TABLE OF CONTENTS
Title Page————————————————————————————–ii
Declaration———————————————————————————–iii
Certification ———————————————————————————-iv
Acknowledgement —————————————————————————v
Dedication ————————————————————————————vi
Table of contents—————————————————————————-vii
List of Tables———————————————————————————xi
List of Figures——————————————————————————-xii
List of plates——————————————————————————–xiv
Abstract ————————————————————————————xvi
CHAPTER ONE
1.0 General Introduction——————————————————————-1
1.1 Natural Polymers (agro wastes)——————————————————6
1.1.1 Corn cob———————————————————————————6
1.1.2 Rice Husk——————————————————————————7
1.1.2.1 Water Imbibition:——————————————————————–8
1.1.2.2 Industrial uses———————————————————————-9
1.1.3 Saw Dust——————————————————————————9
viii
1.2 Background of Study—————————————————————-10
1.3 Scope of Study————————————————————————11
1.4 Importance of Work——————————————————————11
1.5 Literature Review——————————————————————–13
1.5.1 Selection of Borohydride Reducing Agent—————————————16
1.5.1.1 The Borohydride (BH) ion——————————————————–16
1.5.2 The Amine Boranes——————————————————————17
1.5.3 Complexing Agents—————————————————————–18
1.5.4 Stabilizers—————————————————————————-19
1.5.5 Electroless Catalyst Selection—————————————————–20
1.5.6 Non- Noble Metal Application—————————————————-23
1.5.7 Timeline of Printed Circuit Board Manufacture——————————–23
CHAPTER TWO
Materials And Methods——————————————————————–24
2.0 Experimental————————————————————————-24
2.1 Board Materials———————————————————————24
2.1.1 Synthetic—————————————————————————–24
2.1.1.1 Polyvinyl Chloride Sheet———————————————————-24
2.2 Natural ——————————————————————————-24
ix
2.3 Reagents/Chemicals—————————————————————-25
2.4 Equipment—————————————————————————-26
2.5 Analysis ——————————————————————————26
2.6 Process Steps ————————————————————————28
2.6.1 Process Flow Chart —————————————————————–31
2.7 Water Absorption/Imbibition And Thickness Swelling Test —————–32
2.8 Electroless Plating ——————————————————————33
2.8.1 Preparation of Cleaning Solution ————————————————-34
2.8.2 Preparation of Etchants ————————————————————34
2.8.3 Neutralizer —————————————————————————34
2.8.4 Activating Colloid ——————————————————————34
2.8.5 Developer —————————————————————————-35
2.9 Electroless Copper Bath ———————————————————–35
CHAPTER THREE
3.0 Results And Discussion————————————————————-38
3.1 Pictures of Samples produced—————————————————–38
3.2 Peel Test——————————————————————————42
3.3 Results Obtained for Strength of Materials, Water Imbibition And
Physical Properties of Samples—————————————————-44
x
3.3.1 Bending Strength ——————————————————————-44
3.3.2 Tensile strength———————————————————————-52
3.3.3 Moisture Absorption/Water Imbibition——————————————63
3.4 Scanning Electron Microscopy—————————————————-71
3.4.1 Surface Morphology of Corn Cob Sample—————————————72
3.4.2 Surface Morphology of Rice Husk Sample————————————–74
3.4.3 Surface Morphology of Saw Dust Sample—————————————76
3.4.4 Surface Morphology of PVC Sample———————————————77
3.4.5 Surface Morphology of Control Sample—————————————–73
3.5 Application of Scanning Electron Microscopy———————————-79
CHAPTER FOUR
4.0 Conclusions and Recommendations ———————————————82
REFERENCES——————————————————————————84
BIBLIOGRAPHY—————————————————————————90
xi
LIST OF TABLES
Table Title Page
Table i Composition of Electroless Baths Used———————————-35
Table ii Effect of Deposition Time on Peeling
Characteristic of Samples—————————————————43
Table iii Some physio-Mechanical Properties
of Sample PVC Sheet Used for Cladding——————————–44
Table iv Bending Strength Test Result for Saw Dust Samples——————45
Table v Bending Strength Test Result for Rice Husk—————————-47
Table vi Bending Strength Test Result for Corn Cob—————————–49
Table vii Tensile strength of Melamine-Formaldehyde Resin Bound
Saw Dust Samples———————————————————-53
Table viii Tensile strength of Melamine-Formaldehyde Resin Bound
