Flame retardant modification of acrylic fiber with hydrazine hydrate and sodium ions

Recent Advancements in Acrylic Fabric Applications: A Comprehensive Review and Future Trends

Acrylic fibres, as synthetic polymers, have been used extensively in the textile industry to create a wide variety of products, ranging from apparel and home furnishings to car rooftops and carbon fibres. Their widespread application is attributed to a combination of desirable properties, including a soft, wool-like texture, chemical stability, and robust mechanical characteristics. Furthermore, the chemical structure of acrylic fibres can be modified to imbue them with additional features, such as antimicrobial properties, fire resistance, conductivity, water repellency, and ultraviolet protection. This review explores the technological methods employed to functionalise acrylic fibres and discusses future trends in their development.

Melt-Spinning of an Intrinsically Flame-Retardant Polyacrylonitrile Copolymer

Poly(acrylonitrile) (PAN) fibers have two essential drawbacks: they are usually processed by solution-spinning, which is inferior to melt spinning in terms of productivity and costs, and they are flammable in air. Here, we report on the synthesis and melt-spinning of an intrinsically flame-retardant PAN-copolymer with phosphorus-containing dimethylphosphonomethyl acrylate (DPA) as primary comonomer. Furthermore, the copolymerization parameters of the aqueous suspension polymerization of acrylonitrile (AN) and DPA were determined applying both the Fineman and Ross and Kelen and Tüdõs methods. For flame retardancy and melt-spinning tests, multiple PAN copolymers with different amounts of DPA and, in some cases, methyl acrylate (MA) have been synthesized. One of the synthesized PAN-copolymers has been melt-spun with propylene carbonate (PC) as plasticizer; the resulting PAN-fibers had a tenacity of 195 ± 40 MPa and a Young’s modulus of 5.2 ± 0.7 GPa. The flame-retardant properties have been determined by Limiting Oxygen Index (LOI) flame tests. The LOI value of the melt-spinnable PAN was 25.1; it therefore meets the flame retardancy criteria for many applications. In short, the reported method shows that the disadvantage of high comonomer content necessary for flame retardation can be turned into an advantage by enabling melt spinning.

Ingestion of microplastics by pelagic fish from the Moroccan Central Atlantic coast

As in the rest of the world, plastics are the most dominant marine litter category in Moroccan Atlantic waters. This work aims to identify the presence of microplastics in the stomach contents of three small pelagic species of the Central zone of the Atlantic, located between Cape Cantin (33°N) and Cape Boujdor (26°N): Scomber spp., Truchurus truchurus and Sardina pilchardus; Also, to map the spatial distribution of the investigated species. A total of 251 individuals were examined, composed by 118 Scomber spp, 82 Sardina pilchardus and 51 Trachurus trachurus. The characterization of microplastics ingested by those species was identified by FTIR. The results showed the presence of three polymers: Polyamide (PA), Acrylic (PC) and Polystyrene (PS), in 26% of the individuals studied. The presence of polymers was accumulated in Atlantic horse mackerel (Truchurus truchurus) with 30%, then in mackerels (Scomber spp.) with 27%, and European pilchardus (Sardina pilchardus) (9%). Fish containing microplastics in their stomachs are concentrated, mainly in the northern part of the study area. This zone has significant artisanal fishing activity and large rivers that can be source of microplastics.

Ingestion of microplastics by commercial fish off the Portuguese coast

The digestive tract contents of 263 individuals from 26 species of commercial fish were examined for microplastics. These were found in 17 species, corresponding to 19.8% of the fish of which 32.7% had ingested more than one microplastic. Of all the fish that ingested microplastics, 63.5% was benthic and 36.5% pelagic species. A total of 73 microplastics were recorded, 48 (65.8%) being fibres and 25 (34.2%) being fragments. Polymers were polypropylene, polyethylene, alkyd resin, rayon, polyester, nylon and acrylic. The mean of ingested microplastics was 0.27 ± 0.63 per fish, (n=263). Pelagic fish ingested more particles and benthic fish ingested more fibres, but no significant differences were found. Fish with the highest number of microplastics were from the mouth of the Tagus river. Scomber japonicus registered the highest mean of ingested microplastics, suggesting its potential as indicator species to monitor and investigate trends in ingested litter, in the MSFD marine regions.