrect as the actual ratio is likely to vary. The focus of this paper is on the calculation of the substitutability coefficient for secondary materials based on technical characteristics

A step forward in quantifying the substitutability of secondary materials in waste management life cycle assessment studies

Life Cycle Assessment (LCA) is a widespread tool used to guide decision-makers towards optimal strategic choices for sustainable growth. A key aspect of LCA studies of waste management systems where recycling activities are present is to account for resource recovery and the related substitution effects. Although multiple scientific papers assume a 1:1 substitution ratio between similar materials/products, this is often incorrect as the actual ratio is likely to vary. The focus of this paper is on the calculation of the substitutability coefficient for secondary materials based on technical characteristics. A state of the art literature review showed that many different calculation procedures were applied, which led to a wide variety of substitutability coefficients (sometimes provided under different terminology). In this perspective, the objective of this paper is to provide guidelines on the procedure to be followed to calculate the substitutability coefficient for secondary materials, based on technical characteristics. These guidelines are then applied to two waste management case studies, one dealing with bottom ashes from incineration and the other with plastic waste. In total, sixteen technical substitutability coefficients are given for ten secondary materials, based on state of the art and presented case studies. The paper thus represents a step forward in quantifying the substitutability of secondary materials in waste management LCA studies. The guidelines presented may allow other case studies to enrich the list of coefficients, useful for all LCA practitioners in a harmonized way allowing a more correct evaluation of the environmental impacts associated with recycling activities