Determination of the most significant rubber components influencing the hardness of natural rubber (NR) using various statistical methods

• Published in: Heliyon 2024-02, Vol.10 (3), p.e25170-e25170, Article e25170
• Main Authors: Virág, Lilla, Egedy, Attila, Varga, Csilla, Erdős, Gergely, Berezvai, Szabolcs, Kovács, László, Ulbert, Zsolt
• Format: Article
• Language: English
• Subjects: Binary decision tree; Linear regression; Natural rubber; Ridge regression; Shore a hardness; statistical analysis; t-test
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e25170

Manufacturers use a large number of components in the production of modern rubber products. The selection of the constituents of the rubber recipe is primarily determined by the purpose of use. The different fields of applications of rubbers require the presence of appropriate mechanical properties. In this respect, it can be useful to know which substances forming the rubber recipe have significant influence on the different mechanical properties. In this study, the statistical analysis of the influence of rubber components on the hardness of natural rubber (NR) is proposed based on literature review. Based on the literature data, various statistical analyses, like linear regression, constrained linear regression, Ridge regression, Ridge sparse regression and binary classification decision trees were performed to determine which rubber components have the most significant effect on the hardness. In the statistical analyses, the effect of a total of 42 constituents of rubber compound on hardness was investigated. Most of the applied statistical methods confirmed that the traditional frequently used rubber components, such as carbon black and sulfur, have a primary effect on the hardness. However, the substances forming the rubber compound that are not widely used in practice or newly developed components appear differently in the lists of significant additives obtained by the different statistical methods. •In this study, the influence of the components of natural rubber (NR) on the hardness is investigated by statistical analysis based on experimental data from literature.•Anslysis results confirmed that carbon black has - while Quartz sand (SiO2) does not have - significant effect on the hardness of rubbers.•Sulfur was found a key contributor to hardness via cross-linking in sulfur-based rubbers.•Softeners contribute to better dispersing and mixing up the constituents but also can directly soften the vulcanized rubber.•The presented statistical method can be applied also in the industrial practice for the development of rubbers including the identification of the key components affecting the different mechanical properties of the rubber.