Cure Kinetics and Properties of High Performance Cycloaliphatic Epoxy Resins Cured with Anhydride

Flame-Retardant Cycloaliphatic Epoxy Systems with High Dielectric Performance for Electronic Packaging Materials

Flame-retardant cycloaliphatic epoxy systems have long been studied; however, the research suffers from slow and unsatisfactory advances. In this work, we synthesized a kind of phosphorus-containing difunctional cycloaliphatic epoxide (called BCEP). Then, triglycidyl isocyanurate (TGIC) was mixed with BCEP to achieve epoxy systems that are rich in phosphorus and nitrogen elements, which were cured with 4-methylhexahydrobenzene anhydride (MeHHPA) to obtain a series of flame-retardant epoxy resins. Curing behaviors, flame retardancy, thermal behaviors, dielectric performance, and the chemical degradation behaviors of the cured epoxy system were investigated. BCEP-TGIC systems showed a high curing activity, and they can be efficiently cured, in which the incorporation of TGIC decreased the curing activity of the resin. As the ratio of BCEP and TGIC was 1:3, the cured resin (BCEP₁-TGIC₃) showed a relatively good flame retardancy with a limiting oxygen index value of 25.2%. In the cone calorimeter test, they presented a longer time to ignition and a lower heat release than the commercially available cycloaliphatic epoxy resins (ERL-4221). BCEP-TGIC systems presented good thermal stability, as the addition of TGIC delayed the thermal weight loss of the resin. BCEP₁-TGIC₃ had high dielectric performance and outperformed ERL-4221 over a frequency range of 1 HZ to 1 MHz. BCEP₁-TGIC₃ could achieve degradation under mild conditions in an alkali methanol/water solution. Benefiting from the advances, BCEP-TGIC systems have potential applications as electronic packaging materials in electrical and electronic fields.

Preparation and characterization of a low viscosity epoxy resin derived from m-divinylbenzene

To explore thermal and mechanical properties of epoxy material, difunctional aromatic epoxy--divinylbenzene dioxide (DVBDO) had been synthesized by epoxidizing divinylbenzene, using the metal acetylacetone compound grafted Fe3O4 particles as the catalyst. The catalyet had high conversion and epoxy selectivity and could be recyclable. Then the polymerization of DVBDO with different diamine curing agents were reported. The structure and viscosity of DVBDO were firstly characterized. Because it had low molecular weight and viscosity, DVBDO had excellent liquidity and formability. Subsequently to clarify the properties of epoxy thermosets, experiments to determine thermal and mechanical performances were carried out, such as differential scanning calorimetry (DSC), thermal gravimetric (TGA), dynamic mechanical analysis (DMA) and tensile test. It could be observed that the thermoset polymers using DVBDO as epoxy matrix had excellent thermal (Tg was about 201°C) and mechanical properties (tensile strength was 131.99Mpa). Possibly considering that this kind of thermoset polymers had higher rigidity and crosslink density. In conclusion, a new type of one-component liquid epoxy encapsulant material with low viscosity, good filling fluidity, strong heat resistance and excellent storage performance had been developed.

Network Formation and Physical Properties of Epoxy Resins for Future Practical Applications

Epoxy resins are used in various fields in a wide range of applications such as coatings, adhesives, modeling compounds, impregnation materials, high-performance composites, insulating materials, and encapsulating and packaging materials for electronic devices. To achieve the desired properties, it is necessary to obtain a better understanding of how the network formation and physical state change involved in the curing reaction affect the resultant network architecture and physical properties. However, this is not necessarily easy because of their infusibility at higher temperatures and insolubility in organic solvents. In this paper, we summarize the knowledge related to these issues which has been gathered using various experimental techniques in conjunction with molecular dynamics simulations. This should provide useful ideas for researchers who aim to design and construct various thermosetting polymer systems including currently popular materials such as vitrimers over epoxy resins.

Cure kinetics and properties of high-performance epoxy thermosets cured with active ester-terminated poly (aryl ether ketone)

Benzene-1,3,5-triyl tribenzoate (TBB), both 3,5-bis(benzoyloxy)benzoate-terminated poly (aryl ether ketone) oligomers (BPAPK and TMPK), containing active ester (Ph−O−(C=O)− structure), were prepared and served as curing agents for dicyclopentadiene novoalc epoxy (DCPD). The curing kinetics and properties of three epoxy thermosets were systematically investigated. The model reaction of TBB and glycidyl phenyl ether was designed to understand the curing mechanism of oxirane ring with active ester. TMPK/DCPD displays the lowest reaction activation energy, which is the result of the combined influence of free volume and diffusion. In addition, TMPK/DCPD has the highest Tg value (218°C), which enhances 34.6% and 42.5% compared with BPAPK/DCPD and TBB/DCPD, respectively. Meanwhile, TMPK/DCPD also shows superior dielectric and water resistance properties due to no secondary alcohol generated after curing and hydrophobic tetramethyl-substituted biphenyl structure. Herein, TMPK/DCPD as high-performance epoxy thermosets has potential applications in electronic packaging fields.

Molecular-Level Investigation of Cycloaliphatic Epoxidised Ionic Liquids as a New Generation of Monomers for Versatile Poly(Ionic Liquids)

Recently, a new generation of polymerised ionic liquids with high thermal stability and good mechanical performances has been designed through novel and versatile cycloaliphatic epoxy-functionalised ionic liquids (CEILs). From these first promising results and unexplored chemical structures in terms of final properties of the PILs, a computational approach based on molecular dynamics simulations has been developed to generate polymer models and predict the thermo–mechanical properties (e.g., glass transition temperature and Young’s modulus) of experimentally investigated CEILs for producing multi-functional polymer materials. Here, a completely reproducible and reliable computational protocol is provided to design, test and tune poly(ionic liquids) based on epoxidised ionic liquid monomers for future multi-functional thermoset polymers.

Cycloaliphatic epoxidized ionic liquids as new versatile monomers for the development of shape memory PIL networks by 3D printing

Efficient synthesis of cycloaliphatic epoxy IL monomers followed by thermal curing to obtain shape-memory hydrophobic PIL networks is reported for the first time.