reactant 指的是：反應物。
processing aid指的是加工助劑。
例句：
reactant
1、Oxygen is often used as reactant in chemical processes.
在化學過程中，氧氣經常充當為反應物。
2、The effects of temperature, the quantity of catalyst used, and reactant feed rate on hydrosilylation was discussed.
考察了溫度、催化劑用量、加料速率等因素對苯乙烯與甲基二氯矽烷矽氫加成反應的影響。
3、The effect of process conditions, such as microwave, reactant ratio, catalyst andsolvent etc, on the nucleophilic substitution and yield of product were investigated.
考察了微波技術、反應物料比、催化劑以及溶劑等主要條件對親核取代反應和產物收率的影響。
processing aid
1、Effect of binary processing aid on rheology and mechanical properties of HDPE.
復合加工助劑對HDPE流變性能和力學性能的影響
2、Is the production of organic tin heat stabilizers, ACR processing aid of theintegrated enterprise.
是生產有機錫熱穩定劑、ACR加工助劑的綜合企業。
2、Other polymer additives are colorants, antistatic agents, foaming agents,preservatives, and processing aid or lubricants. fugitive tinting colours.
其它聚合物添加劑包括染色劑、抗靜電劑、發泡劑、防腐劑和加工助劑或潤滑劑。標誌色，著色劑，指色劑