近年來，隨著節能之概念提升，對於消耗量最大的汽車燃油也開始被仔細審視，其中輪胎是消耗汽車燃油最大量的部位，因此國際上開始對輪胎性能嚴加設限，而輪胎之優劣絕大多是由胎面膠料之黏彈性質所決定，其中天然橡膠是橡膠材料中最古老但也是最主要之原料之一，因此了解天然橡膠之黏彈性質如何受到其他因素影響對於設計開發新式環保配方非常重要。
本研究是從分子動力學模擬法出發，探討具不同交聯情況及填充劑C60含量的天然橡膠之黏彈性質。對純天然橡膠來說，當分子量足夠高時，分子量對拉伸模數之影響並不明顯，然而不管橡膠中是否有交聯點或是填充劑之存在，應變率都會明顯影響橡膠之拉伸行為，且拉伸模數與應變率之對數會呈現一線性關係；在零剪切黏度方面，分子量與填充情況皆可用理論或經驗式將模擬所求得之數據修正至巨觀物理性質。
考慮巨觀下天然橡膠之機械性質會受到交聯或者填充不均之情況，本研究以特殊之格狀模型施與一特定頻率之週期性應變透過有限元素法，將分子動力學模擬經修正後之物理性質置入巨觀模型中，配合Kelvin-Voigt黏彈模型進行動態力學模擬。發現在填充劑分布完全均勻的前提下，C60之含量越高相位角會越小，天然橡膠會越接近彈性材料。此外本研究亦以不同的格狀排列代表不同之局域性質分布進行模擬，當施加形變於C60分布不均的天然橡膠上時，應力會由C60濃度較高的部位所承擔，且C60分布越不均，動態力學測試所得到的相位角將越大，橡膠整體會越接近純膠料之黏性行為。

Since the fuel efficiency and the wet grip performance are closely related to the mechanical properties of tire rubber, it is very important to understanding the underlying mechanisms. Natural rubber is the main ingredient of tire rubber in which other additives were mixed to reach the required mechanical properties, and the mainly interaction of additives with natural rubber is in the form of composite. An objective of producing rubber composites is to distribute (disperse) fillers as homogeneously as possible so that the resulting mechanical properties of the rubber/filler composite will be uniform. However, it is far from easy to control the distribution and dispersion of fillers in a rubber matrix, because of the interaction forces (Van der Waals force) that cause the formations of clusters in as-produced fillers. Here we calculated the mechanical properties of natural rubber with different filler (C60) content by molecular dynamics simulations first, and the results were considered as the properties of local regimes. Then, different regimes were combined into macroscopic model to simulate heterogeneous material via finite element method. The effect of distribution and dispersion of fillers were investigated.
By the results, we found that the behavior of viscoelastic would be effected by the distribution of filler in rubber matrix. In general, the better the dispersion ability is, the more homogeneous material like.

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