Study on the Relationships between Microscopic Cross-Linked Network Structure and Properties of Cyanate Ester Self-Reinforced Composites

Abstract

Bisphenol A dicyanate (BADCy) resin microparticles were prepared by precipitation polymerization synthesis and were homogeneously dispersed in a BADCy prepolymer matrix to prepare a BADCy self-reinforced composites. The active functional groups of the BADCy resin microparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy. The results of an FT-IR curve showed that the BADCy resin microparticles had a triazine ring functional group and also had an active reactive group -OCN, which can initiate a reaction with the matrix. The structure of the BADCy resin microparticles was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From the TEM results, the BADCy resin microparticles dispersed in the solvent were nano-sized and distributed at 40–60 nm. However, from the SEM results, agglomeration occurred after drying, the BADCy resin particels were micron-sized and distributed between 0.3 μm and 0.6 μm. The BADCy resin prepolymer was synthesized in our laboratory. A BADCy self-reinforced composite was prepared by using BADCy resin microparticles as a reinforcement phase. This corresponds to a composite in which the matrix and reinforcement phase are made from different morphologies of the same monomer. The DSC curve showed that the heat flow of the microparticles is different from the matrix during the curing reaction, this means the cured materials should be a microscopic two-phase structure. The added BADCy resin microparticles as reaction sites induced the formation of a more complete and regular cured polymer structure, optimizing the cross-linked network as well as increasing the interplay between the BADCy resin microparticles and prepolymer matrix. Relative to the neat BADCy resin material, the tensile strength, flexural strength, compressive strength and impact strength increased by 98.1%, 40.2%, 27.4%, and 85.4%, respectively. A particle toughening mechanism can be used to explain the improvement of toughness. The reduction in the dielectric constant showed that the cross-linked network of the self-reinforced composite was more symmetrical and less polar than the neat resin material, which supports the enhanced mechanical properties of the self-reinforced composite. In addition, the thermal behavior of the self-reinforced composite was characterized by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The results of DMTA also establishes a basis for enhancing mechanical properties of the self-reinforced composite.

Research on the Compound Optimization Method of the Electrical and Thermal Properties of SiC/EP Composite Insulating Material

“…This shows that the two crystal particles overlap and cooperate with each other in the mixing and solidification process under the appropriate ratio, which can improve the uniformity of the mixed system. The degree of cross-linking of epoxy resin between particles is increased, which significantly reduces defects at the interface of the composite material [ 40 ].…”

A Manufacturing Process Simulation of Toughened Cyanate-Ester-Based Composite Structures with Respect to Stress Relaxation

“…To make the material tougher and thus suitable for use as a matrix material in primary structures, a method was developed using thermoplastic polyether sulfone (PES) [ 5 , 6 ]. Amongst other possibilities [ 7 ], the reason for choosing PES as a toughener was its ability to create crosslinks with the CE as explained in [ 8 ].The result is a novolac-based CE material with a T g at 390 °C. Despite this high T g , the developed system allowed autoclave curing at 180 °C; nevertheless, it requires a post-curing temperature of 260 °C [ 5 ]…”

Ameliorated Mechanical and Dielectric Properties of Heat-Resistant Radome Cyanate Composites

“…Therefore, CE resin with high thermal stability and low electromagnetic wave dispersion is a prospective resin-based candidate of broadband radome materials in the future [ 11 , 12 ]. However, the large numbers of aromatic rings in the CE molecular structure will lead to considerable brittleness and low toughness of the cured resin system and thereby cannot meet the high tenacity requirement for mechanically protective radomes [ 13 , 14 , 15 ]. Moreover, the substantial toxicity of raw materials for synthesizing CE resin restricts its sustainable applications [ 16 ].…”