Cong nghiep rimg
\ ANH mrCfNG CUA XU^ LY THUY - NHIET DEN MOT S 6 TINH CHAT VAT LY CUA GO BACH DAN (Eucalyptus urophylla) Nguyin Van Dien', Ph?m Van Chirong^
'ThS. Trudng Bgi hoc Ldm nghiep 'PGS. TS. Tnrdng Bgi hoc Ldm nghiep T 6 M TAT
Go rimg trfing n6i chung v4 go B^h dan Uro n6i rifing Id v§t lieu x6p, rSng, mao din, dj hudng c6 khi nSng trao did ^ vin m6i Uvjmg xung quanh din t6i str thay d6i kfch thudc, hinh djmg vi cdc tfnh chSt cc li^ cua go lira inh hudng din chit Iirpng vi 6^ b^n cCia sSn p h ^ - Day la nhirgc diem cUnh ciia gS. Vi thi m§t trong nhfhig xu hudng chu ylu trong vi^c nSng cao chdt lugng g3 dif vi dang dugc cic nhi khoa hgc trgn thi gidi quan tfim \i biln tfnh %h.Bi\ vilt niy, tdc gi& trinh biy kit qui xir 1^ bing phuang phip thdy - nhi^ din mOt s6 tfnh chit vit \^ ciia gS Bach din {Eucalyptus urophylla S.T. Blake). Kit qui nghifin cthi cho thdy, xd ly thfiy - nhifit vdi su thay ddi cic chi d$ nhu nhifit d$ (140°C; 160°C vi 1 SO^C) vi thdi gian (2 gid; 3 gid vi 4 gid) lim cho g8 ting sg 6n djnh kfch thudc: Hfi sd chdng trucmg nd (ASE) ting tCt 30,52% din 40,2% vi Hi^u sudt chdng hfit nudc (WRE) ting ttr 17,61% din 34,44%, giim khdi lugng thd tfch gd tCt 4,18% ddn 28,81%.
Ttr khda: Bfcb ddn (EucatypUis urophylla S.T. Blake;, hi s6 chdng trirong nd (ASE), hi^u sudt chdng hdt nudc cda gS (WRE), khit lufng thi tich (y), xd If thuy - nhi^
I. DAT VAN Bt
"Theo Quyet djnh so: 62/2006/QD-BNN, ng4y 16 thing 8 nita 2006 ciia BO trudng Bp NN&PTNT v^ vi$c phe (iuyet chiin lucre phAt trife giong cSy ISm nghi^ giai doan 2006- 2020" trong quyet djnh da neu tfl c4y g5 Bach djin Id mgt logi cSy uu tien rimg trong, uu di£m cAy Bgch d ^ c6 khd nSng tSng trudng nhanh, go c6 mdu sfic dfp, cirdng dO co ly cao ..., nhiKjic di^m ciia go Bgch ddn c6 nhieu nOi iing suat ngam nSn khi sii dyng go de b} cong venh, nilt, tdch, tri... 0 cdc nudc Chau Au nhu Hd Lan, Phdp, Dfic, Phan Lan da thife lap dugc 5 cong ngh$ xti ly nhi$t diSn hinh nhu: cong ngh^
sOr dung nudc, htri nudc hojc khdng khi (PlatoWood) cua Hd Lan, cong ngh? sii dyng hoi nudc, khi N2 (Le Bois Petdure vd Rectification) cila Phap, xii ly bdng hoi nudc (TheimoWood) cua Phan Lan, cdng nghe sil dyng dau thvc vgt (OHT- Oil Heat Treatment) cila Diic. Xli ly nhiet sir dyng nudc hojc hoi (xu ly thliy - nhi?t) mi diim tit Idn ciia phuong phdp ndy Id ddm bdo tinh on djnh kich thudc [6], thanh phk hda hpc [4], Ihay ddi dui?c mdu
sdc go [1] khdng sti dyng hda chat hay b4t ky chit xiic tdc ndo ngn ldm cho phuong phdp dupc ddnh gid Id than thi$n vdi mdi trudng, cdng ngh$ vd thiit bj don gian vd chi phi gid thdnh cho cong ngh$ thip cBng Id ly do tdc gid chpn phuong phdp ndy ii xit 1^ cho go Bgch ddn.
