Development of reactive rotational moulding process

Abstract

A recent revival of industrial interest in rotational moulding of reactive liquid polymers has led to renewed research efforts in this area of polymer processing. This paper describes the design and construction of a reactive liquid polymer feed system for use in reactive rotational moulding. This feed system allows multiple material shots to be added to the mould without the need to stop mould rotation. The paper also describes work to develop a control technique that explores the exploitation of changes in ultrasound signal properties to monitor viscosity during cure in reactive rotational moulding (RRM). Tests have been conducted on dicyclopentadiene (DCPD) in a static off-line rig, to simulate the conditions that are expected during rotational moulding. The signals propagated through the DCPD indicate a rise in ultrasonic velocity during cure, associated with mechanical property changes owing to increased crosslinking. This technique is non-intrusive, and measurements can be obtained real-time for the duration of cure.