A comparison of flax shive and extracted flax shive reinforced PP composites

In this study, flax shive (FS) and extracted flax shive (EFS) were fully characterized. The results showed that EFS presented lower noncellulose content, smaller porous tunnels and better thermal stability than FS. The 5 % weight loss temperature of EFS was over 200 °C, which can meet the requirements of the processing conditions for the natural fiber reinforced polymer composites. Consequently, the flax shive and extracted flax shive reinforced PP composites were prepared and characterized. It was found that the thermal stability of EFS/PP composites was better than that of FS/PP composites, and both FS and EFS behaved as nucleation agents, which could accelerate the crystallization process of PP in the composites. Mechanical test showed that EFS could be used as a reinforcing material for PP composite when compatibilizer was applied. The flexural strength and modulus of the composites containing 30 % EFS were about 8 % and 100 % higher than that of pure polypropylene, respectively.     

Preparation of lignopolyols from wheat straw soda lignin

Wheat straw soda lignin was modified and characterized by several qualitative and quantitative methods such as (31)P NMR spectroscopy to evaluate its potential as a substitute for polyols in view of polyurethane applications. Chemical modification of the lignin was achieved with propylene oxide to form lignopolyol derivatives. This was performed by a two-step reaction of lignin with maleic anhydride followed by propylene oxide and by direct oxyalkylation under acidic and alkaline conditions. The physical and chemical properties of lignopolyols from each method and the subsequent chain-extended hydroxyl groups were evaluated. Direct oxyalkylation of lignin under alkaline conditions was found to be more efficient than acidic conditions and more effective than the two-step process for preparing lignopolyol with higher aliphatic hydroxyl contents.