Cdng ftghiep rung
NGHIEN CUtJ CAI THIEN TINH CHAT VAT LY VA CO HOC CUA GO XOAN TA {Melia azedarach L.) B A N G HOA CHAT Trinh Hiln Mai
Trudng Bgi hoc Ldm nghiep T O M T A T
TrcHig nghien ciiu nay, g6 Xoan ta {Melia azedarach L.) 10 tuoi dug'c gia cong theo cac tifiu chuan kiem tra tinh chit vat ly vk oa hpc ciia go, ti^p theo, mlu go dugc bifin tinh bang phuong phap ngam tam vdi 3 Ioai h6a chit;
melamine urea formaldehyde (MUF) 6 nong do 15%, 1,3 dymethylol 4,5 djiirydroxy ethylene urea (DMDHEU) o nSng d0 30% vk hat nano Si02 a nong do 2 g/1, Mau go sau ngam tam voi dung djch MUF va DMDHEU duoc say a 40''C trong 48h, 80°C trtmg 24h, r6i tiSp tyc xii ly nhiet d 120''C trong 4h. Mau go sau khi ngam tim vol hat nano SiOj duoc de on dinh a di^u ki|n do i m 65%, nhi?t d§ 20°C trong 2 tuin, KSt qua Idem tra tinh chat co vat ly cho thSy chat luong cua gd Xoan ta bien tinh voi c4c h6a diat noi Iren dui^c cai thiol 6 miic do nhat djnh. Cu th^: hieu suit diong hiit nuoc dat tir 22 - 27%, h5 so chong truong no dat tu 10 - 32%, do Cling tmh tang tir 10 - 60% va kha nang chiu uon (d$ bSn u6n tmh va modul dan hoi u3n ffiih) tang nhf so vdi mlu doi chung, Nghien curu chi ra co thd six dpig phuong phap bien tinh bing hoa c^it de cai t h i ^ tinh chat vat ly va co hoc cho go Xoan ta.
Tir khoa: DMDHEU, go bien tinh, MUF, nano SiOz, tinfa chat cor h^c, vat ly.
I. S^T VAN DE
Xoan ta hay Sau dau co ten khoa hoc la Melia azedarach. L. la mgt lo^ti thue v^t thudc hp Xoan (Meliaceae) phin bo chii ydu d Viet Nam, L^o, Campuehia. Ridng d Viet Nam doc theo tir BSc vao Nam hiiu nhir tinh nao cimg cd sir phan bd ciia cay Xoan mpe tir nhien hoac dugc trdng. Day la loai cSy than gd, kich thirdc ldn, cd thd cao ddn 20 - 30 m, dirdng kinh 30 - 50 cm. Go Xoan thu^c gd nhdm V, cd loi mau hdng hay nan nhg,t, dac xam trang;
gS nhe, mem, dd gia cdng. Gd Xoan sau khi ngim kha bdn, khd bi m6i mgt, cho nen gd Xoan thudng dugc diing trong xay d^rag, trang tri ngi that v i didu kh3c... than v i ciii Xoan cung cip mgt lugng tihi?t ldn. Cay Xoan trdng sau khoing 5 - 6 nam la cd the thu hoach va neu trdng lay gd ldn thi keo dai tii 8 - 10 nam. Dac biet cay Xoan cd kha nang tai sinh (mgc lai tii gdc cii da thu hoach cay) tir 3 - 4 lin. Vdi dac diem sinh hgc nhu tren ciing nhu gia tri su dung ve nhieu mat ndn Xoan Ii loai ciy trdng lim nghidp c6 tiem nang phat trien rdng rai.
Tir nam 2007 - 2010, Thac si Ho Van Giang, Tnrong Dai hgc Lam nghi?p, d i chii tri thue hien de tai nghien cuu cip nhi nude
"Nghien cuu tgo giong Xoan ta (Melia azedarach L.) bien doi gen". De tai di su;
diing cac gen muc tieu de chuydn vao doi tuong Xoan ta, nhim t^io ra gidng Xoan ta bien ddi gen cd k h i nang sinh trudng nhanh, chit lugng gd tdt, gdp phan ning cao gia tri kinh te va gia tri sii dung cua gd Xoan ta.
