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Applications of PMC


ramie. jute. hemp. flax. E-glass. Fibre. Properties ... fibres (flax, hemp, jute, kenaf, ramie (china grass)) - the bast consists of ... – PowerPoint PPT presentation

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Title: Applications of PMC

Applications of PMC
PMC for electronics
  • Alternative names are printed wiring board (PWB)
  • Printed circuit boards, or PCBs, are used to
    mechanically support and electrically connect
    electronic components using conductive pathways,
    or traces, etched from copper sheets laminated
    onto a non-conductive substrate
  • Most PCBs are composed of between one and
    twenty-four conductive layers separated and
    supported by layers of insulating material

Printed Circuit Board (PCB)
Printed Circuit Board (PCB)
  • Layers may be connected together through drilled
    holes called vias
  • Some PCBs have trace layers inside the PCB and
    are called multi-layer PCBs

SR (Solder Resist)
PTH (Plated Through Hole) with plugging material
PCB- Core
  • Made of woven textile-E glass reinforcement
    reinforced epoxy designated as FR-4
  • Why continuous fiber is used as core in PCB?

PCB-Solder Resist
  • Areas that should not be soldered to may be
    covered with a polymer solder resist (solder
    mask) coating
  • The solder resist prevents solder from bridging
    between conductors and thereby creating short
  • Solder resist also provides some protection from
    the environment.

  • The walls of the holes, for boards with 2 or more
    layers, are plated with copper to form
    plated-through holes
  • Function electrically connect the conducting
    layers of the PCB

Electrical Conductive Adhesives
  • Alternatives to solder interconnection.

Metal filled polymer composites
  • Metal fillers act as conductive path to conduct
    heat and electric in the composites

Thermal Conductivity Silver (Ag) Copper
(Cu) Aluminium (Al) Gold (Au) Nikel (Ni)
Electrical Conductivity Silver (Ag) Copper
(Cu) Gold (Au) Aluminium (Al) Nikel (Ni)
Typical dependence of electrical conductivity
(logarithm) on conductive filler volume fraction
Sharp conductivity increase occurs within the
concentration region fc1ltfltfc2 . This
phenomenon is called percolation threshold
Insufficient physical contact of metal fillers
  • The percolation behavior is primarily affected
  • particle size (nano micron size)
  • shape of the filler (flake, spherical, etc)
  • filler particle distribution (segregated or
  • Filler concentration
  • Oxide layer thickness

Example Polyimide Electrically Conductive Die
Attach Adhesive
  • silver filled, electrically conductive polyimide
  • This product is designed for die attachment and
    surface mount applications. Other applications
    include, but are not limited to assembling
    electrical and electronic components.
  • The cure schedule allows for rapid processing and
    the resulting bond exhibits excellent thermal
    stability and adhesion at high temperatures.
  • APPLICATIONS Die attachment Printed
    circuit board fabrication Sealing and high
    performance coatings Advanced material

PMC as Underfill Encapsulant Materials
  • Typically are silica-filled epoxies
  • Underfill encapsulants were
  • developed to encase flip-chip ICs
  • A flip chip has a lower coefficient of thermal
    expansion (CTE) than the substrate onto which it
    is assembled.
  • During thermal cycling, this CTE mismatch results
    in movement of the flip chip, board and
    mechanical fatigue of solder joints. Cyclic
    fatiguing eventually ends in IC failure.
  • An encapsulants effectiveness is measured by its
    ability to delay or prevent failures.

PMC for automotives
  • Composites are being used more and more in the
    automotive industry
  • Due to their strength, weight, quality and cost
  • Many automotive components are already produced
    in natural composites, mainly based on polyester
    or PP and fibres like flax, hemp or sisal.
  • The adoption of natural fibre composites in this
    industry is lead by motives of a) price b) weight
    reduction and c) marketing ('processing renewable
    resources') rather than technical demands

The use of natural fibres in automotive
industries has grown rapidly over the last 5
years, see Table 2
  • Table 2 The use of natural fibres in automotive

Interior part pf Mercedes A-200 made By natural
mat thermoplastic
In 1999, natural fibres used in the automotive
industries comprised 75 percent flax, 10 percent
jute, 8 percent hemp, 5 percent kenaf and 2½
percent sisal.
Table 1 Properties of glass and natural fibres
tensile strength strongly depends on type of
fibre, being a bundle or a single filament
Natural Fibers
  • Bast fibres (flax, hemp, jute, kenaf, ramie
    (china grass)) - the bast consists of a wood core
    surrounded by a stem. Within the stem there are a
    number of fibre bundles, each containing
    individual fibre cells or filaments. The
    filaments are made of cellulose and
    hemicellulose, bonded together by a matrix, which
    can be lignin or pectin

Natural Fibers
  • Leaf fibres (sisal, abaca (banana), palm) - In
    general the leaf fibres are coarser than the bast
    fibres. Applications are ropes, and coarse
    textiles. Within the total production of leaf
    fibres, sisal is the most important.

Natural Fibers
  • Seed fibres (cotton, coir, kapok)
  • Cotton is the most common seed fibre and is used
    for textile all over the world. Other seed fibres
    are applied in less demanding applications such
    as stuffing of upholstery. Coir is an exception
    to this. Coir is the fibre of the coconut husk,
    it is a thick and coarse but durable fibre.
    Applications are ropes, matting and brushes.

  • Acrylic cement is used for the fixation of total
    joint prosthesis
  • The cements used in orthopedic surgery are
    combination of prepolymerized PMMA solid particle
    and the liquid monomer
  • The powder particles are sphere (30 to 150 µm in
    diameter), molecular weight of 20,000 to 2
  • For the reaction to occur,prepolymerized PMMA
    needs to contain an initiator, dibenzoyl
    perioxide (BP)

  • Bone cement, or poly(methyl methacrylate) (PMMA),
    is commonly used to anchor hip prostheses in the
  • The material is very brittle, however, and prone
    to fracture, fatigue and wear.

PMC for Medical Applications
  • Currently PMMA is the polymer most commonly used
    as a bone cement for the fixation of total hip
  • Ideally, a bone cement material should be easy to
    handle, biologically compatible, nonsupporting of
    oral microbial growth, available in the
    particulate and molded forms, easy to obtain,
    nonallergenic, adaptable to a broad range of
    dental and medical applications, in possession of
    high compressive strength, and effective in
    guided tissue regenerative procedures.

Problems of PMMA Bone Cement
  • Strong exothermic setting reaction
  • Toxic effect of the monomer
  • Inability to bond directly to bone - caused
    loosening at the interface
  • Brittle nature
  • - To overcome these problems, many types of
    bioactive bone cements have been developed.

  • To improve the biochemical properties of PMMA
    bone cement, many types of bioactive particle
    fillers have been added into the cement
  • Example of particle fillers are glass ceramic,
    titania (anatase rutile), etc

Recent studies on Bone Cement titania particles
(K. Goto et al., Biomaterials 26 (2005))
Figure (c) Shows direct Contact Between bone
(B) And Cement (C), while Figure (b) Shows
soft Tissue layer Less than 10 um. The
soft Tissue layer In (a) and (d) Is thicker Than
(b) and (c)
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