Development of high thermal insulation and compressive strength BPP foams using mold-opening foam injection molding with in-situ fibrillated PTFE fibers

Zhao, Jinchuan; Zhao, Qingliang; Wang, Long; Wang, Chongda; Guo, Bing; Park, Chul; Wang, Guilong

doi:10.1016/j.eurpolymj.2017.11.001

Cited by 122 publications

(42 citation statements)

References 53 publications

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“…respectively, demonstrating that the fibrillated PTFE can act as a nucleation agent to promote the crystallization of TPEE with a high degree of close packing. The work of PP/PTFE system also showed that introducing PTFE fibrils can greatly increase the crystallization temperature by at least 6 °C [30].…”

Section: Thermal Behavior Of the Tpee/ptfe Nanocompositesmentioning

confidence: 91%

“…Many fibrils are entangled together to generate a reticular structure, which is believed to enhance the melt strength and prevent cells from rupture in the foaming process. Zhao's work shows that highly fibrillated PTFE could improve the foaming ability of PP in the injection-molding foaming process [30,38].…”

Section: Foam Characterizationmentioning

confidence: 99%

“…Interestingly, as shown in Figure 5 Interestingly, as shown in Figure 5, compared with TPEE without PTFE nanofibrils, the crystallization temperature of TPEE with PTFE nanofibrils increases by approximately 6 • C, from 164.3 • C for TPEE without PTFE and to 169.6, 170.6 and 170.8 • C for TPEE with 1%, 3% and 5% PTFE, respectively, demonstrating that the fibrillated PTFE can act as a nucleation agent to promote the crystallization of TPEE with a high degree of close packing. The work of PP/PTFE system also showed that introducing PTFE fibrils can greatly increase the crystallization temperature by at least 6 • C [30]. To qualitatively investigate promotion of PTFE fibrils in the TPEE crystallization kinetics, a modified Avrami analysis was employed, as described in earlier works [39] and the region calculated ranged from 3% to 50% in relative crystallinity to avoid the influence of epiphytic crystal growth.…”

Section: Thermal Behavior Of the Tpee/ptfe Nanocompositesmentioning

confidence: 99%

“…Dispersed micro/nanoparticles such as modified layered nanoclay and carbon particles can act as nucleating agents to increase the cell density in extrusion foaming [22,26] but the blends show little strain hardening response in extensional flow, which is important to stabilize the cell structure. Moreover, uniform dispersion of nanoparticles is extremely difficult and challenging, although particle surface modification that requires more processing can improve the dispersion.Recently, it was observed that introducing micro-fibrils into a polymer matrix can be a new method to enhance the foaming ability [27][28][29][30][31]. Polypropylene (PP) reinforced with fibrillated Polyethylene terephthalate (PET) and Polyethylene (PE) reinforced with fibrillated PP were successfully prepared by Rizvi et al using a fiber-spun system [27,28].…”

mentioning

confidence: 99%

“…Recently, it was observed that introducing micro-fibrils into a polymer matrix can be a new method to enhance the foaming ability [27][28][29][30][31]. Polypropylene (PP) reinforced with fibrillated Polyethylene terephthalate (PET) and Polyethylene (PE) reinforced with fibrillated PP were successfully prepared by Rizvi et al using a fiber-spun system [27,28].…”

mentioning

confidence: 99%

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Improving the Continuous Microcellular Extrusion Foaming Ability with Supercritical CO2 of Thermoplastic Polyether Ester Elastomer through In-Situ Fibrillation of Polytetrafluoroethylene

