طي مدت ماندگاري نوشابه هاي گازدار و اثر آن روي نفوذ گاز كربن ديوكسيد PET مطالعه تغييرات خواص فيزيكي و مكانيكي بطري هاي

Study on the Variation in the Physico-mechanical Properties of PET Bottles During Shelf-life of Carbonated Beverages and its Effect on Permeation of CO2

Variations in the physico-mechanical properties of PET carbonated beverage bullies during shelf-lite have been studied at different temperatures. Several carbonated beverage bottles were kept at two temperatures (10 and 20°C) for 4.5 months. During two weeks physical properties such as pH, density and CO2 gas permeation of bottles as well as the mechanical properties were determined at two temperatures. The results show that pH and density of PET bottles have not changed during shelf-life at two different temperatures, but there is a reduction in pressure of CO2 at 20°C and after 4 months, which it reached half its level. On the other hand. PET bottles show a reduction in meehanical properties after 10 weeks residence time due to the interaction between the beverage and the bottles.