PEMM/COPPE, Universidade Federal do Rio de Janeiro, PO Box 68505, 21945-970, Rio de Janeiro, RJ, Brazil.
Universidade Federal do ABC, Avenida dos Estados, n° 5001, Bairro Bangu, 09219-971, Santo André, SP, Brazil.
Carbohydr Polym. 2017 Jun 1;165:429-436. doi: 10.1016/j.carbpol.2017.02.042. Epub 2017 Feb 22.
The high lignin to cellulose ratio of coir fibers results in low compatibility between these fibers and natural polymers like starch, leading to poor mechanical properties in the composites. Plasma treatment using either air or oxygen proved to be an effective in removing the lignin rich amorphous layer on coir fibers, as it was clearly observed by SEM. The ratio of the FTIR signal related to lignin (1508cm) and cellulose (1317cm) decreases 10 times for air plasma treated fibers and 20 times for oxygen plasma treated samples. Composites of plasma treated short coir fibers and thermoplastic starch presented considerable increase in mechanical properties in comparison to composites made with untreated fibers. Tensile strength increased by up to 300% and elastic modulus improved by a factor of nearly 20 times, which was associated with enhanced fiber-matrix adhesion after plasma treatment with oxygen for 7.2min at 80W power.
椰纤维的高木质素与纤维素比率导致这些纤维与天然聚合物（如淀粉）之间的相容性差，从而导致复合材料的机械性能较差。使用空气或氧气的等离子体处理被证明是一种有效的方法，可以去除椰纤维上富含木质素的无定形层，这可以通过 SEM 清楚地观察到。与木质素（1508cm）和纤维素（1317cm）相关的 FTIR 信号的比值对于空气等离子体处理的纤维降低了 10 倍，对于氧气等离子体处理的样品降低了 20 倍。与使用未处理纤维制成的复合材料相比，经过等离子体处理的短椰纤维和热塑性淀粉复合材料的机械性能有了相当大的提高。拉伸强度提高了 300%，弹性模量提高了近 20 倍，这与在 80W 功率下经过 7.2 分钟的氧气等离子体处理后增强了纤维-基体之间的附着力有关。
