Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/005—Reinforced macromolecular compounds with nanosized materials, e.g. nanoparticles, nanofibres, nanotubes, nanowires, nanorods or nanolayered materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes

Definitions

• Polymeric silsesquioxane resins, networked spherosilicates and oligomeric silsesquioxanes, and networked hybrid (inorganic-organic) materials have all been reported to afford materials with various degrees of porosity. Porous materials have great commercial utility as filters, membranes, for control of material transport, and for thermally and electrical insulative applications in electronics and construction. Molecular level control over the size, shape, and distribution of the porosity in such devices has not fully been achieved because building blocks with rigid and well defined structural elements have not been available.
• Nanoscopic POSS building blocks have been used to modify the surfaces of metals to improve their corrosion resistance and to compatibilize fillers, thus demonstrating their utility for surface modification. POSS building blocks have also been used to form immobilized catalysts upon incorporation into zeolites.
• This invention teaches the use of nanostructured POSS chemicals as agents for the introduction of nanoscopic pores into polymers and as porosity modifiers for macro- and nano- porous materials.
• the nanoscopic features provided by the POSS agents further serve to compatibilize and provide multi-scale levels of reinforcement in polymeric coatings, composites, zeolites, minerals, and nanocomposites.
• POSS-surface modification agents can be incorporated into polymers using compounding, reactive processing and grafting and can be applied to zeolites, mineral and fillers using all conventional coating techniques including slurry, coating, painting spraying, flowing and vapor deposition.
• a wide variety of POSS formula are readily available from commercial silane feedstocks.
• R organic substituent (H, siloxy, cyclic or linear aliphatic or aromatic groups that may additionally contain reactive functionalities such as alcohols, esters, amines, ketones, olefins, ethers or halides).
• X includes but is not limited to OH, Cl, Br, I, alkoxide (OR), acetate (OOCR), peroxide (OOR), amine (NR 2 ) isocyanate (NCO), and R.
• Nanostructured chemicals are defined by the following features. They are single molecules and not compositionally fluxional assemblies of molecules. They possess polyhedral geometries with well-defined three-dimensional shapes. Clusters are good examples whereas planar hydrocarbons, dendrimers and particulates are not.
• Molecular silicas refers to nanostructured chemicals that possess no reactive groups for grafting or polymerization.
• Figure 1 shows the anatomy of a POSS nanostructured chemical
• Figure 2 shows the physical size relationships of a traditional silane applied to a surface as a monolayer (left) and nanostructured coupling agents applies as monolayers
• Figure 3 illustrates inter and intramolecular free volume for a polymer chain
• Figure 4 illustrates accessible porosity relative to morphology in polymer systems
• Figure 5 shows examples of monodisperse molecular silicas
• Figure 6 illustrates a molecular silica alloyed into a polymer
• Figure 7 shows representative reduction of a zeolite pore by POSS.
• FIG. 1 A structural representation for nanostructured chemicals based on the class of chemicals known as polyhedral oligomeric silsesquioxanes (POSS) is shown in Figure 1.
• Their features include a unique hybrid (organic-inorganic) composition that possesses many of the desirable physical characteristics of both ceramics (thermal and oxidative stability) and polymers (processability and toughness).
• R organic substituent (H, siloxy, cyclic or linear aliphatic or aromatic groups that may additionally contain reactive functionalities such as alcohols, esters, amines, ketones, olefins, ethers or halides).
• X includes but is not limited to OH, Cl, Br, I, alkoxide (OR), acetate (OOCR), peroxide (OOR), amine (NR 2 ) isocyanate (NCO), olefin, and R.
• inorganic skeleton coupled with the peripheral groups combines to form chemically precise cubic-like low density building blocks that incorporated in to polymers via co-polymerization have been shown to improve gas diffusion and selectivity properties.
• a particularly advantageous feature provided by nanostructured surface modification agents, like POSS, is that a single molecule is capable of providing five times the surface area coverage relative to that provided by comparable silane coupling agents applied in the hypothetical monolayer fashion.
• Nanostructured Chemicals for Controlling Polymer Porosity The improvement of polymer permeabilities through copolymerization of POSS- monomers into acrylic resins has been demonstrated. This invention however teaches the use of POSS molecular silicas as porosity modification agents in polymers and in macroporous materials such as zeolites and molecular sieves.
• POSS's ability to occupy specific sites within the amorphous and crystalline region of polymers enables alteration of the size of the porosity contained within the polymer.
