Synthesis, characterization, and properties of thermosets based on the cocuring of an acetylene‐terminated liquid‐crystal and silicon‐containing arylacetylene oligomer

Abstract

A thermotropic acetylene-terminated liquid-crystal monomer, 2-methyl-1,4-phenylene bis(4-ethynylbenzoate) (MPBE), was prepared and used as a modification composition to react and cocure with a silicon-containing arylacetylene (PSA) oligomer for improving PSA resin. The curing behavior of the PSA-MPBE resins were characterized by differential scanning calorimetry and Fourier transform infrared spectroscopy. The microstructure and morphology of the PSA-MPBE resins were investigated by scanning electron microscopy (SEM) and transmission electron microscopy. Their dynamic mechanical properties and thermostability were measured by dynamic mechanical analysis (DMA) and thermogravimetric analysis. The results indicate that the thermotropic acetylene-terminated liquid-crystal monomer melted into a schlieren texture. MPBE and PSA could copolymerize to fix the mesogenic domain in the crosslinked network and form a homogeneous-phase sea-island structure, which improved the rigidity and toughness of the materials. DMA showed that the storage modulus of the PSA-MPBE resins increased by about 400 MPa compared to the those of the pure components. The SEM experiments showed a noticeable change in the morphology, from a typical brittle fracture for the pure PSA to microplastic deformation behavior for the PSA-MPBE resins.

Temperature effects on structural integrity of fiber‐reinforced polymer matrix composites: A review

“…(4) Adding thermoplastic liquid crystalline polymers: Han et al . prepared a thermotropic acetylene‐terminated liquid‐crystal monomer, 2‐methyl‐1, 4‐phenylene bis (4‐ethynylbenzoate) (MPBE) and used it as a modification composition to react and co‐cure with a silicon‐containing arylacetylene (PSA) oligomer for improving PSA resin . The results indicated that MPBE and PSA could copolymerize to fix the mesogenic domain in the crosslinked network and form a homogeneous‐phase sea‐island structure that improved the rigidity and toughness of the materials.…”

Environmentally Stable Chiral-Nematic Liquid-Crystal Elastomers with Mechano-Optical Properties

“…Thus, stability in various environments, except under mechanical stimuli, is highly desirable for the development of N* LC elastomers with highly sensitive mechano-optical response behavior. In recent decades, N* LC network polymers with high cross-linking densities have attracted practical interest because of their thermally stable optical properties [35][36][37]. However, dense cross-linking is not appropriate for mechano-optical sensors because of the associated high glass transition temperature and low flexibility [38,39].…”

Highly heat‐resistant branched silicon‐containing arylacetylene resins with low curing temperature

“…However, the thermal curing temperature of PSA resins is usually higher than 200 °C, which limits their further applications 19–23 . In addition to designing new chemical structures, some efforts have been devoted to decreasing the curing temperature of PSAs 24–27 . For example, introducing catalysts can decrease the curing temperature of PSA resins 25 .…”

“…However, the remaining metal ions could affect the dielectric properties of the resulting polymers. In some cases, mixing with other polymers decreases the curing temperature of PSA resins 26 . However, this usually lowers the heat resistance of the resins.…”