Bdn chit cua go Id mpt loai vgt li?u ty nhien cd thi tdi sinh vd su dyng tuin hodn, cd tinh chit vgt 1^, CO hpc cao, hoa vdn vd mdu sSc dgp... Ben cgnh dd go cling cd nhieu nhuijfc diem nhu de bi sau nim, cdn trung phd hogi vd cd kha ntog hut, nhd im dan din b; thay dii kich thudc, hon niia gd Id vdt lipu d; hudng n&i rnirc do thay doi kich thudc theo cdc chieu khdng giing nhau, vi thi go dl bi biin Unh, cong venh, n6t ne. Cd thi ndi ddy Id nhupc diem ldn nhit cila g5 khi sil dyng gS Id vjt li$u. Tinh co nit, ddn nd cua g5 khdng chi gay khd khta trong qud trinh gia cong, chi biin, si dyng md cdn han chi khd ntog sil dyng gi trong mdi trudng cd sy biin dOng ldn vi dO am. Chinh vi thi nghiSn cihi flm ta gidi phdp cdng ngh$ ntog cao tinh chit vgt ly, co hpc cifa go Id vd cilng cin thiit
56 TAP CHi KHOA HQC VA C 6 N G N G H | ; L A M NGHIf P S 6 1 - 2014
Cong nghiep ritng
Tir nhiing nam 1915, bao cao ciia Tiemann [8] da de cap d£n, go sau khi siy a nhi$t do 150°C trong thoi gian 4h, tinh hiit hm giam 10- 25%, nhung cudng do cua go cung co s\r giam nh?. DSn nam 1937, trong bao cao cda Stamm va Hansen [7] thi hien, xii ly nhi?t trong diSu k i ^ CO cac loai chAt khi bao v|, do hm bao hda ciia g5, ti I? co nit, gian na cua go dhx giam xuong. NhGng nam gSn day tac gia Militz (2005), xur ly nhiet cho g6 nhim nang cao cac tinh chat khac nhau ciia no, ch3ng han nhu chong thim nudc, 6n dinh kich thuac, he s6 chong truang nd (ASE), chdng tia UV [5];
Yildiz et al (2002), nghi&n ciiu anh hudng ciia nhi^t dd din h^ s6 ch6ng truong nd (ASE) cCia go Soi. Che do xit ly d nhiet dp 180 C vdi cac miic thdi gian la 2, 4 v^ 10 gid sau dd tinrc hi?n chu ky ngam say. Ket qua thu duoc h$ so ASE d^t khoang 47,64%...[5]; Behbood Mohebby v^ Ibrahim Sanaei (2005), nghien Cliu Ml hudng cua xur ly thuy - nhi$t dkaa. tinh chit v$t ly ciia go Soi (Fagus orientalis). Mau gS (20x20x20mm) duac d^t trong mpt khoang th^p khong ri, chiia diy nudc. Mhx dagc xii ly d nhift dp leO^C, 180°C v^ 200''C trong 4, 5 v^ 6 gid. Mau gd da xur l^ dupc ngam trong nudc 24 gi6r, sau do siy khd, chu ky ngam/s^y dupc lap di lap 1^ 7 lin. K^t qua cho thiy ASE, WRE tang v^ kh6i liipng thS tich bi giam nh? [2]; P.Rezayati Charani v^ c^ng su (2007)
"NghiSn Cliu anh hudng ciia ehe dp xii ly thuy nhi^t ddn s\r dn dinh kich thudc ciia gd sdi".
Mau go dupc xii ly d nhidt dp khac nhau (150''C, 160°C, 170**C) va thdi gian khac nhau (Igid, 3 gid, 5 gid va 7 gid) trong Id phan iing.
Sau dd th\rc hien chu k^ ngam/ siy miu 8 lin.
