فارسی
In the field of material science and fiber technology, one of the crucial concerns is the thermal properties of fibers. Understanding the thermal properties of fibers is important because they play a significant role in determining the performance and various applications of fibers in textiles.
Glass transition temperature (Tg):
Before reaching this temperature, the fibers show a brittle and glassy behavior, but after this temperature, they are softer, and the hardness and strength of the fibers decrease. Factors such as molecular weight, and molecular structure of fiber polymer (polarity of side branches, molecular chain rings, bulky side branches) affect the glass transition temperature.
Melting temperature:
at this temperature, the fibers are completely melted lose their nature, and become a viscous liquid, so the strength and molecular weight of the fibers decrease.
Heat setting:
To maintain their desired shape, size, and structure, textiles are exposed to high temperatures and dry heat. This process is commonly used for polyester and blended fabrics that possess thermoplastic properties, which cause them to deform and stabilize when heated.
Hydro-setting:
In this process, water or steam is applied to the fabric or garment to change its dimensional properties. It’s often used for cellulosic fibers such as cotton and linen, which can absorb and release moisture, allowing them to deform under certain conditions.
Yellowing temperature:
the temperature at which the fibers change color, for example, if the heat setting is not done at the right time, it causes the white color of the fabric to turn yellow at high temperatures.
Thermal conductivity:
Heat and energy are transferred in the body of textile fibers, which is called the thermal conductivity of fibers. Conductive fibers have higher thermal conductivity. This parameter is calculated using the thermal conductivity coefficient.
LOI is a quality control tool that determines relative flammability by indicating the minimum percentage of oxygen required for combustion.
