Effect of cooling temperature on deconsolidation and pulling forces in a thermoplastic pultrusion process

Alsinani, Nawaf; Ghaedsharaf, Mohammad; Lebel, Louis Laberge

doi:10.1016/j.compositesb.2021.108889

Cited by 22 publications

(9 citation statements)

References 37 publications

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“…This excess polymer, consequently, creates a backflow which helps raise the impregnation pressure. [31][32][33][34] This technique does not damage the reinforcing fibers and the fibers typically remain quasi-continuous after they have been processed. The pultrudates are then set to cool off and are cut into pellets of desired length.…”

Section: Introductionmentioning

confidence: 99%

Effect of Flax/PP pellets’ morphology on the mechanical properties of injection-molded parts

Alsinani

Lebel

2022

Journal of Thermoplastic Composite Materials

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Flax and polypropylene (PP) pultrudates of 4.76 mm in diameter were produced using a multi-die pultrusion system. The flax content was 50 vol.%. Pultrusion conditions were varied to produce four porosity content between 4% and 22%. The pultrudates were pelletized into lengths of 6 and 15 mm, and injection-molded with pure PP to reduce the part flax content to 25 wt.%. Results showed that well consolidated pultrudates, having porosities up to 8%, were more resilient to the pelletizing process such that the pellets remained structurally intact after the process. These pellets went smoothly through the hopper into the injection molding machine screw. Pellets with void content higher than 8% lost integrity during pelletizing leading to uniform mixing. Exposed fibers segregated from the polymer in the hopper leading to ununiform mixing. The highest mechanical properties improvement compared to pure PP was using 15 mm pellets that had a prorosity of 8%. The tensile modulus doubled at 4652 ± 113 MPa. The impact strength increased by almost five times at 10.5 ± 0.7 [Formula: see text]. 15 mm pellets provided 1.7 times the impact strength of the 6 mm pellets. These improvement are attributed to low flax fiber thermal degradation and improved fiber dispersion.

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Section: Introductionmentioning

confidence: 99%

Effect of Flax/PP pellets’ morphology on the mechanical properties of injection-molded parts

Alsinani

Lebel

2022

Journal of Thermoplastic Composite Materials

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“…Finally, it suspected that the cooling section also contributed to the increasing measured-to-computed difference in pulling force with respect to speed. As seen in Alsinani et al, 12 the polymer adheres to the die surface when cooling from the processing temperatures until it shrinks and separates. The adhesion length is directly related to the distance on which the polymer cools.…”

Section: Resultsmentioning

confidence: 90%

Effect of high pulling speeds on the morphologies of pultrudates in a thermoplastic pultrusion process

Alsinani

Lebel

2022

Journal of Thermoplastic Composite Materials

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During thermoplastic pultrusion, increasing the pulling speed generally leads to a melted polymer pressure rise in the pultrusion dies. Yet, it was not clear if the polymer pressure’s increase would result in a faster impregnation flow that would compensate for the lower residency time inside the heating dies. Thus, the aim of this study was to verify if the speed-induced pressure can counterbalance the decrease in residency time that is required for impregnation quality and to analyze possible pultrudate morphology’s reconfiguration. Three distant pulling speeds were selected: namely 50, 500 and 1000 mm/min. Using a model, the polymer pressure in the pultrusion dies was computed to reach up to 1.0, 10.42, and 20.6 MPa for the respective pultrusion pulling speed. The morphology’s characterization showed a reconfiguration of the pultrudate at a higher pulling speed leading to larger unimpregnated agglomerations and polymer rich areas. The highest tensile strength achieved was 233.4 ± 1.5 MPa at 50 mm/min and dropped by around 20% when the pulling speed was raised to 1000 mm/min. The pultrudate reconfiguration at higher speed, attributed to delayed melting of PP fibers in underfilled dies, is deemed responsible for the loss in impregnation and mechanical properties.

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“…Surface finish deficiencies and thermal deconsolidation as main problems in thermoplastic composites pultrusion, are attributed to the improper execution of the cooling process. [ 55 ] The cooling temperature also influence the degree of crystallinity, the void content and the mechanical properties of composites. [ 56–58 ] However, there is a lack of studies on the cooling die temperature and geometric parameters, commonly set below the glass transition temperature to prevent the product from losing its shape and possessed a constant cross‐section.…”

Section: In Situ Polymerization Pultrusionmentioning

confidence: 99%

Continuous fiber reinforced thermoplastic composite pultrusion with in situ polymerizable methyl methacrylate: A review

2023

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Compared to thermosetting resins, thermoplastic polymers offer many advantages as fiber reinforced composite matrices, such as excellent toughness, superior corrosion resistance, weldability, and recyclable, etc. However, the processibility of thermoplastic composites is commonly considered as a challenge because of the high viscosity of polymer melts (e.g., polypropylene, polyetheretherketone, etc.), which remarkably hinders their applications. Using low viscosity and in situ polymerizable thermoplastic resins to manufacture continuous fiber reinforced thermoplastic composites have been deemed as a cost-effective emerging approach to surpass the processibility challenges. Therefore, this paper presents an overview of advancement in the engineering, high-performance and room-temperature-processible liquid methyl methacrylate (MMA) resins and their composites up to date. First, the polymerization behavior and kinetic modeling of the MMA resins are reviewed, and the effects of initiators on the polymerization are summarized. In the second part, the pultrusion process and modeling including impregnation, temperature distribution and pulling force are discussed. Next, the mechanical properties and durability of the carbon fiber-, glass fiber-reinforced MMA-matrix composites are presented. Finally, the challenges of the preparation and application of the MMA-matrix composites are identified.

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Effect of cooling temperature on deconsolidation and pulling forces in a thermoplastic pultrusion process

Cited by 22 publications

References 37 publications

Effect of Flax/PP pellets’ morphology on the mechanical properties of injection-molded parts

Effect of Flax/PP pellets’ morphology on the mechanical properties of injection-molded parts

Effect of high pulling speeds on the morphologies of pultrudates in a thermoplastic pultrusion process

Continuous fiber reinforced thermoplastic composite pultrusion with in situ polymerizable methyl methacrylate: A review

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