TABLE OF CONTENTS What does the future hold for rotational moulding? The main areas where there is scope for improvements are materials, moulds and manufacturing equipment. The following sections consider each of these in turn.
Over the next 20 years, many more materials will become available for rotational moulding. It is already apparent that most of the large materials suppliers are taking an interest in the process. In recent years there has been a rapid increase in the fundamental understanding of polymer chemistry. This has led to new types of monomers being combined to create exciting new properties, even in traditional materials such as polyethylene. This work will undoubtedly continue to increase dramatically so that polymers can more easily be designed to have specific characteristics conductivity, paintability, toughness, processability, etc. A fundamental problem that rotomoulders face is avoiding thermal degradation of the plastic. It is encouraging therefore that more researchers with an understanding of the chemistry of thermal stability are turning their attention to rotational moulding materials. Also, the drive towards shorter cycle times reduces the exposure of the plastic to the damaging effects of long times at high temperatures. This will speed up the development of new resins for rotomoulding.
At present, whilst we do not know everything about what makes a good rotomoulding resin, we can define some of the basic requirements thermal stability, low zero shear viscosity, low viscosity soon after melting, and low elastic modulus in the melt. At a more fundamental level...
