26:T493,

The use of metal-organic frameworks (MOF) nanoparticles as nucleating agents in gas dissolution foaming processes is presented. In this work, MOF nanoparticles with three different particle sizes were synthetized and introduced in film composites based on polystyrene at 1 wt.%. The addition of nanoparticles with high affinity to CO₂, which is the gas used as a physical blowing agent, can contribute to increase the nucleation efficiency in comparison with the classical heterogeneous route using non CO₂-philic particles. Nanoparticles dispersion in solids and cellular structure in foams were studied as a function of the particle size and foaming parameters, studying for first time the impact of MOF nanoparticles on the nucleation by gas dissolution foaming. Nucleation efficiencies in the order of 10⁻² were achieved for PS/MOF composites. In addition, the thermal stability of the cellular structure in the composites was enhanced regarding to PS matrix, preserving the cellular structure regardless the foaming temperature. Therefore, MOF nanoparticles have emerged as promising nucleating agents in foaming procedures.

27:T49c,

The importance of this work is the use of waste seashells WSS (5, 10, 15, 20, 25, and 30 wt.%) as a bio-filler to enhance the mechanical and acoustical characteristics of flexible polyurethane foam (FPU). Petroleum-based polyol was partially replaced by 25% castor oil resulting in high renewable content. The WSS was characterized by X-ray photoelectron spectroscopy (XPS). The chemical structure and morphological features for castor oil-based flexible polyurethane waste seashells (CO-FPU-WSS) composites were detected using Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM) techniques, respectively. Besides, the mechanical, non-acoustical and acoustical properties were investigated. The results indicated that bio-based FPU composites possessed better compressive strength than neat FPU foam. In addition, FPU composites enhance the sound absorption below 500 Hz. A 6 cm air gap behind the sample shifted the absorption toward 400 Hz (0.85) for CO-FPU-WSS 25% composite with a broader band. Thus, the FPU foam composite is considered a promising candidate for sound absorption applications such as for the automotive and building industries.

28:T4b3,

A simple preparation method was established for a low water-soluble citric acid crosslinking starch-based foam containing palm oil. The method was performed by pouring the boiling citric acid solution into the starch compound unlike the citric acid starch crosslinking by conventional solution casting. Thermo-physicochemical properties of the starch-based foams were examined. The I₃₃₀₀/I₁₁₄₉ intensity ratio of non-citric acid-containing foam was higher, suggesting greater amounts of the available -OH groups. The addition of citric acid into the starch matrix exhibited weaker thermal stability that was attributed to the lower thermal stability of the substituted ester bonds. The increment of citric acid concentration increased thermoplastic starch foams densities as well as their cell wall thickness. No differences in moisture absorption behavior were observed after soaking in water, the non-citric acid-filled foam exhibited dissolution and changed from its original shape upon drying. Experimental results showed a promising alternative methodology to prepare low water-soluble citric acid crosslinked starch-based foam to replace conventional solution casting.

29:T462,

The non-linear material behaviour of low density polypropylene foams is investigated under several quasi-static loading conditions with a combined modelling technique based on computed tomography data and Voronoi diagrams. A simulation methodology for determining the linear elastic properties is introduced in Hössinger-Kalteis et al. (2021). In this paper, the methodology is extended regarding the material model, where additionally the non-linear region is considered. The model takes into account prop