Rice Husk Samples———————————————————-56
Table ix Tensile Strength of Melamine-Formaldehyde Resin Bound
Corn Cob Samples———————————————————–60
Table x Degree of Water Imbibition And Increase in Size of Saw
Dust with Melamine-Formaldehyde Resin Samples——————–64
Table xi Degree of Water Imbibition And Increase in Size of
Rice Husk Melamine-Formaldehyde Resin Samples——————-66
Table xii Degree of Water Imbibition And Increase in Size of
Corn Cob Melamine-Formaldehyde Resin Samples——————–68
xii
LIST OF FIGURES
Figures Title Page
1 Thickness vs. Time-Comparison between Electroless and
Immersion Deposition. ————————————————————-15
2 A Simplified flowchart of the Laboratory Production of
Particle Board from Agro Wastes.————————————————31
3 A flow Chart of the Stages of Treatment.—————————————–31
4 Schematic Representation of Quick Spot Test to Ascertain
the Deposition of Conducting Metal on the Surface of the Substrates——40
5 Diagram Showing the Peel Test Process——————————————42
6 Plot of Bending Strength of Boards Against % Resin Conc.
for Saw Dust Samples————————————————————–46
7 Plot of Load at Rupture of Boards Against % Resin Con. for
Saw dust Samples——————————————————————-47
8 Plot of Bending Strength of Boards Against % Resin Conc.
for Rice Husk Samples————————————————————-48
9 Plot of Load at Rupture of Boards Against % Resin Con. for
Rice Husk Samples——————————————————————48
10 Plot of Bending Strength of Boards Against % Resin Conc.
for Corn Cob Samples————————————————————-49
11 Plot of Load at Rupture of Boards Against % Resin Con. for
Corn Cob Samples——————————————————————50
12 Plot of Breaking Load of both Clad and Unclad Boards
Against % Resin Conc. for Saw Dust Based Samples————————–51
13 Plot of Extensibility of Samples Against Resin Conc. for
both Clad and Unclad Boards for Saw Dust Based Samples——————51
xiii
14 Plot of Breaking Load of both Clad and Unclad Boards
Against % Resin Conc. for Rice Husk Based Samples————————-54
15 Plot of Extensibility of Samples Against resin Conc. for both
Clad and Unclad Boards for Rice Husk Based Samples———————–55
16 Plot of Breaking Load of both Clad and Unclad Boards
Against % Resin Conc. for Corn Cob Based Samples————————-57
17 Plot of Extensibility of Samples Against Resin Conc. for
both Clad and Unclad Boards for Corn Cob Based Samples——————58
18 Plot of Resin conc. in Relation to Density and Relative
Amount of Water Absorbed by Samples for Saw Dust————————58
19 Plot of Resin Conc. in Relation to Density of Material and Relative
Amount of Water absorbed by Samples for Rice husk.———————-59
20 Plot of Resin Conc. in Relation to Density and Relative
Amount of Water Absorbed by Samples for Corn Cob.———————–61
21 Plot of Extensibility Against Resin Conc. for both
Clad and Unclad Boards for corn cob Based samples————————–62
22 Comparative Plot of Relative Extension against % Resin Conc.
for Unclad Agro waste Boards—————————————————-63
23 Comparative Plot of Relative Extension against % Resin Conc.
for Clad Agro waste Boards——————————————————-63
24 Plot of Resin Conc. in Relation to Density and Relative
Amount of Water Absorbed by Samples for Saw Dust————————65
25 Plot of Resin conc. in Relation to Density and Relative
Amount of Water Absorbed by Samples for Rice Husk———————–67
26 Plot of Resin conc. in Relation to Density and Relative
Amount of Water Absorbed by Samples for Corn Cob————————69
xiv
LIST OF PLATES
PLATES TITLE PAGE
Plate 1 Pictorial Set-Up for Production of Melamine
Formaldehyde Resin in the Laboratory———————————-30
Plate 2 The Electrical Thermostatically Controlled Carver
Hydraulic Press Used for Production of Board Samples—————31
Plate 3 Mini Electroless Copper Line (tabletop unit)—————————-37
Plate 4 A Battery of Plastic Containers Improvised As
Process Tank for Electroless plating of Samples ———————–37
Plate 5 Sample PVC Boards Arranged in the Order of Treatment
from Left to Right, Unclad to Clad—————————————38
Plate 6 Sample PVC Boards Arranged in the Order of Treatment
