Microfibrillated cellulose (MFC) was prepared by controlling the re-precipitation of cellulose prepared in the mixture form of NaOH/Urea solubilized microcrystalline cellulose (MCC) and starch. The cellulose re-precipitation was carried-out in an HCl bath, resulting in a MFC form having relatively lower crystallinity than MCC. The XRD pattern of MFC indicated the partially crystalline structure arising from the imperfect orientation of a cellulose chain obstructed by a starch molecule in the precipitation step. Interestingly, the MFC morphology exhibited a web-like structure with a diameter in the range of 10-20 nm. The water retention value of MFC was extraordinarily high due to its extremely small diameter having high surface area. Further, surface silanization of MFC with organosilane was carried out. Then, the modified MFC was melt-mixed with polypropylene (PP) matrix via a simple melt mixing technique. The morphology and crystallization of the PP/MFC composites were measured. The morphology of organosilane treated MFC exhibited agglomeration of 10 microns in diameter with layered structures arising from the packing of microfibrils. The FTIR spectra showed hydrophobic characteristics of treated MFC observed by the disappearance of original cellulose hydroxyl group and bound water. The crystallinity of treated MFC increased when compared to the untreated MFC, indicating that cellulose chains of unmodified MFC underwent re-orientation occurring in the modification step due to its high crystallinity characteristic. For the PP/MFC-composite containing MFC loading, faster crystallization and higher spherulite growth rate, in case of higher MFC loading, were observed. In addition, the spherulite size decreased with an increase in the crystallization temperature. However, the degree of crystallinity was fairly independent on the MFC-loading. Therefore it can be concluded that the addition of MFC might enable shorter

Fine and well-dispersed clay was prepared via the in situ conversion of the dodecylamine intercalant inside the clay gallery to dodecylamino dimethylene diphosphonic acid (DDD), using a Mannich reaction, so as to create a repulsive force that delaminated the clay platelets. The clay structure and morphology were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) analysis, which revealed changes in the multilayer stacks. XRD analysis showed that the interlayer spacing was largely expanded by the presence of DDD. SEM and TEM images revealed that DDD containing clay (PMMT), but not that without DDD, exhibited transparency, indicating the extremely fine and well-dispersed clay. Polypropylene/PMMT nanocomposites containing 2, 4, 6, 8, and 10 wt % PMMT were prepared by melt extrusion. The obtained compounds were each spun into a monofilament fiber using a small scale spinning machine and then characterized by XRD, Differential scanning calorimetry (DSC), and Thermogravimetric analysis (TGA), plus the sonic modulus was evaluated. The XRD results revealed an increase in the b crystallinity peak in fibers loaded with 2-10 wt % PMMT, indicating that PMMT particles were capable of acting as a b-form nucleating agent. However, only minimal changes in the thermal behavior (T c ) were observed due to the tested samples containing insufficient PMMT content. The mechanical properties, in terms of the tensile strength and sonic modulus value (E), of the polypropylene nanocomposite fibers were higher than those of virgin PP fibers, presumably due to the reinforcement effect of the filled PMMT nanoparticles.

Soybean oil modified cellulose fibril (Oil-g-CF) and organosilane modified cellulose fibril (Silane-g-CF) were prepared using maleinized soybean oil and hexadecyltrimethoxysilane, respectively. Thus obtained modified cellulose fibril was added to polypropylene by a simple melt mixing on a hotplate. PP/modified CF composites with 4.0 wt% filler content were prepared. The composites were subject to a polarized optical microscope to investigate particle dispersion, supramolecular morphology, and crystallization behavior. It was found that Silane-g-CF exhibited smaller particle sizes with better particle distribution when compared to Oil-g-CF. In addition, the etched composite samples unveiled an increase in a number of spherulite crystals as well as a decrease in the spherulite size. The nonisothermal crystallization study of composites revealed that both Oil-g-CF and Silane-g-CF were capable of nucleating PP by facilitating faster crystallization process and raising the number of spherulites. The DSC results indicated that Silane-g-CF was able to perform a more effective nucleation than Oil-g-CF, judged by a higher crystallization temperature. Moreover, PP composites containing Oil-g-CF and Silane-g-CF had higher crystallinity by 7% and 10%, for the first and the latter, respectively, when compared to neat PP.