This study aims to present and evaluate the use of solid-state processing for improving the mechanical properties of polyolefins. Isotactic polypropylene (i-PP) was selected to be studied due to its inferior mechanical properties in comparison to common plastics such as polyethylene (PET) and polyvinyl chloride (PVC). Recently, i-PP has garnered attention due to its attributes such as low-cost and recyclability. However, it requires additional processing to improve its mechanical performance. In this study, cryomilling was used to introduce various concentrations (0.2 - 1 wt. %) of diparamethyldibenzyldiene sorbitol (MDBS), as reinforcing agent, into the i-PP polymer. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the structural and thermal characteristics of the generated blends. Compression molding was utilized to fabricate thin films, and subsequently subjected to tensile testing using a universal testing machine. Results from DSC indicate the ability of cryomilling to generate a homogenous blend by indicating an increase in the crystallization temperature. Moreover, results from the tensile tests showed an increase in tensile strength. The improvements in the mechanical properties of polyolefins with the addition of sorbitol-derivatives can be attributed to the reduction in the average spherulite size of the polymer.
Available at: http://works.bepress.com/sharon-lau/3/