Kraft lignin (KL) dispersions in methoxy polyethylene glycol (MPEG) and in a mixture of palm kernel oil (PKO) with MPEG (PKO/MPEG) were evaluated for v iscoelastic polyurethane foams (VPFs) production with different contents of KL (0-3.9 pphp) and PKO (0 -15 pphp). The influence of the dispersed KL on the foam structure, foam growth profile, foaming reactivity, mechanical properties, and final properties of VPFs were studied. The appearance of the VPF produced with KL dispersion in MPEG/PKO was similar to the control VPF foam. The addition of KL dispersion (0 to 15 pphp), had a significant effect on the growth profile, foaming reactivity, density and consequently on the foam morphology. VPFs produced with 3.9 pphp of KL presented shrinkage values about 4 times when compared to the control. The presence of the KL and PKO did not improve the burning rate of the foam samples compared to the control foam, without KL and PKO. Thermal stability of the produced foams showed no relevant differences regardless of the contents of KL/MPEG/PKO used in comparison to the control. Mechanical properties of VPF can be adjusted by making changes to the standard formulation. It can be concluded that the dispersion of KL in a mixture of MPEG and PKO represents an alternative for incorporating fractions of KL and PKO into VPF. In addition, this study provides new insights for the production of VPF using renewable resources for packaging applications, as well as in the mattress industry.
The focus of this work is to understand the effect of Kraft lignin (KL) treatment with tert‐butyl hydroperoxide (TBHP) and sodium formaldehyde sulfoxylate (SFS) on the properties of the latexes produced by emulsion copolymerization of styrene (Sty) with n‐butyl acrylate (BuA) and methacrylic acid (MAA), with initiator introduced in a shot process. The study intends to understand the effect of KL concentration after peroxide treatment on the properties not only of the latexes, but also on the copolymers themselves. Latexes were characterized in relation to global conversion, average particle size, zeta potential, coagulum concentration, surface tension and latex stability. The polymers were evaluated through molar mass and molar mass distributions, thermogravimetric analysis, and differential scanning calorimetry. The solubility of the KL in water and water/glycol were presented as a function of pH and KL concentration. Stable latexes were produced via emulsion copolymerization with different amounts of KL. The redox initiator system employed in the KL treatment was not efficient to obtain higher conversions. The increase of the KL concentration caused reduction of overall conversion, particle diameter, stability, molar mass and zeta potential. Among the concentrations tested, the greatest concentration of KL, 6.8 wt% relative to the mass of monomer, exhibited the greatest effect on the properties of the latexes and polymers.
Kraft lignin (KL) dispersions in methoxy polyethylene glycol (MPEG) and in a mixture of palm kernel oil (PKO) with MPEG (PKO/MPEG) were evaluated for viscoelastic polyurethane foams (VPFs) production with different contents of KL (0-3.9 pphp) and PKO (0 -15 pphp). The influence of the dispersed KL on the foam structure, foam growth profile, foaming reactivity, mechanical properties, and final properties of VPFs were studied. The appearance of the VPF produced with KL dispersion in MPEG/PKO was similar to the control VPF foam. The addition of KL dispersion (0 to 15 pphp), had a significant effect on the growth profile, foaming reactivity, density and consequently on the foam morphology. VPFs produced with 3.9 pphp of KL presented shrinkage values about 4 times when compared to the control. The presence of the KL and PKO did not improve the burning rate of the foam samples compared to the control foam, without KL and PKO. Thermal stability of the produced foams showed no relevant differences regardless of the contents of KL/MPEG/PKO used in comparison to the control. Mechanical properties of VPF can be adjusted by making changes to the standard formulation. It can be concluded that the dispersion of KL in a mixture of MPEG and PKO represents an alternative for incorporating fractions of KL and PKO into VPF. In addition, this study provides new insights for the production of VPF using renewable resources for packaging applications, as well as in the mattress industry.
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