A novel surface treatment for bamboo flour and its effect on the dimensional stability and mechanical properties of high density polyethylene/bamboo flour composites

In this study, bamboo flour (BF) was chemically modified using alkyl ketene dimer (AKD) or alkali treatment for the preparation of high-density polyethylene/bamboo flour (HDPE/BF) composites with or without compatibilizer maleic anhydride grafted high-density polyethylene (HDPE-g-MAH). The modified BF was characterized by Fourier transformation infrared (FTIR) spectroscopy and contact angle measurement, and the mechanical properties, morphology and water resistance of the HDPE/BF composites were investigated and compared. The results show that highly hydrophobic BF can be obtained by a simple procedure using a common paper sizing agent AKD. AKD can react with the hydroxyl groups in cellulose to form 6-keto ester. The combination of AKD treatment and addition of HDPE-g-MAH is more effective in improving the mechanical properties of HDPE/BF composites than using them alone. The impact strength, flexural strength and modulus of HDPE/A-BF/MAH composite are increased by 100.0%, 197.1% and 61.8% compared with that of HDPE/U-BF composites, and the water absorption and thickness swelling are decreased by 87.7% and 87.4% after immersion in water for one week, respectively. These results indicate that HDPE/BF composites with good mechanical properties and high water resistance can be obtained by AKD treatment. (C) 2018 Elsevier Ltd. All rights reserved.