功能材料
功能材料
공능재료
JOURNAL OF FUNCTIONAL MATERIALS
2013年
24期
3576-3580
,共5页
木材%湿度循环%动态吸着%干缩湿胀%非平衡态
木材%濕度循環%動態吸著%榦縮濕脹%非平衡態
목재%습도순배%동태흡착%간축습창%비평형태
wood%cyclical relative humidity%dynamic sorption%hygroexpansion%nonequilibrium state
为了考察水分周期性作用下木材的动态吸着与干缩湿胀行为,将20 mm(T)×20 mm(R)×4 mm(L)和20 mm(T)×20 mm(R)×10 mm(L)的杨木(populus euramericana Cv)试材置于25℃,相对湿度在45%与75%之间正弦变化的环境中,分别在1、6和24 h 3个周期下测定了多个循环过程中试材含水率和弦、径向尺寸的变化情况。结果表明,试材的含水率及尺寸亦呈正弦变化趋势,但是二者在相位上均滞后于相对湿度的变化；随着周期的增加,含水率及尺寸的振幅有所增加,相位滞后有所下降,而试材厚度的增加具有相反的作用；在动态条件下,试材亦存在吸湿滞后和膨胀滞后,其水分吸着系数和湿度膨胀系数与周期正相关,与试材厚度负相关；前期研究基于针叶材提出的动态吸着模型,对于阔叶树种及不同的试材厚度,均获得了良好的模拟效果。
為瞭攷察水分週期性作用下木材的動態吸著與榦縮濕脹行為,將20 mm(T)×20 mm(R)×4 mm(L)和20 mm(T)×20 mm(R)×10 mm(L)的楊木(populus euramericana Cv)試材置于25℃,相對濕度在45%與75%之間正絃變化的環境中,分彆在1、6和24 h 3箇週期下測定瞭多箇循環過程中試材含水率和絃、徑嚮呎吋的變化情況。結果錶明,試材的含水率及呎吋亦呈正絃變化趨勢,但是二者在相位上均滯後于相對濕度的變化；隨著週期的增加,含水率及呎吋的振幅有所增加,相位滯後有所下降,而試材厚度的增加具有相反的作用；在動態條件下,試材亦存在吸濕滯後和膨脹滯後,其水分吸著繫數和濕度膨脹繫數與週期正相關,與試材厚度負相關；前期研究基于針葉材提齣的動態吸著模型,對于闊葉樹種及不同的試材厚度,均穫得瞭良好的模擬效果。
위료고찰수분주기성작용하목재적동태흡착여간축습창행위,장20 mm(T)×20 mm(R)×4 mm(L)화20 mm(T)×20 mm(R)×10 mm(L)적양목(populus euramericana Cv)시재치우25℃,상대습도재45%여75%지간정현변화적배경중,분별재1、6화24 h 3개주기하측정료다개순배과정중시재함수솔화현、경향척촌적변화정황。결과표명,시재적함수솔급척촌역정정현변화추세,단시이자재상위상균체후우상대습도적변화；수착주기적증가,함수솔급척촌적진폭유소증가,상위체후유소하강,이시재후도적증가구유상반적작용；재동태조건하,시재역존재흡습체후화팽창체후,기수분흡착계수화습도팽창계수여주기정상관,여시재후도부상관；전기연구기우침협재제출적동태흡착모형,대우활협수충급불동적시재후도,균획득료량호적모의효과。
In order to investigate dynamic sorptive and hygroexpansive behavior of wood under cyclic relative hu-midity condition,poplar (populus euramericana Cv)specimens,in the size of 20 mm(T)×20 mm (R)×4 mm (L)and 20 mm (T)× 20 mm (R)×10 mm (L),were exposed to sinusoidally relative humidity between 45%-75% at 25 ℃ for 1,6,and 24 h.Moisture changes and radial and tangential dimensional changes measured dur-ing the cycling gave the following results.Moisture and dimensional changes of the specimens were generally si-nusoidal but lagged behind the imposed humidity.The phase lag decreased and the amplitude increased with in-creasing cyclic periods,while specimen thickness had an opposite effect on the phase lag and amplitude.Under dynamic conditions,the specimens showed sorption hysteresis and swelling hysteresis as well,and moisture sorption coefficient and humidity expansion coefficient of them were in positively correlation with cyclic period, but inversely related to specimens thickness.The dynamic sorption model proposed by a previous study based on softwood obtained good agreement with experiment results in this study for hardwood species and different specimen thickness.
