Research on Water Distribution of Cotton Fiber in Wide Humidity Domain at Low Temperature

Xinjiang is a major cotton-producing region in China, where the late and protracted harvest period gives rise to substantial variations in temperature and humidity, with consequent marked differences in cotton fiber moisture content and breaking strength. The prevalence of low-temperature processing in ginning mills further compromises quality relative to yield. This study investigates the effects of temperature and humidity on the breaking strength of cotton fibers. Results indicate that below 3 °C, fiber brittleness increases and breaking strength diminishes, whereas between 3 °C and 10 °C with moderate relative humidity, optimal strength performance is observed. Breaking strength exhibits a parabolic relationship with relative humidity, initially increasing before subsequently declining. Focusing on the low-temperature interval of −5 °C to 10 °C, this research characterizes cotton fiber moisture states under low, moderate, and high humidity conditions. The results demonstrate that 9 °C/60% relative humidity (RH), 2 °C/30% RH, and 2 °C/60% RH constitute optimal harvesting and processing environments. These conditions not only maintain favorable moisture content but also effectively preserve breaking strength, thereby providing a theoretical foundation and practical technical reference for optimizing harvesting schedules, storage protocols, and ginning parameters in cold-region cotton production.