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By

A.Maheshwaran

BSF-04-012

Presentationon

Improved wood

Course Teacher

Dr.M.Murugesh Ph.DAssistant Professor

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Improved wood(Modified wood)

Specially treated to reduce/retardSpecially treated to reduce/retard

working/to increase strengthworking/to increase strength

Not applicable to timber treated withNot applicable to timber treated withpreservatives/orthodox finishespreservatives/orthodox finishes

Modifying properties of wood ofModifying properties of wood of

Hygroscopicity, working, density &Hygroscopicity, working, density &strength, etc.strength, etc.

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Types

Impregnated woodImpregnated wood

Heat stabilized woodHeat stabilized wood

Compressed woodCompressed wood

Compregnated woodCompregnated wood

Chemically modified woodChemically modified wood

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Impregnated wood

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Description

Collective name for wood impregnated withCollective name for wood impregnated with

all possible impregnantsall possible impregnants

Improving dimensional stability &Improving dimensional stability &

preventing water absorptionpreventing water absorption

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Impreg

Impregnants commercially applied areImpregnants commercially applied are

water water-soluble, thermosetting, phenol-water water-soluble, thermosetting, phenol-

formaldehyde resin-forming systemsformaldehyde resin-forming systems

Veneers treated with a thermosetting, fibreVeneers treated with a thermosetting, fibre

-penetrating resin that is cured without-penetrating resin that is cured without

compression, and then bonded together arecompression, and then bonded together areknown asknown asImpregImpreg

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Making

veneers soaked in aqueous resin-formingveneers soaked in aqueous resin-forming

solutionsolution

impregnated with the resin by vacuum-impregnated with the resin by vacuum-

impregnation, with/without subsequentimpregnation, with/without subsequent

pressure, resin-content equal to 20 to 25%pressure, resin-content equal to 20 to 25%

non-drying conditions for a day or twonon-drying conditions for a day or two

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Making

To permit the uniform distribution of theTo permit the uniform distribution of thesolution throughout the woodsolution throughout the wood

Air dried, assembled & pressedAir dried, assembled & pressed drying of the resin-treated wood also bringsdrying of the resin-treated wood also brings

about checking & honey combingabout checking & honey combing

treatments - confined to veneerstreatments - confined to veneers limited to small valuable specialties such aslimited to small valuable specialties such as

sports goods, shoe-lasts.sports goods, shoe-lasts.

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Effects of Resin Treatment

hygroscopicity & swelling & shrinking - reducedhygroscopicity & swelling & shrinking - reduced

grain-raising and surface checking also reducedgrain-raising and surface checking also reduced

resistant to decay & termite & borer attackresistant to decay & termite & borer attack

Electrical resistance & also resistance to mostElectrical resistance & also resistance to most

chemicals excepting alkalis - increased.chemicals excepting alkalis - increased.

Compression strength, hardness, & density Compression strength, hardness, & density improvedimproved

tensile strength and impact strength are reduced.tensile strength and impact strength are reduced.

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FRI Investigations

The strength properties of inferior IndianThe strength properties of inferior Indian

wood can be improved by treatment withwood can be improved by treatment with

resinsresins Veneers are most profitable than solidVeneers are most profitable than solid

timbertimber

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Compressed wood

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Compressed wood

Considerable improvement in the prooertiesConsiderable improvement in the prooerties

can be obtainedcan be obtained

Compression across fibre increases theCompression across fibre increases the

specific gravity of wood increasesspecific gravity of wood increases

strength propertiesstrength properties

Pressure 90-140 kg/sq.cm. => materials ofPressure 90-140 kg/sq.cm. => materials ofs.gravity 1.2-1.3 obtaineds.gravity 1.2-1.3 obtained

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Making

Either from solid wood/laminated woodEither from solid wood/laminated wood

Lignostone compressing BeechLignostone compressing Beech (Fagus spp.)(Fagus spp.)

from both sides across the grain simultaneouslyfrom both sides across the grain simultaneously

Door handles, bearings, rollers, snowshoes,Door handles, bearings, rollers, snowshoes,

etc.,etc.,

LiognofolLiognofol

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Properties

Good strength propertiesGood strength properties

High resistance to wearHigh resistance to wear

SmoothSmooth

Good elastic propertiesGood elastic properties

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FRI Investigations

Inferior spp Inferior spp Moringa oleieraMoringa oleiera improved improved

by compressionby compression

Best results by compressing at 14% MC &Best results by compressing at 14% MC &

16016000CC

Holoptelia integrifolia Holoptelia integrifolia similar tosimilar to

LignostoneLignostone

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