Synthesis of hydroxypropyl cellulose derivatives modified with amphiphilic diblock copolymer side-chains for the slow release of volatile molecules

Abstract

Hydroxypropyl cellulose (HPC) was used as carrier material to prepare comb-like grafted block copolymers having an amphiphilic core-shell structure. The hydroxyl groups of HPC were partially protected with trimethylsilyl groups and the free OH groups used to initiate the ring opening polymerisation (ROP) of L-lactide. The end-chain of the grafted hydrophobic poly(L-lactide) (PLLA) chain was then functionalised with 2-bromopropionyl bromide which was used to polymerise the tertbutyl acrylate ( t BA) monomer by atom transfer radical polymerisation (ATRP). The hydrophobic P t BA block was then hydrolysed to a hydrophilic poly(acrylic acid) (PAA) block. The resulting amphiphilic grafted copolymer HPC-g-(PLLA-b-PAA) was dissolved in an ethanol/water mixture (9 : 1), such as a typical Eau de Toilette (EdT) formulation. Atomic force microscopy (AFM) and size measurements confirmed the presence of core-shell structures in solution. A significant swelling of HPC-g-(PLLA-b-PAA) in the presence of a volatile bioactive molecule, methyl 2,2-dimethyl-6methylene-1-cyclohexanecarboxylate (RomasconeÒ), was observed by dynamic light scattering (DLS). Furthermore, the presence of HPC-g-(PLLA-b-PAA) significantly decreased the evaporation rate of RomasconeÒ, thus serving as an efficient fragrance delivery system in formulations with high ethanol content.

The preparation of graft copolymers of cellulose and cellulose derivatives using ATRP under homogeneous reaction conditions

“…The three graft-copolymers self-assembled into particles in THF and their sizes were determined using DLS. The cross- PAA-b-PLLA-g-HPC graft copolymers were developed by Berthier et al 71 following a five step procedure ( Figure 12). The macro-initiator was prepared from bromopropionyl bromide using the chain end -OH of PLLA following the ROP polymerisation of LLA onto HPC.…”

Controlled synthesis of EuPO4 nano/microstructures and core–shell SiO2@EuPO4 nanostructures with improved photoluminescence

“…[6][7][8][9] Most core and shell materials are composed of polymers, inorganic solids and metals. [10][11][12] SiO 2 has been widely used to fabricate core-shell materials as a core due to its good properties.…”

Cellulose derivatives and graft copolymers as blocks for functional materials

“…Cellulose graft copolymers with more complex architectures have also been synthesized by combination of ATRP and other polymerizations or chemical reactions for the purpose of preparing cellulosic functional materials. By the combination of ATRP and ring‐opening polymerization, cellulose graft copolymers can be obtained with block or hetero graft chains. Combining ATRP and azide–alkyne ‘click’ reactions, cellulose graft copolymers with block and hetero graft chains have also been synthesized .…”