from Left to Right, Unclad to Clad—————————————38
Plate 7: Sample Saw Dust Boards Arranged in the Order of Treatment
from Left to Right, Unclad to Clad—————————————-39
Plate 8: Virgin unpopulated Printed Circuit Board with Circuit
Patterns Sketched.———————————————————–39
Plate 9a: Spot Test Confirmation of Conducting Metal Deposition Using the
Commercial Board ———————————————————-41
Plate 9b: Spot Test Confirmation of Conducting Metal Deposition using
the PVC Board Sample—————————————————–41
Plate 9c: Spot Test Confirmation of Conducting Metal Deposition using
One of Agro-Waste Samples———————————————–41
Plate 10: Process of Bending Strength Determination Using The UTM——–44
Plate 11: Universal Testing Machine from Micro vision Inc. India.————-52
Plate 12: Process of Tensile Test Determination Using The UTM—————51
xv
Plate 13: Corn Cob Samples of Selected Spot Magnifications——————–67
Plate 14: Rice husk Samples of Selected Spot Magnifications—————–68
Plate 15: Saw Dust Samples of Selected Spot Magnifications—————–70
Plate 16: PVC Samples of Selected Spot Magnifications———————–76
Plate 17 : Control Samples of Selected Spot Magnifications——————–77
Plate 18: Contrast of Sample Surfaces’ Topography w.r.t. Roughness————78
Plate 19 : Surface Morphology of CuCl2Mg02/HCI etch
Showing Wettability/Solderability Potentials—————————80
Plate 20: Surface Morphology of CuCl2Mg02/HCI Unetched
Showing Wettability/Solderability Potentials ————————–80
Plate 21: Surface Morphology of FeCI/HCI etched———————————-80
Plate 22: Surface Morphology CuCl2M202/HCI etched—————————–80
xvi
ABSTRACT
The use of printed circuit board is unavoidable within the electrical and electronic
industries. Various types and models exist, all made from synthetic substrates. The
environmental impact of discards of printed circuit boards as well as the need to go
green globally poses challenges to the printed circuit board manufacturing
industry. In the attendant search for wider utility value for agro-waste based
particle boards, this work presents the research of utilizing agro-waste based
particle boards as virgin substrates for the production of printed circuit board
wafers. The agro-waste materials were pre-treated, ground and pressed into boards
using a Novalac resin (Melamine- formaldehyde). After cutting to sample sizes, the
samples were cleaned and electroless deposition was carried out on the boards
using non-precious metal catalyst ( as against the conventional precious metal
catalyst-Palladium). Material strength characterization of the boards was carried
out to determine the durability of samples when in use. Scanning electron
microscopy of the samples showed good deposition and acceptable roughened
topography which compared well with that of a commercial grade sample. A
simple conductivity test was done with an ammeter to prove the transfer of
electrical current at the surface of the substrates. This phase of work concludes that
there can be deposition on natural waste materials and that going ‘green’ in the
area of circuitry is achievable. Optimization of process conditions will create
another niche for the use of conversion products from agro waste discards while
giving the products a value-added status.
1
CHAPTER ONE
INTRODUCTION
1.0 GENERAL INTRODUCTION
Printed circuit boards are boards used in the connection of lead lines of various electronic
parts/components. Such important circuitry parts like resistors, capacitors, transistors are
housed and connected using metal-clad non-conducting substrates and the whole network
is known as a printed circuit board(1). These boards are made in three basic structural
classes, (i) with a shield or earth plate; (ii) with a multilayer structure; and (iii) as a thin
film, single layer. They are pathways made of copper or some other conducting material
that is etched or laminated onto a rigid or flexible surface. The “printed” means that the
material is deposited onto the substrate and the discrete wires are not used.
