Polyethylene teraphtalate (PET) is one of the most commonly used commercial polyester for textile and other applications. produced in worldwide including packing. In the past decade, annual growth of PET applications is anticipated 5–6% for the textiles and about 5% for packaging applications. The most of PET polymer is used in the field of textiles. Polyester fibers ranked the first place in the worldwide production of synthetic textile fibers with an output of 18.9 million tons which corresponds to 60% of market share where the worldwide production of synthetic textile fibers was 32.995 million tons in the year of 2000. Among the polyester fibers, PET fibers have the largest production capacity compared to polybutylene teraphtalate (PBT) and polytrimethy- lene terephtalate (PTT). Three to 5% waste occurs during PET fiber production. Those wastes can be classified into three distinct groups.
A major problem faced by the plastics industry is that of waste disposal. Recycling material would appear to offer a solution which is satisfactory in terms of preventing envi- ronmental pollution. Increasing interest has recently, been focused on the recycling of plastic wastes, especially Poly (Ethylene Terephthalate) (PET). PET recycling represents one of the most successful and widespread examples of polymer recycling. The main driving force responsible for the increased recycling of post-consumer PET is its wide- spread use particularly in the beverage industry.
Recycling of PET can be carried out according to dif- ferent strategies. In particular, the post-consumer PET can be depolymerised to re-use the regenerated monomers as raw materials for a new polymerisation process (chemical recycling) or can be reprocessed after washing and grind- ing (mechanical recycling). Otherwise, a common problem faced during mechanical recycling of PET is the degrada- tion of the polymer that leads to a reduction of its average molecular weight (MW) , as well as to mechanical properties deterioration.