Jens Schuster

The growing demand for sustainable materials has driven interest in natural fiber-reinforced composites as eco-friendly alternatives to synthetic materials. This research investigates the fabrication and mechanical performance of hemp and sisal fiber-reinforced composites, with a focus on improving fiber–matrix bonding through alkali and fungal treatments. Experimental results show that fungal treatment significantly improves tensile and flexural strength, while hardness slightly decreases. Water absorption tests revealed moderate reductions in hydrophilicity compared to untreated samples, although absolute water uptake remains higher than conventional glass/epoxy composites. Microscopy analysis further confirmed enhanced fiber adhesion and structural integrity in treated specimens. These findings suggest that hybrid composites reinforced with hemp and sisal, particularly with fungal treatment, hold promise for low-to-medium load sustainable applications in the automotive interiors, packaging, and construction industries, where moderate mechanical performance and partial biodegradability are acceptable. This research contributes to the advancement of bio-based composite materials while acknowledging current limitations in long-term durability and complete biodegradability.

The growing demand for sustainable materials has driven interest in natural fi-ber-reinforced composites as eco-friendly alternatives to synthetic materials. This re-search investigates the fabrication and mechanical performance of hemp and sisal fi-ber-reinforced composites, with a focus on improving fiber-matrix bonding through alkali and fungal treatments. Experimental results show that fungal treatment signifi-cantly improves tensile and flexural strength, while hardness slightly decreases. Water absorption tests revealed moderate reductions in hydrophilicity compared to untreated samples, although absolute water uptake remains higher than conventional glass/epoxy composites. Microscopy analysis further confirmed enhanced fiber adhesion and structural integrity in treated specimens. These findings suggest that hybrid composites reinforced with hemp and sisal, particularly with fungal treatment, hold promise for low- to medium-load sustainable applications in the automotive interiors, packaging, and construction industries, where moderate mechanical performance and partial bio-degradability are acceptable. This research contributes to the advancement of bio-based composite materials while acknowledging current limitations in long-term durability and complete biodegradability.

The rapid increase in plastic usage today poses a significant threat to our environment and the planet. It contributes to global warming and negatively impacts biodiversity. Most plastic ends up in landfills, where it can take up to 1000 years to decompose. Shockingly, only 9% of the plastic produced annually is recycled, while an astounding 2 million plastic bags are used every minute worldwide. This paper highlights the primary goal of plastic recycling, with a particular focus on using plastic to manufacture roof tiles. The motivation behind this approach is that everyone deserves a decent roof over their heads. To achieve this, a well-balanced mixture of waste polypropylene (PP), quartz sand, and fly ash minerals was utilized in producing plastic roof tiles. The research employed a hot press process to prepare samples of all composite materials, and no cracks or fractures were observed on the surface of these samples. The results of this innovative process exceed the standards set for most building materials in terms of both mechanical and thermal properties, demonstrating a compressive strength of 99.8 MPa, a flexural strength of 35.6 MPa, and an impact energy absorption of 7.93 KJ/m². Importantly, all samples exhibited zero percent water absorption, making these roof tiles ideal for insulation purposes. Additionally, the resulting roof tiles are lightweight and cost-effective compared to conventional options.

Today, around the world, there is huge demand for natural materials that are biodegradable and possess suitable properties. Natural fibers reveal distinct aspects like the combination of good mechanical and thermal properties that allow these types of materials to be used for different applications. However, fibers alone cannot meet the required expectations; design modifications and a wide variety of combinations must be synthesized and evaluated. It is of great importance to research and develop materials that are bio-degradable and widely available. The combination of PLA+, a bio-based polymer, with natural fillers like sawdust and soybean oil offers a novel way to create sustainable composites. It reduces the reliance on petrochemical-based plastics while enhancing the material’s properties using renewable resources. This study explores the creation of continuous hexagonal-shaped 3D-printed PLA+ samples and the application of post-print fillers, specifically sawdust and soybean oil. PLA+ is recognized for its eco-friendliness and low carbon footprint, and incorporating a hexagonal pattern into the 3D-printed PLA+ enhances its structural strength while maintaining its density. The addition of fillers is crucial for reducing shrinkage and improving binding capabilities, addressing some of PLA+’s inherent challenges and enhancing its load-bearing capacity and performance at elevated temperatures. Additionally, this study examines the impact of varying filler percentages and pattern orientations on the mechanical properties of the samples, which were printed with an infill design.