Jiang

Liu

et al. 2019

Polymers

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In-situ fibrillated polytetrafluoroethylene (PTFE) enhanced nanocomposites were successfully prepared by mixing thermoplastic polyether ester elastomer (TPEE) and PTFE using a twin-screw extruder. Well-dispersed, long aspect ratio PTFE nanofibrils with a diameter of less than 200 nm were generated and interwoven into networks. Differential scanning calorimetry and in-situ polarized optical microscopy showed that the PTFE nanofibrils can greatly accelerate and promote crystallization of the TPEE matrix and the crystallization temperature can be increased by 6 • C. Both shearing and elongational rheometry results confirmed that the introduction of PTFE nanofibrils can significantly improve the rheological properties. The remarkable changes in the strain-hardening effect and the melt viscoelastic response, as well as the promoted crystallization, led to substantially improved foaming behavior in the continuous extrusion process using supercritical CO 2 as the blowing agent. The existing PTFE nanofibrils dramatically decreased the cell diameter and increased cell density, together with a higher expansion ratio and more uniform cell structure. The sample with 5% PTFE fibrils showed the best foaming ability, with an average diameter of 10.4-14.7 µm, an expansion ratio of 9.5-12.3 and a cell density of 6.6 × 10 7 -8.6 × 10 7 cells/cm 3 .2 of 16 has many excellent properties including thermal stability, good elasticity, chemical and oil resistance and, especially, rebound resilience at low-temperatures [3,5]. Also, TPEE has higher tear and impact strengths over a broad range of service temperatures when compared with other traditional TPEs [8]. Because of the extraordinary performance of TPEE, it has attracted increasing interest from many fields such as the sports, automotive and military industries.Although TPEE is an attractive engineering material, its application has to overcome the exorbitant price. To overcome this shortcoming, many attempts have been made to further improve the mechanical properties or to lower the weight (i.e., material consumption). Blending the matrix with micro-sized particles is an efficient method to improve the thermal or mechanical properties of TPEE [9][10][11][12][13]. Paszkiewicz et al. [12] added carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) to poly(trimethylene terephthalate) (PTT)-based TPEE to improve the electrical conductivity. They found that CNTs had greater potential to improve electrical conductivity when compared to GNPs due to the higher purity and higher aspect ratio. Qiu et al. [13] controlled the structure of mixed filler particles in TPEE to enhance the mechanical properties. The results showed that a closely packed particle structure can significantly improve the yield strength by about 40% with a decrease of about 20% in the Young's modulus, which is preferred in TPEE used as an elastomer.Foaming is a very effective way to lower the weight and expand the application of polymers. In recent decades, foamed materials have exhibited a balance between price and...

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Section: Thermal Behavior Of the Tpee/ptfe Nanocompositesmentioning

confidence: 91%

Section: Foam Characterizationmentioning

confidence: 99%

Section: Thermal Behavior Of the Tpee/ptfe Nanocompositesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Improving the Continuous Microcellular Extrusion Foaming Ability with Supercritical CO2 of Thermoplastic Polyether Ester Elastomer through In-Situ Fibrillation of Polytetrafluoroethylene

Jiang

Liu

et al. 2019

Polymers

Self Cite

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Hollow‐Structured Materials for Thermal Insulation

2018

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Heating and cooling represent a significant portion of overall energy consumption of our society. Due to the diffusive nature of thermal energy, thermal insulation is critical for energy management to reduce energy waste and improve energy efficiency. Thermal insulation relies on the reduction of thermal conductivity of appropriate materials that are engineerable in compositions and structures. Hollow‐structured materials (HSMs) show a great promise in thermal insulation since the existence of high‐density gaseous voids breaks the continuity of heat‐transport pathways in the HSMs to lower their thermal conductivities efficiently. Herein, a timely overview of the recent progress in developing HSMs for thermal insulation is presented, with the focus on summarizing the strategies for creating gaseous voids in solid materials and thus synthesizing various HSMs. Systematic analysis of the documented results reveals the relationship of thermal conductivities of the HSMs and the size and density of voids, i.e., reducing the void size below ≈350 nm is more favorable to decrease the thermal conductivity of the HSMs because of the possible confinement effect originated from the nanometer‐sized voids. The challenges and promises of the HSMs faced in future research are also discussed.

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Influence of process parameters on mechanical properties of physically foamed, fiber reinforced polypropylene parts

Kastner

Steinbichler

Kahlen

et al. 2018

J of Applied Polymer Sci

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Due to the high complexity of the foaming technology, the relationship between processing and final properties of parts produced is not completely understood. Investigating the causality chain Processing–Morphology–Properties is of great importance, especially for the automotive industry, in order to be able to tailor the mechanical properties of foamed parts. This article examines and qualifies the effects of seven process parameters (melt/mold temperature, degree of foaming, injection speed, delay time, gas content, and back pressure) on biaxial bending and flexural behavior—the predominant deformation mechanisms in interior automotive applications—of foamed plaques, using the MuCell process. The results clearly show that three major factors (mold temperature, degree of foaming, and delay time) have significant impact on the mechanical properties of the foamed parts. For a clear understanding of these interactions, computed tomography scans of certain plaques are correlated to process parameters and mechanical performance. This article should forge a bridge between production and performance. © 2018 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47275.

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Development of high thermal insulation and compressive strength BPP foams using mold-opening foam injection molding with in-situ fibrillated PTFE fibers

Cited by 122 publications

References 53 publications

Improving the Continuous Microcellular Extrusion Foaming Ability with Supercritical CO2 of Thermoplastic Polyether Ester Elastomer through In-Situ Fibrillation of Polytetrafluoroethylene

Improving the Continuous Microcellular Extrusion Foaming Ability with Supercritical CO2 of Thermoplastic Polyether Ester Elastomer through In-Situ Fibrillation of Polytetrafluoroethylene

Hollow‐Structured Materials for Thermal Insulation

Influence of process parameters on mechanical properties of physically foamed, fiber reinforced polypropylene parts

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