The search for printed circuit boards dates back to the 19th century when telegraph,
telephone and radio inventions were being recognized as practical devices for everyday
use and they all required wiring connections(2). For example, the increasingly complex
radio circuits needed an alternative wiring technology which ought to be simpler than the
existing tedious and error prone wiring technology. As a result, in 1903, Albert Hanson
(3) filed a printed wire patent which was to solve the problem of multi-wire connection
dilemma. His patent clearly described the concept of double-sided through–hole circuitry.
This first circuit pattern touched on so many concepts that are seen to be of modern
origin.
Printed circuit board is synonymous to printed wiring board which is undoubtedly the
most common type of printed circuit. It is a copper-clad dielectric material with
conductors etched on the external or internal layers. It is subdivided into single-sided,
double-sided, and multilayer boards.
2
It performs structural, functional and aesthetic duties in any electronic device, while
ensuring safety and convenience in the handling of point-to-point lead line linkages.
There are five primary types of this board, depending on the desired utility in the
electronic circuitry. These five types are:
1. Motherboard: This is the board that forms the principal circuit board in the
circuitry and it houses the basic components of the system.
2. Expansion board. This is a printed circuit board that plugs into an expansion slot
present alongside the mother board. This board compliments the utility of the
mother board.
3. Daughter board. This is a board that attaches to an expansion board as a
supplementary utility board
4. Network Interface Card (NIC). This is a type of expansion board that is mostly
found in personal computers (PC). It enables the PC to be connected to a local area
network. It is a connector circuit board.
5. Adaptor. This is a type of expansion board that controls the graphics monitor
because it houses the controller chip.
The top side of a printed circuit board is referred to as ‘component side and the bottom
side the ‘solder side’. The components are located on one side of the board and the
conductor pattern on the opposite side necessitating the making of hole (through hole) in
the PCB for the component legs to penetrate the board. Consequently the legs are
soldered to the PCB on the opposite side of where the components are mounted. There
are oftentimes the need for complex PCB designs as a result of product utility and this
prompted the designing and manufacture of PCB boards of various ‘face’ categories(4).
These categories are:
3
1. Single Sided: These are boards that have only the conductor pattern on one side
and the components mounted on the other side. This type of board has serious
limitation with respect to the routing of the wire in the conductor pattern
because the wires cannot cross and have to be routed around each other. This
category of board design is only used in very primitive circuits (5).
2. Double –sided: These are boards with a conductor pattern on both sides of the
board. They have electrical connection between two conductor patterns, this
electrical bridges are called ‘vias’ which are holes in the PCB that are filled
with metal and touches the conductor pattern on both sides. This type of PCB
design is suited for complex circuits.
3. Multi-layer boards: There are boards with one or more conductor patterns inside
them. The multilayer is achieved by laminating several double – sided boards
together with insulating layer in between. The number of layers is known from
the number of separate conductor patterns and is usually even and includes the
two outer layers. The most common ones are the 4 and 8 layers, though some
with as many as 100 layers are obtainable(6). The ‘vias’, which connects the
conductor patterns, becomes a hindrance when only a few of the conductors are
needed in service. Therefore, ‘buried’ and ‘blind’ vias types are used in multilayer boards. This is feasible because the ‘buried’ and ‘blind’ vias are produced
in such a way that they only penetrate as many layers as are necessary. The
blind vias connects one or more of the inner layers with one of the surface
layers without penetrating the whole board, while ‘buried’ vias only connects
the inner layers.
In multi-layer PCBs, whole layers are almost always dedicated to ground and power and
are classified as signal, power or ground planes (7). In situations where it is necessary to
4
have the different components on a PCB connected to different supply voltages, there is
usually more than one of both power and ground planes.
