Transcrystalline morphology and mechanical properties in polypropylene composites containing cellulose treated with sodium hydroxide and cellulase

To evaluate the transcrystalline effects caused by various fibers, which we re untreated, or treated with sodium hydroxide and cellulase, isothermal cr ystallization was performed. It was observed that the untreated and cellula se-treated cellulose fibers (cellulose I) had a nucleating ability to trans crystallize at PP matrix. Especially, cellulose fibers treated with Sodium hydroxide (cellulose II) transcystallized at PP matrix. This result was dif ferent from other's. Cellulose fibers also transcrystallized at PP/MAH-PP m atrix irrespective of the type of cellulose crystalline structure. In PP/MA H-PP/CELL system, MAH-PP was located around the fiber surface at initial cr ystallization time, but was gradually expelled from that with the increase of crystallization time, and existed at outer boundaries of transcrstalline region at the final crystallization time. These phenomena were confirmed b y IR-IRS spectra. The tensile strength of PP/CELL and PP/MAH-PP/CELL compos ites decreased with the increase of isothermal crystallization time. Theref ore, it is thought that transcrystallinity gives rise to negative effect of tensile strength.