The influence of preheating temperature on the mechanical properties of injection-overmolded hybrid glass fiber reinforced thermoplastic composites

Continuous glass fiber reinforced thermoplastic composites have been manufactured and their mechanical properties have been evaluated. A catalyzed monomer is infused through a stack of compacted dry reinforcement under vacuum. The monomer undergoes radical polymerization with a peroxide catalyst. Viscosity and reactivity profile have been characterized to determine the catalyst concentration and temperature of infusion. Glass fiber reinforced thermoplastic composites realized through this method have mechanical properties that are comparable with that of epoxy with an added advantage of excellent toughness and repairability. For example, the residual compressive strength of thermoplastic composites after low-velocity impact is found to be over 140% more than that of epoxy-based composites using the same reinforcement and realized under identical manufacturing methods.

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Thermoplastic Reaction Injection Pultrusion for Continuous Glass Fiber-Reinforced Polyamide-6 Composites

Materials ◽

10.3390/ma12030463 ◽

2019 ◽

Vol 12 (3) ◽

pp. 463 ◽

Cited By ~ 9

Author(s):

Ke Chen ◽

Mingyin Jia ◽

Hua Sun ◽

Ping Xue

Keyword(s):

Mechanical Properties ◽

Glass Fiber ◽

High Speed ◽

Flexural Modulus ◽

Polyamide 6 ◽

Thermoplastic Composites ◽

Fiber Reinforced ◽

Pultrusion Process ◽

Glass Fiber Reinforced ◽

Pultruded Composites

In this paper, glass fiber-reinforced polyamide-6 (PA-6) composites with up to 70 wt% fiber contents were successfully manufactured using a pultrusion process, utilizing the anionic polymerization of caprolactam (a monomer of PA-6). A novel thermoplastic reaction injection pultrusion test line was developed with a specifically designed injection chamber to achieve complete impregnation of fiber bundles and high speed pultrusion. Process parameters like temperature of injection chamber, temperature of pultrusion die, and pultrusion speed were studied and optimized. The effects of die temperature on the crystallinity, melting point, and mechanical properties of the pultruded composites were also evaluated. The pultruded composites exhibited the highest flexural strength and flexural modulus, reaching 1061 MPa and 38,384 MPa, respectively. Then, effects of fiber contents on the density, heat distortion temperature, and mechanical properties of the composites were analyzed. The scanning electron microscope analysis showed the great interfacial adhesion between fibers and matrix at 180 °C, which greatly improved the mechanical properties of the composites. The thermoplastic reaction injection pultrusion in this paper provided an alternative for the preparation of thermoplastic composites with high fiber content.

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The Effects of Strain Rates on Mechanical Properties and Failure Behavior of Long Glass Fiber Reinforced Thermoplastic Composites

Polymers ◽

10.3390/polym11122019 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2019 ◽

Cited By ~ 4

Author(s):

Junjia Cui ◽

Shaoluo Wang ◽

Shuhao Wang ◽

Guangyao Li ◽

Peilin Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Glass Fiber ◽

Ultimate Strength ◽

Fracture Strain ◽

Thermoplastic Composites ◽

Strain Rates ◽

Fiber Breakage ◽

Fiber Reinforced ◽

Glass Fiber Reinforced ◽

Long Glass Fiber

Long glass fiber reinforced thermoplastic composites have been increasingly used in automotive parts due to their excellent mechanical properties and recyclability. However, the effects of strain rates on the mechanical properties and failure mechanisms of long glass fiber reinforced polypropylene composites (LGFRPPs) have not been studied systematically. In this study, the effects of strain rates (from 0.001 s−1 to 400 s−1) on the mechanical properties and failure mechanism of LGFRPPs were investigated. The results showed that ultimate strength and fracture strain of the LGFRPPs increased obviously, whereas the stiffness remained essentially unchanged with the strain rates from low to high. The micro-failure modes mainly consisted of fibers pulled out, fiber breakage, interfacial debonding, matrix cracking, and ductile to brittle (ductile pulling of fibrils/micro-fibrils) fracture behavior of the matrix. As the strain rates increased, the interfacial bonding properties of LGFRPPs increased, resulting in a gradual increase of fiber breakage at the fracture surface of the specimen and the gradual decrease of pull-out. In this process, more failure energy was absorbed, thus, the ultimate strength and fracture strain of LGFRPPs were improved.

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