Theo "At lat cdu tao, dnh chdt go vd tre Viet Nam", eae can bg ciia Vien Khoa hgc Lam nghiep Vi?t Nam d i cdng bd ve mgt sd dac diem ciu tao thd dai, hien vi, tinh chit co vat ly CO ban eua go Xoan ta nhu: khoi lugng the tich, h§ sd CO nit, iing suit udn, nen, va dap, tach (Nguyen Dinh Hung vd cpng su, 2009).
Theo dd, gd Xoan ta mem, nhe, cd van dep, go CO khdi lugng thd tich thip (0,49 - 0,55 g/cm'), he sd co nit the tieh trung binh, dg ben CO hge yeu, dg bin tir nhien trung binh. 0 Viet Nam mdi co cic nghien ciru ve die diem cau t^LO, tinh chat ca, vat ly ciia gd Xoan ta (Le Thu Hiin vd cong su, 2010), cac nghiSn cuu nay cho thay go Xoan ta cd dg hiit nude cao, do bin co hgc thip; do dd gd Xoan ta phu hgp cho sin xu^t d6 mgc noi thit ho|c trong cic ket ciu xiy d\mg it chiu l^rc, khdng diing vao cac ket cau chiu luc v i chiu va cham.
Trong cac giai phip bien tinh gd hien nay
132 TAP CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 1-2018
Cong nghiip rirng thi bidn tinh go bing hda chit la mdt trong
nhutig giii phap tuong ddi cd hieu qui v i dang dupe ting dimg kha rdng rai, cd thd eii thien dupe cac tinh chit co bin eiia gd nhu: tinh hut nude, khi nang dn dinh kich thudc va dp bdn CO hgc, sinh hgc ciia gd. Tuy nhien, mdi loai hda chat khic nhau sS tao ra hieu qui bidn tmh khic nhau ddi vdi timg loai gd. Do do, viec nghien cuu lira chpn hda chit bien tinh phu hgp cho timg loai gd ndi chung, gd Xoan ta ndi rieng la rit quan trpng va cin thidt. Nam 2015, Mdng Due Manh da sii dung Polyetyleneglycol (PEG) de cai thi?n tinh dn dinh kich thudc eiia gd Xoan ta, trong do nghien cuu d i xac dinh dugc khoi lugng thd tich, ty le CO rut va dan nd ciia miu gd bien tinh so vdi mau go ddi chiing. Bdn canh do, cac hda chit nhu: melamine urea formaldehyde (MUF), 1,3 dymethylol 4,5 dyhrydroxy ethylene urea (DMDHEU), bait nano SiOz...
Cting dang dugc su dimg rdng i^i cho bien tinh go tren the gidi va d Viet Nam. Do dd, nghien Cliu niy dupe thue hien vdi muc tieu xac dinh anh hudng cua cac loai hda chit xOr ly (MUF, DMDHEU, SiOi) ddn kha nang chdng hut nude, chdng tnrcmg nd va mdt sd chi tieu vd dp bin CO hpc ctia gd Xoan ta.
n . PHlTONG PHAP NGHIEN ClTU 2.1. Vat iieu nghien cihi
- Go: Gd Xoan ta 10 tudi, dupe khai thac d Bang 1. Kich third'c va so
Quy each mlu (mm) T T x X T x P T
Xuan Mai, Chuong My, H i Ndi.
-Hoa chdt: Melamme urea formaldehyde, DMDHEU, h?t nano Si02.
+ Melamine urea formaldehyde (MUF) su dyng trong nghien cuu cd tdn thuong mai la Synteko 1380 do hang Casco eung cip, d dang bdt, mau trang. Khi pha MUF dang bdt vdi nude tinh khiet d ty le: 60: 40 (khdi hrgng MUF/khdi lugng nude) t ^ thinh dung dich co dp nhdt 2000 - 4000 MPas (25''C), pH 8,5 - 9,6.
+ 1,3 dymethyl 4,5 dihydroxy ethylene urea (DMDHEU) d d^ing dung dich miu nau dd, li hda chat ciia nganh det.
+ Hat nano dioxit silic (SiOz) cd xuat xii Trung Qudc d dang bpt, hat nlro, min vi cd mau tring, dudng kmh hat tir 7 - 40 nm, dp tinh khiet 98%, sijr dung chit phin tin VH - 25 (kem theo hat nano).
