Recycling and reuse of glass fibre (GF)-reinforced composites for high performance engineering applications
Kyriaki Gkaliou [1,2]
Michael Lei , Allan Hjarbæk Holm , Anders Egede Daugaard 
 Grundfos A/S, Department of Material and Technology Support, 8850 Bjerringbro, Denmark  Danish Polymer Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 227, 2800 Kgs. Lyngby, Denmark
Glass fibre-reinforced composite materials are used extensively across the globe due to their highly attractive performance-to-price ratio. With an increasing demand for such composite materials, awareness concerning their waste management is rising. On top of this, the industrial market has placed a focus on the use of recycled materials, raising the need for more efficient and sustainable ways of waste recycling.
Various recycling technologies, such as thermal, chemical, and mechanical, are already in place, with the latest dominating the recycling sector due to its simplicity in developing a fully recycled material. In the case of recycled materials, it is essential to meet specific requirements to ensure high-performance engineering applications. Therefore, this study will focus on the recycling options of GF-based composites and propose routes to valorize the waste fractions generated from the recycling.
Synthesis of solvent-free, extremely soft, and elastic bottlebrush elastomers
Uzair Hashmi, 
Anne L. Skov 
 Danish Polymer center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 227, 2800 Kgs, Lyngby, Denmark
Mimicking softness and mechanical strength of biological tissues is critical for the design of elastomers with applications in wearable electronics and soft robotics. Non-leachability of these elastomers is also important to avoid long-term health risks for consumers. Current fabrication strategies usually require solvents which limit their long-term biocompatibility and affect their conductivity. Herein, we propose an extremely soft, non-leachable elastomer system with tissue-like mechanical properties. We employ a mono-vinyl terminated polydimethylsiloxane (PDMS) in a curing reaction with multi-functional hydride PDMS to generate bottlebrush elastomers. We can tune these elastomers to exhibit ultralow Young’s modulus below 6 kPa and high strain breakage over 400% by modifying the graft density and degree of polymerization of sidechains. These elastomers exhibit superhydrophobicity, with contact angles larger than 1300.The obtained results suggest such elastomers have great potential to be employed in soft robotics and biomedical devices owing to their inherent softness and non-leachability.
In vitro artificial skin membrane including photo responsive hair fibers
Sofie Eriksen 
Anne L. Skov 
 Danish Polymer Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 227, 2800 Kgs. Lyngby, Denmark
In this project, we are developing an artificial skin membrane with photo responsive hair fibers to simulate the skin in an in vitro setup. The artificial skin is desired to substitute testing on animal and human skin when investigating new drugs or new formulations. The artificial skin will consist of multiple layers to imitate the multiple layers in human skin. The hair fibers will consist of liquid crystal elastomers and will be incorporated to capture the shortcut pathway through the follicles.
Delivery through the skin will enable local delivery. With local delivery, the dose needed for a desired effect will likely be significantly lower than oral delivery due to the bypass of the liver. Transdermal delivery is, furthermore, less invasive than injections. The artificial skin membrane will be a great tool in the development phase of new drugs and delivery technologies.
Synthesis of bio-based polymers with use of microwave chemistry
Grammatiki Terzi [1,2]
Anders Egede Daugaard , Peter Jeppe Madsen (2)
[1,2]Danish Polymer Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 227, 2800 Kgs. Lyngby, Denmark
Implementing bio-based polymers into the plastic industry has gained much interest in the past few years. It is, therefore, of particular interest to test and evaluate new bio-based monomers that can be produced through biological processes and their conversion into polymers. The present work is part of the EU project UPLIFT , which explicitly targets monomer production for new packaging materials and improved end-of-life and recycling options. One of the monomers that have been produced in UPLIFT is 4-hydroxyphenylacetic acid, which can be polymerized through classical condensation polymerization, though this requires high heat and long polymerization times.
Condensation polymerization is typically a slow process, and here, we will present an alternative approach using microwave radiation, which permits a fast and efficient polymerization process in 20 minutes compared to several days of classical synthesis. Synthesized polyesters were further evaluated as additives enhancing the mechanical and thermal properties of poly(lactic acid) (PLA).
