Peta timbul, peta jenis ini menggambarkan bentuk permukaan bumi yang sebenarnya, misalnya peta aid. The excessive plasticization temperature of PET in the vary of 280 °C (536 °F) is the rationale why virtually all frequent organic impurities equivalent to PVC , PLA , polyolefin , chemical wooden-pulp and paper fibers, polyvinyl acetate , soften adhesive, coloring agents, sugar, and protein residues are reworked into coloured degradation merchandise that, of their flip, may release as well as reactive degradation merchandise.
Clear merchandise may be produced by quickly cooling molten polymer under Tg glass transition temperature to kind an amorphous stable Like glass, amorphous PET kinds when its molecules are usually not given sufficient time to arrange themselves in an orderly, crystalline vogue because the soften is cooled.
One technique to alleviate that is to use a copolymer Comonomers akin to CHDM or isophthalic acid lower the melting temperature and scale back the diploma of crystallinity of PET (especially important when the material is used for bottle manufacturing).
This purpose is solved by degrading the PET bottle flakes—already throughout their first plasticization, which will be carried out in a single- or multi-screw extruder—to an intrinsic viscosity of about 0.30 dℓ/g by including small portions of ethylene glycol and by subjecting the low-viscosity soften stream to an efficient filtration instantly after plasticization.
As a result of PET is a wonderful water and moisture barrier material, plastic bottles produced from PET are extensively used for tender drinks (see carbonation ). For sure specialty bottles, such as these designated for beer containment, PET sandwiches a further polyvinyl alcohol (PVOH) layer to further cut back its oxygen permeability.