Ket qu^ h? so chong truong nd tang va khdi lupng thi tich giam ciing vdi tang nhiet dp tiep xuc va thdi gian, ASE cao nhit la 47,43% thu dupc d nhi?t dO HO^C thdi gian 1 gid, nhung Xli ly d nhift dp 170°C ASE cd xu hudng giam
khi thdi gian xii ly tang. Hifu suat ch6ng hut nudc (WRE) ciia mau go dupc xur \f a 160 C, nO^C cao hon nhilu so vdi 150°C trong thdi gian 1 gjd. Trong thdi gian 3 gid, 5 gid, gja trj WRE lon hon d ISO'^C hon leO^C va 170°C. 6 150"^ leO^C, nO^C trong thdi gian 1 gid thi gia tri WRE gin bing nhau. WRE ldn nhit la 22,20% thu dupc khi xijt ly d nhift dp 170"C trong thdi gian 1 gid [6]. Cho den nay, cac cdng trinh nghien ciiu ve xii ly thiiy nhiet d Vift Nam cdn h ^ chi, chua iing dung nhilu trong san xuit va nghiSn ciiu. Trong bai vilt nay, tac gia trinh bdy kit qua ve budc dau nghiSn ciiu "anh hudng ciia xii ly thuy - nhift din mpt so tinh chit v^t ly cua gd B^h dan"
gdp phin xay dyng vao cdng nghf xvr 1^ thiiy nhift cho vat lifu gd ndi chung va go Bach dan ndi riSng.
n . VAT LIEU VA PHU'ONG P H A P NGHIEN c t r u
2.1. Vat lieu nghiSn cmi
Gd Bach dan (Eucalyptus urophylla S.T.
Blake) cd dp tudi tii 10 dSn 15 tuli khai thac tai Ba Vi - Ha NOi, tien hanh xe theo kich thudc 25 X 40 X 600 mm (xuyen tSm x tilp tuyin x dpc thd) dl lam miu thit cac tinh chit vat 1^ ctia go sau khi xit ly thuy - nhift, cac miu Xli ly thuy - nhift va chua xii ly thuy - nhiSt (doi chiing) dupc cit trSn cung mpt thanh gd xe cd dac va loi dS so sanh tuong dli va liy tri sd trung bmh cac mau xii 1^ va chua xit ly, sau dd kilm tra tinh chit cua g6, dp am cua gd tmdc khi xii ly do im go bien dpng tii: 25 - 30 %. Xli 1>' thliy - nhift bing may SUMPOT d cac chS dp nhift do (140°C; I60V; 180**C) va thdi gian (2 gid; 3 gid va 4 gid). Sau do cit mlu theo tiSu chuin thic cac tinh chat 20x20x25mm (xuySn tSm x tilp tuySn x dpc tha), sd miu 15/chl do xir ly trong timg tinh chit dl kiem tra danh gia kit qua th\ic nghiem.
T ^ CHi KHOA HQC VA CONG NGHE LAM NGin|:P S6 1 - 2014
2.2. Phuwng phap nghien cihi a) Sff do quy trinh th^c nghiem
Miu go thi nghipm \ a Uro) I
Cong nghiep rang
Thiit bi xil ly thiiy- nhi^t (Sumpot)
Giai doan 1: Xit ly thliy - nhipt (nhipt dp, thdi gian)
Mdu go'BpB dan Uro chua xir ly thiy nhi$t (d5i chiing).
- S6 lupng: 15 mdu/chi do.
Mau gd M:h dan Uro xir ly iet dp (T): 140°C vi thMlgianH ): 2; 3 va 4 gift).
- Sd lupngw mau/che dp.
Giai dogn 2: siy da ty (nhi^tdpduytri: HO'C, thdi gian duy tri: 3 gid);
dp im go: 12%.
Ldm ngu$i ty nhi6n \ (nhipt dp mdi trudng) )
- Miu g5 Bgch dto Uro xu ly thuy - nhipt (nhipt dd (T): leo'C va thdi gian (r ): 2; 3 va 4 gio).
- So lupng: 15 mau/chi dd.
- Mau gd Bach dan Uro xir ly thiiy - nhiet (nhiet dp (T): 180°C va thdi gian (T ): 2; 3 va 4 gid).
