The strong driving force behind the sustainable biomaterial-based society is to replace the fossil fuel-based materials with renewable resources to for example address the climate change. Thermoplastic polymer products are used on a daily bases in every household and they need to possess the properties such as being ductile and formable. However, cellulosic materials do not soften when heated, like the fossil fuel-based thermoplastic polymers. Instead, cellulose thermally degrades before it softens or melts. This challenge of cellulose materials has been addressed in this project by partially modification of the cellulosic material resulting in cellulosic material that do exhibit thermoplastic properties. This project aims to answer the following scientific question: How is the modification distributed and if the modification is distributed differentially on earlywood and latewood fibres as well as if there are any differences between partially modified beaten and unbeaten fibres.