Printed circuit board (PCB) substrates are materials that are polymeric, which perform
the function of structural platforms/bases for the mounting of electronic units in the
electronic industry (8). Literarily, from the definition of the two component make-up of
the phrase, “PCB substrates”, are materials of large number of structural units that are
joined by the synergy of linkages, which forms a stratum on which is mounted electronic
units that collectively make-up a system’s circuit. These supports are nonconductors/dielectrics that are dimensionally, thermally and chemically stable when in
use. The choice properties of such materials are:
a. high dielectric strength
b. low dielectric constant,
c. good flexural strength
d. low thermal coefficient of expansion
e. high resistance to humidity and
f. possession of high degree of fire retardancy
The use of polymers (plastics) as substrate in plating process can be traced back to
the plating of celluloid pen parts in 1905, where electroless silver solution was applied to
the surface of the celluloid material after a stannous chloride sensitization of the surface
of the plastic(9). Some of the advantages of using polymers in place of metals in plating
processes are:
5
a. Plastics give extended shelf life because only the surface of a plated plastic is
prone to corrosion whereas all parts of a metal corrode with an eventual failure
in service (10).
b. The plastics require no other production finishing steps such as buffing, before
plating, whereas metals require such steps and this increases the overall cost of
production.
c. When plastics are plated on, they acquire improved tensile strength, elasticity
and flexural strength, with a reduced total coefficient of thermal expansion. The
plastic material also has an enhanced abrasion and weathering resistance.
Some examples of platable plastics are:
i. acrylonitrite butadiene – styrene (ABS)
ii. poly (phenylene ether)
iii. nylon
iv. polysulfone
v. polypropylene
vi. polycarbonates
vii. Phenolics
viii. Polycarbonate – ABS alloys
ix. Polyesters
x. Foamed polystyrene
xi. Phenolic-paper
xii. Epoxy-paper
xiii. Polyester-glass
xiv. Polyimide glass,
xv. Poly(vinyl chloride)
xvi. Poly(ethersulfone)
6
xvii. Polyetherimide
xviii. Polyetherketone etc.
1.1 NATURAL POLYMERS (agro wastes)
These materials are wastes from the agricultural sector. Most of them have little or
limited utility values. They all have a common base raw material which is cellulose.
These materials are (a) corn cob, (b) saw dust and (c) rice husk.
1.1.1 CORN COB
A corncob is the central core of a maize (Zea mays ssp. mays L.) ear. The corn
plant’s ear is also considered a “cob” or “pole” but it is not fully a “pole” until the ear is
shucked, or removed from the plant material around the ear. Historically, corn cobs were
used in outhouses in lieu of toilet paper, source of furfural( an aromatic aldehyde used in
a wide variety of industrial processes), as fibre in ruminant fodder, smoking pipes. It
contains not less than 40% phosphorus as P205 (ash). The principal chemical constituents
of corn cobs are cellulose, pentosan and lignin. These are mainly from the wood blast and
cortical layers of the cob. Cellulose and lignin are usually good for board manufacture
while the pentosan content of 20.6 percent shows that the corn cobs could be used in the
manufacture of furfurals and other products(11).
The absence of acid and extractive content shows that the board properties may
not be affected because their presence affects board quality ( 12). It is therefore, assumed
7
tentatively that corn cobs might be suitable raw material for particle board manufacture.
The various production steps involved are outlined using the flow chart.
1.1.2 RICE HUSK
Rice husk/hull is a “biogenic opal,” with approximately 20% opaline silica in
combination with a large amount of the phenylpropanoid structural polymer called lignin.
The silica which is amorphous is bound to water in a very intricate manner. This high
percentage of opaline silica within rice hulls is most unusual in comparison to other plant
materials(13 ). It is proposed(14 ) that during the combustion of rice hulls, the silica ash
may form a “cocoon” that prevents oxygen from reaching the carbon inside thereby
retarding burning. Another viewpoint(15 ) is that, since silica and carbon may be partially
bonded at the molecular level, silicon carbide is formed during high-temperature
combustion, and that the presence of this heat-resisting ceramic impedes the easy
combustion of the rice hull. Still other scientists project that at certain temperatures, the
molecular bond between the silica and carbon in the hull is actually strengthened, thereby
preventing the thorough and uniform burning of the hull. This flame-retarding and, at
ordinary temperatures, self extinguishing character as a result of the peculiar silicacellulose structure, impede uniform and thorough burning in a combustion process and
also ensures resistance to water penetration and fungal attack.
