炭化楊木單板制備膠合板的氧指數和熱重分析

林業(yè)工程學(xué)報,2016,1(2):17-20Doi:10.13360/isn,2096-139.2016.02.03炭化楊木單板制備膠合板的氧指數和熱重分析關(guān)明杰',常馨曼',薛明慧',王炳忠2’,翟通軍2(1南京林業(yè)大學(xué)材料科學(xué)與工程學(xué)院南京210037;2連云港南方木業(yè)有限公司,江蘇灌南222500)摘要:通過(guò)研究不同炭化處理溫度下的楊木單板制備膠合板的氧指教和熱重分析,以評價(jià)其阻燃性能。分別將160,180和200℃炭化處理后的單板熱壓制成5層對稱(chēng)結構膠合板,氧指數和熱重分析結果表明:炭化處理后的膠合板氧指數均高于未處理的膠合板,當炭化條件為200℃和2h時(shí),膠合板氧指數最大值為30.3%,達到B3級難然材料標準。由TG-DIG曲線(xiàn)可知,炭化處理前后膠合板的TG、DTC曲線(xiàn)變化趨勢完全一致,主要差異體現在最終的成炭率、肩峰及特征峰對應的具體溫度上。炭化條件為200℃和2h時(shí)的最終成炭奉為21·04%達到最大值;肩峰對應溫度隨炭化溫度的升高而降低,炭化處理后膠合板特征峰對應溫度均小于未處理的膠合板。關(guān)鍵詞:楊木;炭化處理;氧指數;熱重分析;膠合板中圖分類(lèi)號:TU531.2;T653.3文獻標志碼:A文章編號:2096-1359(2016)02-0017-04Oxygen index and thermalgravimetric analysis ofpoplar plywood by carbonized veneerGUAN Mingjie, CHANG Xinman, XUE Minghui, WANG Bingzhong, ZHAI Tongjun(1. College of Materials Science and Engineering, Nanying Forestry Univeristy, Nanying 210037, China;2. Nanfang Wood Products Ltd. Co. Liangyungang, Guannan 222500, Jiangsu, China)Abstract: This paper aimed at investigating the effect of veneer carbonization treatment on the fire resistance propertieof poplar plywood by means of Oxygen Index(OI)and thermalgravimetric analysis. The poplar veneers carbonized in160, 180 and 200 C respectively for 2 h were used to produce five-layer plywood with melamine-urea-formaldehyderesin. a series of parameters of the carbonized plywood were tested in aspects of bonding shear strength, Modulus of Elasticity( MOE), Modulus of Rupture( MOR)and Ol Thermalgravimetric analysis was also used to analyze the thermalproperties of plywood correspondingly. The results showed that the bonding shear strength and mor decreased as the in-crease of carbonized temperature of poplar veneer, while MOE of plywood increased with the increase of carbonized temperature slightly. As a whole, bonding shear strength, MOE, MOR of the plywood from carbonized veneer declined obviously compared with those of control group. Bonding shear strength and mOR of the carbonized plywood from 200C and2 h decreased by 12. 7% and 38. 3% respectively, and MOE of the three carbonized plywood declined 26% to 30%. TheOI results showed that the oI in carbonization treatment groups were higher than that of control group. At the carbonize-tion condition of 200 and 2 h, the ol of the carbonized plywood was 30. 