文摘
This study investigates the issues involving reinforcement of isotactic polypropylene (iPP) spun fibers by molecular adducts originating from the synergistic interactions of polyhedral oligomeric silsesquioxane (POSS) containing silanol functionalities (silanol鈥揚OSS) and di(benzylidene)sorbitol (DBS). The molecular adducts of silanol鈥揚OSS and DBS were low viscosity liquids at fiber spinning temperature, turned into cylindrical domains during fiber spinning, and remained as nanoparticles in the fibers. The fibers were analyzed by differential scanning calorimetry, wide-angle X-ray diffraction , scanning electron microscopy, and transmission electron microscopy. It was observed that iPP compounds with 2鈥? wt % silanol鈥揚OSS and 1 wt % DBS could be spun into fibers with close to 40% reduction in diameter compared to unfilled iPP. These fibers offered 60鈥?0% increase in tensile modulus, 50鈥?0% increase in tensile strength, and 100% increase in yield strength compared to unfilled iPP. The silanol鈥揚OSS particles were found to be of cylindrical shape with approximately 100 nm in diameter and 200鈥?00 nm in length. The improvements in mechanical properties were correlated with iPP crystallinity and orientation factor.