Water-Based Processing of Fiberboard of Acrylic Resin Composites Reinforced With Cellulose Wood Pulp and Cellulose Nanofibrils

Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.

Characterization of Manmade and Recycled Cellulosic Fibers for Their Application in Building Materials

The aim of this study was to characterize two types of cellulosic fibers obtained from bleached wood pulp and unbleached recycled waste paper with different cellulose content(from 47.4 percent up to 82 percent),to compare and to analyze the potential use of the recycled fibers for building application,such as plastering mortar.Changes in the chemical composition,cellulose crystallinity and degree of polymerization of the fibers were found.The recycled fibers of lower quality showed heterogeneity in the fiber sizes(width and length),and they had greater surface roughness in comparison to high purity wood pulp samples.The high purity fibers(cellulose content>80.0 percent)had greater crystallinity and more homogeneous and smooth surfaces than the recycled fibers.The presence of calcite and kaolinite in all of the recycled cellulosic fibers samples was confirmed,whereas only one wood pulp sample contained calcite.The influence of the chemical composition was reflected in the fiber density values.Changes in the chemical composition and cellulose structure of the fibers affected the specific surface area,porosity and thermo physical properties of the fibers.More favorable values of thermal conductivity were reached for the recycled fibers than for the wood pulp samples.Testing the suitability of the recycled fibers with inorganic impurities originating from the paper-making processes for their use as fillers in plastering mortars(0.5 wt.%fiber content of the total weight of the filler and binder)confirmed their application by achieving a compressive strength value of 28 day-cured fiber-cement mortar required by the standard as well as by measured more favorable value of capillary water absorption coefficient.

Photoactivation of peroxymonosulfate by wood pulp cellulose biochar/g-C_(3)N_(4)composite for diclofenac degradation:the radical and nonradical pathways

Metal-free photocatalysts have attracted growing concern recently.Herein,the composites combining g-C_(3)N_(4)with wood pulp cellulose biochar(WPBC/g-C_(3)N_(4))were synthesized to effectively activate peroxymonosulfate(PMS)under visible light for the degradation of diclofenac(DCF).The incorporation of WPBC endowed g-C_(3)N_(4)with enhanced visible light absorption,improved charge separation capability,reduced electrical conductivity,and increased photocatalytic and PMS activation capability.Based on quenching tests,electron paramagnetic resonance(EPR),electrochemical analysis and solvent exchange experiments,both radical and nonradical mechanisms were proposed.Radical species including·OH,h^(+),·O_(2)^(-)were identified to contribute to DCF degradation.The 1O2 and electron transfer were the dominant nonradical pathways for DCF degradation.Moreover,the common influencing factors were examined,and DCF concentration was the most influential factor based on principal component analysis.Generally,the composites exhibited good reusability during consecutive runs.Based on HPLC/MS analysis,four intermediates were detected and the possible DCF degradation pathway was proposed.This work provided a potential strategy based on metal-free WPBC/g-C_(3)N_(4)for the photocatalytic activation of PMS to effectively degrade emerging contaminants in wastewater.