Bio-based aromatic coating components from lignin
Harald Silau [1,2]
Antonios Melas[1,3], Alicia G. Garcia, John M. Woodley, Kim Dam-Johansen, Anders E. Daugaard
CoaST, DPC, CHEC, Prosys, Department of Chemical and Biochemical Engineering Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
Coatings are essential in the modern world to protect steel structures from corrosion in applications from construction to transportation. Currently, most coatings components are derived from petrochemical aromatic raw materials, which in the context of a green transition is not sustainable for future generations. Lignin has for many years been advocated as an interesting bio-based building block, as it is an abundant by-product from the pulp and paper industry available at a low cost, but its valorization to this day is limited.
The challenges of lignin utilization comes from its biopolymer nature with high molecular weight and heterogeneity which results in poor solubility and matrix compatibility thus limiting the content that can be incorporated into coatings. Pre-treatment of lignin through sequential solvent fractionation followed by reductive hydrogenolysis can partially break down the lignin structure to obtain liquid aromatic raw materials with a high degree of hydroxyl functionality. The reduction in molecular weight and lower steric hindrance results in excellent solubility properties, which increase the effectiveness of further chemical transformations of lignin’s hydroxyl groups into bio-based coating components such as epoxy binders or curing agents.
Stretchable and reversible photochromic hydrous TiO2 glycerol-PDMS elastomer for a rewritable film with minimal resolution loss
Chonghui Li [1,2]
Liyun Yu; Weizhen Zhao; Anne Ladegaard Skov
Danish Polymer Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 227, 2800 Kgs. Lyngby, Denmark Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, 100190, Beijing, China
Photochromic materials, which can change color in response to ultraviolet light (UV), are sought-after in the field of rewritable paper. Here, the photo-induced color-switching film was developed by dispersing photochromic compounds (hydrous titanium dioxide, TiO2) into glycerol and subsequently speedmixed the suspension with poly(dimethylsiloxane). Due to the presence of glycerol, the film demonstrated remarkable photochromic performance and outstanding stretchability. The film exhibited rapid and reversible color changes between white and blue with the presence or absence of external UV light. The degree of color changes in the film upon UV irradiation could be controlled by modulating the concentration of hydrous TiO2 and the duration of UV exposure. Micro- and macro-sized patterns could be photo-printed on the film, erased, and then reprinted multiple times. The photochromic film functions as a rewritable film due to its excellent repeatability. Even after 20 cycles of printing and erasing processes, the photo-printed patterns exhibited excellent resolution.
Novel silicone materials with cyclic polymers
Nikoline S. Frederiksen 
Anne L. Skov 
Danish Polymer Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 227, 2800 Kgs. Lyngby, Denmark
Cyclic polymers have been an academic curiosity for decades because of their endless structure that results in unique physical properties compared to the physical properties of linear polymers. The most prominent limitation in the research on cyclic polymers has been the quantities of cyclic polymers that could be prepared in the lab. Improvements in synthetic procedures in recent years have made it possible to produce cyclic polymers in significant amounts which have opened up the possibility of understanding the effect of incorporating cyclic polymers into topological materials.1,2
In this project, we are developing strategies to prepare different types of silicone networks containing cyclic polymers. The properties of the networks are analysed to determine how the networks containing cyclic polymers differ from classical networks of linear polymers and thereby identify possible uses in existing products or make new products.
Temporary abandonment of oil wells using polymer-based plug
Magdalena Skowyra & Maria Echarri Giacchi
Anne Ladegaard Skov, Kitt Malling Ravnkilde., Christian Husum Frederiksen.
Danish Polymer Centre, DTU Chemical and Biochemical Engineering, Technical University of Denmark, Danish Offshore Technology Centre, Technical University of Denmark.
Many of the oil wells in the North Sea are reaching the end of their productive life, and they will need to be plugged and abandoned to ensure that the remaining fluids are contained safely, and the environmental risk is reduced. Traditional cement has several limitations, such as operational issues or crack tendency. We are developing of a novel polymer plug with a shelf life of up to 18 months. The goal is to reduce the pressure build-up in the oil well’s pipeline, simultaneously lowering the costs. The polymer’s working time at room temperature is sufficiently long to pump the liquid down the well. After that, the free-radical cross-linking polymerization is activated at high temperatures, forming a solid polymer plug with low water permeability. Additionally, the material is designed to be environmentally friendly and able to withstand extreme conditions, such as high temperatures and pressures.