Solid State Polymerization of PET and PLA for Properties Enhancement

Garments become worn out during wear, and the textile fibres are fractured and damaged. Environmental factors such as daylight and raindrops, as well as the washing process also weaken the fibre properties. All these make the reuse of the materials difficult.

Using the process of Solid State Polymerisation, this project aims to enhance fibre properties and polymerisation performance of polyester collected from post-consumer textiles, without the application of chemicals. As a result, the physical and chemical properties of the fibre are expected to be improved after the treatment. This method makes good use of the polymerisation property of the polyester, with less chemical and energy consumption.


Current solid state polymerisation processes use single-sized materials to enhance the physical properties of polymers, synthetic materials typically used in plastics and resins. While this is a technique more popularly applied in the manufacture of other industrial products, such as bottle-grade PET, a similar technique can be applied to improving the physical and chemical properties of polyester fibre.

Using heat and vacuum method, the solid state polymerisation in improving molecular weight to recycled PET and PLA from used textiles takes around six hours to process. The physical properties of the treated fibres will be good enough for melt spinning and manufacturing of high value garment.

Industry benefit

Unlike the current industry method, the proposed technology will be able to handle materials of varying forms and sizes, both particles and fibres, and in a wider application. 

Technological breakthrough

The simple and low-cost process required to upgrade the properties of recovered PET and PLA materials proves to be a viable solution to meet the growing demand for fibres in the clothing industry. The solid-state polymerisation process can potentially expand the applications of the recycled polymeric textile materials, bringing in more surprisingly useful benefits to the textile industry.

Licensing Details

For more details, please contact us. (Email:; Tel: (852) 2627 0180)

Related ITF project
Research Start Date 2017-03-30