View
274
Download
27
Category
Tags:
Preview:
DESCRIPTION
Presentation about wood plastic composites, wood filler, plastic wood & wood cement
Citation preview
By
A.MaheshwaranBSF-04-012
Presentationon
Wood Composites
Course Teacher
Dr.I.SekarAssociate Professor
Wood Plastic Composites
Wood plastic
• Plastic ranging from polypropylene to PVCPlastic ranging from polypropylene to PVC• Binders/Fillers – Wood flour to WaxBinders/Fillers – Wood flour to Wax• Wood – saw dust & scrap wood productsWood – saw dust & scrap wood products
Benefits• True hybrid materials & combine best features of True hybrid materials & combine best features of
wood & plasticswood & plastics• Use low cost & plentiful raw materialsUse low cost & plentiful raw materials• Competitively priced Competitively priced • Easily produced & easily fabricated Easily produced & easily fabricated • Available in broad range of finishes & appearanceAvailable in broad range of finishes & appearance• Easily recycled after useEasily recycled after use• No further processing is neededNo further processing is needed• Weather, water, & mould resistantWeather, water, & mould resistant
Properties
Properties
• High resistance to moisture (0.7% High resistance to moisture (0.7% compared to 17.2% in Pine)compared to 17.2% in Pine)
• Moisture not transmitted across plastic Moisture not transmitted across plastic boundariesboundaries
• Good stiffness & impact resistanceGood stiffness & impact resistance• Dimensional stabilityDimensional stability• Resistance to rotResistance to rot• Excellent thermal propertiesExcellent thermal properties
Environmental Benefits
• Negligible waste & that produced is reusedNegligible waste & that produced is reused• No volatile organic compoundNo volatile organic compound• Recycled & reused after their service lifeRecycled & reused after their service life• Disposed using standard methodsDisposed using standard methods• Increase efficiency up to 40% compared to Increase efficiency up to 40% compared to
traditional wood traditional wood
Processing
• Mix of wood & plastic - modified with Mix of wood & plastic - modified with process & additives - to improve process & additives - to improve processing / final properties of WPCprocessing / final properties of WPC
• Compatibiliser/coupling agent – Improve Compatibiliser/coupling agent – Improve blendingblending
• Basic wood product – fine saw dust(40-60-Basic wood product – fine saw dust(40-60-mesh range)mesh range)
• Simple die can be used even for most Simple die can be used even for most complex profilecomplex profile
Wood filler Wood putty or Plastic wood wood dust combined with a binder that
dries and a diluent and a pigment fill imperfections, nail holes or pores in
wood Wood putty or plastic wood - thicker version Wood filler - thinner version
Plastic wood The base product -100%
recycled High-Density Polyethylene (HDPE)
shampoo and detergent bottles, to milk jugs
Some, entirely of HDPE recycled HDPE + with
wood fibers, rubber, fiberglass, or other plastics
Like Natural wood, Plastic lumber is expand & contract with heat (Magnitude
varies) cut and shaped with traditional wood
working tools
Plastic wood will not: Rot (seawalls, docks) crack warp splinter degrade
Plastic wood is: denser than wood virtually maintenance free long lasting stain resistant waterproof UV resistant aesthetically pleasing impervious to insects not affected by exposure to most substances
Plastic wood also: works with any deck fastener requires no painting or sealing used in composite extruded panel plastic
wood for flooring Provides a good shock-absorbing surface
for pedestrian traffic, such as runners and hikers.
Plastic lumber and Wood-plastic composites - difference fiber plastic lumber can
have less than 50% wood fiber.
balloted in ASTM by Committee D20
Standard Test Method for Shear Properties of Plastic Lumber and Plastic Lumber Shapes.
Wood-plastic composites have at least 50% or more wood
balloted in ASTM by committee D07
Standard Test Methods for Evaluating the Mechanical and Physical Properties of Wood-Plastic Composite Products
New technology in plastic composite lumber post-consumer plastics such as high
density polyethylene (HDPE) mixed environmental wastes and plastic
material into extruded composite lumber 65% recycled Cellulostics materials and
30% recycled plastic materials.
