Meaning
Binary organic solvent mixtures establish reference solution viscosity values for aromatic polyesters under standardized laboratory protocols. Quality control technicians employ phenol tetrachloroethane in a fixed weight ratio to dissolve polyethylene terephthalate resin flakes. The reagent combination balances solvent power against viscosity stability during capillary flow measurements.
Dissolution capability remains restricted to aromatic polyesters and specific polyamides, proving ineffective for polyolefins or fluoropolymers.
Viscosity Ratio
Chemical solvation of dense polymer chains relies on the synergistic action of the two solvent components. Phenol disrupts interchain hydrogen bonds while tetrachloroethane reduces overall liquid viscosity for ease of flow through glass capillaries. Testing laboratories utilize phenol tetrachloroethane solutions to determine intrinsic viscosity without inducing thermal degradation.
Variations in solvent blend ratio skew flow timing results.
Degradation Resistance
Solution degradation occurs if samples remain exposed to high temperatures or atmospheric moisture for prolonged periods. Acid generation during extended storage alters solvent properties, rendering historical baseline readings invalid.
Quality Assurance
Intrinsic viscosity data obtained from solvent testing governs raw material acceptance for bottle and fiber applications. Processors compare virgin resin datasheet values against incoming shipments to verify molecular weight retention. Contaminated or degraded lots yield lower intrinsic viscosity, which phenol tetrachloroethane measurements identify before material reaches processing extruders.
