A light-colored hydroxypropyl sulfonated alkali lignin (HSAL) was synthesized based on pine alkali lignin (AL) by grafted-sulfonation and crosslinking reaction processes. The reactions were evaluated by gel-permeation chromatography (GPC), infrared (IR) and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy. The sulfonic group content and the molecular weight ( M w ) of HSAL significantly increased, while the phenolic hydroxyl groups diminished by around 80% compared to AL. The color of HSAL turned to light yellow compared to the dark brown color of AL, that is, it stained less the fiber. The dispersity, heat stability, and dye uptake of dye bath with HSAL was significantly improved compared to sodium lignosulfonate, sulfomethy lated AL, and dispersants of the naphthalene series.
A porous amino resin with a high content of hydroxymethyl groups was prepared via the polycondensation of an excess of formaldehyde with melamine. PEI was then grafted onto the porous amino resin to synthesize a solid amine adsorbent for CO2 adsorption.
Sulfonated alkali lignin (SAL) can be used as dye dispersants, but its dark color may lead to a severe staining problem, thus hindering its application. Here, a UV/H 2 O 2 whitening process was applied to decolorize SAL and the color was faded by 50%. The structural changes of SAL before and after whitening were characterized by GPC, UV−vis, FTIR, fluorescence, and potentiometric titration, and the mechanism of decolorization was deduced. The results show that the contents of aromatic ring, methoxyl, and phenolic hydroxyl groups in SAL decreased by 37%, 64%, and 78%, respectively, while the content of carboxylic groups increased by 187% after being radiated in H 2 O 2 for 20 h. The changes in chromophoric group and the contribution of each chromophoric group to the overall color before and after whitening were also investigated. Due to the removal of chromophores, the staining phenomenon of light-colored SAL (LSAL) was reduced effectively when it was used as a dye dispersant.
Incorporation of flexible monomer is regarded as a valid way to the chemical modification of the highly brittle poly(cyclohexene carbonate) (PCHC), which derived from the copolymerization of CO 2 and cyclohexene oxide (CHO). However, toxic metal catalyst such as cobalt dominates these terpolymerizations which against the green development philosophy. Here, a series of environmentally benign aluminum porphyrin catalysts with different steric and electronic effects for the terpolymerization of CO 2 , CHO, and terminal epoxides with various flexible pendant alkyl groups to adjust the properties of PCHC is reported. The resulting terpolymers display a random distribution of cyclohexene carbonate along the backbone with a regulated terminal epoxide insertion from 30% to 70%. Moreover, the mechanical properties can be well regulated in a wide range indicating the feasibility of the present approach. The present study provides a green way to chemical modification of rigid PCHC.
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