Enhanced dispersion, flame retardancy and mechanical properties of polypropylene/intumescent flame retardant composites via supercritical CO2 foaming followed by defoaming

Huang, Pengke; Wu, Fei; Pang, Yongyan; Wu, Minghui; Lan, Xiaoqin; Luo, Haibin; Shen, Bin; Zheng, Wenge

doi:10.1016/j.compscitech.2018.12.029

Cited by 56 publications

(31 citation statements)

References 66 publications

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“…Furthermore, the solubility of major blowing agents in TPU was higher than that in polystyrene and poly (lactic acid). [25,26] Considering its unique properties stated above, TPU has been widely chosen as a toughening and foamability modifier to blend with polymers.…”

Section: Introductionmentioning

confidence: 99%

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO₂

Wang

et al. 2020

Vinyl Additive Technology

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Currently, the fabrication of microcell and bimodal cell structures (BCS) in polymer foams by using supercritical fluids has become a hot as well as a challenging research area worldwide. In this work, an environmentally friendly, effective, facile, and CO 2-based foaming technique was presented to fabricate microcellular polypropylene (PP) foams with BCS via blending with thermoplastic polyurethane (TPU). The toughness, thermal properties, rheological properties, and foamability of PP were systematically investigated with gradual incorporation of TPU. Representative sea-island structure was observed in the scanning electron microscopy (SEM) images for the fracture surface of various PP/TPU samples. Rheological measurement results demonstrated that the viscoelasticity of various PP/TPU samples was improved remarkably compared with that of pure PP and pure TPU. The impact strength of various PP/TPU samples possessed the highest value as 12.4 kJ/m 2 with the TPU content of 15 wt%. After the addition of TPU, an ameliorative cellular morphology was observed in the SEM micrographs of various PP/TPU samples and their volume expansion ratio was enhanced significantly thanks to their improved melt elasticity. Moreover, it is worth noting that BCS appeared in various PP/TPU foams when the TPU content exceeded 5 wt%.

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Section: Introductionmentioning

confidence: 99%

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO₂

Wang

et al. 2020

Vinyl Additive Technology

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“…Core-back foaming was realized to be an effective way to improve the cellular density of samples produced via FIM. [21][22][23][24][25][26][27] In the typical method of combining FIM with core-back technology, a movable mold is retracted for a short distance immediately or slightly after the gas-laden polymer melt is either fully or partially injected into the mold cavity, leading to the mold cavity being partially opened. There are generally two benefits to this operation: the core-back allows the foamed components more space and the pressure drop rate of the mold cavity increases, resulting in possible improvements in the foaming ratio and cellular density.…”

Section: Introductionmentioning

confidence: 99%

Combining foam injection molding with batch foaming to improve cell density and control cellular orientation via multiple gas dissolution and desorption processes

Zhou

Chen

2020

Polymers for Advanced Techs

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In contrast to solid parts fabricated through conventional injection molding (CIM), foamed parts manufactured via foam injection molding (FIM) exhibit substantial variations in mechanical properties, which are attributed to differences in the cellular structure. In this study, parts with different cellular structures are fabricated via FIM, during which the gas dissolution and desorption processes are controlled by subjecting the gas‐laden melt to reciprocating compression and expansion operations. The results suggest that the cell density can be drastically improved by rapidly decreasing the pressure caused by the mold opening and that the cell orientation obviously occurs in the direction perpendicular to the mold‐opening direction. Moreover, the cell density and cellular orientation can be adjusted by utilizing appropriate mold opening and closing operations, leading to improvements in the resultant ultimate mechanical properties. In particular, the foamed samples fabricated with controlled mold opening‐closing operations exhibit excellent tensile strength and strain‐at‐break, indicating that samples containing a high density of cells oriented along the tensile test direction facilitate the formation of superductility and an increase in tensile strength. Hence, a method that combines FIM with batch foaming has been proposed for improving the cellular structure and controlling the cellular orientation.

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“…10,11 IFR is a category of additive halogen-free flame retardant system, which is always composed of acid source (dehydrating agent), carbon source (carbonific) and gas source (spumific material). [12][13][14] These sources can work together to form porous foamed charred layer in the combustion process, which acts as a barrier to protect the underlying polymer from damage caused by heat, oxygen and other pyrolysis products, thus extinguishing the fire. Generally, a high loading of IFR is needed to achieve good flame retardant effect, however, it is not conducive to the mechanical properties of the matrix, or even causes the severe deterioration of the toughness of polymer resin, which is related to the poor dispersion of IFR and poor interfacial adhesion between IFR and matrix.…”

Section: Introductionmentioning

confidence: 99%

Influence of modified ammonium polyphosphate on the fire behavior and mechanical properties of polyformaldehyde

Kang

Liu

Chen

et al. 2020

J of Applied Polymer Sci

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In this work, three kinds of APP, coated with melamine (MF-APP), silane (GW-APP), epoxy (MC-APP) were employed to compound with novolac resin (Novolac) and melamine (ME), aimed to study the effect of the modified APP on the flame-retardant performance, mechanical properties, and thermal stability of polyformaldehyde (POM). The results showed that composites with modified APP exhibited better flame retardant and mechanical performance than that with unmodified APP. In contrast, GW-APP had the best synergistic effect with Novolac and ME, and POM/GW-APP composites reached UL-94 V-0 rating and its limit oxygen index (LOI) value was up to 34.0%. The morphology of the carbon layer showed that the silane coating material can promote the charring process in condensed phase better than epoxy and melamine coating materials in flame retardant POM system, leading to the formation of integrated char layers with more quantity and higher quality, which effectively delayed the mass and heat transfer during combustion.

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Enhanced dispersion, flame retardancy and mechanical properties of polypropylene/intumescent flame retardant composites via supercritical CO2 foaming followed by defoaming

Cited by 56 publications

References 66 publications

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO₂

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO₂

Combining foam injection molding with batch foaming to improve cell density and control cellular orientation via multiple gas dissolution and desorption processes

Influence of modified ammonium polyphosphate on the fire behavior and mechanical properties of polyformaldehyde

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Enhanced dispersion, flame retardancy and mechanical properties of polypropylene/intumescent flame retardant composites via supercritical CO2 foaming followed by defoaming

Cited by 56 publications

References 66 publications

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO2

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO2

Combining foam injection molding with batch foaming to improve cell density and control cellular orientation via multiple gas dissolution and desorption processes

Influence of modified ammonium polyphosphate on the fire behavior and mechanical properties of polyformaldehyde

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Product

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Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO₂

Thermoplastic polyurethane (TPU) modifier to develop bimodal cell structure in polypropylene/TPUmicrocellular foam in presence of supercriticalCO₂