- Sd lupng: 15 mau/che do.
Kiim tra tinh chit gi
I
Xli ly vd dii chiing
- Khii lupng thi tich (/g).
- Hp si ching truong nd (ASH).
- H$ si ching hfit nudc (WRE).
Bang 01. Chi dp xtr lp thdy - nhipt cho goBfch ddn Nhi^tdp (°C) 140 160 Thdi gian (gid) 2 3 4 2 3 4 2
180
3 4
b) Tieu chuan va phinrag phdp kiem tra tinh chat v$t 1^ ciia go
Xic dinh Khoi luftng tki tich
Tieu chuto kiem tra: TCVN 8048-2: 2009.
Kich tiiudc mau; 20 x 20 x 25 mm.
Dung lupng mau: 15 miu/chi d$.
58 TAP CHi KHOA HQC vA C 6 N G NGHf LAM NGHIEP S 6 1 - 2014
Cong nghiep rCing
Dyng cy kiim tra: Cto dien til dd chinh xdc ± 0,0lg, thudc kep dd chlnh xdc 0,01mm, til siy nhi$t d§ tii da 300°C cd dp chinh xdc ± 0,1 °C.
Quy trmh kiim tra: Miu dupc dat vdo tu siy va tdng din nhipt dp. Nhipt dp cudi cimg Id 103
± 2*'C cho din khd hodn toan. Bi xdc dinh trgng thai khd hoan todn, ta can miu di kiim tra, neu khdi lupng giiia 2 lan cdn lien tiep cdch nhau 2 gid lpeh nhau khdng qua 0,01g thi dung say, tgi thdi diim dd mau dupc coi Id khd kift. Mau khd kipt dupc dua vdo binh hiit im Idm ngupi, sau dd cdn dupc khii lupng mo, g.
Sau dd, dung thudc kpp do kich thudc 3 chiiu cua mlu, tir do tinh dtrpc thi tich Vo, cm^.
Cdng thilc xdc dyih:
, g/cm (2.1) Trong dd:
Yo - khii lupng thS tich go khd kiet, g/cm^;
mf, - khii lupng go khd kiet, g;
Kg - thi tich go khd, cm^.
Xac dinh Hp si chSng tmang n& (ASE) Ti6u chuin kiim tra: ASTM D 4446-08.
Kich thudc mau: 20 x 20 x 25 mm.
Dung lupng mau: 15 mau/chi dp.
Dung cu kiim tra: Thudc kep dp ciiinh xac 0,01mm, til siy nhipt dp tii da 300°C cd dp chinh xdc ±0,l''C.
Quy tiinh kiim tta: Miu ngdm ti-ong nudc 24 gid, sau dd do kich thudc. Tiep theo, dua mau vdo siy khd kift roi do kich thudc. Qua trinh ngam siy thyc hifn chu kjf 7 lan.
Cdng thitc xdc djnh:
(2.2)
^ £ ( , ) = 5 . M z £ t M ^ 1 0 0 % , % Trong dd:
ASE - hp si chong trucmg nd, %;
a iy) - truong nd thi tich trung binh ciia miu dii chiing, %;
a,(y) - truong nd thf tich trung binh cua miu xu ly, %.
a xac dinh theo cdng thuc:
V.-V„ i x l 0 0 % , % (2.3) Trong dd:
^^ - thi tich mdu sau khi ngdm, cm^;
KQ - thi tich mau sau klii say, cm^.
Xdc djnh Hi si ching hut nu&c (WRE) Tifu chuin kiim tta: ASTM D4446-08.
Kich thudc mau: 20 x 20 x 25 mm.
Dtmg lupng miu: 15 miu/chi dp.
Dyng cu kiim tta: Cdn difn tu df chinh xac
± 0,01g, tn siy nhift dp toi da 300°C cd dp chinh xdc ±0,1°C.
Quy trinh kiim tra: Mau ngdm trong nudc 24 gid, sau dd can khdi lupng. Tiip theo, dua mau vdo siy khd kift rdi can khii lupmg. Qua ttinh ngam say thuc hifn chu ky 7 lin.