3%, reaching grade B, standard of refractorynaterials according to the classification for burning behavior of building materials and products( GB 8624-2012) Fromthe TG-DTG analysis curves, the variation tendency of the four groups were consistent, the differences were mainly inthe specific temperatures of final char yield, the acromion and characteristic peaks. Under the condition of 200C andh, the final char yield was 21. 04%, reaching the maximum value among four plywood groups. The temperature of acromion decreased with the rising of carbonization temperature, and the temperature of characteristic peaks in the carbon-ized groups were lower than that of control plywood. Generally, carbonization treatment on veneer improves the final charyield and Ol of plywood. It is supposed to be a new way to improve the fire resistance of plywood without any chemicalKey words: poplar; carbonization treatment; oxygen index; thermalgravimetric analysis; plywood修回日期:2015-11-03中國煤化工收稿日期:2015-07-3基金項目:蘇北科技發(fā)展計劃-科技型企業(yè)技術(shù)創(chuàng )新項目(BC2013425);江蘇高校優(yōu)勢學(xué)利CNMHG作者簡(jiǎn)介:關(guān)明杰,女,副教授研究方向為竹木材的加工利用。 E-mail; mingjieguand@ hotmailcom林業(yè)工程學(xué)報第1卷楊樹(shù)是重要的速生樹(shù)種,基本密度為0.35g/汽對單板進(jìn)行炭化處理。炭化時(shí)間均為2h時(shí),設cm3,顏色淺,含水率高極易加工,我國南北方均定炭化溫度分別為160,180和200℃,分別標記為有廣泛種植。但楊木單板材質(zhì)軟尺寸穩定性差,a、b、c組,另設對照組d(表1)。制成的膠合板易吸濕產(chǎn)生變形,因此其應用受到廣表1楊木單板炭化分組泛限制。為充分利用楊木資源,增加產(chǎn)品的附Tab,1 Carbonization treatment group of poplar veneer加值,需要對楊木單板進(jìn)行改性處理。目前常用的炭化時(shí)間/h炭化溫度/℃改性方法包括物理和化學(xué)改性方法,物理改性方法中常用的是炭化改性,化學(xué)改性方法則包括乙?；瘑伟褰n等方法23)。由于化學(xué)改性方法引入未處理了其他化學(xué)成分,會(huì )對楊木單板的膠合產(chǎn)生消極影響污染大且后期處理工藝復雜。而炭化處理是通122楊木膠合板制備過(guò)對木材進(jìn)行熱處理降低其組分中吸水羥基的密單板涂膠量為220g/m2(雙面),涂膠后的板度,從而減弱木材的吸濕性及內應力加強木材的坯采用5層對稱(chēng)結構組坯陳放熱壓。熱壓工藝尺寸穩定性4。炭化處理很少添加化學(xué)藥劑,污為100℃、1.0MPa、1min/mm,自然冷卻在20染問(wèn)題少、處理工藝簡(jiǎn)單且炭化后木材具有良好的℃、(65±2)%的調制箱中調質(zhì)平衡,制得與表1耐老化性能、尺寸穩定性及安全、環(huán)保等突出優(yōu)對應試驗編號下的膠合板每組膠合板試驗張數為點(diǎn)。而國內外對炭化木質(zhì)材料的物理、力學(xué)、化5張。學(xué)性能研究主要集中在炭化木材上70,對炭化單1.23楊木膠合板物理力學(xué)性能測試板制備的膠合板的可燃性能評估關(guān)注極少。參照GB/T17657-2013《人造板及飾面人造筆者通過(guò)炭化楊木單板制備膠合板,測試膠合板理化性能試驗方法》測定楊木膠合板的膠合強板的極限氧指數,并對其進(jìn)行熱重分析,以期找到度、彈性模量和靜曲強度等物理力學(xué)性能。炭化處理工藝對膠合板性能的影響規律,從而為今1.2.4楊木膠合板氧指數(OD)測定后國內外對炭化木質(zhì)復合材料燃燒性能研究提供將制得的楊木膠合板鋸制成尺寸為100mm技術(shù)參數,為速生材的綜合利用開(kāi)發(fā)、產(chǎn)出高附加10mm(厚度<10.5mm)的試樣,每組試件數量15值產(chǎn)品提供技術(shù)指導參考。個(gè),在每個(gè)試件距離一端50mm處劃線(xiàn)做標記。材料與方法參照GB/T2406-2009,將試件未劃線(xiàn)一端固定在燃燒筒中,使氧氮混合氣流由下向上流過(guò),用1.1試驗材料點(diǎn)火器點(diǎn)燃試樣頂端,同時(shí)觀(guān)察并記錄試件燃燒時(shí)楊木單板500mm×500mm×2mm,取自江蘇間及燃燒長(cháng)度。