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The melamine formaldehyde (MF) resin fiber has been used in various fields due to its excellent heat resistance, but it's mechanical properties still need to be improved. Using melamine and paraformaldehyde as raw materials, 1,4‐cyclohexanedimethanol (CHDM) as the comonomer, a series of modified fibers with different copolymerization ratios are prepared by dry spinning. The research results show that melamine, paraformaldehyde, and CHDM can co‐polymerize by one‐step. The introduction of CHDM can effectively improve the heat resistance and mechanical properties of the fiber. When the addition amount of CHDM is 6%, the copolymeric fibers are cylindrical with a smooth surface and bubble‐free inside, the breaking strength is 1.80 cN/dtex and the elongation at break is 13.75%. Compared with the unmodified fiber, the breaking strength is decreased by approximately 5%, and the breaking elongation is increased by nearly 90%. The thermal properties of the copolymeric fibers are not decreased, and the mass residual rate at 400°C is increased from 36.12% to 46.11%. This study provides a method of copolymeric‐modified without fiber‐forming aid to prepare high‐performance MF fibers. [ABSTRACT FROM AUTHOR]

Seventeen compounds derived from traditional Chinese medicines (TCMs) were tested for their antiviral activity against porcine reproductive and respiratory syndrome virus (PRRSV) in vitro. Visualization with the cytopathologic effect (CPE) assay and the 3-(4, 5-dimethyithiazol- 2-yl)-2,5-diphenyltetrazolium bromide test were used to determine the 50% cytotoxic concentration (CC50) and 50% effective concentration (EC50) in cultured Marc-145 cells. Among the tested compounds, chlorogenic acid and scutellarin showed potential anti-PRRSV activity. The EC50 values were 270.8 ± 14.6 μg/ml and 28.21 ± 26.0 μg/ml and the selectivity indexes were >5.54 and 35.5, respectively. The time-of-addition and virucidal assay indicated that the anti-PRRSV activity of the two compounds could be due to their inhibiting the early stage of virus replication and/or inactivating the virus directly. The inhibition of the virus attachment was not observed in the adsorption inhibition assay. The inhibition ratios of chlorogenic acid and scutellarin were, respectively, 90.8% and 61.1% at the maximum non-cytotoxic concentrations. The results have provided a basis for further exploration of their antiviral properties and mechanisms in vivo. We believe that the chlorogenic acid and scutellarin have a great potential to be developed as new anti-PRRSV drugs for clinical application.