CATEGORIES1. Material Preparation
2. Extruder Design
3. Screw Design
4. Cooling Technology
5. Die technology
6. Fillers
Wood cement
Wood cement wood wool cement boards (WWCB) cement bonded particleboard (CBPB)
General Properties durable and resistant to frost/thaw, fire,
moisture, rot, vermin, fungus and termites easy workability
MANUFACTURING PROCESSES Manufacture of Wood Wool Cement Board
Manufacture of Cement Bonded Particle Boards
Manufacture of Cement Bonded Fibre Boards
Manufacture of WWCB Long wood + cement wool strands (or excelsior) - cut from
debarked logs 400-500mm length prior to cutting the wood wool treated to prevent blue-staining
The logs stored on racks a month to reduce the moisture & sugar content
wood is shredded
salt (CaCl2) solution + Portland cement (2:1 ratio)
spread onto plywood moulds & stacked
The mats pressed at room temperature under 10 psi.
stack is clamped under pressure for another 24 hours then removed from the moulds & cured for 2-3 weeks.
They are subsequently trimmed and finished.
Manufacture of WWCB
Workers collecting sawn logs for shredding
Logs being shredded into wood wool
The wood wool is then soaked in a salt solution
Eltomation Rotating Wood Wool Machine Boards
The pressed and finished boards
Manufacture of CBPC
wood is in particle rather than strand form softwood logs debarked & stored to reduce
moisture and sugar content Portland cement: wood: water in ratio 3:1:1 Water evaporation is monitored CaCl2 added - cement setting The mixture fed to a conveyor
Manufacture of CBPC
mat subsequently cut These stacked & compressed together to
1/3rd of its original height over a 2-3 minute period.
The mats are clamped and heated in a chamber at 70-80 degrees Celsius for 6-8 hours.
boards dried, trimmed and stored for 12-18 days until the cement cures.
Modern CBPB plant
Manufacture of CBFB wood pulped cellulose
fibre (with an air-dry moisture content of 12-16%)
Silica + alumina + water + pulped cellulose
Binders added water removed and mixture
is rolled onto mats, cut, and sized, or moulded
PropertiesProperties
Properties of WWCB insulation fire retardation water resistance resistance to organism attack mechanical properties
Insulation WWCB provides very good insulation, both thermally and
acoustically. Acoustic Insulation Resistance of a plastered wall of 5cm Wood Wool Cement
Boards 36-40dB Resistance of a plastered double wall with air space between
WWCBs 53-57dB Resistance of a permanent shuttered wall with 12cm concrete
core 354-56dB Noise Reduction Coefficient for 2.5cm board 0.7 Thermal Insulation (Evans,1996) Thermal resistance (R) for 2.5cm board 5
Fire Resistance 5cm boards 1 hour resistance 10cm boards 2 hours resistance
Water ResistanceDimensional change after soaking in water for 48 hours: 0.84% thickness swelling 0.21% linear expansion 22% water absorption
Resistance to Organism AttackWWCB is highly resistant to dry rot and other fungal growth as well
as to termites.
Mechanical Properties Specific Gravity
light boards for insulation only 360kg per cubic metre denser boards for roofs and permanent shuttering 450kg per
cubic metre Bending Strength = 20-30kg per cubic centimeter Design load for 2cm board = 50psf Ultimate load for 2cm board = 200psf Allowable span for 2cm board = 122cm Deflection at design load = 0.2cm
Properties of CBPB insulation machinability water resistance mechanical properties
Insulation Thermal Insulation
Thermal conductivity (k value) = 0.35W/m.K Linear thermal expansion = 0.01W/m.K
Electrical Insulation CBPB is resistant to tracking and does not build up static charges, thus be
used as backing panelling for electrical appliances.
Acoustic Insulation The sound reduction for boards of various thicknesses is as follows:
6mm - 28dB 10mm - 31dB 20mm - 33dB 30mm - 36.5dB 40mm - 38dB
Machinability working - CBPB can be worked using hard tipped tools in a similar
manner to timber,plywood or chipboard.
sawing - can be sawn with handsaws, jigsaws with suitable blades or power saws with tungstentipped blades.
drilling - use hand drill or high speed power drill
sanding - manual sanding or mechanical sander preferably applied to both sides of board simultaneously.
fixing - drilling of pilot holes for nails and screws is recommended for most board thicknesses.
