Rezultaty projektu

Zastosowanie materiałów pochodzenia wtórnego stanowi dla wielu gałęzi przemysłu przemysły tworzyw sztucznych bardzo pożądany kierunek rozwoju. Również w przypadku technik addytywnych zakres badań w tej tematyce jest coraz szerszy i obejmuje zarówno prace dotyczące zastosowania nowych odmiana materiałów polimerowych, dodatków w postaci napełniaczy oraz wykorzystania wtórnego odpadów poprodukcyjnych. W badaniach prowadzonych w Instytucie Technologii Materiałów Politechniki Poznańskiej, te trzy kierunki prac są z powodzeniem realizowane. Prezentowany materiał omawia koncepcje prac obejmujących: (a) użycie odpadów z procesu druku 3D z filamentu (MEX); (b) zastosowanie odpadowych napełniaczy ligno-celulozowych w druku 3D; (c) zastosowanie odpadów folii wielowarstwowej w produkcji wyrobów metodami przyrostowymi.

Obecnie poza odpadami z tworzyw sztucznych, odpadami elektronicznymi czy bateriami, bardzo duży nacisk kładzie się na efektywne zagospodarowanie odpadów komunalnych, których według danych GUS Polacy wytwarzają coraz więcej. W 2021 roku Polacy wytworzyli 13,7 milionów ton odpadów komunalnych, co stanowi wzrost aż o 2,8 miliona ton w stosunku do roku 2015. Jedną z grup odpadów komunalnych są odpady wielkogabarytowe, czyli takie, które nie mieszczą się w powszechnie stosowanych pojemnikach na śmieci. Zalicza się do nich głównie meble czy wyroby tapicerowane, co związane jest z dynamiczną sytuacją na rynku nieruchomości. Obecnie, korzystną alternatywą pozwalającą na osiągnięcie zarówno korzyści finansowych, jak i ekologicznych jest utylizacja (recykling) odpadów wielkogabarytowych i ich wykorzystanie w dalszych procesach produkcyjnych w celu zmniejszenia zużycia surowców pierwotnych i naturalnych. Szczególnie wartościowy podczas recyklingu odpadów wielkogabarytowych jest odzysk drewna oraz jego pochodnych, ponieważ szacuje się, że każda odzyskana tona pozwala zredukować emisję CO2 do atmosfery o aż dwie tony, a w dodatku zmniejsza konieczność przeprowadzenia wycinki zdrowych drzew w celu pozyskania materiałów pierwotnych. Ponadto, materiały drewnopochodne zawierają różnego rodzaju spoiwa, lepiszcza czy impregnaty, co utrudnia ich wykorzystanie w produkcji energii. Istotne jest więc poszukiwanie nowych zastosowań materiałowych dla surowców wtórnych generowanych na drodze recyklingu odpadów wielkogabarytowych.

Nowadays, economic development and increasing environmental awareness of society are driving the plastics industry towards more sustainable solutions. It is essential to reduce plastics’ environmental impact and increase the resource efficiency. These approaches are among the pillars of Circular Economy, and align with currently postulated sustainability-driven environmentally friendly trends expressed by European Union (EU) Directives. In recent years, the EU, through directives and climate targets, has obliged member countries to orient industry toward secondary and renewable raw materials. In 2019, the European Green Deal was presented as a map for achieving a sustainable economy [1]. In 2020, the EU presented “A new Circular Economy Action Plan For a cleaner and more competitive Europe”, as well as the 2030 Climate Target Plan [2,3]. One of their main goals is to reduce greenhouse gas emissions. Manufacturing of polymeric foams fits into such outlooks not only by the reduction of weight, material consumption, and costs, but also by providing superior performance in terms of heat and sound insulation or mechanical damping [4].
Economic development, especially considering structural applications, permanently stimulates the development of polymeric foams’ market. According to market reports, in 2022 the global polymer foam market size was valued at ~USD 125 billion [5]. At that time, it has already partly recovered after COVID-19 pandemic, which affected the demands, production facilities, raw materials supply and distribution chains. Later, it was affected by the military conflict at Ukraine. Nevertheless, the forecasts indicate market grow at a compound annual growth rate exceeding even 5% to 2032 [6]. The increasing demand for lightweight materials in packaging, automotive, furniture and bedding, construction, aerospace, and other industries drives the polymer foam market.
Along with the market share, the popularity of polymer foams among the researchers has been significantly increasing over the last two decades, which can be expressed by the number of publications indexed in Scopus database related to the polymer foams and their most common types. By far the most popular are polyurethane (PU) foams with over 1000 publications per year, outnumbering other types (below 300 publications per year). Their popularity is attributed to the wide possibilities of introducing new raw materials or modifiers, including bio-based or recycled ones, and the potential engineering of their performance. Therefore, PU foams are very absorptive toward innovations, which definitely stimulates scientific activities. Also, their scientific popularity mirrors their industrial popularity, either in rigid or flexible form, applied respectively as thermal insulation, and sound or mechanical damping materials. They are commonly applied in construction and building sector, whose development is directly associated with the wealth of the society and stronger than ever economic migration [7].
Unfortunately, the development of plastics’ sector implicates increased waste generation. It has significantly contributed to the development of the concept of a Circular Economy, the introduction of which implies a significant reduction in the adverse impact of human activity on the environment. Currently, in addition to plastic waste, electronic waste, or batteries, a robust emphasis is being placed on the efficient management of municipal waste, which, according to Statistics Poland, people are producing more and more. In 2021, Poles generated 13.7 million tons of municipal waste, an increase of as much as 2.8 million tons compared to 2015 [8]. It is essential to collect them separately (currently about 40%), which improves and reduces the cost of their management by energy recovery or recycling. One of the groups of municipal waste is bulky waste, i.e., waste that does not fit into commonly used garbage containers. This mainly includes furniture, upholstered goods, carpets, rugs, bicycles, or baby carriages. The first two groups dominate among them, which is related to the dynamic situation in the real estate market, including rentals and, consequently, the renovation and refurbishment of apartments.
In the current situation, a favorable approach to bulky waste management, allowing to achieve both financial and environmental benefits, is to recycle and use it in further production processes in order to reduce the consumption of primary and natural resources, which qualifies as a smarter use and production of products. Therefore, it is imperative to look for opportunities for further use of this type of waste, enabling them to be kept in a loop, which will be an important step towards the Circular Econ-omy.
The presented study investigated the method of upcycling of furniture-type waste PU foams, a part of bulky waste stream into novel materials with potential applications in construction and building sectors. Materials have been prepared by compression molding technology with the application of an innovative binders composed of diisocyanate and inorganic salts, whose in situ decomposition yielded gas release providing the porous structure of final materials and generated compounds binding waste PU foam scraps. The impact of applied foam type and binder formulation on the structure, mechanical, and thermal insulation performance of resulting materials have been explored.
Presented results indicated that the proper procedure of waste PU foam upcycling and application of innovative binder enable maintaining the porous structure typical for PU foams. Considering current environment-oriented policies aimed at reducing materials’ environmental impacts, such an approach may provide compromise between the relatively low specific weight, mechanical performance, and other functionalities required by the particular applications, such as reduced thermal conductivity.

