Improving mechanical and thermal properties of short carbon fiber/polyamide 6 composites through a polydopamine/nano‐silica interface layer

Although a large body of literature has reported that PA6 modification enhances melt strength and improves foam quality, the relationship between melt viscosity and foaming quality remains ambiguous. This paper aims to select four PA6 with different viscosities to explore the effect of the viscosity of the material on foaming quality. First, the foamed materials of four PA6 were prepared by core‐back injection foaming technology. In addition, the crystallization properties and rheological behavior of four PA6 were systematically studied by rotational rheometer and differential scanning calorimetry. The morphologies of composite foams with different viscosities were analyzed using scanning electron microscopy. It was found that the cell size and cell density of M2400 with low viscosity were 114 μm and 1.87 × 105 cells/cm3, respectively. With the increase of viscosity, the cell size and cell density of M2500I decreased to 98.3 μm and 2.66 × 105 cells/cm3, respectively. However, as the viscosity continues to increase, the cell size increases, and the cell density decreases. The findings indicate that the secret to good foaming is rheological behavior. The lower viscosity is challenging to prevent cell growth and easy to break, while high viscosity causes poor fluidity which deteriorates foaming quality and surface quality. It provides guidance for preparing foaming materials with excellent performance and surface through a modification that enhances melt strength.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of viscosity on foaming behavior and surface quality of foamed Polyamide 6

Luo,

Liu,

et al. 2023

“…However, the potential of using CNTs as conductive fillers is limited by the difficulty of CNTs dispersion in polymers. The hybrid fillers with different aspect ratios such as CB and CNTs has been reported to achieve relatively low filler content, this not only to improve the flexibility and PTC effect of PTC materials, but also to reduce the initial resistivity 22–26 . The reason is the synergistic effect of multiple conductive paths constructed by hybrid fillers with different appearances.…”

Section: Introductionmentioning

confidence: 99%

“…The hybrid fillers with different aspect ratios such as CB and CNTs has been reported to achieve relatively low filler content, this not only to improve the flexibility and PTC effect of PTC materials, but also to reduce the initial resistivity. [22][23][24][25][26] The reason is the synergistic effect of multiple conductive paths constructed by hybrid fillers with different appearances. Based on the hybrid fillers of 4 wt % CB and 0.5 wt% CNTs, the initial resistivity of the PTC composites was reduced by approximate two ordersmagnitude, and their PTC intensity was improved simultaneously by around 30%.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and performance evaluation of the flexible positive temperature coefficient material for self‐regulating thermal control

et al. 2023

In this study, three kinds of newly flexible positive temperature coefficient (PTC) materials are fabricated by a simple preparation method. Due to introducing the hybrid filler of carbon nanotube and carbon black, these materials exhibit remarkable PTC effect including the PTC intensity of more than four‐orders magnitude and the resistivity‐temperature coefficient of 154%/°C. The Curie points of PTC materials are regulated to room‐temperature range by the low melting phase and influenced by melting onset temperatures of their solid–liquid phase change. With the help of transmission electron microscope, the micro‐capsule structure of the phase change regions is observed, and the hybrid conductive fillers randomly distribute in the blend matrix to construct three‐dimensional conductive network. Using the PTC materials as a heating element, the equilibrium temperature of the controlled device can be maintained around their Curie point without any control method. Moreover, the adaptive thermal control effect becomes more obvious with the increase of ambient temperature and initial heating power. Furthermore, the thermal control accuracy fluctuates within 0.15°C without any external control method, and is improved to round 0.08°C in combination with the switch control method. This study provides a new method for the thermal control of electronic devices in the requirement of lightweight and miniaturization at low temperature environment.

“…The incorporation of micro and nanoscale additives into PAs to increase the mechanical properties while maintaining the overall weight became an important research subject. [15][16][17] Mainly; SiO 2, 18 clay, 19 calcium carbonate, 20,21 and carbonaceous materials such as carbon nanotubes, 22,23 carbon fiber (CF), 24 carbon black (CB), 25 exfoliated graphite, 26 and lately graphene 27 and graphenerelated materials 28,29 are being used to enhance the mechanical properties of polymers while maintaining the desired weight. Nevertheless, several challenges remain for the incorporation of such small-scale additives into the polymer matrix.…”

Section: Introductionmentioning

confidence: 99%

The effect of reinforcement aspect ratio on the performance of PA66 composites with recycled carbon fiber and upcycled graphene nanoplatelets: An interface characterization from process to modeling

Dericiler

Zafar

Şaş

et al. 2023

The use of recycled reinforcements in structural applications is growing due to concerns about the environmental impact and economic costs associated with energy‐intensive production techniques of virgin fibers. However, limited research has explored the integration of multiscale reinforcements with different aspect ratios into PA66 composites to enhance their performance. In this study, the effect of reinforcement aspect ratio on PA66 composites by incorporating recycled carbon fibers and waste tire‐derived graphene nanoplatelets (GNP) with oxygen surface functional groups is investigated. The objective of this work is to improve mechanical properties of the composites by promoting nucleation and enhancing the fiber/matrix interface. Through high shear mixing, recycled carbon fibers and GNP are effectively dispersed within the PA66 matrix. The alignment of these reinforcements during the injection molding process is monitored using the developed flow model, coupled with experimental rheological data. The resulting composites demonstrate significant improvements in mechanical properties due to enhanced interfacial interactions, including improved tensile properties up to 94%, flexural properties up to 86% compared to the neat PA66 by successfully integrating waste tire‐driven GNP and recycled carbon fibers. This study contributes to the development of sustainable materials for load‐bearing applications, utilizing recycled reinforcements with different aspect ratios.