Modification of Polypropylene Fiber Through Blending Hydroxyl‐Functionalized Polypropylene

ABSTRACT Hydroxyl‐functionalized polypropylene (PPOH) is first incorporated into polypropylene (PP) to prepare modified fiber by melt spinning. Herein, PPOH with low molecular weight and wide molecular weight distribution (MWD) is prepared by controlling the reaction temperature and comonomer feed to reduce the viscoelasticity. The maximum MWD is 4.9 and the minimum weight‐average molecular weight is 28 kDa. The spinnability of the PP/PPOH blend is evaluated by rheology. The steady‐state shear curves indicate that the viscosity of the PP/PPOH blend is well maintained in the range required for melt spinning. All PP/PPOH blends are successfully prepared into as‐spun fibers. Nevertheless, PP/PPOH with higher comonomer content is impossible to undergo further hot drawing and heat setting. The presence of slight hydroxyl groups hardly hinders the orientation and crystallization of PP/PPOH fiber. However, PP/PPOH fiber exhibits better mechanical properties than pure PP fiber, especially at the low blend ratio. The tensile strength of PP/PPOH fiber with 3 wt% PPOH reaches 704 MPa, which is 31% higher than that of pure PP fiber. PPOH enhances the interfacial bonding strength between fiber and epoxy resin, making PP/PPOH fiber expected in the engineering field as a fiber‐reinforced material.