Flax–gypsum composites are an emerging class of environmentally friendly materials that combine the mechanical properties of gypsum with the advantageous characteristics of flax fibers. The production of flax–gypsum composites involve the incorporation of flax fibers, derived from the flax plant, into gypsum matrix systems. In order to create a uniform distribution of fibers within the gypsum matrix, the hand lay-up approach has been used to produce the specimens. The fiber content and orientation significantly influence the resulting mechanical and physical properties of the composites. Various tests were conducted on the samples, such as a flexural test, a compression test, a density test, a water absorption test, and a microscopy test. The addition of flax fibers imparts several desirable properties to the gypsum matrix. When combined with gypsum, these fibers enhanced the composite’s mechanical properties, such as flexural strength and compressive strength. The results indicated improved compression and flexural strengths due to effective load transfer within the matrix, for up to 10% of fiber loading. A decrease in composite density upon flax fiber addition results in a lighter material, enabling insights for various applications.

The main objective of this work is to evaluate the mechanical and thermal strength of a recently developed composite made of Cissus quadrangularis fiber coupled with Polylacticacid (PLA) in comparison to other natural fibers. This study investigated three different fiber and PLA compositions—20%, 30%, and 40%, respectively used to produce a composite. In contrast, another composite with the same volume percentage was created using calcium hydroxide Ca(OH)₂ to coat the fibers in order to alter their microcrystalline structure and enhance their mechanical properties. The composite was created using an injection molding procedure. Tests were performed to assess the improved properties. According to a preliminary study, the mechanical characteristics of PLA combined with treated Cissus quadrangularis fiber are increased when compared to PLA coupled with untreated Cissus quadrangularis fiber and neat PLA. Calcium hydroxide acted as a binding agent in fiber to enhance stress transmission in the matrix, increasing tensile and flexural modulus as well as toughness elongation. Further DSC analysis showed that the inclusion of the preceding components increased the glass transition temperature and melting temperature. The temperature at the beginning of deflection has risen as a result of showing how increasing HDT, fiber–matrix adhesion, and fiber content are related. The morphological analysis was performed on both untreated and chemical-treated fiber composites by using an optical microscope to see the interaction with the fiber matrix.

Fundamentally, the mechanical characteristics of 3D-printed polymeric objects are determined by their fabrication circumstances. In contrast to traditional polymer processing processes, additive manufacturing requires no pressure during layer consolidation. This study looks at how a high-pressure autoclave chamber without oxygen affects layer consolidation throughout the fused deposition modelling process, as well as the mechanical qualities of the products. To attain high strength qualities for 3D-printed components such as injection-molded specimens, an experimental setup consisting of a 3D printer incorporated within a bespoke autoclave was designed. The autoclave can withstand pressures of up to 135 bar and temperatures of up to 185 °C. PLA 3D printing was carried out in the autoclave at two different pressures in compressed air and nitrogen atmospheres: 0 bar and 5 bar. Furthermore, injection molding was done using the same PLA material. Tensile, flexural, and Charpy tests were carried out on samples that were 3D printed and injection molded. In nitrogen, oxidation of the environment was prevented by autoclave preheating before printing, and autoclave pressure during printing considerably promotes layer consolidation. This imprinted mechanical strength on the 3D-printed items, which are virtually as strong as injection-molded components.

Plastic is being used increasingly in daily life. Most of it is not recyclable, and the remaining plastic cannot be used or decomposed. This causes increased plastic waste, contributing to global warming due to thermal recycling. The major objective of this research was to utilise the maximum plastic waste possible to manufacture bricks that compete with the properties of conventional bricks without affecting the environment and the ecological balance. A balanced mixture of high-density polyethylene (HDPE), quartz sand, and some additive materials, such as bitumen, was used to produce these bricks. Various tests were performed to assess the bricks’ quality, such as compression, water absorption, and efflorescence tests. These bricks had a compression strength of 37.5 MPa, which is exceptionally strong compared to conventional bricks. The efflorescence and water absorption tests showed that the bricks were nearly devoid of alkalis and absorbed almost no water. The obtained bricks were light in weight and cost-effective compared to conventional bricks.

Carbon fiber reinforced polymers (CFRPs) have spread to a wide range of industries in recent decades, including the automobile, aeronautics, and space industries. Recently, the emergence of new requirements for improved properties and features has become one of the major drivers of the introduction of innovative methodologies and process optimization. In this study, the effect of nanomaterials on the behavior of carbon fiber-reinforced polymer (CFRP) composites was investigated experimentally. The grafting of TiO2 and SiC nanomaterials onto the surface of fibers was performed by mixing nanomaterials in the epoxy resin. CFRPs were manufactured using vacuum assisted resin transfer molding (VARTM) in this study and characterized using mechanical and thermal testing. The primary test parameters were carbon fiber with epoxy resin and 0% nanomaterials by weight. An increase in properties was observed in nanocomposite with 2% wt. of nanomaterials when compared with 0, 0.5, and 1% wt. Between 0 wt.% and 2 wt.%, the tensile strength, flexural strength, impact strength, hardness, and HDT properties were increased by 17%, 39%, 32%, 14% and 21%, respectively, due to the addition of nanomaterials into the resin.