Benzoylation Treatment
Benzoylation is an important transformation in organic
synthesis [43].
Benzoyl chloride is most often used in fiber treatment.
Benzoyl chloride includes benzoyl(C6H5C=O) which is attributed to the decreased
hydrophilic nature of the treated fiber and improved interaction with the hydrophobic PS matrix.
The reaction between the cellulosic hydroxyl group of the fiber and benzoyl chloride is shown in Eqs. 5 and 6 [44].
Fiber OH þ NaOH!Fiber ONaþ þ H2O ð5Þ Benzoylation of fiber improves fiber matrix adhesion,thereby considerably increasing the strength ofcomposite, decreasing its water absorption and improving its thermal stability.
Josephetal. [44] and Nairetal.[41] used NaOH and benzoyl chloride
(C6H5COCl) solution for surface treatment of sisal fibers. A hypothetical model of the interface of PSbenzoylated sisal fiber composite has been postulated by Nair et al. [41]. It was observed that the thermal stability of treated composites were higher than that of untreated fiber composites.
A similar method was also applied by Wang [45] to improve the interfacial
adhesion of flax fiber and polyethylene (PE) matrix.
The fiber was initially alkaline pre-treated in order to activate the hydroxyl groups of the cellulose and lignin in the fiber; then the fiber was suspended in 10% NaOH and benzoyl chloride solution for 15 min.
The isolated fibers were then soaked in ethanol for 1 h to remove the benzoyl chloride and finally was washed with water and dried in the oven at 80C for 24 h.