Macromolecular Symposia最新文献

Noise reduction is included in the main tasks to deal with when working in the field of automotive and aerospace industries. When trying to improve comfort, it is crucial to research and enhance acoustic properties. Nanofibers can be a viable solution to address sustainability and noise absorption while ensuring material savings through lightweight nonwoven mats. They are also very intriguing for potentially improving the acoustic properties of conventional materials even in combination with them. The process and connection between improved noise absorption and nanofibrous membranes are still not fully known or confirmed. For this reason, in this preliminary study different nanofibrous morphologies are obtained via electrospinning, leading to the possibility to correlate acoustic absorption with nanoscale morphologies, mainly focusing on nanofibers’ diameter, which is easily tailorable. For this reason, an impedance tube was used to draw a first measurement method approach.

Carbon fiber-reinforced polymers (CFRPs) are widely used in different industries due to their exceptional mechanical properties and low density. However, delamination and poor vibration damping capacity pose significant challenges to their application. This study focuses on the production of nanofibrous polyamide 12 (Nylon 12) mats obtained through electrospinning to improve the structural properties of epoxy CFRP laminates. Three different Nylon 12 solutions have been prepared using various solvents, and the process parameters for electrospinning have been optimized. The nanofibers produced by the solution with a mixture of formic acid and anisole solvent showed different morphologies depending on the solution concentration. An increase in Nylon 12 concentration leads to thicker, porous fibers. Thermal analysis has demonstrated that the electrospinning process does not alter the thermal properties of the polyamide. The results suggest that the use of PA12 nanofibrous membranes could represent a promising strategy for improving interlaminar fracture toughness in laminated CFRPs.

In this work, polypropylene (PP)-based filaments for Fused Filament Fabrication (FFF) containing boron nitride (BN) or talc (T) were developed and used to formulate multi-functional 3D-printed parts with enhanced thermal conductivity and mechanical properties. More specifically, skin-core structures, with BN in surface layers and talc in the core, were optimized and characterized. Results show that confining BN to surface layers improves in-plane thermal conductivity due to filler alignment during printing. Furthermore, the obtained structures maintain mechanical properties comparable to PP/T mono-material samples, despite reduced filler content and the presence of multi-material interfaces, demonstrating the potential of the proposed strategy for creating high-performance multi-material parts through FFF.

This study investigates the synthesis of a silica-based (SiO₂) glassy material incorporating a polyphenol-rich grape extract (G) to develop a bioactive glass-like system for food and beverage packaging. Using the sol-gel method, grape extract is incorporated into the silica matrix at 5% (SiO₂-G5) and 15% (SiO₂-G15). Structural and thermal stability analyses (FTIR and TGA/DTG) show that SiO₂-G5 exhibits greater stability than SiO₂-G15. Encapsulation rate analysis reveals that, in SiO₂-G15, part of the extract remains surface-bound rather than fully entrapped, making it more vulnerable to degradation. Furthermore, in vitro release studies evaluate whether the material can release polyphenolic compounds into a liquid medium, potentially providing antioxidant activity. The results indicate that SiO₂-G5 releases nearly 100% of the bioactive molecules, while SiO₂-G15 shows limited release due to molecular aggregation within the silica matrix. These findings highlight SiO₂-G5 as a promising bioactive material for glass-based food and beverage packaging, ensuring both enhanced stability and controlled antioxidant release.

This work aims to synthesize silica-based hybrid materials incorporating beetroot extract (Br) via the sol–gel method at different concentrations (4, 8, and 24 wt%). The hybrids are analyzed using colorimetric and Fourier-transform infrared (FTIR) spectroscopy to assess their structural and functional properties. Colorimetric analysis confirms a significant color change compared to the transparent SiO₂ reference, with increasing extract content leading to darker and more saturated materials. This is further supported by the ΔE parameter, which reaches a value of 50.0 in SiO₂+24Br%. FTIR spectroscopy reveals the successful incorporation of Br within the silica network and the formation of hydrogen bonding interactions between SiO₂ and Br, as evidenced by shifts in the OH bending and Si–O–Si stretching bands. Additionally, characteristic beetroot peaks confirm the integration of polyphenolic compounds within the silica matrix. The persistence of these functional groups suggests that the bioactive molecules remain embedded in the hybrid material, potentially preserving their functionality.

This study explores the recycling potential of High-Impact Polystyrene (HIPS) used in medical packaging by examining its thermal, rheological, and mechanical properties. Recycled HIPS, derived from both post-industrial and post-consumer waste, shows performance comparable to virgin HIPS with only minor differences in thermal stability, glass transition temperature, and mechanical properties. Although post-consumer HIPS exhibits a lower melt flow rate, likely due to a higher molecular weight, its processing remains within acceptable limits. Overall, the results confirm the feasibility of mechanically recycling HIPS waste for healthcare packaging, while future research will address contamination risks and the effects of multiple recycling cycles.