2.2. Phuong phap nghien ciru
2.2.L Cdc budc tien hdnh xiir ly biin tinh mdu go Xoan ta
Gd Xoan ta dupe chat ha, tien hanh xe pha rdi xe thanh, say den dp am 15 - 18% sau do gia cdng mau de kiem tm cac tinh chit: ti le tang khdi lupi^, ti le ting thd tich, ti le hiit nude, ti le truang nd, do ciing tirih, do ben udn tnih, modul din hdi udn tuih. Kich thudc v i sd lupng mlu ciia mdi loai dupe ghi trong bang 1.
lirgng man thi nghiem
T T ChitiSu Solu^ng
mau Tieu chuan
Ti le tang khdi lugng, ti le tang 1 thS tich, ti le hut nude va truong
nd (the tich)
20 X 20 X 30
2 3 4
E>Q cling tinli D o ben uon tinh Modul dan boi uon tinh
50 X 50 X 50 20 X 20 X 300 20 X 20 X 300
60 60 60
TCVN 8048-16:2009 (ISO 4860-1982) TCVN 8048-12:2009 (ISO 3350:1975) TCVN 8048-3 :2009 (ISO 3133:1975) TCVN 8048-4:2009 (ISO 3349:1975) Ghi chu: Tai ca co 4 series Ihi nghlem, bao
gdm 3 series cua mdu go biin tinh vol 3 loai hoa chdt va 1 series cua mdu doi chirng (khong thue
hien qud trinh lam hoa chdt). Sd lu^mg 15 mdujseriesfhoa chai.
tJsS c m KHOA HOC VA CONG NGHE LAM NGHIEP SO 1-2018
Cong nghiip rung
Dd xac dinh inh hudng cua loai hda chit den chat lugng go biln tinh, tien hanh qua trinh ngim tim ip I\rc trong didu kien co dinh tit ca cic ylu td inh hudng nhu: ndng dp, nhiet dd, thdi gian v i ip suat ngim tim... Can cii vao cac nghien ciiu trudc diy (Dieste vd cong si^, 2008; Trinh Hiin Mai, 2010; Phan Tung Hung vd cong su, 2013) l\ra chgn tri sd ndng dp hda chit ngam tim cho mSi Ioai hda chit nhu sau:
Ddi vdi MUF: 15%; DMDHEU: 30% (sii dimg chit xiic tie MgCb: 1,5%); SiOa: 2 g/1. Dung mdi l i nude tinh khilt, duoc tmh toan de pha vdi cac hda chit va tao dupe cac dung dich vdi ndng dp nhu tren. Su dung may khuay tdc do 6000 v/phut khuiy deu dung dich trong vong 2 gid trudc khi tam. Miu thii ciia cac tinh chit khac nhau trong eung mgt series dugc tim 1 Ian trong bdn tam hinh try cd chieu cao 80 cm, dudng kmh day 40 cm, lugng dung dich pha cho mdi lan tim la 10 lit.
Che dd tim ip luc d6i vdi c i 3 loai hda chit tren: Nhidt dd: nhi§t do phdng 25°C; Ap suit:
10 bar; Thdi gian duy tri ip suit: 4h. Sau khi kit thue qui trinh tim miu vdi hda chit, mau dupe vdt ra, lau s^ch hda chat bam tren bl mat, va de rio d dilu ki?n phdng 1 ngay, sau dd:
- Ddi vdi mau go sau ngam tim vdi MUF va DMDHEU dupe siy d 40''C trong 48h, 80°C trong 24h, rdi tidp tuc xu ly nhidt (curing) d nO^C trong 4h. Tilp theo, de miu on dinh 2 tuin trong dieu ki?n dg am 65%, nhiet dp 20*'C trudc khi tiln hinh kiem tra thih chit co v$t ly.
- Ddi vdi mau gd sau ngim tim vdi nano SiOi dupe dl on djnh d dieu kien dp am 65%, nhidt do 20°C trong 2 tuin trudc khi tiln hanh kiem tra tmh chit co vit ly.
