R. Buitrago-Sierra, J. F. Santa, J. Ordoñez,
Volume 16, Issue 3 (9-2019)
Abstract
Polypropylene (PP) has been one of the most widely used polymers due to the versatility and cost benefits obtained with this material. In this work, composites of PP modified with nanostructured ZSM-5 zeolite were prepared and their thermal and mechanical properties were evaluated. Zeolites were synthetized by hydrothermal method and the crystallization time was modified to evaluate the effect of that parameter on zeolites properties. Scanning electron microscopy, thermal analyses, x-ray analysis, among others, were used to analyse the nanostructured particles. Composites were prepared by melt mixing in a torque rheometer and compression moulding. After obtaining the composites, mechanical and thermal properties were evaluated. The results showed that some properties (surface area, and crystallinity) of zeolites depend on the crystallization time. Young’s modulus and elongation at rupture of composites were modified when the zeolites were added to the polymer matrix. No significant modifications were found on thermal properties.
Ardalan Aalipour, Azam Moosavi,
Volume 21, Issue 0 (3-2024)
Abstract
This study evaluates the mechanical performance of a metakaolin-based geopolymer matrix reinforced with quartz particles and polypropylene fibers, in comparison with a Portland cement-based matrix. Compressive strength, shrinkage, and flexural strength tests reveal that incorporating 20 wt% quartz particles significantly improves the mechanical properties of both matrices. The combined use of quartz particles and fibers contributes to shrinkage crack control and dimensional stability through synergistic effects involving particle–matrix interactions, fiber–matrix bonding, fiber surface characteristics, and toughening mechanisms. In the geopolymer matrix, the reinforcement effect of quartz particles is more pronounced due to the formation of a strong and chemically active interfacial bond. Compared with Portland cement composites, quartz particles increase the flexural and compressive strengths of geopolymer composites by approximately 2.5 and 1.3 times, respectively. The addition of 0.5 wt% polypropylene fibers slightly reduces strength but enhances energy absorption and alters the failure mode from brittle to more ductile. Overall, the results highlight the role of fibers in suppressing or arresting brittle fracture in cementitious and geopolymeric composites.
