Synthesis of Chitosan Surfactants

Abstract

Chitosan surfactants were prepared in a three‐step reaction starting with glycol chitosan (GC) and chitosan oligosaccharides (COS). In the case of GC, water‐insoluble products were obtained, the functionalisation of which were proven via IR spectroscopy. Starting with COS, a broad variety of products with different ratios of ionic and hydrophobic side chains were prepared and characterised by NMR and partially by IR spectroscopy. Thermogravimetric analysis showed that the thermal stability of functionalised COS did not change. The critical micelle concentration (cmc) was determined from surface tension measurements to be 0.01 mg · mL−1 for a sample of ionic to hydrophobic units of 1:1.magnified image

Synthesis and Photopolymerization of 2,2-Di((Acryloyloxy)Methyl)Butyl Bis(2-(Acryloyloxy)Ethyl)Carbamate

“…The photoinitiators used in this study, 2-hydroxy-2-methylpheny-propane-1-one (1173), 2,4,6-trimethyl benzoyldiphenyl phosphine oxide (TPO), benzophenone (BP) and ethyl-4-dimethylaminobenzoate (EDAB), were donated by Runtec Chemistry (Changzhou, Jiangsu, P. R. China). [17] Trimethylolpropane (67 g, 0.5 mol), dimethyl carbonate (135 g, 1.5 mol) and DABCO (0.56 g, 5 mmol) were heated at 75 • C for 16 h. Then methanol and excess dimethyl carbonate were removed by distillation. EDO was obtained in quantitative yield and was used without further purification for the next step.…”

Synthesis of a Difunctional Orthogonal Coupler for the Preparation of Carbohydrate‐Functionalized sP(EO‐stat‐PO) Hydrogels

“…Because of differences in reactivities between the two carbonate functional groups towards amino nucleophiles, it is possible to perform these reactions selectively. Recently, the reactivity of difunctional carbonate couplers with different leaving groups (LGs) was reported, and their coupling ability towards amino acid methyl esters and glucosamine was determined; [5] LGs were para-nitrophenol, phenol, imidazole and acetone oxime. It was shown that the substitution reaction is much faster than the addition reaction; no conversion of the five-membered ring carbonate was observed below 70 8C.…”

Synthesis, Characterization, and Selectivity of Bifunctional Couplers

“…In the past, an asymmetric A,A 0 -carbonate coupler [(2-oxo-1,3-dioxolan-4-yl)methylphenyl carbonate, A1] was developed in our group to selectively combine monodisperse functional amine building blocks and polyamines within a single molecule. [2][3][4][5][6][7][8][9][10] At low temperatures (0-25 8C) the phenyl carbonate of the bifunctional coupler was first substituted selectively with hydrophilic, hydrophobic, or ionic primary amines to result in functionalized couplers, or with polyamines to result in a polyamine-coupler adduct. Then, at higher temperatures (60-80 8C) the functionalized couplers are reacted with a polyamine, respectively, the polyamine-coupler adducts are reacted with amine building blocks to produce multifunctional polymers.…”

“…During these reactions the cyclic carbonate ring is opened and a urethane group with an adjacent hydroxyl group is formed. Based on coupler A1, several functionalized couplers were prepared and successfully used for the modification of branched polyethyleneimine (B-PEI), [2][3][4][5][6][7] chitosan, [9] and aminofunctional polysiloxane. [10] Polymers bearing amine groups, the so-called polyamines, are an interesting class of polymers.…”

“…Different structures of polylysine are available or can be synthesized: a-poly(L-lysine), e-poly(L-lysine), and branched poly(L-lysine). [16] The carbonate coupler A1 was successfully used in reactions with primary amine groups in B-PEI, some preliminary results concerning the modification of PVAm, PAAm, chitosan, and polylysine were also reported, [7,9] however, A1 cannot be used for the modification of L-PEI and the secondary amine groups of B-PEI, because both functional groups of this coupler are nonreactive to secondary amines. Further, upon reaction of coupler A1 with amines, phenol is produced as side-product.…”