表面活性劑加(jia)入到液(ye)(ye)體中時(shi),即使(shi)濃(nong)度非常小,也會自發(fa)(fa)地引起表(biao)(biao)面(mian)(mian)或界(jie)面(mian)(mian)間張力的強烈降低(di)(di)。表(biao)(biao)面(mian)(mian)活性(xing)(xing)劑(ji)結構上具有兩性(xing)(xing)特點,其一端具有親水(shui)(shui)性(xing)(xing),另(ling)一端則具有疏水(shui)(shui)性(xing)(xing)。這種兩性(xing)(xing)分(fen)子會自身(shen)定向(xiang)排列(lie)在溶(rong)液(ye)(ye)表(biao)(biao)面(mian)(mian)上,極性(xing)(xing)基團伸向(xiang)水(shui)(shui)中,而疏水(shui)(shui)的烴基則伸向(xiang)空氣或者油的界(jie)面(mian)(mian),從而降低(di)(di)液(ye)(ye)體的表(biao)(biao)面(mian)(mian)張力。表(biao)(biao)面(mian)(mian)活性(xing)(xing)劑(ji)能起乳化(hua)、分(fen)散、增(zeng)溶(rong)、潤濕、發(fa)(fa)泡(pao)、消泡(pao)、潤滑、洗滌、柔軟、抗(kang)靜電、防腐蝕(shi)等作用。
表面活性劑在(zai)制漿造紙(zhi)工(gong)業中的使(shi)用越(yue)(yue)來越(yue)(yue)受到造紙(zhi)科學工(gong)作者的重視。據報(bao)道在(zai)英國表面活性劑的消費為紙(zhi)張總產量的0.05%左(zuo)右。
甜(tian)菜堿類表(biao)面(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)算是(shi)應用在清(qing)潔產品中(zhong)常見的(de)兩性(xing)(xing)表(biao)面(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji),所(suo)謂兩性(xing)(xing)表(biao)面(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji),是(shi)分子中(zhong)同時具(ju)有陽(yang)離(li)(li)子親(qin)水基(ji)團和(he)陰離(li)(li)子親(qin)水基(ji)團,在中(zhong)性(xing)(xing)介質中(zhong)呈(cheng)兩性(xing)(xing)。基(ji)本上甜(tian)菜堿類表(biao)面(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)可以和(he)其他任(ren)何種(zhong)類的(de)表(biao)面(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)復(fu)配使(shi)用,其基(ji)本的(de)分子結構是(shi)由季銨鹽(yan)型陽(yang)離(li)(li)子和(he)羧(suo)酸型陰離(li)(li)子(通常)所(suo)組成,原諒(liang)我偷(tou)懶不畫(hua)這個化學式吧。。我想(xiang),我真畫(hua)的(de)話,大家也(ye)會(hui)看(kan)著頭暈(yun)的(de)。
制漿(jiang)過(guo)程(cheng)主要是從要材中(zhong)(zhong)將木素、半纖(xian)(xian)維(wei)素、樹(shu)脂、色素以(yi)及灰分(fen)等盡量(liang)地與(yu)纖(xian)(xian)維(wei)素分(fen)離(li)(li)開,表(biao)面(mian)活(huo)(huo)性(xing)劑(ji)的(de)(de)作用(yong)就在(zai)于分(fen)離(li)(li)雜(za)質(zhi),提純(chun)纖(xian)(xian)維(wei)素。在(zai)生(sheng)產人(ren)(ren)造(zao)纖(xian)(xian)維(wei)的(de)(de)過(guo)程(cheng)中(zhong)(zhong),人(ren)(ren)們往往在(zai)漿(jiang)粕的(de)(de)堿浸(jin)漬時(shi)添加(jia)表(biao)面(mian)活(huo)(huo)性(xing)劑(ji),這(zhe)是借助表(biao)面(mian)活(huo)(huo)性(xing)劑(ji)的(de)(de)分(fen)散(san)作用(yong)和(he)(he)洗滌(di)作用(yong)來達到(dao)除(chu)去樹(shu)脂的(de)(de)效果。在(zai)漂(piao)白工序中(zhong)(zhong)添加(jia)滲透(tou)性(xing)好的(de)(de)陰離(li)(li)子和(he)(he)非(fei)離(li)(li)子表(biao)面(mian)活(huo)(huo)性(xing)劑(ji),能取(qu)得均一(yi)的(de)(de)漂(piao)白效果。此外(wai),在(zai)紙(zhi)(zhi)漿(jiang)漂(piao)洗過(guo)程(cheng)中(zhong)(zhong)加(jia)入洗滌(di)活(huo)(huo)性(xing)物質(zhi)烷基苯(ben)磺酸鈉和(he)(he)壬(ren)基酚聚(ju)氧乙烯醚,也能獲得良好的(de)(de)洗滌(di)效果。另外(wai)在(zai)廢紙(zhi)(zhi)脫墨(mo)、造(zao)紙(zhi)(zhi)施膠、毛毯洗滌(di)及造(zao)紙(zhi)(zhi)涂布(bu)涂料(liao)分(fen)散(san)劑(ji)等,表(biao)面(mian)活(huo)(huo)性(xing)劑(ji)都有(you)廣泛的(de)(de)應用(yong)。