Glass packaging takes a step forward

In a joint research project incorporating scientists from the United Kingdom, France and the DUBBLE beamline at the European Synchrotron Radiation Facility (ESRF), the teams monitored the change in the structure of zeolites, crystalline solids, which they claim helped to create an almost perfect glass when heated under controlled conditions that respected this structure.

The teams say they were able to do this by recording vibrations involving groups of atoms in zeolites that subsequently characterise the glass. The full results of the research were published in the last issue of Science​ magazine.

Zeolites are porous crystalline aluminosilicates, presenting a regular arrangement of cages. In their natural state, they are components of soils and can be barriers against the migration of radioactive elements. In their synthetic form, zeolites are industrially applied as components of washing powders and in the cracking of petroleum to make gasoline.

Due to their cage structure, zeolites have a low-density configuration. They melt at around 900°C, lower temperatures than most similar materials, such as silica (sand), which melts at twice this temperature.

What the scientists have discovered is that if the heating process is carried out at a slower and more controlled rate, low-frequency vibrational modes are responsible for destabilizing the microporous crystalline structure. When the cages collapse, zeolites contract, becoming 60 per cent more denseheavier than in their original form, and they adopt the structure of an improved glass.

"We have discovered the triggering mechanism",​ says Neville Greaves, first author of the paper.

The scientists say that the upstart of the controlled heating is a mechanically and chemically stronger glass than the glass that is commonly used today.

"We believe this is the key to the synthesis of perfect glass",​ said Neville Greaves.

Would this mean that, if dropped, sophisticated fragrance bottles would no longer break?

"This research could lead to that, but it is still far away. This would also mean making glass invulnerable to water, for instance",​ Greaves said.

The current study is on-going and the researchers say that the final aim is to find out the conditions in which the perfect glass forms.

The discovery could be good news for glass manufacturers, who for many years have seen their business eroded by increasingly sophisticated resins that are cheaper to produce, stronger and often come with a finish that can match the quality of glass.

US company Eastman Chemicals recently launched a glass polymer that it has developed specifically for premium cosmetics and fragrance products. The company claims that the flexibility of Eastar Copolyester EB062 means that it can be blow-moulded into a broad range of shapes using a thick wall that does not compromise quality.

The advent of such glass alternatives means that glass packaging manufacturers have to move fast to progress their industry if they are going to stand up to the tough competition such resins now provide. But, this latest European research looks like a step in the right direction.