Thermal and mechanical properties of polyethylene glycol (PEG)-modified lignin/polylactic acid (PLA) biocomposites.

In this study, a method was proposed to prepare biocomposites from polylactic acid (PLA) and polyethylene glycol (PEG)-modified lignin using twin-screw extrusion process. The structure of PEG-modified lignin was studied by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatographic (GPC) analysis. The effects of different contents of soda lignin and PEG-modified lignin on PLA composites were studied by tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and degradation analysis. The experimental results showed that the addition of PEG-modified lignin enhanced the heat resistance of PLA composite. PLA could be combined with up to 30 % PEG-modified lignin, with no significant reduction in tensile strength properties. Compared with PLA-L30, the tensile stress and elongation at break of PLA-PL30 were increased by 26.4 % and 78.9 %, respectively. This approach provided a new way to produce high-performance lignin based-PLA composites and had certain industrial application value.

Preparation of functional bamboo by combining nano-copper with hemicellulose and lignin under high voltage electric field (HVEF).

A simple and effective method for preparing functional bamboo by combining nano-copper with hemicellulose and lignin was proposed. The influences of HVEF treatment time and voltage on the reaction of nano-copper with hemicellulose and lignin were studied. The combination was characterized by scanning electron microscopy-X-ray energy dispersive spectrometer (ESEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The results indicated that the O/C ratio and OH content of the treated bamboo decreased, the number of CHO groups decreased, the number of CO groups increased, and the nano-copper interacted with the hemicellulose and lignin in the bamboo. Copper was presented in the treated bamboo in the form of Cu0, Cu+ and Cu2+. The concentration of copper increased with the increasing treatment time or voltage. The bamboo underwent the high-voltage electrostatic in situ impregnation copper treatment had significant antibacterial properties and excellent UV protection performance. Therefore, the in situ impregnation of nano-copper particles with an HVEF treatment is simple and effective to produce functionalized bamboo, and has broad application prospects.