Attributes:
a) They are highly resistant to moisture penetration and fungal decomposition.
b) They do not transfer heat very well.
c) They do not smell or emit gases.
d) They are not corrosive with respect to aluminum, copper or steel where corrosion is
induced/propagated by either alkaline or acidic environmental conditions.
8
In their raw and unprocessed state, rice hulls constitute a Class A or Class I insulation
material( 16). It is a by-product with very low protein and available carbohydrates, but
contains very high crude fiber, crude ash and silica. Of all cereal byproducts, the rice hull
has the lowest percentage of total digestible nutrients (less than10%) ( 17). Surprisingly,
rice hulls require no flame or smolder retardants. Nature has freely given to this
agricultural waste product all of the combustion properties needed to pass the Critical
Radiant Flux Test (ASTM C739/E970-89), the Smoldering Combustion Test
(ASTMC739, Section 14), and the Surface Burning Characteristics Test (ASTM E84).
Recent testing( 18) done by R&D Services indicates an average Critical Radiant Flux
(CRF) of 0.29W/cm2
, a smouldering combustion weight loss between 0.03% and 0.07%,
a Flame Spread
Index (FSI) of 10 and a Smoke Development Index (SDI) of 50.
1.1.2.2 Water Imbibition:
All organic materials will absorb or release moisture until they come into equilibrium
with the relative humidity of the surrounding air. The high concentration of opaline silica
on the outer surface of the rice hull impedes the atmospheric transfer of moisture into the
hull. Also, 2.1% to 6.0% of the rice hull consists of a bio polyester called cutin, which, in
combination with a wax produced by the rice plant, forms a highly impermeable barrier.
Nature employs several very effective strategies to protect the kernel of rice from the
water and high humidity generally associated with the cultivation and growth of this
plant. Consequently, studies done(19 ) on rice hulls at 25°C indicate that the equilibrium
moisture content of rice hulls at 50% relative humidity is at or below 10%, while at 90%
relative humidity, the equilibrium moisture content of rice hulls remains at or below 15%.
A Moisture Vapor Sorption Test (ASTM C739, Section12) conducted by R&D Services(
20) indicates a gain in weight of only 3.23%. This is well below the moisture content
needed to sustain the growth of fungi and mould.
9
1.1.2.3 Industrial usesThese include:-
Mesoporous molecular sieves, which are applied as catalysts for various chemical
reactions, as a support for drug delivery system and as adsorbent in waste water
treatment, Pet food fibre, Building material, Pillow stuffing, Fertilizer, SiC production,
Fuel, Brewing to increase the lautering ability of a mash, Juice extraction to improve
extraction efficiency of apple pressing and as rice husk ash aggregates and fillers for
concrete and board production, economical substitute for micro silica / silica fumes,
absorbents for oils and chemicals, soil ameliorants, as a source of silicon, as insulation
powder in steel mills, as repellents in the form of “vinegar-tar”, as a release agent in the
ceramics industry, as an insulation material for homes and refrigerants
1.1.3 SAW DUST
Wood waste is wood that no longer has value at its current location, it may be a waste
product of a process, it may be from shipping/receiving, it may be from construction or
de-construction, etc. It is produced from manufacturing, forestry, construction, deconstruction sectors, municipalities and utilities. Sources include pallets/skids, crates,
wire reels, scrap wood, sawdust, shavings, milling residue, processed wood, cut offs,
trees, branches, brush, stumps and bark. Sawdust is composed of fine particles of wood. It
is produced from cutting with a saw, hence its name. It has a variety of practical uses,
including serving as mulch, fuel, manufacture of particle board. Until the advent of
refrigeration, it was often used in ice houses to keep ice frozen during the summer(21 ).
Historically, it has been treated as a by-product of manufacturing industries with inherent
hazard, especially in terms of its flammability( 22). It is also sometimes used to soak up
spills, allowing the spill to be easily swept clean. Perhaps the most interesting application
10
of sawdust is in pykrete, a slow-melting, much stronger ice composed of sawdust and
frozen water.
