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The aim of this study was to overcome drawbacks of the inhomogeneous dispersion and facile agglomeration of nano-ZnO/poly(N-isopropylacrylamide) composite hydrogels (nano-ZnO/PNIPAm composite hydrogels) during synthesis and improve the anti-mold property of the nano-ZnO/PNIPAm composite hydrogels. Here, nano-ZnO/PNIPAm composite hydrogels were prepared by the radical polymerization method. Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), differential scanning calorimeter (DSC), and dynamic light scattering (DLS) were used to characterize the effects of different dispersants on the particle sizes, dispersions, and phase transition characteristics of the nano-ZnO/PNIPAm composite hydrogels. The anti-mold properties of nano-ZnO/PNIPAm composite hydrogels were studied. Results revealed that the nano-ZnO/PNIPAm composite hydrogel prepared by the addition of nano-ZnO dispersion liquid exhibited the smallest particle size, the most homogeneous dispersion, and the highest stability. The addition of the dispersant did not change the phase transition characteristics of nano-ZnO/PNIPAm, and the nano-ZnO/PNIPAm composite hydrogels (Pf) exhibited good anti-mold properties to the bamboo mold.

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In recent years, bamboo has been widely used for building materials and household goods. However, bamboo is flammable, so a flame-retardant treatment for bamboo is urgently needed. In this work, nano MgAl-layered double hydroxide (MgAl-LDH) coated on bamboo, which was called MgAl-LB, was synthesized by an in situ one-step method. To determine the optimal in situ time, the effects of different reaction times on LDH growth on the bamboo surface and the flame retardancy of the MgAl-LBs were investigated. The SEM observations show that LDH growth on the surface of bamboo was basically saturated when the in situ reaction time was 24 h. Abrasion experiments show that MgAl-LDH coating has good abrasion resistance. The fire performance of the MgAl-LBs was evaluated by cone calorimeter tests, which indicated that the THR and TSP of the MgAl-LBs were significantly lower than those of untreated bamboo. Taking into account the energy consumption problem, determining the reaction time of 24 h is the optimal reaction time. Compared with untreated bamboo, the THR and TSP of MgAl-LB prepared at 24 h decreased by 33.3% and 88.9%, respectively.

This study investigated the antibacterial activity of nano-zinc oxide (ZnO) composite hydrogels on the types of mold organism that commonly affect bamboo. The nano-ZnO was produced via the in situ method in poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAm-co-AAc)) hydrogel. The structures and properties were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), equilibrium swelling ratio (ESR), deswelling and swelling tests, and antimicrobial activity. The nano-ZnO particles were monodispersed in the P(NIPAm-co-AAc) hydrogel. The concentration of the nano-ZnO was higher in the ZnO/P(NIPAm-co-AAc) hydrogel than in the ZnO/PNIPAm hydrogel. The swelling properties in the ZnO/P(NIPAm-co-AAc) hydrogel were more favorable than those of the ZnO/PNIPAm hydrogel, while the deswelling properties were more favorable in the ZnO/PNIPAm hydrogel. The hydrogels that contained more ZnO nanoparticles demonstrated greater antimicrobial properties against Trichoderma viride and Penicillium citrinum of bamboo, while the all of the hydrogels had much less antimicrobial activity against Aspergillus niger.