表面活性劑有不同的分(fen)(fen)類(lei)方(fang)法(fa)。其一是按(an)(an)(an)離(li)(li)子(zi)類(lei)型(xing)(xing)(xing)(xing)分(fen)(fen)類(lei)。將表(biao)面活性(xing)(xing)(xing)劑溶(rong)(rong)于水中，按(an)(an)(an)離(li)(li)解(jie)(jie)與不離(li)(li)解(jie)(jie)，可分(fen)(fen)為離(li)(li)子(zi)型(xing)(xing)(xing)(xing)表(biao)面活性(xing)(xing)(xing)劑與非離(li)(li)子(zi)型(xing)(xing)(xing)(xing)表(biao)面活性(xing)(xing)(xing)劑。離(li)(li)子(zi)型(xing)(xing)(xing)(xing)表(biao)面活性(xing)(xing)(xing)劑又(you)可按(an)(an)(an)產生電荷的性(xing)(xing)(xing)質分(fen)(fen)為陰離(li)(li)子(zi)型(xing)(xing)(xing)(xing)、陽(yang)離(li)(li)子(zi)型(xing)(xing)(xing)(xing)和兩性(xing)(xing)(xing)型(xing)(xing)(xing)(xing)。其二是按(an)(an)(an)溶(rong)(rong)解(jie)(jie)性(xing)(xing)(xing)分(fen)(fen)類(lei)，分(fen)(fen)為水溶(rong)(rong)性(xing)(xing)(xing)表(biao)面活性(xing)(xing)(xing)劑與油(you)溶(rong)(rong)性(xing)(xing)(xing)表(biao)面活性(xing)(xing)(xing)劑。其三是按(an)(an)(an)分(fen)(fen)子(zi)量(liang)分(fen)(fen)類(lei)，分(fen)(fen)為低分(fen)(fen)子(zi)表(biao)面活性(xing)(xing)(xing)劑與高(gao)分(fen)(fen)子(zi)表(biao)面活性(xing)(xing)(xing)劑。其四是按(an)(an)(an)用途分(fen)(fen)類(lei)，分(fen)(fen)為潤濕劑、乳化(hua)劑、抗靜(jing)電劑、柔軟劑、勻染劑等(deng)。

表(biao)(biao)(biao)面活(huo)(huo)性劑(ji)分(fen)子結(jie)構的特征，是(shi)(shi)包括性質完(wan)全不(bu)(bu)同的兩部(bu)分(fen)，一(yi)部(bu)分(fen)是(shi)(shi)與油(you)(you)有親(qin)(qin)(qin)和性的親(qin)(qin)(qin)油(you)(you)基，另一(yi)部(bu)分(fen)是(shi)(shi)與水(shui)有親(qin)(qin)(qin)和性的親(qin)(qin)(qin)水(shui)基。不(bu)(bu)同品種(zhong)的表(biao)(biao)(biao)面活(huo)(huo)性劑(ji)，其(qi)親(qin)(qin)(qin)水(shui)性與親(qin)(qin)(qin)油(you)(you)性的強弱是(shi)(shi)不(bu)(bu)同的。表(biao)(biao)(biao)面活(huo)(huo)性劑(ji)的一(yi)個重(zhong)要性能指標(biao)是(shi)(shi)親(qin)(qin)(qin)水(shui)親(qin)(qin)(qin)油(you)(you)平衡值（HLB值）。HLB值較(jiao)高(gao)的表(biao)(biao)(biao)面活(huo)(huo)性劑(ji)，其(qi)分(fen)子的親(qin)(qin)(qin)水(shui)性較(jiao)高(gao)，HLB值較(jiao)低則表(biao)(biao)(biao)示親(qin)(qin)(qin)油(you)(you)性較(jiao)高(gao)。

幾種表(biao)(biao)面(mian)活(huo)性(xing)劑(ji)(ji)的HLB值(zhi)(zhi)(zhi)如表(biao)(biao)3所示。HLB值(zhi)(zhi)(zhi)在表(biao)(biao)面(mian)活(huo)性(xing)劑(ji)(ji)的選用中有重(zhong)要意義。例(li)如，HLB值(zhi)(zhi)(zhi)為1~3可作(zuo)為消泡劑(ji)(ji)，HLB值(zhi)(zhi)(zhi)3~6為油包水型(xing)乳(ru)化劑(ji)(ji)，HLB值(zhi)(zhi)(zhi)8~18為水包油型(xing)乳(ru)化劑(ji)(ji)，HLB值(zhi)(zhi)(zhi)12~15為潤濕劑(ji)(ji)。

表(biao)(biao)面(mian)活性(xing)(xing)劑(ji)在軟(ruan)質(zhi)PVC中(zhong)的(de)應用(yong)(yong)，主要是用(yong)(yong)作抗(kang)靜(jing)電劑(ji)、防霧劑(ji)、PVC糊降粘劑(ji)等。有關性(xing)(xing)能將在以下有關部分中(zhong)介紹。表(biao)(biao)面(mian)活性(xing)(xing)劑(ji)在軟(ruan)質(zhi)PVC中(zhong)應用(yong)(yong)時，應特(te)別注意其對PVC熱穩定性(xing)(xing)的(de)影響。某些陽離(li)子(zi)型的(de)表(biao)(biao)面(mian)活性(xing)(xing)劑(ji)對PVC的(de)熱降解有促進作用(yong)(yong)。非離(li)子(zi)型表(biao)(biao)面(mian)活性(xing)(xing)劑(ji)則不會引(yin)起PVC降解。