Flame Retardancy and Mechanism of Bismaleimide Resins Based on a Unique Inorganic–Organic Hybridized Intumescent Flame Retardant

Bioapplication of cyclodextrin-containing montmorillonite

Recent progresses in the integration of CDs and montmorillonite, as well as applications of CD-containing montmorillonite hybrid host systems are summarized in this review. Several efficient synthesis strategies, such as ion exchange, metal coordination, supramolecular strategies, polymerizations and organic synthesis methods, have been discussed during the preparation of CDs/montmorillonite hybrid composites. In particular, diverse instrumental techniques were highly recommended for characterizing the as-obtained hybrid systems, including their chemical composition and structures, crystallinity, surface/self-assembled morphologies, as well as other particular physiochemical properties, providing a direct guide for promoting the desired structures and exploring various applications. It should be noted that the introduction of functional groups, as well as the integration of CDs and montmorillonite granted the thus obtained CD-containing montmorillonite hybrid host systems a lot of unique features, providing great opportunities for expanding the practical applications to a series of biological and environmental areas, such as biosensors, sorption and decontamination of bio/environmental hazardous materials, biostudies about aqueous dispersity, stability and biocompatibility, drug loading and target delivery, controlled and sustained drug release, as well as antibacterial.

Design and Application of Highly Efficient Flame Retardants for Polycarbonate Combining the Advantages of Cyclotriphosphazene and Silicone Oil

A novel flame retardant (HSPCTP) was successfully designed and incorporated into a polycarbonate (PC) matrix. Combining the advantages of cyclotriphosphazene and silicone oil, PC/HSPCTP composites passed UL-94 V-0 rating testing with only 3 wt% HSPCTP, and their LOI value increased from 25.0% to 28.4%. The findings showed that HSPCTP exhibits both gas-phase and solid-phase flame-retardant effects. Furthermore, the incorporation of HSPCTP into PC could suppress the release of smoke. Finally, the flame-retardant mechanism is discussed in depth.

Cyanate ester resin based composites with high toughness and thermal conductivity

A new cyanate ester resin-based composite with higher toughness and thermal conductivity was developed. First, a poly(n-butyl acrylate)/poly(methyl methacrylate-co-acrylamide) (PBMAM) core-shell structured latex was prepared by seeded emulsion polymerization. Second, hexagonal boron nitride (h-BN) particles were modified by a surface coupling agent, 3-(2-amino ethyl amino)propyl trioxysilane, to improve the dispersion in cyanate ester resin (BADCy). Third, PBMAM and the modified boron nitride were mixed with BADCy resin to increase mechanical properties and thermal conductivity. The monomer conversion in the emulsion polymerization process of the PBMAM was monitored by determining the solid content. Its particle size was characterized by dynamic laser scattering, and the morphology of the particles was characterized using scanning and transmission electron microscopes. The modified boron nitride (ABN) was verified by FTIR and TGA measurements. The mechanical properties and thermal conductivity of the BADCy/PBMAM/ABN composites were determined at various BN contents. Results showed that the unnotched impact strength of the composite increased by 151% and the thermal conductivity increased by 85% at a PBMAM content of 5 wt% and ABN content of 6 wt%. With the enhanced properties and ease of fabrication, the developed composites have good potential for application in high-end industries such as microelectronic packaging.

Flame retarding epoxy composites with poly(phosphazene-co-bisphenol A)-coated boron nitride to improve thermal conductivity and thermal stability

A novel poly(cyclotriphosphazene-co-bisphenol A)-coated boron nitride (PCB-BN) was synthesized by in situ polymerization on the surface of BN. The epoxy/PCB-BN composites showed the enhanced thermal conductivity with the improved flame retardance.

Synthesis and properties of a new halogen-free flame-retardant epoxy resin curing agent

A novel intumescent flame-retardant curing agent, poly-( meta-xylylenediamine spirocyclic pentaerythritol bisphosphonate) (PMXSPB), was synthesized and subsequently characterized using Fourier transform infrared, proton nuclear magnetic resonance, and mass spectroscopies. PMXSPB was used as a flame-retardant and curing agent for preparing halogen-free flame-retarded epoxy (EP) resins. The thermal stability, mechanical properties, flame resistance, and morphology of the char layer of flame-retarded EP resins were investigated using thermogravimetric analysis, tensile and Charpy impact tests, limiting oxygen index (LOI), the UL94 test, and scanning electron microscopy, respectively. The results demonstrated that the addition of PMXSPB improved the flame resistance of EP resin composites, and the residual char ratio at 600°C was significantly increased. The flame-retarded composites filling with 3.01% phosphorus content (EP 100 g and PMXSPB 35 g) exhibited the best combination of properties, including a higher glass transition temperature (147°C), good thermal stability, an initial weight loss temperature of 269°C, and an LOI of 31.2. The vertical burning test reached the UL94 V-0 level, and the tensile and impact strengths were 51 MPa and 4.8 kJ m−2, respectively.

Novel tough and thermally stable cyanate ester resins with high flame retardancy, low dielectric loss and constant based on a phenolphthalein type polyarylether sulfone

Tough cyanate ester resins with good compatibility, low dielectric loss, high flame retardancy and thermal stability were developed.

Synthesis and characterization of a phosphorus-containing flame retardant with double bonds and its application in bismaleimide resins

A novel reactive phosphorus-containing flame retardant was synthesized and used to modify bismaleimide resin. According to investigations, the modified bismaleimide resin has good mechanical properties, thermal stability and flame retardancy.

Novel phosphorus–nitrogen–silicon flame retardants and their application in cycloaliphatic epoxy systems

In this work, we prepared two novel reactive-type halogen-free and UV-curable phosphorus–nitrogen–silicon synergistic flame retardants.

Multifunctional cyclotriphosphazene/hexagonal boron nitride hybrids and their flame retarding bismaleimide resins with high thermal conductivity and thermal stability

A novel hybridized multifunctional filler (CPBN), cyclotriphosphazene/hexagonal boron nitride (hBN) hybrid, was synthesized by chemically coating hBN with hexachlorocyclotriphosphazene and p-phenylenediamine, its structure was systemically characterized. Besides, CPBN was used to develop new flame retarding bismaleimide/o,o'-diallylbisphenol A (BD) resins with simultaneously high thermal conductivity and thermal stability. The nature of CPBN has a strong influence on the flame behavior of the composites. With the addition of only 5 wt % CPBN to BD resin, the thermal conductivity increases 2 times; meanwhile the flame retardancy of BD resin is remarkably increased, reflected by the increased limited oxygen index, much longer time to ignition, significantly reduced heat release rate. The thermogravimetric kinetics, structures of chars and pyrolysis gases, and cone calorimeter tests were investigated to reveal the unique flame retarding mechanism of CPBN/BD composites. CPBN provides multieffects on improving the flame retardancy, especially in forming a protective char layer, which means a more thermally stable and condensed barrier for heat and mass transfer, and thus protecting the resin from further combustion.