The Function of Blowing Agents

To improve control of the formation of the foam during the process, and to achieve a uniform cell structure, other additives (called nucleating agents) are often used. It is also possible to extrude some thermoplastics in an expanded form by means of direct gassing, together with nucleating agents. 

The main gases used as blowing agents are listed below. 

Name/type Formula Molecular weight Boiling point (°C) 

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