Polyester fibres structure modification using some organic solutions
The treatment causes only minor decrease in fi bre, i.e. yarn strength, while breaking elongation increases signifi cantly, almost up to 150 % in comparison to the untreated sample. Organic solvents, i.e. plasticizer solutions in the organic solvents mixture infl uence fi bre properties in a very favorable way, i.e. they can enable better dyeing, better moisture absorption, easier treatment in further phases of textile products manufacture and generally better usability. X-ray structural analysis was used to examine the infl uence of the treatment of polyester fi bres in the form of fi lament yarn, fi neness 75/26 dtex, with solutions 0.3, 0.6 and 0.9 % hydroquinone and α-naphtole in the solvent mixture which contained chlorophorm and methanol (solubility parameter δ=11.7) on changing of crystalline degree and crystallite size. It was found that treated fi bres showed sharper refl exion on diffractograms than untreated ones, i.e. they showed higher crystalline degree but smaller crystallite size.
Sorption of organic solvents by packaging materials: polyethylene terephthalate and TOPAS®
The sorption of organic solvents (1-butanol and 1-octanol) by polyethylene terephthalate and TOPAS® (cyclic olefin copolymers or COC) was investigated at 3, 23 and 42 °C and was studied by coupling two techniques (in an off-line way): supercritical fluid extraction to GC/MS. Supercritical fluid extraction (SFE) is widely perceived as a technique for the extraction of low to moderately polar compounds. The results obtained enable us to determine the corresponding diffusion coefficients and to show the relation existing between the diffusion coefficient and the following factors: the temperature, the size of diffusing molecules and the crystallinity degree of packaging materials. Therefore, the diffusions of 1-butanol and 1-octanol are less important in PET than in TOPAS® (completely amorphous).
Determination of Potential Migrants from Commercial Amber Polyethylene Terephthalate Bottle Wall
Potential migrants were isolated from commercial polyethylene terephthalate (PET) bottles using Soxhlet extraction. The concentrated extract was then subjected to GC/MS analysis. A total of 19 migrants has been identified. The majority of compounds appeared to be intermediate reaction products or residual monomers of their dehydration and transesterification products. Several processing aids such as fatty acids and commonly used plasticizers were also identified. The amount of seven compounds present in the major portion of exhaustive extract of the PET bottle wall ranged from 800 µg/g polymer to as low as 0.6 µg/g.