Let's learn more about carbon fiber precursors! 🤔 The precursor material is critical for the ultimate properties of the resultant carbon fiber. The main precursor raw materials for CF production are PAN and pitch- and cellulose-based (such as rayon and lignin) materials. Their precursor production techniques vary, and each requires a different conversion process to be used in carbon fiber manufacturing. 👀 An ideal precursor material should be easily converted to CF, give a high carbon yield after carbonization, and allow it to be processed economically. PAN-based precursor has 68% carbon content and has a carbon yield of 50%–55% after carbonization, whereas a cellulosic precursor has a carbon content of 44.4% but has a carbon yield of only 25%–30% in practice. Pitch-based precursors have higher carbon content and a higher yield of 85% but with poorer compression and transverse properties as compared with PAN-based CFs. 🕵🏻‍♂️ Nowadays, PAN is the main precursor material used for commercial CF manufacturing (around 96% of global production). The choice of the precursor material deeply affects the final properties. This can be clearly seen when commercially available CFs’ tensile strength and modulus properties are combined on a graph like this one. The tensile strength and modulus of CF is directly related to the internal and external flaws and the crystal size, structure, and orientation within the fiber. 😉 In addition to tensile strength and modulus values, some other distinctive differences are available between the resultant carbon fibers. For example, mesophase pitch-based CFs have the highest density of 1.9–2.2 g/cm3, meanwhile, cellulosic-based CFs have the lowest density of 1.66. And, cellulosic-based CFs have the highest breaking elongation of 1.67%–1.82%, meanwhile, pitch-based CFs have the lowest electric resistivity. 😁