Four kinds of lignophenols (Lps) were derived from native bamboo (Sinocalamus affinis) lignin through phase separation system by using four kinds of phenols (p-cresol, catechol, resorcinol and pyrogallol) as derivatives and 72% concentrated sulfuric acid as catalyst. The resulting lignophenols were characterized by 1 H-NMR, FT-IR, and GPC analysis. Then they were blended with polyhydroxybutyrate (PHB) to cast thin biocomposite films. The mechanical properties, water-absorbing qualities, and thermal properties of films were tested and discussed. The results indicated that phase separation treatment can effectively improve phenolic hydroxyl contents of lignins. The lignin macromolecule was significantly reduced to small size and well-soluble polymers. The best amounts of added Lps in composite films depended upon the kind of phenols. In present study, the mechanical properties, water-absorbing qualities, and thermal properties of biocomposite films showed good results at less than 10% Lps' addition. This provides a possibility that a new kind of biodegradable films can be made up of engineering plastics and lignin. INTRODUCTIONThe development of commercially viable "green products" based on natural resources for both matrices and reinforcements for a wide range of applications is on the rise (Satyanarayana et al. 2009). Lignin, as the second most abundant renewable biopolymer in nature and an inexpensive and currently underutilized waste product from papermaking and biorefinery industries, has been a candidate for renewable materials; however, it is often difficult to blend with other biopolymer due to its complex and irregular structure. So it is necessary to modify lignin.Phenol chemical modification is one kind of method to modify lignin. Recently a class of lignin-based functional polymers, the lignophenols, has originally been designed and their synthesis process from native lignin has been developed. This process includes the phase separation reaction system composed of phenol derivatives and concentrated acid. In the process, native lignin is modified by selectively grafting phenol derivatives to benzyl position. The separated lignin derivatives have several structural characteristics, for example being highly phenolic, very light colored (pinkish white) and highly stable, which is in contrast to conventional lignin (Funaoka et al. 1989). PEER-REVIEWED ARTICLEbioresources.com Qian et al. (2015). "PHB-lignophenol films," BioResources 10(2), 3169-3180. 3170Polyhydroxybutyrate (PHB) is accumulated by a wide variety of micro-organisms as an intracellular storage source of organic carbon and chemical energy. PHB has mechanical strength, elastic modulus, thermal moldability, and biocompatibility. It has attracted much attention as a biocompatible and biodegradable thermoplastic polymer, but its application has often been limited by its brittleness. In recent years, fillers from renewable source have been increasingly used in the preparation of PHB-based biocomposites.Bamboo encompasses 1,250 species within 75 ge...

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Bamboo (Sinocalamus affinis) lignophenols (Lps), synthesized using a phase separation system, were used as a natural plasticizing additive to complex with pulp (short fiber and fluffy short fiber) sheets. The structural features of Lps were analyzed by gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, and proton-nuclear magnetic resonance ( 1 H-NMR). The pulp sheet absorptivity of Lps, as well as the physical properties of complex sheets, were discussed. Results showed that when the concentration of bamboo Lps solution was 10 g/L, the absorption amount of Lps in the sheets made up of short pulp fibers (12%) was slightly higher than that of sheets made of fluffy short pulp fibers (10%), while physical properties, such as tightness, tensile strength, elongation, bursting, and tearing, were improved obviously after the addition of Lps. More obvious improvement in the physical strength was found in sheets made up of fluffy short pulp fibers. Results indicated that the amount of absorbed Lps was of the same importance as the properties of the pulp fibers. It is necessary to adjust the properties of both the Lps and sheets to get the best mechanical strength for the pulp sheets.

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In the conventional pulp and papermaking process, lignin in black liquor is mostly burned for energy. It has not been widely used as a functional polymer. To use both cellulose and lignin component, unique kraft cooking conditions were used in bamboo cooking in this study, and acid precipitation was used to extract lignin from the black liquor. Under different pH values, the precipitated lignins were characterized and compared by gel permeation chromatography (GPC), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Lignin dissolution in acidic conditions was studied. Pulps with high lignin content were used to synthesize oil absorption materials, which were prepared by grafting butyl methacrylate (BMA) onto the cellulose chain. Sodium silicate was used as an initiator, and 1,4-butane dioldimethacrylate (BDDMA) was used as a crosslinker. The structures of grafted copolymers were characterized by FTIR, scanning electron microscopy (SEM), and thermogravimetry (TG). The acid precipitation process was found to be effective and has important implications for the further lignin applications. The grafting reaction between pulps and BMA was successful. The silicone oil absorption capacity of the obtained materials was 15.3 g/g.