Acylation of silk and wool with acid anhydrides and preparation of water‐repellent fibers

Abstract

Silk and wool fibers were acylated with two acid anhydrides, dodecenylsuccinic anhydride (DDSA) and octadecenylsuccinic anhydride (ODSA), at 75°C with N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) as the solvent, the latter of which allowed higher weight gains to be reached. The weight gain and acyl content of wool was always higher than that of silk. Tensile properties of silk remained unchanged regardless of weight gain, whereas wool displayed a noticeably higher extensibility at high weight gain. Fine structural changes of acylated wool were detected by DSC analysis. Moisture regain and water retention of acylated silk and wool decreased significantly, whereas water repellency increased. SEM analysis showed the presence of foreign material firmly adherent to the surface of both silk and wool, whose amount increased with increasing weight gain. These deposits were attributed to the presence of the modifying agents at the fiber surface on the basis of the characteristic IR bands. The possible application of silk and wool fibers acylated with DDSA or ODSA for the preparation of water-repellent textile materials is discussed.

Surface Functionalization of “Rajshahi Silk” Using Green Silver Nanoparticles

“…Finally, from the XRD spectra it is possible to conclude that the crystalline nature of the untreated and treated samples was not altered by AgNPs, which could be clarified further by the fact that the Bragg's angle is the same for both samples. characterized by strong bands over 3000 cm −1 (due to OH and NH stretching vibrations) and various amide bands at 1550, 1250, and 650 cm −1 (from stretching vibrations of CN and NH deformation vibrations), which are typical of polypeptides and proteins and allow their conformational characterization [33]. Compared with the FT-IR spectrum of the untreated silk fabric, the spectrum of the silver-coated silk fabric also has these characteristic peaks, making it possible to observe the chelation between silk and silver.…”

Protein Fibre Surface Modification

“…Acylation agents include dodecenylsuccinic anhydride and ctadecenylsuccinic anhydride, anhydrides such as succinic anhydride and phthalic anhydride, and solvents including dimethyl sulfoxide and dimethylformamide (Arai et al 2001;Davarpanah et al 2009). Wool is noted to gain more weight and acyl content than silk.…”

“…Silk and wool both increase in water repellency and decrease in moisture regain and water retention. Deposits are observed (via SEM), which are attributed to the modifying agents (Arai et al 2001). Acylation provides an enhanced surface for the grafting of chitosan to wool or silk to provide antibacterial and anti-felting properties and superior dyeing ability in an environmentally friendly fashion (Davarpanah et al 2009; Ranjbar-Mohammadi et al 2010).…”

Physical properties of wool fibers modified with isocyanate compounds

“…The acylation of silk and wool with anhydride compounds possessing a long hydrocarbon chain as the pendant group led to the production of effective water repellent fibers. 1 Interestingly, the optimum effect was reached at relatively low weight gain (3-6% w/w).…”

“…We recently focused the attention on dibasic acid anhydrides and isocyanates. [1][2][3][4][5] These are acylating agents whose target reactive sites are the nucleophiles present in several amino acid side chains, including amino, guanidyl, imidazole, hydroxyl, phenolic, carboxyl, and free sulphydril groups. 6,7 The yield of the reaction is strongly influenced by a number of experimental parameters, including properties of the solvent, chemistry of the acylating agent, accessibility and reactivity of nucleophiles into the fibers, reaction temperature, and time.…”