Crystallization Kinetics Study of Impact Polypropylene Copolymer with Kenaf as Nucleating Agent and Reinforcement

Abstract

Impact Polypropylene Copolymer (IPC) is an material which combines properties of isotactic Polypropylene (iPP) and its own high impact toughness. However, the crystallization kinetics might be lower than iPP, which may affect the manufacturing cycles. Kenaf was used as the addition in IPC, in which kenaf acts as a nucleating agent as well as reinforcement for IPC. Kenaf was alkalized with NaOH 6 v.v% for about 8 hours to remove the dirt on the surface and to reduce lignin, which contributed polarity to kenaf. The alkalization improved the compatibility of kenaf fiber with IPC. The crystallization kinetics study was conducted by employing the Avrami model to Differential scanning calorimetry data in order to obtain half-time, Avrami index (morphology parameter) and Avrami crystallization kinetics. The addition of 5 wt.% kenaf was found to be an optimum concentration to improve crystallization kinetics. The addition of more than 5 wt.% kenaf (15 wt.% and 20 wt.%) did not improve crystallization kinetics which may be due to the agglomeration, thus preventing efficient heat transfer between nucleating seeds and the matrix. The connection between crystallization kinetics and mechanical properties was also established for the IPC+ kenaf system.

Keywords

• crystallization kinetics
• impact polypropylene copolymer
• kenaf fiber
• nucleating agent
• polymer reinforcement