Nanoporous microspheres with divinylbenzene (DVB), styrene (St), and lignin were synthesized by an emulsion-suspension polymerization method. Several types of lignins were used: (1) kraft lignin before (L-unmod) and after modification with methacryloyl chloride (L-Met) and (2) low-molecularweight kraft lignin unmodified (LWL-unmod) and modified with methacrylic anhydride (LWL-Met). LWL was prepared by ultrafiltration of industrial black liquor using a ceramic membrane with a molecular weight (Mw) cut-off of 5 kDa. The synthesis was optimized by addition of different amounts of lignins. The microsphere texture was characterized using low-temperature nitrogen adsorption and small angle X-ray scattering analyses. The microspheres were nano-and mesoporous with a specific surface area in the range of 0.1-409 m 2 /g. The morphology of the copolymers was studied using field emission scanning electron microscopy and atomic force microscopy. The thermal properties were studied using differential scanning calorimetry and thermogravimetric analysis methods. A significant difference in the microsphere roughness is affected by lignins due to the presence of lignin nanoparticles at the surface of the microspheres. Molecular modeling was used to predict the sorption properties of the copolymers affected by various fields around the particles. The particle size, polydispersity and zeta potential of the St ? DVB, L-Met ? St ? DVB and L-unmod ? St ? DVB samples were measured by dynamic light scattering. Additionally, the point of zero charge of the samples was determined using potentiometric titration. The materials studied have a great potential for sorption processes due to their developed porosity and the presence of a number of active surface functionalities.
In this study, a novel method for the synthesis of hybrid, porous microspheres, including divinylbenzene (DVB), triethoxyvinylsilane (TEVS) and methacrylated lignin (L-Met), is presented. The methacrylic derivatives of kraft lignin were obtained by reaction with methacryloyl chloride according to a new experimental protocol. The course of the modification of lignin was confirmed by attenuated total reflectance (ATR-FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The emulsion-suspension polymerization method was employed to obtain copolymers of DVD, TEVS and L-Met in spherical forms. The porous structures and morphologies of the obtained lignin-containing functionalized microspheres were investigated by low-temperature nitrogen adsorption data and scanning electron microscopy (SEM). The microspheres are demonstrated to be mesoporous materials with specific surface areas in the range of 430–520 m2/g. The effects of the lignin component on the porous structure, shape, swelling and thermal properties of the microspheres were evaluated.
The preparation and the thermal and mechanical characteristics of lignin-containing polymer biocomposites were studied. Bisphenol A glycerolate (1 glycerol/phenol) diacrylate (BPA.GDA) was used as the main monomer, and butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) or styrene (St) was used as the reactive diluent. Unmodified lignin (L) or lignin modified with methacryloyl chloride (L-M) was applied as an ecofriendly component. The influences of the lignin, its modification, and of the type of reactive diluent on the properties of the composites were investigated. In the biocomposites with unmodified lignin, the lignin mainly acted as a filler, and it seemed that interactions occurred between the hydroxyl groups of the lignin and the carbonyl groups of the acrylates. When methacrylated lignin was applied, it seemed to take part in the creation of a polymer network. When styrene was added as a reactive diluent, the biocomposites had a more homogeneous structure, and their thermal resistance was higher than those with acrylate monomers. The use of lignin and its methacrylic derivative as a component in polymer composites promotes sustainability in the plastics industry and can have a positive influence on environmental problems related to waste generation.
The paper investigates the properties of unsaturated polyester resins and microcrystalline cellulose (MCC) composites. The influence of MCC modification on mechanical, thermomechanical, and thermal properties of obtained materials was discussed. In order to reduce the hydrophilic character of the MCC surface, it was subjected to esterification with the methacrylic anhydride. This resulted in hydroxyl groups blocking and, additionally, the introduction of unsaturated bonds into its structure, which could participate in copolymerization with the curing resin. Composites of varying amounts of cellulose as a filler were obtained from modified MCC and unmodified (comparative) MCC. The modification of MCC resulted in obtaining composites characterized by greater flexural strength and strain at break compared with the analogous composites based on the unmodified MCC.
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