1、增(zeng)塑劑與樹脂間的(de)相(xiang)容(rong)(rong)(rong)性(xing)(xing)(xing)(xing)：一般來說，助(zhu)(zhu)劑只有(you)與樹脂間有(you)良好(hao)的(de)相(xiang)容(rong)(rong)(rong)性(xing)(xing)(xing)(xing)，才能使助(zhu)(zhu)劑長期、穩定、均(jun)勻地存于制(zhi)品中，更好(hao)地發(fa)揮其(qi)功能，如果相(xiang)容(rong)(rong)(rong)性(xing)(xing)(xing)(xing)不(bu)好(hao)，則易發(fa)生(sheng)“出汗”或(huo)“噴霜”現象(xiang)；但有(you)時相(xiang)容(rong)(rong)(rong)性(xing)(xing)(xing)(xing)不(bu)好(hao)，制(zhi)品要(yao)(yao)求(qiu)不(bu)太(tai)嚴格(ge)，仍然(ran)(ran)可以有(you)較(jiao)差(cha)的(de)相(xiang)容(rong)(rong)(rong)性(xing)(xing)(xing)(xing)，如填充劑與樹臘(la)間相(xiang)容(rong)(rong)(rong)性(xing)(xing)(xing)(xing)較(jiao)差(cha)，只要(yao)(yao)填充劑的(de)粒(li)度(du)小，仍然(ran)(ran)能基本(ben)滿足制(zhi)品性(xing)(xing)(xing)(xing)能要(yao)(yao)求(qiu)，顯然(ran)(ran)用偶聯劑或(huo)表面(mian)活(huo)性(xing)(xing)(xing)(xing)劑處理，才能充分發(fa)揮其(qi)功能。

2、增(zeng)塑劑(ji)(ji)的(de)耐久性：助(zhu)劑(ji)(ji)損(sun)失主(zhu)要通過三條途徑(jing)揮發、抽出(chu)和(he)遷移主(zhu)要與(yu)助(zhu)劑(ji)(ji)的(de)分子量(liang)大小，在介質中(zhong)的(de)溶(rong)解(jie)度及在樹脂中(zhong)的(de)瘠解(jie)度有關(guan)。

3、增塑(su)劑對加工(gong)條件的(de)(de)適(shi)應(ying)性：某些(xie)樹(shu)脂的(de)(de)加工(gong)條伴較(jiao)苛刻，如加工(gong)溫度高(gao)，時應(ying)考慮所選助(zhu)劑會否分解，助(zhu)劑對模具(ju)、設(she)備(bei)有否腐蝕作用。

4、制(zhi)品用途對助劑的制(zhi)約：不同用途的制(zhi)品對助劑的氣味、毒性、電(dian)氣性、酎候(hou)性、熱(re)性能等均有一定(ding)的要求。

5、增(zeng)塑劑(ji)(ji)配合中(zhong)的(de)協(xie)同(tong)作(zuo)用(yong)(yong)和相(xiang)對抗(kang)(kang)作(zuo)用(yong)(yong)：在同(tong)一樹脂體(ti)系中(zhong)，有時(shi)其(qi)中(zhong)兩種(zhong)(zhong)助(zhu)(zhu)劑(ji)(ji)會(hui)產生“協(xie)同(tong)作(zuo)用(yong)(yong)”，比單獨各用(yong)(yong)某(mou)一種(zhong)(zhong)助(zhu)(zhu)劑(ji)(ji)，發揮效(xiao)果功(gong)能大的(de)多。但是如配合不當，兩種(zhong)(zhong)助(zhu)(zhu)劑(ji)(ji)間產生“對抗(kang)(kang)作(zuo)用(yong)(yong)”削(xue)弱每種(zhong)(zhong)助(zhu)(zhu)劑(ji)(ji)的(de)功(gong)能，甚至使某(mou)種(zhong)(zhong)助(zhu)(zhu)劑(ji)(ji)失去作(zuo)用(yong)(yong)，這點應特別(bie)注意，如炭黑與胺類(lei)或酚類(lei)擾氧劑(ji)(ji)并用(yong)(yong)就會(hui)產生對抗(kang)(kang)作(zuo)用(yong)(yong)。