2.2.2. Kiem tra tinh chat cua mdu go Men tinh vd ddi chung
- Tinh toin ti 1? ting khdi lupng (WPG) ciia go:
fVPG (%) = " " ' " " " " x l O O m„
Trong dd: mo - khoi lupng miu go khd
kiet trudc khi tim hda chit, g;
mi - khdi lugng miu gS kho kiet sau khi tim hoa chit, g.
- Tinh toan ti lg tang thi tich (BE) ciia go:
BE(%) = ^' " ^'' X 100 Trong dd: Vo - thi tich miu g§ kho kiet trudc khi tim hda chit, mm ;
V] - the tich mau go khd kiet sau khi tim hda chat, mm^.
- Tinh toan hi?u suat chong hut nude WRE (Water Repellent Effectiveness):
Trong do:
WRE - hieu suit chong hut nude cua mlu gd biln tinh,%;
WUdc - ti 1? hut nude cua miu go ddi chiing, %;
WUbi - ti le hiit nude ciia mau g5 bien tmh, %, - Ti le hiit nude (WU) dupe xac djnh theo cong thiic:
WU (%) = «100
Trong do:
WU - ti Id hiit nude ciia mau gd, %;
mi - khdi lupng ciia mlu gd sau khi ngam nude d eac mdc thdi gian khae nhau, g;
mi - khdi lupng ciia miu gd khd kiet sau biln tinh, g.
Tmh toan h? so chdng trucmg nd ASE (Anti Swelling Efficiency):
ASE (%) TS,, -TS„
TS,^ xlOO Trong dd: ASE - h | s6 chong huong nd ciia mau go bien tinh,%;
TSdc - ti Id truang nd the tich cua mau go ddi chiing, %;
TSbt - ti Id trucmg nd thi tich cua m5u gd biln tinh, %.
Ti le truong nd thi tich (TS) dugc xac dinh theo cdng thue:
75'(%) = !-xlOO T^P CHi KHOA HQC VA CONG NGHE LAM NGHIfP SO 1-2018
Cong nghiip rirng Trong do: TS - ti le tnrong nd thd tichkhi
ngim nude ciia miu gd khi ngim miu 2 tuin trong nude, %;
V| - thd tichciia miu go sau khi ngim nude, mm';
Vl - the tichcua miu gd khd kiet sau biln tinh, mm'.
- Cac chi tidu khic nhu: dO cung tirih, dp ben udn tihh, md dim dan hoi udn tnih dugc xic dinh theo phuang phip quy dinh trong tieu chuin trinh biy d bing 1.
m . KET QUA VA THAO L U ^
3.1. Ti le tang kh6i lugng (WPG) cua m i u go biea tinh
Cac thi nghiem da su dung 03 loai hda chit dd xu ly gd Xoan ta, dd li hat nano Si02, MUF v i DMDHEU, do nano SiOi dupe sii dung vdi ndng dg rit nhd nen trong qua trinh tinh toan da khdng xem xet din ti le tang khdi lupng (WPG) cua g3 biln tihh bing nano SiOa- Kit qua tinh toin ti le tang khdi hrpng cua go biln tmh bing MUF vi DMDHEU dupe thi hien trong bang 2.
Bang 2. Ti 1^ tang khoi luong cua mau go biln tiah Dac tnrag mau
Tri so tnmg binh Sai quan phuong
WPG (%) DMDHEU
11,35 0,68
MUF 8,74 1,27 Tir bing 2 cho thiy, ti le tang khdi lugng
cua gd xu ly bing DMDHEU ldn ban so vdi gd xii ly bing MUF. Dilu niy cd nghia ring, luong hda chit DMDHEU di chuyen vao va tdn tai trong gd nhilu ban so vdi MUF.
Nguyen nhin la do MUF co kieh thudc phin tu ldn ban so vdi DMDHEU nen khi ning tich tu vio trong gd cung kem hon.
3.2. Ti 1^ tang t h i tich (BE) eua m l u go biln tinh
Nghien ciiu ciing da xac dinh ti 1^ tang thd
tich cua gd biln tmh khi xtr l^i bing DMDHEU va MUF. Co che chu yeu lam tang kich thudc eua gd do li do trong qua trinh ngam tim cac hda chit mdt phin da di chuyen vao khoang trong giua cac te bao va vach te bao (giiia cac mixencellulo), thue hien qua trinh polymer hdatrong giai d o ^ "curing" vi tich tu d trong vich t l bio gd din din kich thudc gd tang len (Hill, 2006). Kit qua xic dinh ti le ting thi tich ciia gd Xoan ta biln tinh dupe the hien trong bing 3.