The environmental impact of saw dust comes from the large amount of sawdust and
wood waste that is generated which is dumped without being fully utilized. Over a period
of time the wood waste is burnt or used for heating and when not removed from dump
area decomposes and emits methane, a greenhouse gas that is about 21 times more
harmful to the environment than carbon dioxide(23 ).
1.2 BACKGROUND OF STUDY:
This project stems from the fact that Nigeria today is matching towards a technological
independence of which the actualization of skill acquisition in the area of electronic
components, starting from the basic circuitry manufacture is one of it. Consequently the
production and acquisition of the skill of manufacturing this bare board will ensure the
non-dependence of our industries on imported bare boards which invariably cuts down
the overall production of electrical and electronic components/parts.
The utilization of waste cellulosic agro-materials will further make the cost of producing
the bare boards significantly cheaper while providing another means of converting the
wastes to utility items supporting the laudable ‘waste to wealth’ initiative of the country.
It will also create employment for the teaming youths.
The understanding and utilization of the cheap non precious metal catalyst reagents will
not only reduce the cost of manufacturing but also encourage the search for safer, cheaper
and more environmentally friendly alternatives to the palladium and/organic catalysts that
are presently in use, thereby keeping us abreast with the western technological approach
to this technology. The primary target of this study is to discover alternative raw
materials for the production of printed circuit board, different from the petrochemical
11
based resources (synthetic polymers) considering the fact that our petrochemical industry
is not actively operational. The successful completion of the study will open a new
frontier in the actualization of the concept of ‘green’ electronics which will provide a
sustainability and efficient cycling status to this sector. It will also enhance the required
techno-socio-economic impact of utilizing renewable resources while bringing down the
cost of producing these board with attendant low cost electrical/electronic products. The
dependence on foreign expertise and/product importation will be reduced or completely
eradicated.
1.3 SCOPE OF STUDY:
This project boarders around the preparation of particle boards from agro wastes and the
determination of relevant properties that will ensure the possible utilization of the
material wafers for printed circuit board manufacturing. A preliminary electroless copper
deposition will be carried out to ascertain the feasibility of depositing copper on the
substrates. A further work at a higher level will perfect the plating process and upscale to
the industrial manufacturing stage and mass production.
1.4 IMPORTANCE OF WORK:
The aim of the electronic manufacturing industry has long been to achieve a reliable
circuit design with repeatable electrical characteristics, good mechanical properties and
acceptable aesthetics(24). Until the 1950s, electronic circuits and systems were
assembled by using individual wires to connect each of the components. The components
were then mounted on what were known as long strips and sockets.
In response to the desire by the consumer for repeatable performance, smaller sizes
and lower costs, it became very necessary for the development of assembly schemes that
would allow for greater manufacturing efficiency. The printed circuit board method
12
proved very successful in providing the contact between components, laminates of an
insulating material are best suited for these work.
This study which is aimed at locally producing a non-conducting substrate for use
in the manufacture of printed circuit board, is very important to the scientific world
considering the areas of interest in the search for raw materials (synthetic (PVC) and
natural (sawdust, rice husk and corn cob)). The use of the agro-wastes, if successful will
open up a cheap source of raw material supply, apart from the fact that the overall cost of
producing those substrates will be reduced due to the elimination of chemical roughening
step of the sheets (etching). The overall time and energy for processing the board will be
minimized from the skipping of the etching step. On the other hand, the utility value of
those ‘ascribed’ wastes will be greatly enhanced and the negative environmental impact
will be totally eliminated. The study will also explore the possible recyclability of the
boards in any event where damage occurs to the circuit. There is also the possibility of
having an electronic item with close to hundred percent local content raw material input
which are also environmentally friendly and inexpensively sourced.
The study will also present us with the understanding of the possibility of cladding on
unprocessed (not like paper sheets) cellulosic material knowing that all three natural
materials chosen for this study (saw dust, rice husk and corn cob), are all cellulose based.
The degree of permanence achieved with the metal deposition will be verified by the
simple peel test.
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