New Insights into Segmental Packing, Chain Dynamics and Thermomechanical Performance of Aliphatic Polyurea Composites: Comparison between Silica Oxides and Titanium (III) Oxides

Abstract

Polyurea (PU) is intrinsically reinforced by its microphase-separated morphology, giving its excellent mechanical properties. In this study, it is shown how a high-index PU formulation applies easy diffusion of hard segments into the soft phase of the PU matrix and tune its chain mobility. Moreover, the interaction of micro (>100 nm), nano (<100 nm) fillers with the microdomains and their thermomechanical properties are unraveled. Herein, nanosilica oxide (NS) and micro titanium (III) oxide (Ti 2 O 3 ) are incorporated at low loadings into a solvent-free two-component aliphatic PU via insitu polymerization. While NS achieves an interfacial interaction with urea groups and forms a tight hard segmental packing, the large-sized Ti 2 O 3 assembles the interconnected PU chain network, improving its crystallinity. Strong reinforcement by NS is noticed when tensile strength increased from 26 to 31 MPa and on the maximum thermal degradation temperature by 21 °C increment from the neat PU. In contrast, the soft segmental dynamics are triggered with the presence of Ti 2 O 3 as indicated in the reduction in glass transition temperature and the 288% improvement in the storage modulus. This study provides an insightful perspective in designing robust PU composites, effective for myriad applications including strong and flexible films in circuit boards and photovoltaic (PV) cells.

Unveiling Carbon Fiber Reinforced Polyurea Composites Engineered through Vacuum Assisted Resin Transfer Molding: An In-depth Analysis of Mechanical, Thermal, and Degradation Performance

“…The first and second decompositions occurred at the temperature ranges of 270−520 °C and 520− 700 °C. The two-step degradation temperature is attributed by the decomposition of hard and soft segments of polyurea at the first and second steps, 49 respectively. CF-PU-4L presented the highest onset and degradation temperatures at 10% and 50% mass losses.…”

Reinforcement of nest‐like Zn layers on the surface of carbon fibers for rigid polyurethane composites

“…[3][4][5] At present, the researches on RPU are mainly focused on the improvement of strength and toughness. Researchers have attempted to add different types of reinforcement materials to RPU in order to improve its mechanical properties, such as inorganic particles, 6,7 metal particles, 8,9 fibers 10,11 and organic nanoparticles, 12,13 and so on.…”