Tri(2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-1-oxo-4-hydroxymethyl) phenylsilane (TPPSi) was employed as a flame retardant and polydimethylsiloxane-g-styrene-g-methyl methacrylate copolymer (PSM) as a compatibilizer in polycarbonate–acrylonitrile-butadiene-styrene (PC–ABS) blends. The effect of TPPSi and PSM on the flame retardancy and compatibilization of PC–ABS was investigated by UL-94 vertical burning tests, DMA and SEM. The results indicated that the PC–ABS blend with 8 wt% TPPSi and 5 wt% PSM possessed both high flame retardancy and impact strength. It was found that PSM played an effective compatibilization role in the PC–ABS–TPPSi blend and elevated the thermal stability of the blend. A synergistic flame-retardant mechanism between phosphorus and silicon was presented by TGA, SEM/EDX analysis, FT-IR and Raman spectra of the residue.
Recently, open tubular capillary electrochromatography (OT-CEC) has captured considerable interest; its efficient separation capability hinges on the interactions between analytes and polymer coatings. However, in situ growth of stimuli-responsive polymers as coatings has been rarely studied and is crucial for expanding the OT-CEC technique and its application. Herein, following poly(styrene-maleicanhydride) (PSM) chemically bonded onto the inner surface of the capillary, a dual pH/temperature stimuli-responsive block copolymer, P(SMN-COOH), was prepared by in situ polymerizing poly( N -isopropylacrylamide) carboxylic acid terminated [P(N-COOH)] in PSM. An OT-CEC protocol was first explored using the coated capillary for epimedins separation. As a proof of concept, the developed OT-CEC system facilitated hydrogen bonding and tuning the hydrophilic/hydrophobic interactions between the test analytes and the P(SMN-COOH) coating by varying buffer pH and environmental temperature. Four epimedins with similar chemical structures were baseline separated under 40 °C at pH 10.0, exhibiting dramatical improvement in separation efficiency in comparison to its performance under 25 °C at pH 4.0. In addition, the coated capillary showed good repeatability and reusability with relative standard deviations for migration time and peak area between 0.7 and 1.7% and between 2.9 and 4.6%, respectively, and no significant changes after six runs. This work introduces a paradigm for efficient OT-CEC separation of herbal medicines through adjusting the interactions between analytes and smart polymer coatings, addressing polymer coating design and OT-CEC challenges. Graphical Abstract
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