Interface Reinforcement of Pulp Fiber Based ABS Composite with Hydrogen Bonding Initiated Interlinked Structure via Alkaline Oxidation and tert-Butyl Grafting on Cellulose

Abstract

Interface optimization in preparing natural fiber based biocomposite becomes a key factor that determines overall properties, especially mechanical performance. The solution for upgrading interfacial adhesion stemmed from polar fiber and nonpolar polymer remains unclear. Here, a kind of pulp fiber/acrylonitrile-butadiene-styrene (ABS) composite with content ratio of 1:1 was fabricated by functionalizing the cellulose fiber to coordinate interaction between fiber and ABS. With addition of 5 wt % polyacrylamide (PAM) there existed an interlinked three-element structure in composite. Three types of treatment to cellulose fiber, including alkali immersion, pivaloyl chloride grafting for 10 h and 20 h were conducted. Pulp fiber that was treated with alkali for one hour, followed by pivaloyl chloride reaction for ten hours, proved to be effective for interfacial adhesion. X-ray Photoelectron Spectroscopy (XPS) analysis reveals 21.9% of carbonyl and 12.1% of ester function in this fiber, which corresponds to oxidation and grafting. For its composite SEM picture displays that most of cellulose fiber are rooted in ABS and evident traces of tearing or fracture can be observed after tension test. DMA test indicates that this modified pulp fiber/ABS composite exhibits great compatibility, because of combined loss modulus peak ranging from 80 °C to 100 °C. Moreover, the well miscible composite has a tensile strength of 58.1 MPa and elastic modulus of 2515 MPa, increasing by nearly 50% and 60% from those of pure ABS, respectively.