• the availability of a wide range of sizes of POSS nanostructures (cages) further augments this capability ( Figures 5, 6).
• POSS nanostructured chemicals possess spherical shapes, like molecular spheres, and because they dissolve and melt, they are also effective at reducing the viscosity of polymer systems. Viscosity reduction is desirable for the processing of highly filled and high viscosity plastics.
• the nonreactive incorporation of molecular silicas into polymers through conventional blending techniques greatly enhances the permeabilities of common plastics (Table 2).
• the degree of enhancement is dependent upon the size of the silicon-oxygen cage, the overall size of the nanostracture (R-group effects), the wt % (or volume %) of incorporation, and the interfacial compatibility between the polymer and the nanostructure.
• the ability to control and tailor these features affords permeability increases ranging from one to three orders of magnitude in common commercial grade polymers.
• the gas selectivity of these alloyed polymers can be controlled through a similar manipulation of these variables. In some cases both selectivity and permeability have been simultaneously improved relative to the base polymer. In all cases the incorporation of POSS-monomers, POSS-resins, molecular silicas results in the retardation of permeability for carbon dioxide relative to all other gases.
• HDPE 51 225 542 LDPE 219 610 3,294 —
• PP polypropylene
• HDPE high density polyethylene
• LDPE low density polyethylene
• PC polycarbonate
• Nanostructured Chemicals for Controlling Properties and Porosity of Zeolites POSS-reagents and in particular POSS-silanols are also proficient at coating the interior surfaces of minerals, zeolites and in particular layered silicates.
• the POSS-entity can effectively reduce the pore size openings and impart greater compatibility of the pore toward selective entry and exit of gases and other molecules.
• This enhanced compatibility directly results from the compatibilizing influence of the organic R-groups located on each of the corners of the POSS cage.
• the ability of these R groups to enable compatibility is directly derived from the principal of like dissolves like. This fundamental principal simply states that substances of like composition (or chemical potential) are more compatible than substances for dissimilar composition.
• POSS can modify silicates and other like materials and thereby compatibilize them with organic and inorganic compositions.
• POSS-silanols will bond to the interior (and exterior) surfaces of such materials through the elimination of water to form thermally stable covalent linkages. Once bound to the interior surface of a pore in a molecular sieve, the POSS will thereby reduce the effective diameter of the pore by an amount equal to its diameter. For example, the diameter of a 5A molecular sieve containing a POSS-silanol of diameter 1.5A would be effectively reduced to a pore size of 3.5 A. Pore size reduction in such materials would therefore render them effective for the separation of gases in accordance to their molecular or working diameters (Table 3). Table 3. Comparative molecular diameters and molecular weights of gases.
• the degree of pore reduction that can be accomplished through such a method is dependant upon the size of the silicon-oxygen cage and the overall size of the nanostructure.
• the interfacial compatibility of the POSS coated molecular sieve will also be enhanced through the choice of the R-group on the POSS nanostructure.
• gas separations based on Graham's law are conducted relative to the molecular weight of a gas molecule which typically results in a high separation rate but low selectivity. Alternately, gas separations base on Henry's law utilize solution diffusion and consequently have low separation rates. Gas separation based on nanoscopic pores or equivalent nanoscopic hole sizes offers both a high rate of separation and high selectivity.
• Alloying Polymers with Molecular Silicas Prior to compounding all molecular silicas and polymers should be predried at 60°C to 100°C under vacuum for three hours or via a similarly effective procedure to ensure removal of traces of water. Molecular silicas are introduced using a weight loss feeder at the desired wt % into the barrel of a twinscrew compounder containing polypropylene operating at 120RPM and operating at 190°C. The residence time can be varied from lmin to 10 min prior to extrusion and pellatization, grinding, or molding of the alloyed polymer.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Nanotechnology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Composite Materials (AREA)
• General Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Silicon Polymers (AREA)

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• 2006
  • 2006-02-14 EP EP06748210A patent/EP1848762A4/en not_active Withdrawn
  • 2006-02-14 WO PCT/US2006/005412 patent/WO2006086789A2/en not_active Ceased
  • 2006-02-14 JP JP2007555373A patent/JP2008530312A/ja not_active Ceased

Non-Patent Citations (1)

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