Cdng thitc xdc dinh:
WRE = ^^>^^>^\00%,% (2.4)
Trong do:
WRE - he si ching hiit nudc, %;
r , - hiit nudc trung bmh cua mau doi chung, %;
T^ - hfit nudc tnmg bmh cua mau xil ly, %.
T xdc dinh theo cdng thiSc:
„ m.-ttif.
-xl00%,% (2.5) Trong dd:
m,- khii lupng mau sau khi ngam, g;
m, - khoi lupmg HMu khd kift, g.
m . KET QUA NGHIEN Ctltl
3.1. Anh hudrng cia ehe dp xir ly thiy - nhift den khii lu6ng thi tich gSBgch din
Tir kit qua nghien ciru vd sau khi xu ly thing bdng phin min Excel ta dupc kit qua ghi ttong bdng 02.
TiM" CHi KHOA HQC VA CONG NGHf LAM NGHIEP S 6 1-2014
Cong nghiep rang Bang 02. Khii luftng thi tich cda gdBfCh ddn (g/cn{'
D}c tnmg thong ke
DC
Che df xir ly nhift dp (T) va thdi gian ( T ) 140°C 140°C- MO'C 160°C- 160°C 160°C 180°C - 2 gid 3 gid - 4 gid 2 gid - 3 gid - 4 gid - 2 gid
180°C - 3 gid
180°C - 4 gid X
S
s%
p%
Min Max C(93%)
0,593 0,003 0,011 0,035 0,575 0,610 0,006
0,568 0,002 0,010 0,030 0,553 0,583 0,005
0,561 0,004 0,014 0,051 0,540 0,591 0,008
0,558 • 0,002 0,007 0,025 0,546 0,571 0,004
0,527 0,002 0,007 0,020 0,517 0,537 0,004
0,518 0,004 0,014 0,043 0,499 0,542 0,008
0,513 0,002 0,008 0,026 0,502 0,528 0,005
0,464 0,002 0,009 0,034 0,450 0,483 0,005
0,455 0,002 0,008 0,032 0,448 0,480 0,004
0,452 0,002 0,006 0,020 0,443 0,463 0,003 Tir ket qua d bang 02, ta xdy dvcng dupc do the tich cua gd Bach dan:
thi ^nh hudng cua chi dp xic ly vdi Ichoi lupng
L F H l i
I
i =IT
. i 2
i iJ I
140-4 160-2 160-3 Chi att xtr ly thOy - nhi^t
16CM 180-2 180-3 180-4
mnh 01. Biiu do quan hp gidra chi dp xir If vii khoi luftng thi tich Xli 1^ Id 2 gid, 3 gid va 4 gid khii lupng thi tich cua gd Bgch dan giam tir 12,15% din 13,42%.
- Xu 1^ thuy nhift d nhift dp 180°C thdi gian xfi ly 2 gid, 3 gid vd 4 gid khoi lupng thi tich cfia gS Bgch ddn gidm til 21,7% den 28,81%.
Diiu ndy cd tiii gidi thich khi gi dupc xfi ly tiiuj- nhift mpt so chit chiit suit cd phdn tfi lupng tiiip trong go vd ttong rupt ti bdo bj logi bd ra ngodi. Nhift dp cao, flidi gian xfi 1^ ddi Nh$n xit:
Qua qud trinh tiiuc nghifm ta thiy khoi lupng thi tich cfia gi Bgch dan dd xfi {•} thu^
- nhift so vdi go Bgch ddn chua xu If gidm din khi nhift dp tdng va tiidi gia tdng, cy thi nhu sau:
- Xfi ly fliuy nhift d nhift 140°C thdi gian id 2 gid, 3 gid vd 4 gid khoi lupmg thi Hch cua go Bgch ddn gidm din tfi 4,18% din 5,81%.
