Effect of Acetylation with Perchloric Acid as Catalyst in Sugarcane Bagasse Waste

ABSTRACT

Sugarcane bagasse is used as a byproduct of agro-industrial production. However, natural fibers’ hydrophilic characteristics prevent their application in natural fiber/polymer composites due to the hydroxyl groups (–OH) presented in the cellulose molecule. Because of this, several treatments have been proposed. In this research, the acetylation’s influence on sugarcane bagasse fiber’s structure and properties was investigated, and the effect of the amount of perchloric acid as the catalyst to isolate the lignin and decrease its polarity. Sugarcane bagasse fiber was chemically characterized after modification by Fourier Transform Infrared (FTIR) spectroscopy and degree of substitution (DS). Surface morphology, crystallinity, and thermal stability of fibers were evaluated by Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Thermogravimetry (TGA). A small amount of catalyst content has a significant effect on the DS, causing improved surface morphology and increased thermal stability due to acetylation. However, the crystallinity and lignin content of the fibers decreased after acetylation. According to chemical composition, the crystallinity decreased due to the amorphous phase from hemicellulose deposition. The decrease in the crystalline cellulose enhanced the acetylation reaction and substituted more hydroxyls groups per glucose unit according to DS values. Thus, the catalyst has an essential role in the efficiency of acetylation with sugarcane bagasse fiber.

摘要

甘蔗渣是农业工业生产的副产品. 然而，由于纤维素分子中存在羟基（–OH），天然纤维的亲水特性阻碍了其在天然纤维/聚合物复合材料中的应用. 因此，人们提出了几种治疗方法. 研究了乙酰化反应对甘蔗渣纤维结构和性能的影响，以及高氯酸用量对分离木质素和降低木质素极性的影响. 采用傅立叶变换红外光谱（FTIR）和取代度（DS）对改性后的甘蔗渣纤维进行了化学表征. 利用扫描电子显微镜（SEM）、X射线衍射（XRD）和热重分析（TGA）对纤维的表面形貌、结晶度和热稳定性进行了研究. 少量的催化剂含量对DS有显著的影响，由于乙酰化作用导致表面形貌的改善和热稳定性的提高. 乙酰化后纤维的结晶度和木质素含量降低. 根据化学成分，半纤维素沉积形成的非晶态相导致结晶度降低. 结晶纤维素的减少促进了乙酰化反应，并根据DS值在每个葡萄糖单元中取代了更多的羟基. 因此，催化剂对甘蔗渣纤维乙酰化反应的效率起着至关重要的作用.

关键词:

• 甘蔗渣
• 乙酰化
• 高氯酸
• 替代度
• 热性能

KEYWORDS:

• Sugarcane bagasse
• acetylation
• perchloric acid
• degree of substitution
• thermal properties

Acknowledgments

This research was funded by FAPERJ (E-26/260.026/2018 and E-26/010.001800/2015).

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by the Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro [E-26/260.026/2018 and E-26/010.001800/2015].