Enhancing the nonleaching antimicrobial performance of PET materials

Significance 

Antimicrobial poly (ethylene terephthalate) (PET) materials are widely used in several industrial applications owing to their excellent chemical and mechanical properties. Due to their considerable interest in both industrial and academic fields, various reports have documented the three commonly used fabrication methods including chemical modification, blending and surface treatment. Whereas chemical modification is tasked with the prevention of leaching antimicrobial components, the method is costly, complicated and environmentally unfriendly. Consequently, the leaching of the antimicrobial components evident in the surface coating method is yet to be addressed. However, findings in recent research have revealed that facile melting blending through PET and nonleaching antimicrobial polymers such as polypropylene grafted poly (hexamethylene guanidine) (PP-g-PHMG) exhibit high potential of achieving desirable cost-effective and nonleaching characteristics.

To this end, Wei Cao, Dafu Wei, Anna Zheng and Yong Guan from the East China University of Science and Technology developed cost-effective antimicrobial PET materials with enhanced nonleaching properties for large-scale industrial applications. These materials were prepared by melt blending the PET with PP-g-PHMG. The antimicrobial properties and nonleaching performance of such materials were therefore verified. The work is currently published in the European Polymer Journal.

In the study, the antimicrobial activities of the purified PET/PP-g-PHMG with different PHMG content was evaluated using Staphylococcus aureus and Escherichia coli bacteria. The authors noted the incapability of pure PET to deactivate the two bacteria. However, the antibacterial rates increase with the gradual increase in the PHMG content. As such, the material surface exhibited excellent antimicrobial properties reaching 98% and 99.9% for E. coli and S. aureus respectively. This was attributed to a combined effort between the difference in the PET matrix and PP-g-PHMG compatibility as well as the induced heterogenous repulsive crystallization effect.

On the other hand, the nonleaching performance of the as-prepared PET materials was validated based on the inhibition zone test. Specifically, the diameters of the inhibition zones were measured to determine the antimicrobial capacity. For PET/PHMG films, a small inhibition ring was observed. This was, however, not the case with PET/PP-g-PHMG due to the increase in the nonleaching characteristics. According to the authors, this could be related to the potential chemical bonding between the PET and PP-g-PHMG as a result of the anhydride group present.

In summary, East China University of Science and Technology scientists successfully developed a far better processing method for antimicrobial PET materials. Specifically, they achieved the desired objectives of excellent antimicrobial activities, significantly enhance nonleaching performance and environmental consciousness thus offering an alternative preparation method. Therefore, the paper findings will promote cost-effective and large-scale industrial processing of nonleaching antimicrobial PET materials. This would surely increase their industrial output considering their promising potential application in PET engineering and packaging materials.

Enhancing the nonleaching antimicrobial performance of PET materials - Advances in Engineering

About the author

Dr. Dafu Wei is an assistant professor at East China University of Science and Technology (ECUST), Shanghai, China. He received his Ph.D. degree in Materials Science from ECUST in 2011. And he was a visiting scholar at University of New Brunswick, Canada, 2012-2013.

His current research focus is in the areas of reactive extrusion polymerization and processing, and functional polymer materials. He hopes to develop environment-friendly solvent-free synthesis of functional polymers using an extruder as reactor and prepare functional materials via reactive extrusion processing. The ultimate goal is developing functional materials, such as non-leaching antimicrobial materials for practical applications in health, sanitation, and biomedicine, etc. He won a First Prize and a Third Prize of Shanghai Technology Innovation Award. He has over 40 publications and over 10 patents, including 2 US patents. Some of his research results have been used in the industry.

School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.

About the author

Wei Cao received Bachelor degree in Polymer Materials and Engineering from Nanjing Institute of Technology in 2016 and Master degree in Materials Science and Engineering from East China University of Science and Technology in 2019. During receiving for Master degree, he mainly focused on the non-leaching antimicrobial poly(ethylene terephthalate) (PET) materials. Some progress on the synthesis of antimicrobial compound of PHMG (polyhexamethylene guanidine) and further reaction with the amino-modified surfaces of PET was made in the early study.

Furthermore, the developed melting blending between neat PET and polypropylene-g-PHMG provided a facile and easy-to-scale-up way to obtain non-leaching and antimicrobial PET.

About the author

Dr. Yong Guan currently holds an associate professorship position at East China University of Science and Technology (ECUST), Shanghai, China. He received his Ph.D. degree at University of New Brunswick (Canada) in 2007.

His research interests are in the areas of synthesis and functionalization of polymers via reactive extrusion. Recently his work focuses on the antimicrobial modification and applications of polypropylene, polyethylene, nylon, cellulose fibers etc. He has over 60 SCI papers and over 20 authorized patents. Some of his research results have been industrialized.

School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.

Reference

Cao, W., Wei, D., Zheng, A., & Guan, Y. (2019). Surface enrichment and nonleaching antimicrobial performance of polypropylene grafted poly (hexamethylene guanidine) (PP-g-PHMG) in poly (ethylene terephthalate)/PP-g-PHMG. European Polymer Journal, 118, 231-238.

Go To European Polymer Journal

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