- Xfi ly thuy nhift d nhift df leo'c thdi gian
60 TAP CHi KHOA HQC vA C 6 N G NGH? LAM NGHIJP S 6 1 - 2014
Cong nghiep rang
lam phan huy cac polyme thdnh t i bao dgc bift Id hemicellulose cang ldn d i n d i n m i t mat khoi lupng go. Dgc bift Id d c h i dp nhift dp 180 C thdi gian xfi Iy Id 2 gid, 3 gid va 4 gid khoi lupng t h i tich cfia go Bgch ddn dd x u Iy thfiy - nhiet bi gidm manh.
3.2. Anb htedng cua ehe dp xir ly thOy - nhi^
din hp si ching truimg nifgBBfch din Tfi kft qua nghien cfiu vd sau khi x u I^
thong bdng phin men Excel ta dupc ket qud ghi trong bdng 03.
Bang 03. Hp si ching truang n& (ASE) cua gd Bgch ddn (%) Che df yiii ly nhift dp (T) va thdi gian ( r ) Ddc tnmg
thong ke MO'C- 140°C- 140°C- 160''C- 160°C- I60°C- 180°C- 180°C- 180°C- 2 gid 3 gid 4 gid 2 gid 3 gid 4 gid 2 gid 3 gid 4 gid X 30,52 31,01 31,21 35,44 36,03 37,29 39,55 39,91
S 0,32 0,15 0,57 0,35 0,40 0,25 0,37 S% 1,23 0,57 2,22 1,37 1,56 0,96 1,43 P% 4,35 2,58 9,38 4,58 6,09 3,88 4,21 Min 29,31 30,30 24,55 33,43 32,37 35,88 37,46 Max 33,66 32,88 33,93 38,01 38,46 39,75 41,67 C(955i) 0,68 0,31 1,23 0,76 0,86 0,53 0,79 Tfi k i t qud d bang 03 ta xdy dyng dupc do hf so ching truong nd:
thj quan hf gifia nhift dp vd thdi gian d i i vdi
39,91 0,31 1,20 4,51 37,69 42,20 0,66
40,20 0,29 1,13 4,53 38,23 42,75 0,63
140-2 140-3 14IM 160-2 160-3 160-4 160-2 1B0-3 1B0-4 Chi d9xi>l!^ thuy-nhi$t
Hinh 02. Bieu ^ quan hf giOu ehe ^ xirly vai ASE
N h | n x6t: nhi?! cd tac dpng rd r?t d i n s\r on dinh kich C3n CII vao kit qua d bang 03 va dd th; hinh thudc cua go Bach dan. He sd ASE tang rd r?t 02 ta thiy h§ so ASE dSu ldn hon 0, biln ddi tu cung vdi tang nhiet dO va thdi gian xir ly, dieu 30,52% den 40,2%. Chiing td qua trinh thuy nay cd thS gjai thich nhu sau:
T ^ CHI KHOA HOC VA C 6 N G N G H E L A M NGHIFIP S 6 1 - 2014 61
Cong nghiep rang Su tin tai cua cdc nhdm hydroxyl ttong cdc
thdnh phin tgo nen vach t i bao, sy hmh tiianh vd sd cdc lien kit hydro gifia vach mao din vd nudc Id nguyen nhan Idm cho gS bj co rfit hoac ddn nd. Khi tang nhiet dp vd tang thdi gian xfi Iy microfibrils cellulose dupc bao quanh bdi mpt hf thong vd nhiiu hf thing khdng ddn hdi do tdng Hen kit ngang ttong khu phfic hpp lignin, hemicellulose dupc-phdn huy" cd chpn Bang 04. Hipu suit ching hut
Ipc va phdn ung tiidnh mdt mgng ludi ky mrdc, nfn khd nang dan nd cfia go gidm di r8 rft hay ndi each khac tinh i n dinh kich thtrdc go dupc tang Ifn.
3.3. Anh hudng cua chi dp xdr ly thiiy ~ nhipt din hipu suit ching hit ntr&c gp B(^ch ddn
Tfi k i t qud nghien cfiu vd sau khi xfi 1;^
thing bing phdn men Excel ta dupc kit qud ghi ttong bdng 04.
