Lignin is a natural biopolymer with a complex three-dimensional network, commercially obtained from wasteliquid of paper pulp and bioethanol production, and could be a candidate for preparation of environment-friendly...Lignin is a natural biopolymer with a complex three-dimensional network, commercially obtained from wasteliquid of paper pulp and bioethanol production, and could be a candidate for preparation of environment-friendlybio-based polyphenol material. In the present work, the demethylated wheat straw alkali lignin (D-Lig), preparedby demethylation of wheat straw alkali lignin (Lig) using an in-situ generated Lewis acid, was used to synthesizebio-based phenol formaldehyde resin adhesive (D-LPF) applied in plywood. Effects of synthetic process’s factors,including lignin substitution for phenol, NaOH concentration and molar ratio of formaldehyde to phenol, on thebonding strength and free formaldehyde content of D-LPF were investigated in detail, and the optimum syntheticprocess of D-LPF was obtained as following: Lignin substitution for phenol 60%, NaOH concentration 5.0% andmolar ratio of formaldehyde to phenol 2.0, and under the optimum reaction condition, the D-LPF presented lower free formaldehyde content (0.18%) and higher bonding strength (2.19 MPa), which was better than those ofcontaining-lignin phenol formaldehyde resin adhesive (LPF). Additionally, the curing behavior of the adhesivewas studied by differential scanning calorimetry (DSC) combined with gel time. It can be obtained that D-LPFresin adhesive had the shortest gel time, and fastest curing rate, compared with those of PF and L-PF resin adhesives. The curing kinetics data was fitted well by Kissinger model using non-isothermal DSC method, and theaverage activation energy value was 85.3 kJ/mol, slightly higher than that of commercial PF resin, while lowerthan that of LPF (90.2 kJ/mol). Finally, based on the analytical results of high temperature fourier transform infrared spectroscopy (FTIR), a possible curing mechanism of D-LPF was proposed.展开更多
Reactive acrylate microgels with different reactive groups such as carboxyl, hydroxide groups had excellent properties such as quick-dry, low viscosity, high adhesion and hardness, which made them extensively used in ...Reactive acrylate microgels with different reactive groups such as carboxyl, hydroxide groups had excellent properties such as quick-dry, low viscosity, high adhesion and hardness, which made them extensively used in preparing paints or in coating-modification. Reactive acrylate microgels were prepared by emulsion co-polymerization with zwitterions surfactant, anionic surfactant and nonionic surfactant as co-emulsifier. The water-base baking paints made from reactive acrylate microgels and melamine-formaldehyde resin had excellent combination properties. The aluminium powder can be well-dispersed in the paints. The influences of monomer components on the properties of the water-base baking paints were discussed in this paper. And the baking paints were also compared with the marketing solvent acrylate baking paints. It was found that the water-base acrylate amino baking paints had better combination properties than the organic solvent acrylate baking paints, which means that the water-base baking paints had a bright marketing future.展开更多
基金This work was supported by the National Natural Science Foundation of China(51473024)by University Science Research General Project of Jiangsu Province(16KJD430001)。
文摘Lignin is a natural biopolymer with a complex three-dimensional network, commercially obtained from wasteliquid of paper pulp and bioethanol production, and could be a candidate for preparation of environment-friendlybio-based polyphenol material. In the present work, the demethylated wheat straw alkali lignin (D-Lig), preparedby demethylation of wheat straw alkali lignin (Lig) using an in-situ generated Lewis acid, was used to synthesizebio-based phenol formaldehyde resin adhesive (D-LPF) applied in plywood. Effects of synthetic process’s factors,including lignin substitution for phenol, NaOH concentration and molar ratio of formaldehyde to phenol, on thebonding strength and free formaldehyde content of D-LPF were investigated in detail, and the optimum syntheticprocess of D-LPF was obtained as following: Lignin substitution for phenol 60%, NaOH concentration 5.0% andmolar ratio of formaldehyde to phenol 2.0, and under the optimum reaction condition, the D-LPF presented lower free formaldehyde content (0.18%) and higher bonding strength (2.19 MPa), which was better than those ofcontaining-lignin phenol formaldehyde resin adhesive (LPF). Additionally, the curing behavior of the adhesivewas studied by differential scanning calorimetry (DSC) combined with gel time. It can be obtained that D-LPFresin adhesive had the shortest gel time, and fastest curing rate, compared with those of PF and L-PF resin adhesives. The curing kinetics data was fitted well by Kissinger model using non-isothermal DSC method, and theaverage activation energy value was 85.3 kJ/mol, slightly higher than that of commercial PF resin, while lowerthan that of LPF (90.2 kJ/mol). Finally, based on the analytical results of high temperature fourier transform infrared spectroscopy (FTIR), a possible curing mechanism of D-LPF was proposed.
基金supported by the Science Foundation of Shanghai Municipal Education Commission (Grant No.03AK59)
文摘Reactive acrylate microgels with different reactive groups such as carboxyl, hydroxide groups had excellent properties such as quick-dry, low viscosity, high adhesion and hardness, which made them extensively used in preparing paints or in coating-modification. Reactive acrylate microgels were prepared by emulsion co-polymerization with zwitterions surfactant, anionic surfactant and nonionic surfactant as co-emulsifier. The water-base baking paints made from reactive acrylate microgels and melamine-formaldehyde resin had excellent combination properties. The aluminium powder can be well-dispersed in the paints. The influences of monomer components on the properties of the water-base baking paints were discussed in this paper. And the baking paints were also compared with the marketing solvent acrylate baking paints. It was found that the water-base acrylate amino baking paints had better combination properties than the organic solvent acrylate baking paints, which means that the water-base baking paints had a bright marketing future.
