Modification of rheological responses under elongational flow at non-isothermal condition

• Main Authors: Yamaguchi, Masayuki, Seemork, Jiraporn, Phulkerd, Panitha, Ali, Mohd Amran Bin Md
• Format: Conference or Workshop Item
• Language: English
• Published: 2023
• Online Access: http://eprints.utem.edu.my/id/eprint/27916/1/Modification%20of%20Rheological%20Responses%20under%20Elongational%20Flow%20at%20Non-Isothermal%20CONDITON.pdf; http://eprints.utem.edu.my/id/eprint/27916/; https://pubs.aip.org/aip/acp/article-abstract/2997/1/020004/2895373/Modification-of-rheological-responses-under?redirectedFrom=fulltext

Rheological responses under elongational flow at non-isothermal condition are significantly important for actual polymer processing. Drawdown force, defined as a force required to stretch a molten polymer, was evaluated as the non-isothermal rheological response using polypropylene (PP) in this study. It was found that the die length affected the drawdown force, which was pronounced for a system having a long relaxation time. The prompt crystallization after passing through a long die would be responsible for this phenomenon. Furthermore, the addition of a nucleating agent was quite effective to increase the drawdown force, at which the shape of a nucleating agent has to be considered. The accelerated crystallization by the addition of a fibrous nucleating agent resulted in the pseudo shish-kebab structure, leading to high modulus in the flow direction. Finally, the addition of a low-viscous acrylate polymer was found to enhance the drawdown force of PP. Due to the prompt solidification of the acrylate polymer under a rapid cooling condition, the dispersions acted as rigid fibers before the crystallization of PP. These modification methods will be available to improve the processability at various processing operations at which a molten polymer is stretched at non-isothermal condition.