Background/Objectives: Meniscus injuries represent a critical challenge in orthopedic medicine due to the limited self-healing capacity of the tissue. This study presents the development and characterization of polycaprolactone/graphene oxide (PCL/GO) scaffolds fabricated using 3D bioprinting technology for meniscus cartilage regeneration. Methods: GO was incorporated at varying concentrations (1%, 3%, 5% w/w) to enhance the bioactivity, mechanical, thermal, and rheological properties of PCL scaffolds. Results: Rheological analyses revealed that GO significantly improved the storage modulus (G’) from 36.1 Pa to 97.1 Pa and the yield shear stress from 97.2 Pa to 507.1 Pa, demonstrating enhanced elasticity and flow resistance. Mechanical testing showed that scaffolds with 1% GO achieved an optimal balance, with an elastic modulus of 614 MPa and ultimate tensile strength of 46.3 MPa, closely mimicking the native meniscus’s mechanical behavior. FTIR analysis confirmed the successful integration of GO into the PCL matrix without disrupting its chemical integrity, while DSC analysis indicated improved thermal stability, with increases in melting temperatures. SEM analysis demonstrated a roughened surface morphology conducive to cellular adhesion and proliferation. Fluorescence microscopy using DAPI staining revealed enhanced cell attachment and regular nuclear distribution on PCL/GO scaffolds, particularly at lower GO concentrations. Antibacterial assays exhibited larger inhibition zones against E. coli and S. aureus, while cytotoxicity tests confirmed the biocompatibility of the PCL/GO scaffolds with fibroblast cells. Conclusions: This study highlights the potential of PCL/GO 3D-printed scaffolds as biofunctional platforms for meniscus tissue engineering, combining favorable mechanical, rheological, biological, and antibacterial properties.

Polyvinyl alcohol (PVA) is a biodegradable synthetic polymer with high chemical resistance and excellent mechanical and oxygen barrier properties. Besides these superior properties, it is water-soluble, which provides its wide usage. However, its solubility depends on some factors. Although the temperature is one of these factors and increasing temperature could promote solubility, there is a solubility limit according to hydrolysis degree. In this study, PVA solutions at various concentrations were obtained by mixing fully hydrolyzed PVA1500 and water. Solutions were characterized by density, surface contact angle and dynamic viscosity measurements. Then, solvent casting was used to obtain films, and physical and mechanical properties were determined. Tensile test results showed optimum values at 10–12.5 wt.% PVA concentration. Also, vacuum drying changed the mechanical behavior of films significantly at all concentrations. While ultimate tensile stress values almost doubled and modulus values increased approximately three times, elongations critically decreased. Solutions were also subjected to waste carbon fiber (CF)/polyamide 12 (PA12) prepregs for recycling purposes. Lay-up and compression molding processes were applied to produce CF/PA12 composites. It was seen that mechanical results were significantly increased with increasing PVA concentration.

Thanks to their superior properties such as light weight, higher strength and stiffness, corrosion resistance, the use of plastic matrix composites become attractive in many applications. The weight reduction in the automotive sector is one of these applications. By use of plastic matrix composites, weight and CO2 emission reduction in automobiles could be achieved easily. In this study, carbon fiber and epoxy matrix were processed via filament winding method to produce composite drive shaft. Prior to production, finite element modeling were performed to determine the safest design parameters. Various winding angles were analyzed under torsional loading and number of layer was determined according to the failure index and strength ratio criteria. As a result of the numerical analysis, it was seen that the design with the minimum cost in terms of strength was the 10-layer model with a winding angle of +/- 45 degrees. To validate the design, the composite shaft was produced with the determined configurations and tested. The fiber volume fraction and the void content of the produced composite were found as ~46% was ~0.28%, respectively. No plastic deformation was observed in the torsion test. In the flattening and drift-expansion tests, plastic deformation occurred at 39 kN and 106.5 kN, respectively. Compared with a steel shaft, the obtained composite shaft has an 80% reduction in weight, and this could lead to a 1% fuel saving in passenger vehicles.

Polipropilen (PP), otomotiv, ambalaj, ev eşyaları ve tekstil endüstrisi gibi pek çok alanda kullanılan termoplastik bir polimer türüdür. Boru sektöründe de yaygın olarak kullanılmaya başlanmıştır. Bunun başlıca nedeni metallerde olduğu gibi korozyon oluşmaması ve buna karşı ek bir korumaya ihtiyaç duyulmamasıdır. Bu sayede çelik ve çimento sistemlerinin yerini almaktadır. Boru sistemlerinde kompozit malzemelerin kullanılması daha hafif ve ince yapılar sağlamakta ve maliyetleri azaltmaktadır. Ancak, özellikle boru çapları büyüdükçe, kompozit yapı gerekliliği artmaktadır. Bu amaçla termoset kompozitler kullanılsa da PP kompozitlerin bunlara göre birçok avantajı bulunmaktadır. Bunlar yüksek dayanım, hafiflik, yüksek kimyasal direnç, düşük su emilimi, düşük maliyetli ve geri dönüşüm kabiliyetidir. Ancak PP kompozit üretimindeki temel sorun fiber-matris arayüzey oluşumudur. Bu sorunun üstesinden gelmek için melez iplikler geliştirilmiştir. Çeşitli türleri olmakla birlikte genel olarak takviye elyaf ve polimer elyaf karışımlarından oluşmaktadırlar. Bu sayede, sıcaklık altında işlenmesi sırasında polimer elyaf ergiyip takviye elyafları içine daha iyi emdirilebilir. Bu çalışmada cam elyaf takviyeli PP borular elde etmek amacıyla elyaf sarma işlemi uygulanmıştır. PP'yi daha kolay takviyelendirmek için cam elyaf/PP melez iplikler kullanılmıştır. Geleneksel olarak termosetlerin işlenmesinde kullanılan elyaf sarma işlemi, ısı ve basınç sistemleri ilavesiyle melez iplikler için modifiye edilmiştir. Helisel ve çevresel sarım teknikleri, ayrıca bunların kombinasyonu uygulanmıştır. Üretilen borulardan çevresel ve eksenel yönlerde numuneler alınmıştır. Çekme, eğme ve darbe testleri yapılarak, sonuçlar takviyesiz borular ile karşılaştırılmıştır. Üretilen tüm melez iplikli borular takviyesiz boruya göre daha yüksek modül ve dayanım göstermiştir. Genel olarak kombinasyonlu sarım tekniğiyle üretilen kompozit borudan özellikle çevresel yönde en yüksek sonuçlar alınmıştır.