Li Na,Chen Panpan,Liu Dongni,Kang Gaowei,Liu Liu,Xu Liyun,Yu Jianyong,Li Faxue,Wu Dequn
Cotton fabric has a wide application due to its hygroscopicity, air permeability, and large production of cotton fiber used to make the fabric. However, cotton materials are a safety hazard during its application because of flammability (limiting oxygen index is about 18%). In order to improve the flame retardancy of cotton fibers and reduce the damage of its mechanical properties, novel P/Si based flame retardant (PFR) nanoparticles were synthesized by one-step radical polymerization. Vinyl phosphoric acid and tetramethyl divinyl disiloxane were introduced into the nanoparticles. The structure, morphology and thermal stability of PFR was characterized by fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis test (TGA). Durable flame retardant cotton fibers were prepared by dip-coating and plasma induced crosslinking methods. Micro-calorimeter (MCC) characterization showed that the peak of heat release rate (pHRR) and the total heat release (THR) were reduced by 47.3% and 29.8% for modified cotton fibers compared with pure cotton fibers. Limiting oxygen index (LOI) of modified cotton fibers was increased to 27%. The residue carbon of modified cotton fibers was 19.0% at 700 °C, while the value of pure cotton fibers was 3.0%. Besides, durability of the modified cotton fibers was approved by cyclic washing test. In addition, flame retardant mechanism was revealed by collecting and analyzing condensed and gaseous pyrolysis products. The data of FE-SEM for residue carbon, FT-IR spectra of products at different pyrolysis temperatures and pyrolysis gas chromatography mass spectrometry (Py-GC–MS) showed that PFR was a synergistic flame retardant contained barrier and quenching effecting applied on cotton materials. Graphical abstract Novel phosphorus-silicon based nanoparticles were synthesized by one-step radical polymerization and applied to improve the flame retardant of cotton materials by dip-coating and plasma induced crosslinking.
Qiu Shi,Siqi Huo,Cheng Wang,Guofeng Ye,Lingfeng Yu,Zhengping Fang,Hao Wang,Zhitian Liu
The implementation of current flame-retardant strategy is often accompanied by the deterioration of other properties, e.g., mechanical and optical properties. Herein, a flame-retardant, hyperbranched polymer was synthesized by using trichlorovinylsilane (TVS), triethylenetetramine (TETA) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw materials, which was named as TTD and applied to epoxy resin (EP). Our result shows that TTD is able to catalyze and participate in the curing of EP. Furthermore, the EP-TTD samples exhibit high transparency, glass-transition temperature and good UV-blocking properties at a low TTD addition (≤ 4 wt%). Notably, TTD enhances the toughness and robustness of EP. The elongation at break, tensile strength, flexural strength, and impact strength of EP containing 4 wt% TTD are 54%, 42%, 29%, and 29% higher than those of pure EP. Meanwhile, the incorporation of 7 wt% TTD endows EP with a limiting oxygen index (LOI) of 40.0%, a UL-94 V-0 rating, and a 13% reduction in total smoke production (TSP), indicating the significantly enhanced fire safety. During burning, TTD exerts promoting carbonization and quenching effects to suppress the heat transfer and smoke release. Therefore, this work provides an effective strategy to fabricate high-performance, fire-safe epoxy resins using P/Si-containing, hyperbranched polymers.
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