Synthesis and properties of amino acid esters of hydroxypropyl cellulose

Abstract

The amino acid esters of hydroxypropyl cellulose (HPC) [R′ = H (2a), CH3 (2b), CH2CH(CH3)2 (2c), CH2CONH2 (2d), CH2CH2CONH2 (2e), CH2CH2CH2CH2 NHOCOC(CH3)3 (2f)] were synthesized in good yield by the reaction of t‐butoxycarbonyl (t‐Boc)‐protected amino acids with hydroxy groups of HPC (1; molar substitution (MS), 4.61). The amino acid functionalities displaying varied chemical nature, shape, and bulk were utilized and the bulk of the substituent on the α‐carbon of amino acids was elucidated to be of vital significance for the observed degree of incorporation (DSEst). The 1H NMR spectra and elemental analysis were employed to determine the degree of incorporation of amino acid moiety (DSEst) and almost complete substitution of the hydroxy protons was revealed for 2a, 2b, and 2f. The presence of the peaks characteristic of the carbonyl group in the FTIR spectra furnished further evidence for the successful esterification of HPC. The starting as well as the resulting polymers (1 and 2a–f) were soluble in polar organic solvents; however, the esterification of 1 with bulky organic moieties resulted in an increased hydrophobicity as all of the amino acid‐functionalized polymers (2a–f) were insoluble in water. The onset temperatures of weight loss of 2a–f were 175–230 °C, indicating fair thermal stability. The amino acid functionalization led to the enhanced polymer chain stiffness, and the glass transition temperatures of the derivatized polymers were 30–40 °C higher than that of 1 (Tg 3.9 °C; cf. Tg of 2a–f, 35.1–43.3 °C). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2326–2334, 2008

Amino acid‐functionalized ethyl cellulose: Synthesis, characterization, and gas permeation properties

“…Although the amino acid‐containing polymers have engrossed substantial prominence as a new class of bioactive polymeric materials,18–37 only a few significant research endeavors concerning the amino acid functionalization of cellulose derivatives have been reported so far 39. The hydroxy anchors of EC and the carboxy termini of amino acids provide an ample opportunity of bringing about a successful conjunction of the two biocompatible families of materials.…”

“…The hydroxy anchors of EC and the carboxy termini of amino acids provide an ample opportunity of bringing about a successful conjunction of the two biocompatible families of materials. Our previous efforts to effect the derivatization of organosoluble cellulosic polymers with a variety of substituents are quite evident of the fact that the tailoring of pendants on the cellulosic backbone results in a significant alteration of solubility, thermal, charge/discharge, and gas permeation characteristics as desired for specific applications 39–45. Hence, amino acid esterification of EC is anticipated to lead to the enhanced CO 2 separation performance, making these materials interesting candidates for gas separation membranes.…”

“…38 Although the amino acid-containing polymers have engrossed substantial prominence as a new class of bioactive polymeric materials, [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] only a few significant research endeavors concerning the amino acid functionalization of cellulose derivatives have been reported so far. 39 The hydroxy anchors of EC and the carboxy termini of amino acids provide an ample opportunity of bringing about a successful conjunction of the two biocompatible families of materials. Our previous efforts to effect the derivatization of organosoluble cellulosic polymers with a variety of substituents are quite evident of the fact that the tailoring of pendants on the cellulosic backbone results in a significant alteration of solubility, thermal, charge/discharge, and gas permeation characteristics as desired for specific applications.…”

Oriented and low‐density tin dioxide film by sol–gel mineralizing tin‐contained hydroxypropyl cellulose lyotropic liquid crystal for laser‐induced extreme ultraviolet emission

“…The microgel particle behaviors of HPC have been revealed depending on temperature recently 42, 43. The cholesteric phase can provide a multistructural units from single chiral macromolecule to cholesteric superstructure with long‐range order, as makes it available to serve as a template for preparing optical materials,44, 45 inorganic oxide materials,46 and so forth 47, 48. Here we report a fabrication of porous SnO 2 film using lyotropic cholesteric LC of ethanol‐aqueous HPC and was characterized and the morphology of SnO 2 after decomposing HPC is investigated, and demonstrated EUV generation at a 10 10 W/cm 2 laser incident.…”

Amino acid modified cellulose whiskers

“…With regard to cellulose, some recent studies have described the successful modification of cellulose fibrous networks and hydroxypropyl and ethyl cellulose with amino acids having as an objective to develop cell-adhesive structures, hydrophobic drug carriers and gas separation membranes, respectively. 7,8,9,10 In fact, amino acids are the building blocks of proteins and peptides and are involved in the development of a wide range of biocompatible applications or architectures. 9 These include controlled drug delivery systems, 11 celladhesive structures, 7 chiral recognition materials 12 and polymers 13 to mention only a few.…”