Santos Paulo, Silva Abílio P, Reis Paulo N B
Centre for Mechanical and Aerospace Science and Technologies (C-MAST), University of Beira Interior, 6201-001 Covilhã, Portugal.
University of Coimbra, CEMMPRE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal.
Polymers (Basel). 2023 Feb 7;15(4):821. doi: 10.3390/polym15040821.
Two epoxy resins with different viscosities were enhanced up to 1 wt.%, applying a simple method with carbon nanofibers (CNFs). These were characterized in terms of static bending stress, stress relaxation, and creep tests. In bending, the contents of 0.5 wt.% and 0.75 wt.% of CNFs on Ebalta and Sicomin epoxies, respectively, promote higher relative bending stress (above 11.5% for both) and elastic modulus (13.1% for Sicomin and 16.2% for Ebalta). This highest bending stress and modulus occurs for the lower viscosity resin (Ebalta) due to its interfacial strength and dispersibility of the fillers. Creep behaviour and stress relaxation for three stress levels (20, 50, and 80 MPa) show the benefits obtained with the addition of CNFs, which act as a network that contributes to the immobility of the polymer chains. A long-term experiment of up to 100 h was successfully applied to fit the Kohlrausch-Williams-Watts (KWW) and Findley models to stress relaxation and creep behaviour with very good accuracy.
采用一种使用碳纳米纤维（CNF）的简单方法，将两种不同粘度的环氧树脂增强至1 wt.%。通过静态弯曲应力、应力松弛和蠕变试验对其进行了表征。在弯曲试验中，Ebalta和Sicomin环氧树脂中分别添加0.5 wt.%和0.75 wt.%的CNF，可提高相对弯曲应力（两者均高于11.5%）和弹性模量（Sicomin为13.1%，Ebalta为16.2%）。由于其界面强度和填料的分散性，较低粘度的树脂（Ebalta）出现了最高的弯曲应力和模量。在三个应力水平（20、50和80 MPa）下的蠕变行为和应力松弛表明，添加CNF具有益处，CNF形成一个网络，有助于聚合物链的固定。成功进行了长达100小时的长期实验，以非常高的精度将科尔劳施-威廉姆斯-瓦特（KWW）模型和芬德利模型应用于应力松弛和蠕变行为。
