Preparation and applications of the tertiary copolymer poly(ethylene glycol) methacrylate/methyl methacrylate/diethyl allylphosphonate

Preparation and applications of hydrophilic quaternary ammonium salt type polymeric antistatic agents

A novel ammonium salt type polymeric antistatic agent (PDSH) was synthesized from methacrylatoethyl trimethyl ammonium chloride, styrene, and 2-hydroxyethyl methacrylate via radical polymerization. Antistatic poly(acrylonitrile-co-butadiene-co-styrene) (ABS)/PDSH composites were prepared by blending PDSH with ABS resin. The results showed that the surface resistivity of ABS/PDSH composites with PDSH addition decreased significantly. The surface resistivity of ABS/PDSH composites containing 20 wt% PDSH was around 109–1010 Ω, which was about 106 times lower than that of neat ABS. At the same time, ABS/PDSH composites had good thermal stability and hydrophilicity. The PDSH was more uniformly dispersed within the ABS resin and had less influence on the mechanical properties of the composites. With the demonstrated properties, the prepared copolymer PDSH can serve as a well-integrated antistatic agent and display potential for the antistatic treatment of ABS.

Enhanced thermal conductivity and flame retardancy of polyamide 6/flame retardant composites with hexagonal boron nitride

High performance composite of polyamide 6 (PA6)/flame retardant (FR)/hexagonal boron nitride (hBN) was prepared via twin screw extrusion, followed by injection molding. The heat dissipation of the composite was significantly improved by incorporating 40 vol% of hBN, and the corresponding thermal conductivity was up to 5.701 W/(m·K), nearly 17 times that of the PA6/FR composites. In addition, the combination effect of hBN and FR to the flame retardancy of the composites was observed, and the addition of hBN could dramatically enhance the flame retardancy of composites, achieving a UL94 V-0 rating with a limited oxygen index (LOI) value of 37%. This multifunctional modification would broaden the application field of PA6 composites in light-emitting diode (LED) lamps, electronic products, and so on.

Recent Developments in Organophosphorus Flame Retardants Containing P-C Bond and Their Applications

Organophosphorus compounds containing P-C bonds are increasingly developed as flame retardant additives due to their excellent thermal and hydrolytic stability and ease of synthesis. The latest development (since 2010) in organophosphorus flame retardants containing P-C bonds summarized in this review. In this review, we have broadly classified such phosphorus compounds based on the carbon unit linked to the phosphorus atom i.e., could be a part of either an aliphatic or an aromatic unit. We have only considered those published literature where a P-C bond was created as a part of synthetic strategy to make either an intermediate or a final organophosphorus compound with an aim to use it as a flame retardant. General synthetic strategies to create P-C bonds are briefly discussed. Most popular synthetic strategies used for developing P-C containing phosphorus based flame retardants include Michael addition, Michaelis-Arbuzov, Friedels-Crafts and Grignard reactions. In general, most flame retardant derivatives discussed in this review have been prepared via a one- to two-step synthetic strategy with relatively high yields greater than 80%. Specific examples of P-C containing flame retardants synthesized via suitable synthetic strategy and their applications on various polymer systems are described in detail. Aliphatic phosphorus compounds being liquids or low melting solids are generally applied in polymers via coatings (cellulose) or are incorporated in the bulk of the polymers (epoxy, polyurethanes) during their polymerization as reactive or non-reactive additives. Substituents on the P atoms and the chemistry of the polymer matrix greatly influence the flame retardant behavior of these compounds (condensed phase vs. the gas phase). Recently, aromatic DOPO based phosphinate flame retardants have been developed with relatively higher thermal stabilities (>250 °C). Such compounds have potential as flame retardants for high temperature processable polymers such as polyesters and polyamides. A vast variety of P-C bond containing efficient flame retardants are being developed; however, further work in terms of their economical synthetic methods, detailed impact on mechanical properties and processability, long term durability and their toxicity and environmental impact is much needed for their potential commercial exploitations.