Microcellular Injection Molding

Gong, Shaoqin; Yuan, Mingjun; Anilchandra, A. R.; Kharbas, Hrishikesh; Osorio, Andrés F.; Turng, Lih‐Sheng

doi:10.3139/217.1883

Cited by 42 publications

(28 citation statements)

References 46 publications

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“…While working with Mucell ® process to form the foamed samples, N 2 gas was used as the supercritical fluid and inserted inside the barrel during the screw recovery process. After moulding, packing pressure was eliminated to allow the nucleation and subsequent cells growth expands the parts and provides the essential pressure to pack it out against the mould walls [9]. With conventional injection moulding no N 2 gas was used and after the moulding, packing pressure was applied.…”

Section: Preparation Of Unfoamed and Foamedmentioning

confidence: 99%

Biocomposites based on poly(lactic acid)/willow-fiber and their injection moulded microcellular foams

Zafar¹,

Zarrinbakhsh²,

Mohanty³

et al. 2016

Express Polym. Lett.

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Abstract. Natural fiber reinforced biocomposites have recently attracted many researchers because of their biodegradability, cost effectiveness and ecofriendliness. The present study investigates the properties of willow-fiber reinforced poly(lactic acid) based composites and their foam processability. Microcellular foams of the composites were prepared by foam injection moulding using nitrogen gas as the blowing agent. The effects of willow-fiber addition on the morphology, mechanical properties, thermal stability, crystallization, and heat deflection temperature (HDT) were studied. At 30 weight percent [wt%] willow-fiber content, unfoamed composites showed good improvement in specific tensile and flexural moduli. Addition of willow-fiber increased crystallinity and the rate of crystallization and yielded narrow crystallite size distribution as observed by differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) results of the foamed composites revealed that increase in willow-fiber content caused smaller average cell size and higher cell density. Specific notch impact strength of foamed composites at both 20 and 30 wt% willow-fiber content showed increasing trend compared to that of their unfoamed counterparts.

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Section: Preparation Of Unfoamed and Foamedmentioning

confidence: 99%

Biocomposites based on poly(lactic acid)/willow-fiber and their injection moulded microcellular foams

Zafar¹,

Zarrinbakhsh²,

Mohanty³

et al. 2016

Express Polym. Lett.

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“…4, all samples exhibited a sandwich-type structure, with solid walls encapsulating a foamed core. This may be attributed to three factors: (1) rapid cooling at the polymer-mold interface hampers cell nucleation and growth, (2) the supercritical nitrogen diffuses out of the polymer-gas solution and escapes through the mold vents, and (3) cell embryos dissolve back into the polymer melt due to increased solubility at lower temperatures (Gong et al, 2005). The largest cells occurred in the center of the part, most notably seen in Fig.…”

Section: Morphology Of the Microcellular Pla And Pla-sf Compositesmentioning

confidence: 96%

“…Note that with conventional injection molding, no supercritical fluid (SCF), nitrogen in this case, was introduced into the material. Additionally, the pack/hold stage is absent in microcellular injection molding due to the homogeneous packing pressure that results from the nucleation and growth of cells (Gong et al, 2005). This homogeneous packing pressure has been shown to drastically reduce the shrinkage and warpage of microcellular injection molded parts when compared to conventional injection molding, greatly enhancing the dimensional stability of molded parts with a complex geometry (Kramschuster et al, 2005).…”

Section: Sample Preparationmentioning

confidence: 99%

Injection Molded Solid and Microcellular Polylactide Compounded with Recycled Paper Shopping Bag Fibers

Kramschuster

Pilla

Gong

et al. 2007

International Polymer Processing

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Recycled paper shopping bag fibers were melt-compounded using a batch mixer with biobased/biodegradable polylactide (PLA) at 10 and 30 wt.% using silane as a coupling agent. These PLA/fiber composites were then injection molded to produce both solid and microcellular tensile bars. The mechanical properties (specific modulus, specific tensile strength, specific toughness, and strain at break) of the neat PLA and PLA composites were tested and the cell morphology of the microcellular samples was examined using scanning electron microscopy. It was observed that the addition of the recycled paper shopping bag fibers resulted in an increase in cell density and decrease in average cell size for the microcellular components when compared with the neat PLA. The addition of the fibers increased the specific modulus of both solid and microcellular components, and high fiber contents (30 wt.%) resulted in an increase in specific tensile strength, yet yielded a decrease in the strain at break and specific toughness. The storage modulus was also improved with the addition of 10 and 30 wt.% fibers for both solid and microcellular components. 436 Carl Hanser Verlag, Munich Intern. Polymer Processing XXII (2007) 5

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“…This reduces the amount of plastic used, thereby reducing the cost of many mass-produced plastic items. For microcellular PLA, the addition of MWCNTs not only will affect the material properties directly as a second phase, but also will affect the cell morphology by acting as a nucleating agent for microcells (Chandra et al, 2005;Gong et al, 2005;Han et al, 2004;Lee et al, 2005a, b;Nam et al, 2002;Shen et al, 2005;Wang et al, 2004;Yuan et al, 2004;Zheng and Park, 2005).…”

Section: Introductionmentioning

confidence: 94%

Solid and Microcellular Polylactide-Carbon Nanotube Nanocomposites

Pilla

Kramschuster

Gong

et al. 2007

International Polymer Processing

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In this study, polylactide (PLA)-multi-walled carbon nanotube (MWCNT) nanocomposites were melt-compounded using a twin-screw extruder. Solid and microcellular tensile bar specimens were produced via conventional and microcellular injection molding, respectively. Various characterization techniques were applied to study the static and dynamic mechanical properties, degree of MWCNT dispersion, cell morphology, and crystallization behavior. The addition of a small amount of MWCNTs led to a decrease in the cell size and an increase in the cell density of the microcellular PLA specimens. A transmission electron microscopy analysis of the PLA-MWCNT specimens revealed a higher degree of MWCNT dispersion in the microcellular PLA-MWCNT composite compared with its solid counterpart, indicating that the microcellular injection molding process further dispersed the MWCNTs. For both solid and microcellular specimens, the addition of 1.5 wt% MWCNTs reduced the specific strength, specific toughness and strain-at-break while exerting less impact on the specific modulus. The storage modulus was not affected significantly with the addition of MWCNTs, but was found to be higher for the microcellular specimens compared with their solid counterparts. Finally, the crystallinity of PLA increased with the addition of MWCNTs. 418 Carl Hanser Verlag, Munich Intern. Polymer Processing XXII (2007) 5

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Microcellular Injection Molding

Cited by 42 publications

References 46 publications

Biocomposites based on poly(lactic acid)/willow-fiber and their injection moulded microcellular foams

Biocomposites based on poly(lactic acid)/willow-fiber and their injection moulded microcellular foams

Injection Molded Solid and Microcellular Polylactide Compounded with Recycled Paper Shopping Bag Fibers

Solid and Microcellular Polylactide-Carbon Nanotube Nanocomposites

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