Microcellular foaming of polypropylene containing low glass transition rubber particles in an injection molding process

Wang, Chicheng; Cox, Karen; Campbell, Gregory A.

doi:10.1002/vnl.10115

Cited by 9 publications

(3 citation statements)

References 7 publications

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“…Therefore, carbon dioxide has received more attention than nitrogen in polymer foam production. In recent years, several research groups have studied the foaming process using carbon dioxide as a BA in various polyolefin matrixes − as well as polyolefin composites. ,− Significant work ,− has also been reported in foaming studies with nitrogen, and at least one investigation has examined mixtures of carbon dioxide and nitrogen . The impact of carbon dioxide and nitrogen on the rheological properties of polyolefins during the foaming process has been sparsely examined in the literature, and such knowledge is required for optimizing processing conditions.…”

Section: Introductionmentioning

confidence: 99%

Rheological Comparison of Chemical and Physical Blowing Agents in a Thermoplastic Polyolefin

Qin

Thompson

Hrymak

et al. 2006

Ind. Eng. Chem. Res.

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The influences of popular blowing agents (BAs), both chemical and physical types, in solution with a thermoplastic polyolefin (TPO) were investigated with an in-line capillary rheometer nozzle attached to a conventional reciprocating 55-ton injection molding machine. In the experiments, two types of masterbatch chemical BAs (endothermic and exothermic type) were dry mixed with the TPO resin and compared against two types of physical BAs (carbon dioxide and nitrogen) directly injected into a specially designed injection nozzle containing static mixer elements (SMX type). The effects of the main processing conditions (injection speed, pressure, temperature, and BA type and concentration) on the TPO melt rheology were studied. The viscosity reduction behaviors of chemical BAs and physical BAs were compared. The type of BA had a strong influence on the viscosity reduction behavior of the TPO melt, with the maximum viscosity reduction of 47% with 3.2 wt % CO 2 at 250 °C. Both physical and chemical BAs were found to successfully fit a previously developed viscosity model for single-phase gas-polymer solutions.

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Section: Introductionmentioning

confidence: 99%

Rheological Comparison of Chemical and Physical Blowing Agents in a Thermoplastic Polyolefin

Qin

Thompson

Hrymak

et al. 2006

Ind. Eng. Chem. Res.

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“…Suh of the Massachusetts Institute of Technology and his research team [1] developed the microcellular foaming technique. Wang et al [2] applied this technique to MuCell®. Later, Lee et al [3] studied the viscosity change of microcellular plastics during the molding process and found that the biggest difference between MuCell® and conventional foaming is the cell structure.…”

Section: Introductionmentioning

confidence: 99%

Study of Foaming Morphology in Microcellular Injection Molded TPU/MWCNT Composites under Gas Counter Pressure

Chung,

Huang,

Lin

2024

NHC

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Due to the global environmental issues, microcellular injection molding (MuCell) process with the advantages of the energy saving, environmentally friendly and light weighting has become more and more popular in industry. In order to improve the common defects of uneven cell size and cell rupture in MuCell, this study aims to ameliorate the issues of excessively large open-cell structure and density reduction caused by cell rupture in MuCell with thermoplastic polyurethane (TPU). TPU 1185A supplied by BASF was selected as the material, to which multi-walled carbon nanotubes (MWCNT) were added and a gas counter pressure (GCP) control was applied, subsequently. The cell structure change was observed via scanning electron microscope (SEM). The results showed that adding nanotubes to TPU can increase the viscosity of the polymer melt and lower the average cell size, which will significantly reduce the number of cells with a diameter greater than 100 μm. With the GCP technique employed, the overall cell size was further reduced as well as the number of cells with a diameter greater than 100 μm, and the cell density was further increased.

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“…In 1980, Su [5] introduced supercritical fluid state into injection molding process. During the entire research and development process, Wang [6] was the first person to apply it to microcellular injection molding. In this technology, cell size and distribution are the two most essential properties of the microcellular injection molding parts.…”

Section: Introductionmentioning

confidence: 99%

Establishing a rapid cooling complex mold design for the quality improvement of microcellular injection molding

Chang

Chiu

Chen

et al. 2020

Polymer Engineering & Sci

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Injection molding is one of the most widely‐used processes for the production of plastic parts, due to the utilization of diverse materials, the complex product‐shape moldability, and the rapid mass production. In relation to the environmental issues, light‐weight technology and green molding solutions are becoming more important. Microcellular injection molding technology is one of the green molding solutions for saving materials, as well as reducing the weight of molded parts. However, the molding process brings about some defects, including a sliver flow mark on the surface and uneven mechanical properties that are caused by the uneven cell size and their distribution within the part. Dynamic molding temperature control technology seems to be an effective way of improving the product quality. Until recently, there has been very little discussion about high‐efficiency cooling methods. A new complex mold for a cooling system has been designed. The basis cooling ability of different materials was investigated. The complex mold design has a faster cooling rate, and it has a greater surface temperature uniformity. This cooling technology was used to improve the quality of microcellular injection molded parts, which improves the glossy finish by about 73%. The results show that the faster cooling rate brings about the more uniform cell size with higher cell density from 9.43E+11 to 1.92E+12 cells/cm3. Otherwise, the cell size reduced from 192.92 to 84.97 μm.

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Microcellular foaming of polypropylene containing low glass transition rubber particles in an injection molding process

Cited by 9 publications

References 7 publications

Rheological Comparison of Chemical and Physical Blowing Agents in a Thermoplastic Polyolefin

Rheological Comparison of Chemical and Physical Blowing Agents in a Thermoplastic Polyolefin

Study of Foaming Morphology in Microcellular Injection Molded TPU/MWCNT Composites under Gas Counter Pressure

Establishing a rapid cooling complex mold design for the quality improvement of microcellular injection molding

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