Biobased auxetic foams: an assessment of manufacturing and multifunctional properties

生物基拉胀泡沫：制造和多功能特性的评估

• 批准号: 2752792
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2752792
• 关键词: Biobased; auxetic; foams; assessment; manufacturing

Auxetics are a class of mechanical metamaterials exhibiting a negative Poisson's ratio; that is, they expand laterally when extended longitudinally. Foams with auxetic characteristics also possess other desirable features in terms of indentation resistance to shear, energy absorption under cyclic quasi-static and dynamic loading, resistance to low kinetic energy impact, the enhanced dynamic modulus under relative humidity conditions, and tailorable shape memory properties. Over the years, multiple manufacturing processes have been developed to transform conventional foams into auxetics, ranging from thermo-mechanical (involving volumetric compression, annealing, and cooling) to chemical treatments (exploiting acetone and carbon dioxide to soften foam cell walls). No artificial auxetic foam metamaterial has, however, so far been knowingly produced.Recent developments in bio-based polyurethanes (and related foams) make producing bio-based negative Poisson's ratio foam materials a distinct possibility. Vegetable oil-based polyols (such as castor oil and soybean oil) have been recently used in different blends to produce biobased open- and closed-cell foams via free-rising both at the laboratory scale and commercially, showing improved compression and thermal properties compared to fossil-based counterparts. An auxetic foam made of bio-based substrates would further increase the appeal of using this class of metamaterials in a wide range of applications because of the enhanced life cycle properties and global warming power reduction compared to their fossil counterparts. Moreover, auxetic biobased foams would also be among the first mechanical metamaterial products designed to be sustainable and eco-friendly from the onset. Potential applications of such materials range from the aerospace industry, where enhanced impact resistance and lightweight would contribute to improved efficiency, to sports equipment in running shoes, helmets, and padding, which would benefit from the unique properties of this class of materials.In this context, the objectives of this project are:- Characterise available castor and soy oil-based PU foams from the chemical, thermal, and morphological aspects, combined with mechanical (quasi-static, dynamic, and viscoelastic), acoustic and vibration testing.- Manufacture biobased auxetic open- and closed-cell metamaterial foams through different conversion routes.- Assess the viability of the auxetic foams obtained through the different processes by investigating the morphology and the mechanical, acoustic and vibration responses following a Design of Experiment procedure.- Adapt existing constitutive models available for foams' mechanics, vibration, and acoustics to describe the corresponding properties of these new classes of biobased metamaterials.

辅助学是一类机械超材料，表现出负泊松比。也就是说，它们在纵向延伸时横向扩展。具有辅助特性的泡沫在抗剪切抗性，循环准静态和动态载荷下的能量吸收，对低动能能量影响的抵抗力，在相对湿度条件下增强动态模量以及可量身定制的形状内存性能。多年来，已经开发了多个制造过程来将常规泡沫转化为辅助物质，从热力学（涉及体积压缩，退火和冷却）到化学处理（利用丙酮和二氧化碳到软泡沫细胞壁）等等。然而，到目前为止，尚无人工辅助泡沫超材料的超材料。基于生物的聚氨酯（及相关泡沫）的发展使生产基于生物的泊松泊松比率泡沫材料具有明显的可能性。植物油基多元醇（例如蓖麻油和大豆油）最近在不同的混合物中使用，通过在实验室和商业上进行自由升级，生产基于生物的开放式和闭孔泡沫，与基于化石的配料相比，可以改善压缩和热特性。由生物基底物制成的辅助泡沫将进一步提高在广泛应用中使用此类超材料的吸引力，因为与化石对应物相比，生命周期性能增强和全球变暖功率。此外，辅助生物基泡沫也将是最早旨在从发病开始的机械超材料产品之一。此类材料的潜在应用包括航空航天行业，在该行业中，增强的影响力和轻巧将有助于提高效率，到跑步鞋，头盔和衬垫的运动器材，这将受益于这类材料的独特特性。在这种情况下，该项目的目标是： - 表征可用的Castor和Soy基于QUAIN的QUAIN机构，并与化学，热量，热量，热形成，并将其组合在一起。 - 通过不同的转换途径来制造动态和粘弹性），声学和振动测试。-通过不同的转换途径生产生物基辅助开放式和闭合电池的超材料泡沫。-评估通过对机械，声学，估计和振动的量子效果进行的辅助泡沫的可行性，通过不同的过程获得的辅助泡沫的可行性 - 力学，振动和声学，以描述这些新的生物基材料类的相应特性。