Flexural strength and dynamic mechanical properties of polypropylene/natural rubber blends and the effect of autoclave sterilization : a preliminary study for customized rubber dam clamp

Name: Paphavarin Rangsantham

keyword: Autoclave

; Dynamic mechanical properties

; Flexural strength

; Natural rubber

; Polypropylene

; Rubber dam clamp

Abstract: Introduction: The aim of this study was to identify the optimum ratios of polypropylene and natural rubber (PP/NR) for a customized rubber dam clamp in dentistry. This study was focused on the flexural strength and dynamic mechanical properties of PP/NR in various ratios. Moreover, the impact of autoclave sterilization was also considered. Materials and methods: Six proportions of PP/NR blends (100/0, 90/10, 80/20, 70/30, 60/40 and 50/50) were prepared and assessed for flexural strength using a three-point bending test and dynamic mechanical properties were measured through an automatic dynamic mechanical analyzer. After these tests, the PP/NR with 100/0, 90/10, 80/20 ratios were selected and underwent autoclave sterilization for 1, 5 and 10 cycles. Then, the flexural strength testing was repeated and investigated. Results: The flexural strength of PP/NR blended materials was statistically significant difference in every group of this study. The autoclave sterilization test revealed that the flexural strength of PP/NR 90/10 and 80/20 ratios were significantly increased after sterilization for 1, 5 and 10 cycles. In addition, the PP/NR 90/10 ratio was also comparable to the 100/0 ratio (pure PP). The dynamic mechanical properties test showed all PP/NR blends remained stable during autoclave sterilization condition (121 °C, 30 minutes). Furthermore, the PP/NR 90/10 and 80/20 ratios displayed dynamic mechanical properties similar to pure PP at room temperature (25 °C), mimicking clinical conditions. Conclusion: The lower NR content in PP/NR blends results in significantly higher flexural strength, and autoclave sterilization has an effect on this property. The dynamic mechanical properties of all PP/NR blends were also influenced by NR addition, with lower NR content suggesting favorable elastic characteristics. The findings suggest that the PP/NR blend with 90/10 ratio might be considered as an alternative material for developing rubber dam clamp.

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Panupat Phumpatrakom

Role: advisor

Name: Panjaporn Wongwitthayakool

Role: co-advisor

Created: 2024

Modified: 2568-05-13

Issued: 2025-04-06

DOI: 10.14457/TU.the.2024.44

eng

Level: Master's Degree

Descipline: Endodontics

Grantor: Thammasat University

DegreeName: Master of Science

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