Synthesis and compressive behaviors of PMMA microporous foam with multi-layer cell structure

Zhou, Danfeng; Xiong, Yuanlu; Yuan, Huan; Luo, Guoqiang; Zhang, Jian; Shen, Qiang

doi:10.1016/j.compositesb.2018.11.118

Cited by 44 publications

(23 citation statements)

References 41 publications

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“…Zhou et al [10] prepared PMMA microporous foams with a multi-layer cell structure via a combination of multi-layer hot melt pressing and a supercritical carbon dioxide foaming method. Their results indicated that nucleation and the directional growth of the cells are promoted by the introduction of the multi-layer interface into the PMMA matrix.…”

Section: Research Progress Of Various Foaming Methodsmentioning

confidence: 99%

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Recent Trends of Foaming in Polymer Processing: A Review

et al. 2019

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Polymer foams have low density, good heat insulation, good sound insulation effects, high specific strength, and high corrosion resistance, and are widely used in civil and industrial applications. In this paper, the classification of polymer foams, principles of the foaming process, types of blowing agents, and raw materials of polymer foams are reviewed. The research progress of various foaming methods and the current problems and possible solutions are discussed in detail.

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Section: Research Progress Of Various Foaming Methodsmentioning

confidence: 99%

“…The processing techniques of polymer foams mainly include foam extrusion molding and foam injection molding. These molding methods with a supercritical fluid, such as carbon dioxide (CO 2 ) or nitrogen (N 2 ), can be foamed with lighter weight and higher-dimensional stability of polymer foams than their solid counterparts [9,10,11,12].…”

Section: Introductionmentioning

confidence: 99%

Recent Trends of Foaming in Polymer Processing: A Review

et al. 2019

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“…Foaming in thermoplastic polymers has attracted attention, since it provides the produced materials with a combination of desirable properties like thermal insulation and high specific strength, with low density [ 1 ]. Different foaming approaches like mechanical physical and chemical have been used [ 2 , 3 , 4 ]. The polymeric foams are also known as porous polymeric material, as they consist of a polymeric matrix, which contains an important number of small pores.…”

Section: Introductionmentioning

confidence: 99%

Injection Molded PP Foams Using Food Ingredients for Food Packaging Applications

et al. 2021

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A new approach to the creation of polypropylene (PP) based foaming materials was developed using food grade foaming agents that were coated on the PP pellets. More specifically, sodium bicarbonate and organic acids were used to coat PP pellets using either polyethyleneoxide (PEO) or lipid esters as coating stabilizers. In order to overcome the problem of the thermal decomposition of sodium bicarbonate at temperatures lower than the PP melting temperature, which makes the direct foaming during melt mixing impossible, the proposed methodology was proved quite efficient. Thus, new PP masterbatches were prepared, where the foaming agents were incorporated as coating at PP pellets at contents up to 10%, and initially used in Lab scale injection machines in order to find the best combination of materials that resulted in the production of foamed articles. Subsequently selected material combinations were tested in an industrial scale injection molding machine, where an optimization of the injection parameters was attempted. The outcome of this was the production of PP articles with significantly increased void fraction, up to 14%, decreased thermal conductivity, up to 20%, and various pore sizes as was observed via microscopic examination using SEM and CLSM.

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“…Supercritical CO 2 (scCO 2 ) is an environmentally friendly solvent and blowing agent in a wide range of applications including polymerization [15,16], polymer purification [17] and foaming [2,10,18,19], coating applications, heating transfer [20], and powder formation [21], which attributed to its characteristics of chemical inertness, non-toxicity, near-zero surface tension, great penetration ability, moderate supercritical condition, and low cost [22]. ScCO 2 has been demonstrated to be an environmentally friendly alternative in some applications owing to its penetrating and swelling effects.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Changes of Aramid Fiber Due to Reaction with Toluene 2,4-diisocyanate under Tension in scCO2

Kong

2019

Polymers

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High modulus aramid fiber, such as Kevlar 49, is conventionally prepared by the heat annealing of high strength aramid fiber under a suitable tension at high temperature, especially higher than 500 °C. This enables the mobility of a rigid molecule chain to be rearranged into a more perfect crystalline or orientation structure under tension. However, annealing decreases the tensile strength, since the thermal degradation of the molecular chain at high temperature cannot be avoided. Kevlar 49 fibers treated in supercritical carbon dioxide (scCO2) under tension could improve their mechanical properties at a low temperature. The effects of the tension on the mechanical properties and structure of the Kevlar 49 fibers were studied by mechanical testing, wide-angle and small-angle X-ray scattering (WAXS, SAXS), and scanning electron microscopy (SEM). The results show that the mechanical properties, crystallinity and orientation of the fiber can be improved when the tension is less than 0.6 cN/dtex, which may be due to the increasing of the mobility of a rigid segment with the help of the plasticization of scCO2 and re-arrangement of macromolecular chain into crystalline and orientation structure under tension. What’s more, the amorphous region also was enhanced by crosslinking reaction of toluene 2,4-diisocyanate (TDI) with the chain end groups of the macromolecules in the amorphous regions. However, a decrease of tenacity was found when the tension was higher than 0.6 cN/dtex, which is because the tension was so high that the microfibril was broken. The results indicated that treating the Kevlar 49 fiber in scCO2 under a suitable tension with TDI as a crosslink agent can simultaneously improve both the tenacity and modulus of the fiber.

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Synthesis and compressive behaviors of PMMA microporous foam with multi-layer cell structure

Cited by 44 publications

References 41 publications

Recent Trends of Foaming in Polymer Processing: A Review

Recent Trends of Foaming in Polymer Processing: A Review

Injection Molded PP Foams Using Food Ingredients for Food Packaging Applications

Microstructural Changes of Aramid Fiber Due to Reaction with Toluene 2,4-diisocyanate under Tension in scCO2

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