Bang 3. Ti le tang the tich ciia mSu gS bien tinh Dac tnmg mau
Tri so tnmg binh Sai quan phuong
DMDHEU 5,10 0,48
BE (%) MUF
3,43 0,47 Tu ket qua bing 3 cd the thay, ti le tang die
tich cua go bien tuih b i i ^ DMDHEU km hon so vdi MUF. Dieu nay hoan toin phii hpp vdi kit qui xac dinh ti lg tang khdi hipng ciia miu trinh biy d phan treiL
3.3. Ti le htit nird^c va hieu suat chong hut nird^c cua go bien tinh
Dien bien ti le hiit nude trong thdi gian 2 tuin ngim nude cua go Xoan ta bien tinh va gd Xoan ta ddi chiing dupe the hien trong hinh I.
T ^ P c m KHOA HQC VA CONG NGHE LAM NGHIEP SO 1-2018 135
Cdng nghiip rung
—•—DC - - » - S i 0 2 - * - M U F . - • . . DMDHEU 0 48 96 144 192 240 288 336 384
TliOT gian ngam niroc, h
Hinh 1. Ti le hiit nirdc ciia g3 dli chirng va bien tinh theo thod gian ngim nu-iS^c vach t l bao...; nhimg vdi miu go biln tuih, hat nanoSiOi tao thinh Idp mang mdng bao phu cac bd mat rdng xdp ciia gdgiy nen rao can lim giim kha nang thim thiu ciia nude vao go, hoac cac phan tu MUF, DMDHEU tich tu trong go (rupt, vach td bao, vi cac khoang trdng khic) do qua trinh polymer hda da ngan can siie hiit nude ciia gd, do dd ti le hiit nuoc ciia miu gd biln tinh giam ro ret so vdi mau gS ddi chiing.
Tii hmh 1 ta thiy, tdc do hiit nude ciia go ddi chiing ldn hon rit nhilu so vdi go bien tmh va din dn dinh vio giai doan bit diu tu ngiy thii 4.
Ngoii ra, can cu vao sd lieu tmh toan trong bang 4 vi dd thi troi^ hinh 1 cho thiy ti le hut midc ciia go bien tuih vdi 3 loai hda chit ddu nhd hon so vdi gd ddi chung. Dieu nay cd thi dupe giai thich nhu sau: khi ngam gd vio nude, vdi miu gd ddi chiing, nuoc nhanh chong thim vao cac khoang trdng cuagd nhu tia gd, rdi din khoang trdng giiia cac t l bio. Id m^eh, rudt t l bao.
Bang 4. Ti le hut nutrc cua go Xoan ta doi chungvi bien tinh sau 14 i^ay ngam nude Dac tnrng mliu
Tri s3 tnmg binh Sai quan phuong
Ddi chirug 130,52
12,59
Ti 1| hut nuorc, % SiOj DMDHEU 99,72 102,57 14,76 7,45
MUF 94,75 9,93
S 20 S i s
"S
J 10
.= 5 Ki02 DMDHEU MTIF
m
Hinh 2. Hieu suat cb6ng hut nude cua gS Xoan ta bien tinh sau 2 tuiin ngam nu-6^c TAP CHI KHOA HQC VA CONG NGHf LAM NGHIEP SO 1-2018
Cdng nghidp rung Qua ket qui xac dinh ti le hiit nude eiia gd
Xoan ta sau 2 tuin ngam nude, nghien ciiu ^ tinh dupe hidu suit chdng hiit nude ciia cac loai gd bien tinh bing eac hda chit khac nhau. Kit qui dupe thi hien tren hmh 2.
Bieu do hidu suit ehdng hiit nude ciia gd Xoan ta bien tuih eho thiy, sii dyng 3 toai hda chit deu lam tang kha nang chiu nude cua go Xoan ta. Tren phuong dien danh gia khi ning Bang 5. Ti le truvng no^ the ti'ch cua go Xoan
chdng hiit nude ciia gd biln tinh cd the ket hiin ring, biln tinh bing MUF se mang Iai higu qua cao hon so vdi viec su di^g hai hda chit cdn Iai la nano SiOi va DMDHEU d cac ndng dp hda chit da sii d^ng.
