Resolving Non Target Solvent Attack Dynamics in High Temperature Cellulosic Separations
Maintaining solvent moisture at 13.0 percent and temperatures below 108°C prevents non-target synthetic polymer breakdown during cellulosic extraction.
Auto-Oxidation
Degradative Reaction
Chemical degradation occurs when polymers react with atmospheric oxygen at ambient temperatures. Spontaneous auto-oxidation targets the unsaturated fatty acids in spin finishes and the polymer chains of natural fibres during storage. This reaction proceeds via a free radical mechanism where oxygen reacts with labile carbon atoms.
Radical Mechanism
Initiation occurs when heat or light triggers the formation of a radical within the molecular structure. During the propagation phase of auto-oxidation, these radicals react with molecular oxygen to form peroxy radicals which then pull hydrogen from other chains. This creates a self sustaining cycle that continues until the available oxygen is consumed or the radicals are neutralized by inhibitors.
The accumulation of hydroperoxides during this stage marks the transition from a slow induction period to a rapid phase of structural breakdown.
Finish Stability
Lubricants applied to yarns during spinning often contain additives to suppress these reactions. When auto-oxidation affects spin finishes, the residue becomes tacky and yellowed, which leads to increased friction.
Fabric Storage
Warehoused goods are vulnerable when exposed to air and residual catalysts from bleaching. Prolonged auto-oxidation reduces the degree of polymerisation in cotton, causing a loss of tensile strength and poor dye uptake. Regular monitoring of peroxide values provides a metric for assessing the extent of damage in stored greige goods.