/HI* WRE cua gSBach ddn (%) Che do xfi 1^ nhift df (T) va thdi gian ( r ) DJctnmg
thingkS MO'C- 146°C- 140°C- 160°C- 160°C- I60°C- 180°C- 180°C- 180°C- 2 gid 3 gid 4 gid 2 gid 3 gid 4 gid 2 gid 3 gid 4 gid
20,10 22,76 24,03 26,50 30,64 33,02 34,44 0,56 0,77 0,62 0,63 0,51 0,77 0,43 2,39 2,44 1,99 2,99 1,65 7,49 8,91 6,33 9,80 5,64 20,12 22,15 27,08 28,53 31,58
33,41 38,32 37,22 1,10 1,65 0,91 X
s s%
p%
Min Max
C(95%)
17,61 0,35 1,36 4,21 15,47 19,68 0,75
18,43 0,55 2,15 7,66 15,80 23,46 1,19
2,16 2,98 6,71 10,41 17,04 17,55
23,75 27,96 27,62 31,05 1,20 1,65 1,33 1,35 Tft ket qud d bdng 04 tdc gid xdy dyng dupc vdi hifu suit ching hfit nudc:
d i thj quan hf gifla nhift dp vd thdi gian d i i
140-2 U O J n w iaO.2 HO-3 I B M I S M 180-3 180-4
Chi dtxfFl;^ thfiy-nhr^t
62
Hinb 03. Bieu do quan hp giira chi dp xi ly vdi If RE
TAP CHi KHOA HQC VA CONG N G H $ LAM N G H l J P SO 1 - 2014
Cong nghiep rittig Nh§n xet:
Mau go doi chumg khi mdi ngam vao nudc, nudc nhanh chon thdm vao cac khoang trong giGa cac tl bao, lo mach, ru^t tS b^o cd kich thudc ldn, tia go ... Nhimg mau xu ly thuy - nhiet kha nang thim thau cua nudc vao go giam rd ret. Nhin vao dd thj cho thay khi tang nhi^t dp va thai (T = 140**C - ISO^'C;
T = 2 - 4 gid) iam cho hi?u sudt ch6ng hut nudc cang tang.
can cii vao kSt qiia d bang 04 va dl thj hinh 03 ta thdy h^ sd chdng hiit nudc WRE bien ddi tit 17,61% din 34,44%. He sd WRE tSng rd r$t cimg vdi tar^ nhi^t dp va thdi gian xii ly, chiing td xuc ly d nhiet dp cao, thdi gian xic ly dai iam Ioai bd nhthig chat chiet suat, iam tien thliy phan hemicellulose trong go lunh thanh micropores trong thanh tS bao va gia tang ma sat n$i b$ tao thanh chiing, lam giam kha nSng thdm thau cua nudc vao gd, do do h$ s6 ching hiit nudc ciia go trong qua trinh xic ly thuy nhift tang.
De xudt hudng su dung go B^ch dan Uro sau khi xur ly thuy - nhiet
Theo kit qua nghiSn cuu, go B^ch dan sau khi xu ly thuy nhi?t da nSng cao dupc tinh In djnh kich thudc, Tuy nhien, khoi lupng thS tich g5 1^ cd xu hudng giam dilu do se lam tin that khoi lupng va giam tinh chdt ca hpc.
Ngoai ra, go Bach dan cd tinh chdt ca hpc trung binh do vay, nSn sii dung trong cdng ngh? sdn xudt dl mpc thong d\mg nhu ban ghe, gia sdch, tu trang tri, tu bSp,... cac lo?ii san pham khdng cdn chiu luc cao.
Theo kit qua nghiSn cuu d tren cho thay, go B^ch dan sau khi xit ly thuy nhift tinh on djnh kich thudc cao, v^y ta nen sir dvng lam cac san phdm cho cdng trinh xay d\mg nhu khung, khuon cica va cila thdng phdng,... se mang 1^
hi?u qua cao trong su dung va giam chi phi gid thanh nhu thay the cac san pham ma trudc day ngudi ta quen dung cac loai go quy de iam cac san phdm ndy.
