Search

In this study, bamboo and glass fibers were successfully added into bisphenol A–aniline-based benzoxazine resin by hot pressing method. The effect of water absorption on the mechanical properties of the neat benzoxazine and its composites was studied. The composites prepared in this study has been proved to exhibit better water resistance than some conventional natural fiber/polymer composites due to good hydrophobicity of the benzoxazine matrix. From the mechanical tests, the tensile performance of both neat benzoxazine and the composites degraded seriously after prolonged immersion in water. However, neat benzoxazine and the composites maintained relatively higher residual flexural properties (residual mechanical properties refer to the ratio of strength and modulus of the saturated samples to that of the nonaged samples) after 20 days of water immersion. The effect of water molecules on the fracture surface morphologies of the composites was studied using a scanning electron microscope (SEM). The SEM images showed that the interfacial bonding between fibers and the matrix degraded seriously due to the attack of water. [ABSTRACT FROM AUTHOR]

Glass fiber/polymerized cyclic butylene terephthalate (GF/pCBT) and its nanosilica-modified thermoplastic composites were manufactured via vacuum-assisted molding pressing process. Subsequently, the effects of temperature and nanosilica fillers on the macroscopic mechanical behavior of glass fiber-reinforced pCBT composites were discussed. Failure morphologies of specimens were observed by scanning electron microscopy (SEM). Experimental results show that pure GF/pCBT composites have good mechanical properties, whereas their half-strength degradation temperature (T S = 0.5) is relatively lower. It is also found that nanosilica-modified composites have higher heat resistance performance, and T S = 0.5 point of the modified composites enhanced by 10°C. SEM observations show that the smooth fracture surface in the broken composites appears at higher temperatures, which indicates that the toughness of nanosilica-modified GF/pCBT composites is improved. [ABSTRACT FROM AUTHOR]

Monitoring the curing defects as well as damages that occur in the fabrication and application process is important for ensuring the safety of composite structures. In this paper, a highly sensitive 1‐D line sensor is designed to achieve self‐sensing and diagnosing functionalities in both the fabrication and application of glass fiber reinforced epoxy (GF/epoxy) composites. The sensor consists of multi‐walled carbon nanotube coated glass fiber (MWCNT@GF), which is sensing the damage by the principle of resistance change. Due to the vacuum‐assisted resin infusion process, the MWCNT@GF sensor is embedded into GF/epoxy composite laminates, and hence, it can monitor the resin frontal flow, curing, and especially the flow defects. In the subsequent application, the tensile performance of a GF/epoxy composite joint is evaluated by not only the force‐displacement curve but also the displacement‐dependent resistance change of the sensor. Tensile damage modes are distinguished, which is for the first time to be reported. The MWCNT@GF sensor is mechanically stable and highly sensitive; hence, it can be used to follow the composite performance from fabrication until the end of life. [ABSTRACT FROM AUTHOR]