Our journey toward developing particulate bone powder reinforced PLA composites began with a shared curiosity about sustainability and practicality in materials engineering. Across our institutions and research environments, we often encountered the same challenge: while biodegradable polymers such as Poly Lactic Acid (PLA) are widely promoted as sustainable alternatives to conventional plastics, their mechanical limitations restrict broader engineering applications. PLA is brittle, relatively weak under load, and often unsuitable for structural components without modification. This recurring limitation motivated us to explore how PLA could be strengthened without compromising its environmental advantages.
At the same time, several members of our team were independently working on waste-derived materials and low-cost manufacturing methods. Animal bone waste, generated in large volumes by food-processing industries, repeatedly emerged in our discussions. Bone is naturally stiff, mineral-rich, and mechanically robust, yet it is frequently treated as a disposal problem rather than a resource. Bringing these ideas together, we began asking a simple but compelling question: could animal bone waste be converted into a functional reinforcement for PLA using an industry-friendly process?
From the outset, we were committed to keeping the approach practical. Rather than focusing on complex surface treatments or expensive processing routes, we selected compression molding as the manufacturing technique. Compression molding is widely used in industry, particularly in low- to medium-volume production, and is valued for its simplicity, low energy consumption, and cost effectiveness. Several of us had prior experience working with this process in academic laboratories and industrial settings, which helped guide early experimental decisions.
One of the first challenges we encountered was preparing bone powder with consistent particle size and cleanliness. Processing natural waste materials often introduces variability, and ensuring reproducibility required careful preparation and repeated trials. In the lab, this stage involved a great deal of hands-on work, from cleaning and grinding the bone material to sieving and drying it before mixing with PLA. These steps, while time-consuming, were critical in achieving reliable results later in the study.
Once the materials were prepared, we moved on to optimizing the molding process. Here, collaboration within the team played a central role. Some authors focused on experimental design and statistical planning, while others concentrated on sample fabrication and mechanical testing. To systematically understand how processing conditions influence material properties, we adopted a Design of Experiments (DOE) framework. Bone powder content was varied from 5% to 20% by weight, and key compression molding parameters such as die temperature, applied pressure, and dwell time were carefully controlled.
Mechanical testing was a particularly rewarding phase of the work. Tensile, flexural, and hardness tests allowed us to quantify how the composites performed relative to neat PLA. When the first set of results showed noticeable improvements in strength and stiffness, it was a clear validation of our initial hypothesis. Tensile strength improved by up to 19.26%, hardness increased by 24.39%, and flexural strength showed an enhancement of about 15%. These gains were encouraging, especially considering the simplicity of the materials and process used.
At the same time, the data reminded us that materials engineering is always about balance. As bone powder content increased, the composites became stiffer and stronger but less ductile. Discussing these trade-offs within the team helped us better frame the results and think critically about potential applications. Rather than viewing reduced ductility as a drawback, we recognized it as an expected outcome that could be managed through material design depending on end-use requirements.
To strengthen the industrial relevance of the study, we applied Taguchi optimization techniques to identify the optimal combination of compression molding parameters for tensile strength. This step was driven by a shared belief that research should offer clear, actionable insights. The optimization results transformed experimental observations into practical guidelines that manufacturers could realistically adopt.
Scanning Electron Microscopy (SEM) analysis added another important layer of understanding. Examining fracture surfaces allowed us to visually assess particle dispersion and interfacial bonding. Seeing relatively uniform distribution of bone powder within the PLA matrix and evidence of good adhesion was a moment of reassurance, as it confirmed that the mechanical improvements were supported by sound microstructural behavior.
Beyond the technical outcomes, this research was meaningful to us on a broader level. It demonstrated how bio-waste materials can be reimagined as valuable engineering resources. By combining biodegradable PLA with animal bone powder, we aligned material performance with sustainability principles and circular economy concepts. For many of us, this alignment reflects the direction we hope materials research will increasingly take.
Looking ahead, this work has opened several new avenues for exploration. We are interested in investigating surface modification of bone particles, hybrid reinforcement strategies, and long-term biodegradation behavior. The collaborative experience of this project has also strengthened our interest in interdisciplinary and application-oriented research.
In sharing the story behind this paper, we hope to highlight not only the results, but also the process of learning, experimentation, and teamwork that shaped the study. We believe this work shows that meaningful improvements in sustainable materials can be achieved using low-cost resources, simple manufacturing methods, and thoughtful experimental design.