Towards an effective approach to determine the true fiber/matrix interfacial strength and its effect on damage mechanisms in micro/nano cellulose hybrid composites

Abstract

Fiber/matrix adhesion controls the macroscopic properties and affects the damage initiation and progression in polymer matrix composites (PMC). This SPRINT proposal aims to understand the effect of micro- nano-scale cellulose interfacial coupling agents on the strength of fiber/matrix interface and the influence of the modified interface on damage mechanisms in glass fiber (GF)/carbon fiber (CF)-reinforced thermosetting PMC. Microfibrillated cellulose (MFC-USP-Brazil) and cellulose nanocrystals (CNC-TAMU-USA), in liquid suspensions, will be integrated in GF and CF composite laminates by coating these fibers through immersion (TAMU) and spraying (USP) processes followed by vacuum-assisted resin transfer molding (VARTM). Subsequently, we will carry out qualitative and quantitative analyses on the modified composites' interfaces via in situ real-time tensile testing inside a scanning electron microscopy (SEM) (TAMU). The magnitude of true fiber/matrix interface adhesion will be determined via imaging, tracing and tracking the damage/fracture micro-mechanisms at the interface. The goal of this proposal is aligned with those pursued by Brazilian PI Tarpani in the linked APR-FAPESP Project (2017/25766-7), and in line with the current and future American PI Asadi´s research plans. The outcomes of this SPRINT project will allow us to engineer the interface of hybrid composites using MFC/CNC to achieve a longer service life for lightweight enhanced structural composites (high performance/weight ratio) in aerospace, marine and automotive industries in Brazil and USA. Through two mutual visits, the PIs will learn about the research and facility at the host institute and give seminars to communicate and share their latest research and educational achievements. This grant will establish a solid foundation for a long and fruitful collaboration between TAMU and SMM-EESC-USP. (AU)