3.4. Ti le chong tnrong nd^ ciia go biln tinh Ti lg truang nd thi tich ciia mau gd biln tuih va mlu ddi ehiing sau 2 tuan ngam nude dupe trinh biy trong bing 5 vi huih 3.
ta doi chirng vi bien tfnh sau 2 tuan ngam nude D|c trung mlu
Tri so trung binh (M) Sai quan phuong (SD)
Doi chirng 14,41
1,01
Ti II trtrong no* the tfch, % SIO, DMDHEU 12,79 9,45 0,73 1,08
MUF 12,97 0,72
DC Si02 DMDHF.U MIIF Hinb 3. Ti l | tnrong no" the tich ciia go Xoan ta bien tinh sau 2 tuan ngam n
35 •
;S 30 8 25 p 2 0
=1
Si02 nMDHFIJ MTIF3
Hinh 4. H£ so chong tnrong na ciia go Xoan ta bien tinh
TAP c m KHOA HOC VA CONG NGHE LAM NGHIEP SO 1-2018
Cdng nghifp rung
Kit qui thi nghi?m thi hien, go Xoan ta sau khi xtr ly biln tinh vdi 3 loai hda chat khic nhau da cd su cai thign nhit dinh vl ti le truong nd thi tich do hiit nude. Cu thi, ti le truang nd the tich cua gS biln tmh da giam tir 10% din 30%. Trong do, gd xu Iy vdi DMDHEU cd hieu qui cao nhit ddi vdi truong nd the tich khi hiit nude, hg sd chdng truong nd thi tich (ASE) len tdi 32% trong khi do he sd chdng truang nd the tich (ASE) ciia gd bien tinh vdi nano SiOj va MUF chi khoing 10%
(Hinh 4). Nhu viy, cd nghia li eac phin tu
DMDHEU cd khi nang di chuyin va tichtiitfii nhit vio trong vich tl bao, nim d khoang trong giiia cac mixen, tao ndn ti Id tang thi ticli BE sau khi bien tinh cao nhit (Bang 3), do do han chl khi nang truong nd thi tfch do hut nude tdt nhat so vdi gS bien tinh vdi hai hoa chat con lai.
3.5. Dp cung tinh ciia gS bien tinh Kit qua xac dinh dd cdng tmh eiia gd Xoan ta bien tinh va go ddi chiing tren 3 mat cat dugc tb£
hien trong eac bing 6 va huih 5.
Bang 6. fid cung tiTnh tren cac mSt cat ciia go Xoan ta doi chirng vi bien tinh LoaigS
Doi chirng SiO:
DMDHEU MUF
M^t cit Tri so trung binh 5.100 6.597 8.057 6.634
ngang (N) Sai quan phuong
471 569 825 486
Mat cat suyen tSm (N) Tri so trung
binh 4.265 5.145 5.660 4.764
SaiquSn phuong 331 581 514 467
MSt cat tiep tuyen (N) Tri so trung
binh 3.925 4.765 5.008 4.754
Sai quan phuang
450 421 321 445
13 DC
sSi02
0 D M D H E U
M C M C X T N g a i i g
M C T T
Qua sd Ii$u ve dQ cung tihh cua go Xoan ta bien tinh va doi chung niian thay, hSu h€t cac nilu g6 duQC xij ly deu co do ciing tmh cao horn so voi mSu g6 doi chung tren ca 3 mat cat. Tuy
Hinh 5. Dd cirng tinh ciia gS Xoan ta bien tinh
nhign, ti 1^ tSng ciia cac mSu gd xii ly bang cic hoa chSt khac nhau la khSng giong nhau, hon nita CO mpt quy lu^t nhSt dinh. Do ia, dp cung tlih ciia mau go xil ly bang DMDHEU la to 138 T ^ P CHi KHOA HQC VA C 6 N G NGHE LAM NGHIf P S 6 1-2018
^g nhat, sau dd ddn miu xti ly bing Si02 v i cudi 3.6. D9 ben uon tinh v i md dun dan hoi uon ciing li MUF. Mot sd nghien ciiu da chi ra ring, tinh ciia g5 bien tinh
neu hda chit tich tu trong vach t l bao cing Sd Ii?u trong bing 7 va hinh 6a, 6b the hien nhieu, dd cung cang duoc cai thien dang kl, dilu dp bin udn tinh va md dun dan hdi udn tmh nay diing vdi DMDHEU (Dieste vd cpng su, ciia go Xoan ta bien tinh v i go ddi chiing.