Water Resistance Thickness swelling
<1.0% after 2 hours soaking <1.5% after 24 hours soaking <2.0% after >24 hours soaking
Longitudinal and Transverse Swelling 2.7mm/m from air dry to water saturated 0.1mm/m for each 1% change in moisture content of the
board 1.4mm/m for each 30% change in relative humidity of
ambient air
Mechanical Properties modulus of elasticity = 4500N per cubic
mm bending strength = 10-15N per cubic mm
(depending on density and raw materials) compressive strength = 15N per cu mm density = 1250kg per cubic metre
APPLICATIONSAPPLICATIONS
Applications of Applications of CBPBCBPB
External ApplicationsExternal Applications
• flat roofing • prefabricated structures(including
housing) • mobile homes • permanent formwork • balcony parapets and floors • cladding for industrial and warehouse
buildings • tunnel linings
External ApplicationsExternal Applications
• sound barrier walls on highways • fire barriers • pavillions • separating and party walls • soffits • agricultural buildings • swimming pool surroundings and
paving
Internal ApplicationsInternal Applications
• sound insulation and fire resistant partitions and doors
• linings for timber frame housing
• fire resistant doors, walls and ceilings
• built-in furniture • column and beam
casings
Internal ApplicationsInternal Applications
• lift shaft and duct linings • back boards for
electrical and gas appliances
• glue laminated structural members
• flooring in greenhouses • linings for bathrooms
and laundries
Applications of Applications of WWCBWWCB
Most important Most important applicationsapplications• thermal and acoustic insulation • for low-cost housing
thermal and acoustic thermal and acoustic insulation insulation • basements • floor units • permanent shuttering • partitioning • sound insulation in walls, ceilings and
floors • roofs • sound barriers • thermal insulation (often combined with
other insulation products such as polystyrene and polyurethane)
Applications for Low-Cost Applications for Low-Cost HousingHousing• relative low price of products since wood wool
can be produced from inferior quality wood which is unsuitable for sawmills
• simple technology required to produce boards, etc - see photograph below of plant in the Philippines
• in most countries in the world wood and the components of cement are readily available
• low enough weight to allow handling panels without the use of cranes or heavy machinery
Applications for Low-Cost Applications for Low-Cost HousingHousing• highly skilled labourers are not required for board
manufacture or building construction which allows boards to be made and buildings to be constructed locally and cheaply
• the construction process is quite fast and simple
• high insulation value
• easy handling and workability
• important properties such as fire, water, termite and fungi resistance
References:References:• http://www.umeciv.maine.edu/rla/images/DSC00088.JPG
• http://www.tangram.co.uk/TI-Polymer-Plastic&Composite_Windows.html
• http://www.tangram.co.uk/TI-Wood_Plastic_Composites.html
• http://www.tangram.co.uk/TI-Wood_Plastic_Composites_Review.pdf
• http://www.cis.tennessee.edu/EPAMACT/other/Plywood/pcwpVT1.shtml
• http://www.renewresources.com
• http://www.machinerydata.com/HowToMakePlasticWood.htm
• http://www.cierraindustries.com/plasticlumber.asp
• http://en.wikipedia.org/wiki/Wood-plastic_composite
• http://www.awc.org/Publications/download.html
• http://www.awc.org/HelpOutreach/faq/FAQfiles/Plastic_Wood-Lumber.html
• http://www.panelworldmag.com/vserver/hb/display.cfm?MagazineKey=6&IssueKey=461&SectionKey=389&ArticleKey=620
• http://www.fpl.fs.fed.us/documnts/pdf1997/wolfe97a.pdf#search=%22wood%20cement%20products%22
• http://www.ccaconference.org/pre/pdf/Gong.pdf#search=%22wood%20cement%20products%22
• http://www.anu.edu.au/Forestry/wood/cfb/contents.html
• http://www.fpl.fs.fed.us/documnts/pdf1996/geime96b.pdf#search=%22cement%20wood%22
• http://www.aciar.gov.au/web.nsf/doc/JFRN-5J47AH
• http://www.anu.edu.au/Forestry/wood/nwfp/woodwool/woodwoolphil.html
• http://www.toolbase.org/Technology-Inventory/walls/wood-fiber-composite-forms
Thank you
Recommended