Bach Marcelo Jorge, Barbosa Kelvin Techera, Fonseca Cristiane da Silva, Gatto Darci Alberto, Beltrame Rafael, Missio André Luiz, Labidi Jalel, Delucis Rafael de Avila
Post-Graduate Program in Environmental Sciences (PPGCAmb), Federal University of Pelotas, Pelotas 96010-610, Brazil.
Postgraduate Program in Mining, Metallurgical and Materials Engineering, Federal University of Rio Grande do Sul, Porto Alegre 91501-970, Brazil.
Materials (Basel). 2025 Apr 25;18(9):1950. doi: 10.3390/ma18091950.
This study aimed to assess the mechanical and morphological properties of rigid polyurethane foams (RPUFs) reinforced with cellulose nanocrystals (CNC) at varying concentrations, exploring also effects of expansion under confinement for use in sandwich panels. RPUFs with 1%, 3%, and 5% CNC were tested, with the 3% CNC content delivering the best combination of mechanical performance and cellular structure. While the RPUF with 5% CNC showed a 78% increase in cell length, its compressive strength dropped by 55%, likely due to CNC agglomeration. Confining the RPUF during expansion improved the density by 23%, which in turn led to an approximately 90% increase in core shear stress. Flexural tests revealed that confined panels exhibited better force-displacement responses, with core shear strength rising by 55% compared to unconfined panels. These results suggest that CNC-reinforced and confined RPUFs are well-suited for structural applications requiring both strength and insulation.
本研究旨在评估不同浓度纤维素纳米晶体（CNC）增强的硬质聚氨酯泡沫（RPUF）的力学和形态性能，同时探讨在受限条件下膨胀对用于夹芯板的影响。测试了含1%、3%和5% CNC的RPUF，其中3% CNC含量的样品在力学性能和泡孔结构方面表现出最佳组合。含5% CNC的RPUF泡孔长度增加了78%，但其抗压强度下降了55%，这可能是由于CNC团聚所致。在膨胀过程中对RPUF进行约束可使密度提高23%，进而使芯层剪切应力提高约90%。弯曲试验表明，受限夹芯板表现出更好的力-位移响应，其芯层抗剪强度比未受限夹芯板提高了55%。这些结果表明，CNC增强且受限的RPUF非常适合需要兼具强度和隔热性能的结构应用。