IV. K £ T LUAN
Kit qua nghien ciiu Cong nghp xii ly thuy - nhiet cho gd Bach dan thong qua thong s6 ehl dp xuc ly nhiSt dd (140^; 160'*C va 180**C) va thdi gian (2 gid; 3 gid va 4 gid) cho go B^ch dan, tdc gia di din mdt so kit lu$n: Khoi lupng thi tich ciia go Bach dan sau khi xii ly thuy- nhi?t giam ddn 4,18% - dSn 23,81%; Hf s6 ching truang nd ASE tang ddn tir 30.52% din 40,2% khi nhift df va thdi gian xii ly tang va Hifu sudt chdng hiit nudc WRE tdng ddn tG 17,61% den 34,44% khi nhift dp va thdi gian Xli ly tang thdng qua 9 ehe dp yxt ly thiy - nhift Dilu do, cd thS minh chiing rdng s\i anh hudng nhiet dp va thdi gian ciia phuong phdp XU ly thliy - nhift den mpt sd tinh chdt v^t ly cua gd Bach ddn.
TAI LIEU THAM KHAO
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2. Behbood Mohebby' Ibrahim Sanaei (2005).
Influences of the hydro-thermal, treatment on physical properties of beech wood (Fagus orientalis).
Department of Wood & Paper Sciences, Faculty of Natural Resources & Marine Sciences, Tarbiat Modarress University, P.O. Box 46414-356, Noor, Iran.
3. Behbood Mohebbyl, Kamran Yaghoubi2 and M.
Roohiiia3 (2007). Acoustic Properties of Hydrothermally Modified Mulberry (Morus alba L) Wood Wood & Vspsr Sciences, Faculty of Natural Resources, Taibiat Modares University, P.O. Box 46414-356, Noor, Iran.
4. Hill, C.A.S. (2006). Wood modification. Chemical, thermal and other processes. John Wiley & Son.
5. Militz H. (2005). 21" century products from physical or chemical modification of raw materials.
Gottingen, Germany.
6. P. Rezayati Charani'*, J. Mohammadi Rovshandeh^ B. Mohebby', O. Ramezani 4 "Influence of hydrothermal treatment on the dimensional stability of beech wood". Caspian J. Env. Sci. 2007, Vol. 5 No.2 pp.
125-131, The University of Guilan, Printed in I.R Iran.
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T-\P CHi KHOA HQC VA CONG NGHf LAM NGHB^P S 6 1 - 2014 63
Cong nghiep rCntg
EFFECT OF THE HYDRO - THERMAL TREATMENT ON PHYSICAL PROPERTIES 0¥ Eucalyptus urophylia S.T. BLAKE WOOD
Nguyen Van Dien, Pham Van Chuong SUMMARY
Plantation wood in general and Eucalyptus urophylla wood in particular is a soft, hollow, capillaiy, anisotropic material and easily moisture exchange with surrounding environment which leads to change its size, the physical and mechanical properties and affect the quality and durability of the wooden product Tliis is the main drawback of wood. Therefore, wood modification is one of the major trends in improving wood quality which has been attracted many the world's scientists interests. In this article, we present the effects of hydro- thermal treatment on some physical properties of Eucalyptus urophylla ST Blake wood. The research results show that hydro-thermal treatment with the regimes of temperatures (140"C, 160°C and ISO'C) and times (2 hours, 3 hours and 4 hours) drastically improve its dimensional stability: Anti-swelling efficiency (ASE) increased from 30.52 % to 40.2 % and Water repellency effectiveness (WRE) increased from 17.61 % to 34.44
% , density loss from 4 . 1 8 % t o 28.81 % .
Keywords; Anti-swelling efficiency (ASE), density (y). Eucalyptus urophylla S.T. Blake, hydro-therm^
treatment, water repellency effectiveness (WRE)
Ngu&i phdn bifn: TS. Vu M^nh Tu*ng Ngay nhgn bai: 11/02/2014 Ngay phdn bi^n: 04/3/2014 Ngay quyit dinh dang: 07/3/2014
64 TAP CHI KHOA HQC vA C 6 N G NGH? LAM NGHIEP SQ 1 - 2014
