Recent advances in vegetable oil-based polymers and their composites

Polymeric foams can be found virtually everywhere due to their advantageous properties compared with counterparts materials. Possibly the most important class of polymeric foams are polyurethane foams (PUFs), as their low density and thermal conductivity combined with their interesting mechanical properties make them excellent thermal and sound insulators, as well as structural and comfort materials. Despite the broad range of applications, the production of PUFs is still highly petroleum-dependent, so this industry must adapt to ever more strict regulations and rigorous consumers. In that sense, the well-established raw materials and process technologies can face a turning point in the near future, due to the need of using renewable raw materials and new process technologies, such as three-dimensional (3D) printing. In this work, the fundamental aspects of the production of PUFs are reviewed, the new challenges that the PUFs industry are expected to confront regarding process methodologies in the near future are outlined, and some alternatives are also presented. Then, the strategies for the improvement of PUFs sustainability, including recycling, and the enhancement of their properties are discussed.

https://www.mdpi.com/1996-1944/11/10/1841/pdf/1

Polyurethane Foams: Past, Present, and Future

Evaluation of biological degradation of polyurethanes.

Growing water and land pollution, the possibility of exhaustion of raw materials and resistance of plastics to physical and chemical factors results in increasing importance of synthetic polymers waste recycling, recovery and environmentally friendly ways of disposal. Polyurethanes (PU) are a family of versatile synthetic polymers with highly diverse applications. They are class of polymers derived from the condensation of polyisocyanates and polyalcohols. This paper reports the latest developments in the field of polyurethane disposal, recycling and recovery. Various methods tested and applied in recent years have proven that the processing of PU waste can be economically and ecologically beneficial. At the moment mechanical recycling and glycolysis are the most important ones. Polyurethanes’ biological degradation is highly promising for both post-consumer and postproduction waste. It can also be applied in bioremediation of water and soil contaminated with polyurethanes. Another possibility for biological methods is the synthesis of PU materials sensitive to biological degradation. In conclusion, a high diversity of polyurethane waste types and derivation results in demand for a wide range of methods of processing. Furthermore, already existing ones appear to be enough to state that the elimination of not reprocessed polyurethane waste in the future is possible.

Polyurethane Recycling and Disposal: Methods and Prospects

Frequent and frequently deliberate release of plastics leads to accumulation of plastic waste in the environment which is an ever increasing ecological threat. Plastic waste represents 20–30% of the total volume of solid waste contained in landfills because in addition to the large amount of waste generated, plastic waste is recalcitrant and remains deposited in these landfills for long periods of time. Paradoxically, the most preferred property of plastics – durability – exerts also the major environmental threat. Polyurethanes (PU) represent a class of polymers that have found widespread use in medical, automotive and industrial fields. The wide use of PUs in our society makes their biodegradation of equal importance to their manufacturing. The balance between creating stable polymers that resist degradation and minimize their potential long-term environmental impact continues to be one of the major issues with the general use of these materials. Despite their microbial resistance, they are susceptible to the attack of fungi and bacteria. Currently, as environmental concerns have become so significant great effort needs to be made to degrade these plastics under environmentally benign conditions. In the present report we seek to highlight the efforts made in the last few years for the degradation of polyurethanes using microorganisms or enzymes.

Brenda Raúd

Papers

Biodegradation study by Pseudomonas sp. of flexible polyurethane foams derived from castor oil