Preparation of Colloidal Low-Density Polyethylene Latexes by Flow-Induced Phase Inversion Emulsification of Polymer Melt in Water

Akay, G.; Li, Tong

doi:10.1006/jcis.2001.7615

Cited by 29 publications

(28 citation statements)

References 30 publications

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“…It was also used to remove the evolved gases (NO x ). Further details of the Haake Rheometer and Rheomix in this type of operation is available [22]. Two types of experiments were carried out; either using uncoated silica particles or coated silica dispersion (Bindzil CC30) in both cases the size of silica particles were identical at 7 nm.…”

Section: Preparation Of Silica Supported Cobalt Catalyst Using the Hamentioning

confidence: 99%

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Akay

2016

Catalysts

106

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Abstract:A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV) induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m 2 /g and X-ray Diffraction (XRD)-based catalyst size controlled in the range of 1-10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied) when the catalyst/support molar ratio is typically 0.1-2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) studies, the micro-and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6-2 nm thick lamellar sheets of 10-100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm 3 . A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano-particles dispersed in water which also contains the catalyst precursor nitrate salt. This support-catalyst precursor fluid must have a sufficiently low viscosity but high elastic modulus (high extensional viscosity) to form films and bubbles when exposed to processing energy sources such as microwave, thermal, ultra-sound or UV-radiation or their combination. The micro-to-nano structures of the catalyst system are essentially formed at an early stage of energy input. It is shown that the primary particles of silica are transformed to a proto-silica particle state and form lamellar structures with the catalyst precursor. While the nano-structure is forming, water is evaporated leaving a highly porous solid support-catalyst precursor which then undergoes decomposition to form a silica-catalyst oxide system. The final catalyst system is obtained after catalyst oxide reduction. Although the XRD-based catalyst size changes slightly during the subsequent heat treatments, the nano-structure of the catalyst system remains substantially unaltered as evaluated through TEM images. Howev...

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Section: Preparation Of Silica Supported Cobalt Catalyst Using the Hamentioning

confidence: 99%

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Akay

2016

Catalysts

106

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“…Either of the two phases in an oil-water system, containing non-ionic surfactant, can become the continuous phase, depending on the system's composition and processing history [9,10]. Emulsification of polymers, either as resins or as polymer melts, can also be achieved by changing the thermodynamic and/or deformation variables [5,11]. In the case of PUI phase inversion has been described as a stage-wise process [7].…”

Section: Introductionmentioning

confidence: 98%

Catastrophic phase inversion in region II of an ionomeric polymer–water system

Saw

Brooks

Carpenter

et al. 2004

Journal of Colloid and Interface Science

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“…Block co-polymers from stearyl methacrylate and DMAEMA exhibit self-organising behaviour in different organic solvents [4]. Water soluble polymers containing long aliphatic side chains have the potential to be used as dispersing agents for strongly hydrophobic materials such as polyethylene in water [5]. In water solution, amphiphilic polymers form aggregates and these can be identified with rheometry [6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and solution rheology of poly[(stearyl methacrylate)-stat-([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide)]

Vesterinen

Rich

Seppälä

2010

Journal of Colloid and Interface Science

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Preparation of Colloidal Low-Density Polyethylene Latexes by Flow-Induced Phase Inversion Emulsification of Polymer Melt in Water

Cited by 29 publications

References 30 publications

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Catastrophic phase inversion in region II of an ionomeric polymer–water system

Synthesis and solution rheology of poly[(stearyl methacrylate)-stat-([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide)]

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