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The solubilization of lignin in self-aggregating triblock amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) in aqueous solution has been studied utilizing liquid-state proton nuclear magnetic resonance spectroscopy (1 H NMR) and diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY NMR). Our hypothesis for copolymer micelle incorporation of lignaceous species includes a "hydrophilic-aromatic interaction model", in which lignin derivatives with amphiphilic characteristics, known to be abundant in the effluent from pulp mill and pretreatment of various lignocellulosic materials, have an affinity for these micelles, and tend to form relatively organized structures within them. Here we show how the chemical/structural features of lignin units and small molecule lignin models determine their solubilization behavior in the micelles. It was found that a buildup of concentration series of lignin and lignin-based model compounds guaiacol, eugenol, phenol, guaiacylglycerol-beta-guaiacyl ether, ferulic acid in Pluronic ® F68-deuterium oxide solution results in significant upfield chemical shifts of PEO-(CH 2-CH 2) and PPO-(CH 3) proton resonances, and at a critical guest concentration (CGC), dramatic upfield shifts due to gross structural transitions in the micelles. We present evidence that copolymer micelle-lignin interactions depend on both chemical functional group characteristics of solute (i.e., polarity, Hbonding ability) and π-π interactions between aromatic/conjugated groups. Our results demonstrate how the loci of incorporated solute in the block copolymer micelles are affected by these features.

Powdered cellulose-reinforced (20 wt%) polypropylene composites were prepared by melt compounding and subsequent injection moldings. We assessed the effect of cellulose reducing ends on the capacity of powdered cellulose to reinforce polypropylene composites after seven days exposure to air circulation during the conditioning of samples. Tensile tests on the composites were performed at 5.08 mm/min. Fourier transform infrared spectroscopy revealed some changes that occurred within the composites by demonstrating a practical decrease in –C=O (1744 cm−1) absorption band intensity. A thermogravimetric analysis indicated differences within the thermal behavior of the prepared composites, showing a higher onset of degradation. Scanning electron microscopy of the fracture areas, together with load–extension curves, further characterized the development of interfacial cellulose/matrix adhesion as well as the brittle and ductile behavior of the composites. The results indicate that the thermal and tensile properties of powdered cellulose/polypropylene are improved by decreasing the amount of cellulose reducing ends in the system.

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