Effect of Processing Parameters on the Mechanical Properties of Injection Molded Thermoplastic Polyolefin (TPO) Cellular Foams

Wong, Steven; Lee, John W. S.; Naguib, Hani E.; Park, Chul

doi:10.1002/mame.200700362

Cited by 80 publications

(55 citation statements)

References 23 publications

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“…Compared with conventional rubbers, their enhanced recyclability, improved colorability, and better design flexibility have dramatically increased their use in automotive applications [2]. Researchers have employed many methods to foam TPV [3, 4], TPU [5–7], and TPO [8–15]. With a batch‐foaming process [11–13], a well‐defined cell morphology is produced in these foamed samples.…”

Section: Introductionmentioning

confidence: 99%

Effect of nanoclay addition on the foaming behavior of linear polypropylene‐based soft thermoplastic polyolefin foam blown in continuous extrusion

Zhai

Park

2011

Polymer Engineering & Sci

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The goal of this study is to fabricate a soft foam with high cell density and high foam expansion based on thermoplastic polyolefin (TPO), and to supply a potential candidate for soft thermoset foams. It was found that a linear polypropylene (PP)‐based TPO foam exhibited very poor cell morphology because of its weak melt strength. Nanoclay was introduced into the TPO to improve its foaming behavior. The extrusion foaming experiments demonstrated that the introduction of 0.5 wt% nanoclay significantly increased the cell morphology and expansion ratio of TPO/clay nanocomposite foams due to the enhanced cell nucleation and the possible cell coalescence suppression at low temperatures. At a high nanoclay content of 2.0 wt%, the cell density and foam expansion of foams increased continuously compared with the 0.5 wt% nanoclay addition. Our study suggested that it was possible to produce soft TPO foams with a well‐defined cell structure and high foam expansion using a continuous method, but that a proper PEOc content control was needed to maximize foam expansion. POLYM. ENG. SCI., 2011. ©2011 Society of Plastics Engineers.

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Section: Introductionmentioning

confidence: 99%

Effect of nanoclay addition on the foaming behavior of linear polypropylene‐based soft thermoplastic polyolefin foam blown in continuous extrusion

Zhai

Park

2011

Polymer Engineering & Sci

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“…However, it is known that the differences of shearing stress and temperature in both the direction of the flow and the direction perpendicular to the flow usually result in a nonuniform cell structure, which deteriorates the mechanical properties of the foamed products . In this regard, the effects of processing parameters (e.g., injection speed, melt temperature, shot size, and the dosage of SCF) on the cell structure have been extensively researched . Besides, the effect of the fillers on the cell nucleation was also studied .…”

Section: Introductionmentioning

confidence: 99%

Polystyrene Foam with High Cell Density and Small Cell Size by Compression‐Injection Molding and Core Back Foaming Technique: Evolution of Cells in Cavity

Bai

Dong

Xiao

et al. 2018

Macro Materials & Eng

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Many efforts have been made to obtain uniform cell structures from foam injection molding techniques. However, cell nucleation mechanism and complex dynamics during the cell formation have rarely been well understood. Here, high‐pressure foam injection molding (HPFIM) is achieved by combining the injection–compression molding with core back foaming (ICMCBF) technique. The influences of compression pressure and time on the cell structure of polystyrene foam during the foaming process are studied. Compared with low pressure for conventional foam injection molding, high compression pressure (200 bar) and fast pressure drop rate of ICMCBF endow the foam with the highest cell density (1.59 × 107 cells cm−3), and the smallest cell size (15 µm). The tensile strength and impact strength are enhanced by about 60% (from 22.3 to 35.6 MPa) and 80% (from 3.6 to 6.8 MPa), respectively. This study gives a critical understanding of the cell nucleation and growth mechanism of the foam injection molding and supplies a new strategy for the fabrication of foam with uniform cell structure.

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“…Because of their light weight, low cost, good mechanical properties, and relative ease of molding into complex shapes, they have become an important class of materials for the automotive industry 3. Thermoplastic polyolefins as one of thermoplastic elastomers can be completely recyclable 4. However, TPO would burn easily once exposed to fire due to its chemical structure.…”

Section: Introductionmentioning

confidence: 99%

Intumescent flame retardant TPO composites: Flame retardant properties and morphology of the charred layer

Wang

Feng

Chang

et al. 2011

J of Applied Polymer Sci

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Intumescent flame retardant thermoplastic polyolefin (TPO) composites were prepared to study the relationships between their structure of charred layer (including of the multicellular intumescent layer and the charry layer) and flame retardant properties. They were characterized using the LOI and UL-94 test, which indicated that the best fire retardant behavior (V-0 rating and LOI reach to 28.1%) was obtained at the formulation of TPO/ammonium dihydrogen phosphate/starch (100/60/ 20). Thermal gravimetric analysis demonstrated that the presence of ammonium dihydrogen phosphate/starch promoted the esterification and carbonization process in lower temperature range while enhancing the thermal stability of intumescent flame retardant TPO in high-temperature range. Scanning electron microscope and optical microscope were shown that, with combustion time prolonged, the intumescent layers obtained greater number of cells, and the charry layer became more compact while the size of the carbon granules became smaller on the surface. Introduction of starch had an obvious effect on the structure of the intumescent and charry layers. The charry layer of the composites with the content of 20 phr starch was more compact and uniform than that of the composites with 50 phr. The weight ratio of ammonium dihydrogen phosphate to starch in the intumescent flame retardant was fixed as 3 : 1 which cooperated with each other well to promote a compact charry layer and to obtain the better flame retardancy performance. Therefore, the better the charred layers produced, and the better flame retardant properties they obtained.

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Effect of Processing Parameters on the Mechanical Properties of Injection Molded Thermoplastic Polyolefin (TPO) Cellular Foams

Cited by 80 publications

References 23 publications

Effect of nanoclay addition on the foaming behavior of linear polypropylene‐based soft thermoplastic polyolefin foam blown in continuous extrusion

Effect of nanoclay addition on the foaming behavior of linear polypropylene‐based soft thermoplastic polyolefin foam blown in continuous extrusion

Polystyrene Foam with High Cell Density and Small Cell Size by Compression‐Injection Molding and Core Back Foaming Technique: Evolution of Cells in Cavity

Intumescent flame retardant TPO composites: Flame retardant properties and morphology of the charred layer

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