2008).
Bang 7. D$ ben u6n tinh ciia go Xoan ta bien tinh Loai go biSn
h'nh Doi chirng
SiO:
DMDHEU MUF
Dg beu uon finh (MPa) Tri so trung binh Sai quan phuong
76,3 7,5 93,4 3,2 86,4 4,5 85,4 8,6
f-
H "0 JL •
3-dzl
-1 - S 2 0 . - | - — • - - - | - - | -
0 • •
Mo dun dan hdi udn Unh (GPa) Tri so trung binh Sai quan phuong
7,3 0,4 7,7 0,3 8,0 0,4 7,5 0,7
^ ^
„ | 1 • •
• • • •
• • • •
DC Si02 DMDHEU MUF Hinh 6a. D9 beo uon tinh ciia gS Xoan ta bien ti'nh vii g5 doi chirng
BC Si02 DMDHEU M J F Hinh 6b. Mo dun dan hdi uon tfnh ciia gS Xoan ta bien tinh
TAP CHi KHOA HQC VA CONG NGHf LAM NGHIEP SO 1-2018
Cong nghifp rung
Tix kit qua xac dinh do ben udn tmh vi md dim din hdi cho thiy, cac gia tri do dugc ciia miu gd bien tinh va miu gd ddi chiing cd khac nhau nhimg khdng nhilu. Hay ndi cich khic, xii ly biln thih bing 3 Ioai hda chat da Iua chpn chi tao nen su cii thien nh? vl khi nang chiu uon eiia gd. Ket qui nay phii hop vdi cac nghien ciiu ve cucrng dd udn vi md dun din hdi udn tirih cua gd bien tinh bing hda chit (Trinh Hien Mai, 2010; Diest vd cong su, 2008). C\L thi dugc giii thich nhu sau: Gd bien tmh vdi hda chat nhu MUF, DMDHEU cd dd am thang bing (EMC) giam so vdi gd ddi chiing, dilu nay lim tang cudng do co hpc ndi chung ciia go; tuy nhien, do cic hda chit co thd tich til trong vach te bao, gay nen hien tugng truong nd "bulking", lim giam so lugng mixen chiu l\re tren mot don vi dien ti'ch mat cit ngang cua vich t l bao, do do lira giim cudng dp chiu hrc ciia gd, hai hien tugng nay bii trii cho nhau, lam cho gia tri eua cudng dp udn va md dun dan hdi udn tinh ciia gd biln tinh Mng hda chit thay ddi khdng nhieu so vdi gd ddi chiing (Hill, 2006).
IV. KET L U ^
Gd Xoan ta sau khi xCr ly vdi 3 loai hda chit:
Melamine luea formaldehyde (MUF) ndng dp 15%, 1,3 dymethylol 4,5 dyhrydroxy ethylene urea (DMDHEU) nong dp 30% v i h^t nano Si02 ndng dp 2 g/1 cd chit lugng dugc cii thien d miic dg nhat dinh thdng qua cac chi tieu nhu:
hieu suit chdng hiit nude dat tir 22 - 27%, he sd chdng truong nd dat tir 10 - 32%, dp ciir^
tmh ting tu 10 - 60% v i khi ning chiu uon (dp bin udn tmh va modul dan hdi uon tihh) ting nhe so vdi miu ddi chiing. Kdt qui cho thiy ed the su dvmg phuong phip bien tmh bang hda chit de cai thien tinh chit vit ly vi co hpc ciia go Xoan ta. Tuy nhien, day mdi chi li nghien
Cliu tham dd budc dau ve khi ning biln tinh gd Xoan ta bang cac loai fioa chat, can tilp tuc nghien cihi siu hon vl sir khuech tan va tichtu ciia cic hda chit vio ben trong ciu tnic tl bao go hoac trdn be nmt gd bang cac phuong phap hidn dai, eiing nhu anh hudng ciia ndng dp hoa chit va cac thong sd cdng nghe ciia qua trinh bien tinh gd den chit lugng go Xoan ta bien tuih.
