Miscibility of Chitosans/Polyamide 6 Blends

Abstract

ABSTRACT:Chitosans with different degrees of deacetylation were prepared by a chemical method, and miscibility between chitosan and polyamide 6 was examined as a function of the degree of deacetylation in chitosan. From dynamic mechanical analysis and solution viscosity measurement, it may be concluded that there are specific interactions between amorphous regions of both polymers and that the miscibility of the blends becomes better as the degree of deacetylation in chitosan decreases.KEY WORDS Chitosan / Degree of Deacetylation / Polyamide 6 / Blends / Miscibility / Recently, more focus has been concentrated on natural polymers, because natural polymers are inexhaustible resources with biocompatible and biodegradable properties, and they do not cause environmental problems. Therefore, many blending systems containing natural polymers are being studied. 1 -15 Chitosan is an N-deacetylated product of chitin that is the second most abundant polysaccharide in nature. Moreover, it has very useful functional groups such as hydroxyl, amine and acetamide groups, and also shows antimicrobial activity. Thus, it is used in various fields 11 • 12 ranging from a simple flocculant for waste water treatments to medical uses. In particular, interesting observations on the blends of chitosan with some synthetic polymers such as poly(vinyl alcohol), 13 poly-(vinylpyrrolidone), 14 and poly(ethylene oxide) 15 have been reported. Recently, Ratto et al. 7 examined the miscibility of chitosan/polyamide blends and reported that the blends are partially miscible. But, they used solely a chitosan with 80% degree of deacetylation.In this study, we control the degree of deacetylation of chitosan by a chemical method and investigate the miscibility of chitosan/polyamide 6 (PA6) blends as a function of the degree of deacetylation. EXPERIMENT AL MaterialsChitosan was purchased from Sigma Chemical Co., U.S.A. and purified by reprecipitation. 16 Chitosan was dissolved in 5% acetic acid and filtered with stainless steel mesh. The solution was poured into sodium hydroxide solution, and the precipitates were washed and dried in a vacuum at 60°C. The viscosity average molecular weight 1 7 was determined by the Mark-Houwink equation: [17]=KM: where K=l.8x 10-3 cm 3 g-1 in 0.1 M acetic acid/0.2 M NaCl solvent at 25°C and a is 0.93. The viscosity average molecular weight of the raw chitosan was 8.1 x 10 5 g mo1-1 . PA6 was supplied by Hyosung T & C, Korea and used without purification.t To whom correspondence should be addressed.Blending samples were prepared by dissolving chitosan and PA6 in formic acid. The solution was cast on a polystyrene plate and the solvent was evaporated under reduced pressure. Deacetylation and AcetylationTo prepare almost fully deacetylated chitosan, 18 the purified chitosan with 80% deacetylation was deacetylated as following procedure: The chitosan was first treated with 47% sodium hydroxide solution at 110°C for 2 h under nitrogen atmosphere, and the sample was filtered and washed with hot water. This procedure was r...

Pervaporation dehydration of aqueous ethanol solution using H-ZSM-5 filled chitosan membranes

“…4 shows the tanδ curves of chitosan control membrane and filled chitosan membranes. The chitosan control membrane shows a peak at 208 • C, which may related to the ␣-relaxation of chitosan [22], and the peak below 100 • C is attributed to absorbed moisture [23]. In comparison, the T g of H-ZSM-5(50)-CS-08 membrane shifts to 232 • C due to the rigidification of polymer at the interface [13] which may result in the formation of voids.…”

Main properties and current applications of some polysaccharides as biomaterials

“…Blends or composites were also prepared in the same way as mentioned previously for chitin: chitosan/polyamide 6,112 chitosan/cellulose fibres,113, 114 chitosan/poly(ethylene oxide) (POE),115 chitosan/ poly(vinyl pyrolidone) (PVP) and chitosan/poly(vinyl alcohol) (PVA) 116. The advantage of chitosan is its biodegradability but also its hydrophilic character in addition to the presence of polar groups that are able to form secondary interactions (OH and NH 2 groups involved in hydrogen bonds with other polymers), and its antibacterial activity.…”

Miscible chitosan/tertiary amide polymer blends

“…Other researchers also encountered a similar difficulty in determining the T g of chitosan. 6,9,32 Since all the tertiary amide polymers show distinct T g 's, the inability to detect the T g of chitosan is not really a problem in order to ascertain the miscibility of the blends. If the chitosan/tertiary amide polymer blend is miscible, the T g value of the blend will shift away from that of the tertiary amide polymer with increasing chitosan content in the blend.…”

“…2 Chitosan is the deacetylated product of chitin, normally with a degree of deacetylation greater than 50%. Blends of chitosan with cellulose, 3,4 polyamides, 5,6 poly(vinyl alcohol) (PVA), [7][8][9] and poly-(ethylene oxide) 10 have been studied. Chitosan/ cellulose blends are transparent and the two polymers mix intimately as shown by scanning electron microscopy.…”