Starch/PVA-based nanocomposites reinforced with bamboo nanofibrils

Abstract

a b s t r a c tThis work aimed to evaluate the effect of including different concentrations of bamboo nanofibrils on physical, mechanical, morphological and structural properties of nanocomposites from cassava starch and polyvinyl alcohol (PVA). Nanocomposites were prepared with blends of starch/PVA and nanofibrils of bamboo. Chemical pre-treatments and mechanical defibrillation were used to obtain the nanofibrils. The mixture containing 3% of starch and 4% of PVA in the proportion of 20/80 (starch/PVA) were chosen after preliminary testing. Atomic force microscopy (AFM) and transmission electronic microscopy (TEM) were used to characterize the bamboo nanofibrils. Microstructure of the nanocomposites was evaluated using scanning electron microscopy (SEM) and X-ray diffractrometry (XRD). Physical and mechanical properties were also evaluated. Results showed that pre-chemical treatments increased the content of the alpha-cellulose in bleached pulp by approximately 112% in relation to the native fiber. Increasing the number of passages through the defibrillator reduced the average diameter of the bamboo nanofibrils (from 82 ± 29 nm to 10 ± 6 nm). Addition of 6.5% nanofibrils improved the tensile strength and elongation at the break of the nanocomposite by 24 and 51%, respectively, but reduced the tensile modulus by 40% in relation to control (unreinforced) blend. Nanofibrils decreased the transparency of the nanocomposite films. The water vapor permeability and water solubility of the nanocomposite containing high contents of nanofibrils decreased up to 20% and 30%, respectively, in relation to the control blend.

Chitosan/Cellulose Nanofibril Nanocomposite and Its Effect on Quality of Coated Strawberries

“…at a working speed of 1,700 rpm and 5 A electric current, according to the methodology described by Bufalino et al [15] with same modifications. e nanofiber suspension obtained in the defibrillator was added to different chitosan concentration solutions after 24 h of stirring, and with the aid of an ultrasound, it was incorporated in different concentrations (3% and 5%) and then subjected to stirring for 1 h. e films were obtained by the same methodology as described by Guimarães et al [16,17].…”

“…: 1,010,352) 1% (v/v). e solution was maintained under constant agitation for 24 h. e films were obtained by the casting method [16,17]. Different concentrations (1% and 2% of chitosan) were uniformly poured on Petri dishes and dried at room temperature for 16 h.…”

“…e water vapor permeability (WVP) of the elaborated films was determined using the 96-80 standard from ASTM, adapted by Guimarães et al [17].…”

Preliminary study for acetylation of cassava bagasse starch and microfibrillated cellulose of bamboo

“…Starch-based bioplastic have been employed several sources, such as banana [1], potato [2], sago [2][3][4][5], rice [6], corn [7], soybean [8], and cassava [9]. Cassava starch has been broadly utilized to be used in bioplastic reinforced with clay nanoparticles [9], thermoplastic chitosan [7], poly lactic acid [10], gelatin [11], bamboo nanofibrils [12], bacterial cellulose [13], and green coconut fiber [14] in order to overcome drawbacks of starch-based bioplastic, such as mostly water-soluble, low resitancy, and low mechanical property. Cassava starch production generates by-product [9], i.e cassava bagasse or pulp consisted a fibrous material containing 30-60% residual starch [15].…”

“…In this research it was considered to prepare bioplastic or cassava bagasse starch-based biocomposite reinforced with microfibrillated cellulose of bamboo, bamboo cellulose fiber. Bamboo denotes as potential fiber sources for biocomposites matrix [17][18], as composite filler for polyvinylchloride (PVC) [15], reinforcing nanocomposite starch-polyvinylacetate (PVA) [12], reinforcing polylactic acid (PLA) [20], reinforcing starch-based composite [21]. However, both (cassava bagasse starch and bamboo microfibrillated cellulose) have shortcomings regard with their properties.…”