TAI L I | U THAM KHAO
1. Dieste A, Krause A, Bollmus S, Militz H {2008J.
Physical and mechanical properties of plywood produced with 1.3 - dimethylol - 4.5 - dihydroxy ethylene urea (DMDHEU) - modified veneers of Betulasp and Fagussylvatica. HolzRoh - Werkst 66: 281-287.
2. Ho Van Giang (2010). Nghien cuu tgo pong Xoan ta (Meliaazedarach L.) bien doi gen. Bao cdc torn tai de tai cap Nh^ nuac.
3. Nguyin Dinh Hung, Le Thj Thu Hi^n, Do Van Ban (2009). At lat cau tgo, tinh chdt go vd tre Viet Nam.
Nh^ xuat ban Nflng nghiep,
4. LS I h u H l n , Bd V3n Ban, Nguyin Tii Kim (2010). Tinh chdt vdt ly, co hgc vd hudng su dung go cua mdt so lodi cdy cho trong rimg sdn xuat viing Bong Nam bp. Kf yeu Hoi nghi Khoa hoc Cong nghe Lam n ^ i e p voi phat trien mng bin vung va bien doi khi h ^ trang 406-411.
5. Galium Hill (2006). Wood modification: chemical, thermal and other processes. John Wiley & Sons, 2006.
6. Phan Tiing Hung, Trinh Hiln Mai, Nguyin Phan ThiSt (2013). ^nA hudng ciia nong dp hgt nano SiOi den mpt so tinh chdt ca vat ly cda gd Keo lai (Acacia mangium x Acedia auriculiformis) vd go Mo (Manglietiag^auca dandy) bien tinh. Tgp chi Wng nghiip vd Phdl triin nong thon, ISSN 1859-4581, S615, thang 8, 2013.
7. Trjnh Hien Mai (2010). Nghien cdu bien tinh vdn mong bdng nhua melamine formaldehyde dung cho san xudt vdn ddn. De tai cap co scr, Tnrong Dai hpc Lam nghiep.
8. Moig E)iic Mgnh (2015). Nghien cuu gidi ph^
bien tinh dn dinh Idch thirdc go Xoan ta (Melia azedarach L) l ^ g Polyetylraiglycol (PEG). Khoa luan tot nghiep Dai hpc Nong lam Thdi Nguyen,
T>4P CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 1-2018
Cong nghiep rung
STUDY ON IMPROVEMENT OF PHYSICAL AND CHEMICAL PROPERTIES OF MELL4 AZEDARACH L. BY CHEMICALS
T r i n h H i e n M a i Vietnam National University of Forestry S U M M A R Y
In this study, 10 year old Meliaazedarach L. wood was processed according to standards for physical and mechanical testing. Then, the wood samples w ^ e modified by impregnation with 3 types of chemicals:
melamine urea formaldehyde (MUF) at a concentration of 15%, 1,3 dimethylol 4,5 dyhrydroxy ethylene urea (DMDHEU) at a OMicentrationDf 30% and SiOi nanoparticles at a concentration2 g/I, After impregnation with MUF and DMDHEU, the wood samples were dried at 4CfC for 48h, SCC for 24 hours, then heat treated at no^C for 4h. The wood samples impregnated with Si02 were stabilized at 65% moisture content, 20''C for 2 weeks. The results of physical and mechanical testing showed that the quality of Meliaazedarach L. wood modified with these diemicals was improved to a certain extent. Specifically, the water repellenteffectivraess (WRE) was fi'om 22 - 27%, the anti swelling efBciency (ASE in volume) was from 10 - 32%, the static hardness uicreased from 10 - 60% and the flexural strength (modulus of rupture and modulus of elasticity) inireased s l i ^ d y compared with the control samples. The studyindicated that modificatim by chemicals can be used to improve the physical and mechanical properties of Meliaazedarach L, wood.
Keywords: DMDHEU, mechanical and physical properties, modified wood, MUF, nano SiOi.
Ngay nhan bai Ngay phan bien Ngay quyet djnh dang
02/01/2018 29/01/2018 06/02/2018
T^P CHi KHOA HOC VA CONG NGHE LAM NGHIEP SO 1-2018
