High refractive index and flame retardancy of epoxy thermoset cured by tris (2- mercaptoethyl) phosphate

The Flame-Retardant Mechanisms and Preparation of Polymer Composites and Their Potential Application in Construction Engineering

Against the background of people's increasing awareness of personal safety and property safety, the flame retardancy (FR) of materials has increasingly become the focus of attention in the field of construction engineering. A variety of materials have been developed in research and production in this field. Polymers have many advantages, such as their light weight, low water absorption, high flexibility, good chemical corrosion resistance, high specific strength, high specific modulus and low thermal conductivity, and are often applied to the field of construction engineering. However, the FR of unmodified polymer is not ideal, and new methods to make it more flame retardant are needed to enhance the FR. This article primarily introduces the flame-retardant mechanism of fire retardancy. It summarizes the preparation of polymer flame-retardant materials by adding different flame-retardant agents, and the application and research progress related to polymer flame-retardant materials in construction engineering.

Development of Novel Triazine-Based Poly(phenylene sulfide)s with High Refractive Index and Low Birefringence

High-refractive-index (high-n) polymers with a high optical transparency and low birefringence (Δn) have been desired in progressive optoelectronic devices. However, the trade-off between high-n and low-Δn remains a challenge at present. Here, the development of a novel array of high-n, high-sulfur-containing, highly transparent, colorless poly(phenylene sulfide) (PPS) polymers bearing triazine units in the main chains is reported. Six new triazine monomers T1-T6 with various pendant groups via different linkers (-O- and -NH-) could be prepared for developing PPSs with high-n and low Δn values. These PPSs (P1-P6) were obtained by the polycondensation of T1-T6 with commercial aromatic dithiol, 4,4'-thiobisbenzenethiol, respectively, which showed very high-n values (n av: 1.6902-1.7169 at 633 nm), high optical transparency (T % > 90% @ 400 nm), and low birefringence (Δn = 0.0015-0.0042). All the PPSs displayed high n ∞ values (1.6340-1.6654), providing valuable information for the development of high-n triazine-based PPS materials for application not only in the visible region but also in the near-infrared region.

Sulfur-containing polymers from terpolymerization of active methylene compounds, carbon disulfide, and dihalohydrocarbons: synthesis and properties

Sulfur-containing polymers with a high refractive index were synthesized via terpolymerization of active methylene compounds, CS₂, and dihalohydrocarbons in excellent yields with high molecular weights.

Imparting high flame retardancy to epoxy resin with ultra-low loading of 5,10-dihydro-phenophosphazine-10-oxide functioned triazine

High mechanical properties and flame retardancy of epoxy are important for its applications. A novel star-shaped flame-retardant 5,10-dihydro-phenohphosphazine-10-oxide functioned triazine (TRIDPPA) with high efficiency is synthesized, and its structure is characterized. TRIDPPA is used as the co-curing agent for diglycidyl ether of the bisphenol A/4,4-diaminodiphenyl methane system. The introduction of TRIDPPA greatly improves the flame retardancy of the cured epoxy resins. The epoxy resin (ER)/TRIDDPA1.0 resin acquires a limiting oxygen index value of 30.7% and UL-94 V-0 rating when the mass fraction of TRIDDPA is 1.0 wt% with only 0.086 wt% of phosphorus content. The cross-link density of ER/TRIDDPA1.0 is increased, and the glass transition temperature is improved by 5°C. Besides, tensile strength and toughness of ER/TRIDDPA1.0 are also enhanced.

A highly efficient gas-dominated and water-resistant flame retardant for non-charring polypropylene

In this work, a novel mono-component and gas-dominated flame retardant, named DPPIP, was prepared through an amidation reaction of diphenylphosphinyl chloride and piperazine, and used to flame retard PP.