Currently, in addition to plastic waste, electronic waste, or batteries, a robust emphasis is being placed on the efficient management of municipal waste, which people are producing more and more. One of the groups of municipal waste is bulky waste, i.e., waste that does not fit into commonly used garbage containers. This mainly includes furniture, upholstered goods, carpets, rugs, bicycles, or baby carriages. Simultaneously, the environmental awareness of the society is noticeably growing, which is expressed by the development of 9R Principle – Refuse, Rethink, Reduce, Reuse, Repair, Refurbish, Remanufacture, Repurpose, Recycle, Recover. All of these activities are aimed at extending the life of products and their parts, which represents a further step from a linear economy to a Circular Economy in relation to processes involving the efficient use of materials, such as recycling or energy recovery. Commonly applied energy production from waste is the lowest level of circularity. In the current situation, a favorable alternative, allowing to achieve both financial and environmental benefits, is to recycle bulky waste and use it in further production processes to reduce the consumption of primary and natural resources. Therefore, it is vital to look for opportunities for further use of this type of waste, enabling them to be kept in a loop, which will be an important step towards the Circular Economy.
The presented study aimed to investigate the possibility of producing novel particleboards with potential use in the construction, building, or furniture sector from cork waste, particularly engineered wood and polyurethane (PU) foams from post-consumer furniture products. Materials have been prepared by compression molding technology with the application of innovative binder composed of diisocyanate and inorganic salt, whose in situ decomposition led to the gas generation providing porous structure of final composites, and produced compounds strengthening the interfacial bonding inside the material. The impact of applied formulations on the structure (density, porosity, chemical structure, surface wettability), mechanical (static and dynamic), and thermal insulation performance of resulting composites have been explored. Presented results indicated that by the proper engineering of materials’ composition, the compromise between the weight, mechanical performance and other functionalities required by the particular applications can be found. Generally, it was proven that the proposed method of bulky waste management may yield materials with performance comparable to the commercially available solutions, which could provide novel ways for its efficient utilization.

While plastic waste and e-waste often dominate public discourse and legal regulations, municipal waste, particularly bulky wastes originating mainly from furniture, upholstered goods, or carpets, pose a significant challenge due to their large-scale generation aligning with the development and enrichment of society. Therefore, their efficient collection and keeping in a loop by developing novel utilization ways should be considered among the priorities of municipal waste management. Herein, the presented work presents the novel composite materials obtained from two types of commonly generated bulky wastes: flexible polyurethane foams used as mattresses and medium-density fiberboards often applied in furniture products. Composite materials have been prepared using the commonly applied compression molding method, with the addition of an innovative binder composed of a diisocyanate and inorganic salt, whose in situ decomposition led to the gas generation providing the porous structure of final composites, and produced compounds strengthening the interfacial bonding inside the material. The impact of changes induced by the chemical interactions on the visual appearance, morphology, mechanical, thermal, and insulation performance of prepared composites has been evaluated. Observed changes pointed not only to the proper directions in the development of formulations for desired composites but yielded auspicious conclusions on the further applications of the examined binder composition.