-To develop the process for isolating bacterial polyesters so that they are of suitable purity and melt behaviour to process into biodegradable oriented food containers.
-To develop new machinery for melting, forming and orienting these polymers in a reproducible manner.
-To characterise the physical, chemical and biodegradation properties of these new containers.
The objectives of this project are as follows:
to develop the process for isolating bacterial polyesters so that they are of suitable purity and melt behaviour to process into biodegradable oriented food containers;
to develop new machinery for melting, forming and orienting these polymers in a reproducible manner;
to characterise the physical properties, chemical properties and biodegradation properties of these new containers.
The major species in the cellular residue that are responsible for the generation of odour during melt processing have been identified.
An instrumented technique for determining polymer colour has been developed and work is progressing to isolate the species associated with colour formation.
The thermal and physical properties of polyhydroxybutyrate/hydroxyvalerate (PHB/HV) copolymers have been characterised and the relationship of these properties to HV content quantified. The effects of organic impurities in melt stability have been quantified and the effect of inorganic impurities are under investigation.
The work on developing polymer processing has led to development of a novel device for plastification, metering and moulding preforms.
To enable the gathering of data on stress and strain behaviour and orientation at high strain rates, an instrumented high speed stretching rig has been constructed.
The work is progressing towards the goal of producing a processable polymer of sufficient purity for food containers and an integrated device to convert polymer granules into oriented containers.