試件燃燒時(shí)間達到3min或者燃省灌南縣,單板氣干含水率為7%-10%;三聚氰胺燒長(cháng)度超過(guò)50mm時(shí),所需最低氧氣濃度即為試改性脲醛樹(shù)脂,固含量52.6%,黏度190mPa·s,由件氧指數。經(jīng)反復測試,找出達到臨界值的氧氣濃江蘇舜天利華木業(yè)有限公司提供。度,得到試件的氧指數。炭化箱,南京恒裕儀器設備制造有限公司,型1.2.5楊木膠合板熱重分析號THX-3;電加熱蒸汽鍋爐,上海捷士服裝機械有將制得的楊木膠合板研磨成粉末并過(guò)60目限公司,型號DZC-4.5E。JF-3氧指數測定儀,南(0.25mm)篩網(wǎng),將所得粉末置于高純動(dòng)態(tài)氮氣京市江寧區分析儀器廠(chǎng);TG209F3 Tarsus型熱重內,從室溫升至700℃(升溫速率為10℃/min),分析儀,德國 NETZSCH公司。進(jìn)行熱重分析。1.2試驗方法1.2.1楊木單板炭化2結果與分析由電加熱蒸汽鍋爐提供炭化處理過(guò)程中所需2.1膠合板物理力學(xué)性能的過(guò)熱蒸汽作為保護氣體,隔絕氧氣的同時(shí)參與部楊木膠合板的膠合強度、彈性模量和靜曲強度分加熱,使溫度過(guò)高時(shí)木材不致燃燒損毀。測試結果見(jiàn)表2。隨著(zhù)炭化溫度的升高,膠合板的將楊木單板放入炭化箱中調節炭化箱溫度至膠合強度和靜rV凵中國煤化工彈性模量卻預設溫度。溫度達到后,打開(kāi)電加熱蒸汽鍋爐維略有提高這可CNMH板的表面潤持蒸汽壓力0.2MPa,持續向炭化箱中通入過(guò)熱蒸濕性降低膠液滲透少,形成的膠層更厚膠層為脆第2期關(guān)明杰,等:炭化楊木單板制備膠合板的氧指數和熱重分析性多孔高密度層,可提高膠合板的彈性模量,但對規定:B1級為難燃材料,B2級為可燃材料,B1級氧強度的貢獻不大。因此,隨著(zhù)炭化溫度的升高,處指數O≥30%,B2級氧指數OI≥26%。由圖1可理后的單板壓制的板材抗彎彈性模量有增高的現知,C組的氧指數達到B級難燃材料的標準,而A、象,但與對照組相比,炭化單板所制膠合板的3項B、D組均為B2級可燃材料。單板炭化處理可以在性能指標都有明顯下降,抗彎彈性模量的下降最明定程度上提高膠合板燃燒的氧指數,從而降低膠顯,降幅達到26%~30%,而C組的靜曲強度下降合板的燃燒性能達到38.3%,膠合強度的下降達到12.7%。表2炭化單板膠合板的基本物理力學(xué)性能Tab 2 Basic physical and mechanical properties ofplywood by carbonized veneer/M編號膠合強度彈性模量靜曲強度A2.2244.33B2.14C2.06D2.36673753.17圖1膠合板氧指數Fig 1 Oxygen index of plywood2.2膠合板氧指數膠合板的氧指數如圖1所示,D組的氧指數為2.3膠合板熱重分析9.2%,A組為29.8%,B組為29.5%,C組為采用熱重法得到程序控制溫度,各組試件的質(zhì)30.3%,即炭化組膠合板的氧指數均大于對照組,量隨溫度變化的曲線(xiàn)(TG曲線(xiàn))及對熱重曲線(xiàn)進(jìn)但測試出的炭化組之間氧指數差異不明顯。根據行一次微分所得的微商熱重曲線(xiàn)(DTG曲線(xiàn))如圖GB8624202《建筑材料及制品燃燒性能分級》2所示。80A組2.580B組TO7.5§240-10.02010020030040050060070012500200300400500600700溫度/℃80+C組TO80D組DTG50004005006000100200300400500600700溫度/℃C溫度/℃圖2各組試件的TG-DIG曲線(xiàn)Fig 2 TG-DTG curves of carbonized groups and control group由TG和DTG曲線(xiàn)可看出:在室溫至100℃范是由于殘余木質(zhì)素的熱解。4組試件在280~295圍內出現一個(gè)失重峰,此階段主要是楊木膠合板的℃之間均出現一個(gè)肩峰,該峰值說(shuō)明以半纖維素和水分析出,當溫度達到80℃時(shí)已基本完全失重;在木質(zhì)素為主要的聚合物在此溫度階段達到熱解最100-400℃范圍內出現一個(gè)較大失重峰,這是由大程度,楊木膠合板進(jìn)入以纖維素和木質(zhì)素為主要于大量的揮發(fā)分析出,溫度達到400℃時(shí),膠合板熱解聚合物的20-35,之間,DTG曲的失重率約為70%;溫度高于400℃后,隨著(zhù)溫度線(xiàn)出現一個(gè)牛中國煤化質(zhì)素出現熱的增加,失重速率逐漸放緩,這時(shí)木材的失重主要解高峰1,互,曲線(xiàn)變化趨勢20林業(yè)工程學(xué)報第1卷完全一致,主要差異體現在最終的成炭率、肩峰及nal of Central South University of Forestry Technology, 2014特征峰對應的具體溫度上。34(3):99-1034組膠合板熱解的最終成炭率、肩峰及特征喹[2]雷得定,周軍浩,劉波,等.木材改性技術(shù)的現狀與發(fā)展趨勢[J].木材工業(yè),2009,23(1):37對應溫度見(jiàn)表3,未處理組最終成炭率為20.55%,Lei DD, Zhou J H, Liu B, et al. 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