Pressureless sintering of polycarbonate powder compacted at ambient temperature

• Published in: Polymer engineering and science 1998-12, Vol.38 (12), p.1985-1996
• Main Authors: Vick, Linda W., Kander, Ronald G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Evaluation; Exact sciences and technology; Machinery and processing; Miscellaneous; Plastics; Polycarbonates; Polymer industry, paints, wood; Polymerization; Production processes; Sintering; Technology of polymers
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.10368

Solid‐state processing of polymer powders through compaction and sintering has potential advantages over conventional polymer processing methods. However, pressureless sintering of compacted polymer powders has been unsuccessful. In a previous paper (2), room temperature compaction of polycarbonate powder was studied to better understand the fundamental mechanisms that control polymer compaction. This paper focuses on the pressureless sintering of room temperature compacted polycarbonate powder. Thermomechanical analysis was used to characterize the dependence of dimensional recovery on time, temperature, and compaction pressure for compacts formed from both aged and unaged polycarbonate. It was found that all polycarbonate compacts exhibited irreversible expansion when heated to relatively low temperatures (∼ 50°C), with large‐scale expansion occurring near its glass transition temperature. It was concluded that irreversible expansion of polymer compacts is driven by entropic factors. Therefore, parameters that affect the degree of particle deformation during compaction also affect the degree of dimensional recovery that occurs during pressureless sintering.