Thermodynamic Equilibrium Shifts of Cyclic Oligomers during High Temperature Yarn Texturing
High heater temperatures mobilize PET cyclic trimers, driving surface crystallization that glazes texturing discs and requires strict HPLC wash thresholds.
Thermal Transesterification
Polymer Reorganisation
Molecular chains within polyester fibres undergo an exchange of ester groups when exposed to high temperatures during heat setting or curing. This thermal transesterification modifies the crystalline structure and physical properties of the synthetic material. The reaction typically occurs at temperatures near the melting point of the polymer where molecular mobility is high.
Fabric Stability
Controlled application of this process allows for the permanent setting of pleats or the stabilisation of fabric dimensions. During the heating phase, thermal transesterification facilitates the relaxation of internal stresses created during spinning or weaving. This ensures the garment maintains its shape after repeated domestic laundering.
The stability achieved depends on the precise balance of time and temperature in the oven.
Dyeing Sensitivity
Excessive heat can lead to a reduction in the number of available dye sites within the fibre. Variations in thermal transesterification across a fabric width cause uneven colour uptake during subsequent wet processing. Precise temperature monitoring across the stenter frame is required to maintain a uniform molecular response.
Material Limits
Prolonged exposure to extreme heat can degrade the polymer and reduce the tensile strength of the finished goods. Heat settings must be optimized to avoid excessive thermal transesterification and fibre damage.