polymer compositepolymer - 2 composite 2

• In the case of an intercalate, the organic component is inserted between the layers of the clay such that the inter-layer spacing is expanded, but the inter-layers still bear a well-de

Ion-conducting polymer

2

Highly conductive solid polymer electrolytes (SPEs) will make a

dramatic impact on the electric and hybrid –electric vehicles (EV / HEV) industry by eliminating hazards related to the use of their

liquid counterparts.

Several approaches are being used to improve the ionic

conductivity of PEO-based SPEs In our studies, we have

synthesized and characterized a star-shaped borate ester

plasticizer which was then incorporated into the

polyethylene oxide polymer matrix in different proportions (Figure 1).

Proton-conducting polymer

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PLED (polymer light emitting diode)

Non-linear optics polymer

9

10

Liquid Crystal Display (LCD)

Liquid crystal

Liquid

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Liquid Crystal Molecules

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Composite materials

Composite materials (or composites) are engineering

materials made from two or more components

One component is often a strong fibre such as fiberglass, quartz, kevlar or carbon fiber that gives the material its tensile strength, while another component (called a matrix) is often a resin such

as polyester or epoxy that binds the fibres together, transferring load from broken fibers to unbroken ones and between fibers that are not oriented along lines of tension Also, unless the

matrix chosen is especially flexible, it prevents the fibers from buckling in compression Some composites use an aggregate

instead of, or in addition to, fibers

Composite materials

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A Cermet (金屬陶瓷) is a composite material composed of

ceramic (cer) and metallic (met) materials The metal is

used as a binder for an oxide, boride, carbide, or alumina Generally, the metallic elements used are nickel,

molybdenum, and cobalt Depending on the physical

structure of the material, cermets can also be metal matrix composites, but cermets are usually less than 20% metal

by volume

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Apatite is a group of minerals, with the formula

Ca5(PO4)3(F,Cl,OH)

Apatite is one of very few minerals which are produced and

used by biological systems Hydroxylapatite is the major

component of tooth enamel, and a large component of bonematerial

Fluorapatite is slightly stronger than hydroxyapatite; thus,

fluoridated water, which will allow exchange in the teeth of hydroxyl ions for fluoride ions, slightly strengthens the teeth

Hydroxyapatite (HA)

Hydroxyapatite (HA)

象牙質

琺瑯質

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造骨細胞

Biomimetic scheme of bioactive MCM-41 matrix as bone tissue engineering; useful in the preparation of bioceramic implants with previously adsorbed antibiotic and/or antinflammatory drugs, allowing treating locally the

infections or inflammatory response of the living tissue surrounding the

implantation area.

Solid State Sciences 7 (2005) 233–237

Phosphorous-doped MCM-41 as bioactive material

SEM micrographs and EDS analysis of MCM-41 and

P-MCM-41 samples before and after soaking in SBF

of an intercalated or exfoliated hybrid (Figure 1)

• In the case of an intercalate, the organic component is

inserted between the layers of the clay such that the

inter-layer spacing is expanded, but the inter-layers still bear a

well-defined spatial relationship to each other

• In an exfoliated structure, the layers of the clay have been completely separated and the individual layers are distributed throughout the organic matrix

• A third alternative is dispersion of complete clay particles

(tactoids) within the polymer matrix, but this simply represents use of the clay as a conventional filler

Figure 1 Formation of nanocomposites from layered

silicates and polymers

Clays and Clay Modifications

• Common clays are naturally occurring minerals and are

thus subject to natural variability in their constitution

• The purity of the clay can affect final nanocomposite

properties

• Many clays are aluminosilicates, which have a sheet-like

(layered) structure, and consist of silica SiO4 tetrahedra

bonded to alumina AlO6 octahedra in a variety of ways A

2:1 ratio of the tetrahedra to the octahedra results in smectite

clays, the most common of which is montmorillonite

• The thickness of the layers (platelets) is of the order of 1

nm and aspect ratios are high, typically 100-1500 The clay

platelets are truly nanoparticulate

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Mineral Ideal formulab CECc

b: x depends on the origin of the mineral; montmorillonites can show a degree of substitution x in the octahedral sheet in the range 0.05- 0.52 Natural samples generally show substitutions in both octahedral and tetrahedral sheets, which renders the real situations more complex

c: Cation-exchange capacity

• The clays are also characterised by their ion (e.g cation) exchange capacities, which can vary widely

• One important consequence of the charged nature of the clays is

that they are generally highly hydrophilic species and therefore

naturally incompatible with a wide range of polymer types

• A necessary prerequisite for successful formation of polymer-clay nanocomposites is therefore alteration of the clay polarity to make the clay ‘organophilic’

• An organophilic clay can be produced from a normally hydrophilic clay by ion exchange with an organic cation such as an

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• Although the organic pre-treatment adds to the cost of the clay, the clays are nonetheless relatively cheap feedstocks with minimal limitation on supply

• Montmorillonite is the most common type of clay used for

Factors Affecting the Type of Organo-Clay Hybrid Formed

• the exchange capacity of the clay

• the polarity of the reaction medium

• the chemical nature of the interlayer cations

Both thermosets and thermoplastics have been incorporated

into nanocomposites, including:

DOP: dioctyl phthalate, a plasticizer

• PVC shows significantly lower and broader glass

transition values with increased plasticizer content

• Effect of clay, however, is less obvious

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