Graft Modification of Starch Nanoparticles Using Nitroxide-Mediated Polymerization and the “Grafting to” Approach

Abstract

Starch nanoparticles (SNP) were modified with synthetic polymers using the "grafting to" approach and nitroxidemediated polymerization. SG1-capped poly(methyl methacrylate-costyrene) (P(MMA-co-S)) copolymers with low dispersity and high degree of livingness were first synthesized in bulk. These macroalkoxyamines were then grafted to vinyl benzyl-functionalized SNP to obtain biosynthetic hybrids. The grafted materials, SNP-g-P(MMA-co-S), were characterized by 1 H NMR, FTIR, TGA, and elemental analysis. The total amount of grafted polymer and the grafting efficiency were evaluated for different molecular weights (5870− 12150 g•mol −1 ) of the grafted polymer, the polymer addition approach (batch or semibatch) and the initial polymer loading (2.5, 5, or 10 g polymer/g SNP). The proposed approach presented in this work to graft modify SNP allows for a precise surface modification of the nanoparticles, while permitting that the final properties of the resulting biohybrid to be tunable according to the choice of polymer grafted.

Grafting pH‐Responsive Copolymers to Cold Water‐Soluble Starch Using Nitroxide‐Mediated Polymerization

“…The products were purified three times by the addition of 30 mL THF, vortexing for one minute, and centrifugation (6000 rpm, 10 min, 21 °C). [ 38 ] The products were stored wet with THF to prevent irreversible aggregation.…”

“…The direct grafting to of starch via NMP has only been recently demonstrated by our group in the grafting of crosslinked starch nanoparticles (SNPs). [ 37,38 ] We have recently also demonstrated the successful grafting from NMP of both CWS (linear) and SNPs. [ 39–41 ] However, the NMP grafting to of linear starch has not yet been reported.…”

Polysaccharide nanoparticles: from fabrication to applications

“…the ''grafting to'' and ''grafting from'' reactions. 159 In ''grafting to'' reactions (Scheme 7a), functionalised polymers are prepared in Scheme 6 Schematic representation of the polysaccharide NP incorporation with polymer systems: (a) polymer-grafted polysaccharide NP and (b) polysaccharide NPs in a polymer matrix.…”

“…160 According to Cunningham and coworkers, SNPs could be modified with synthetic polymers by using the two grafting reactions mentioned above via nitroxide-mediated polymerisation. 31,159 The ''grafting from'' approach was carried out in three main steps under inert conditions, which are SNP-macroinitiator preparation, ''grafting from'' reaction, and acid hydrolysis (purification). Graft modified SNP with poly(methyl methacrylate-co-styrene) (P(MMA-co-S)), PMA, and poly(acrylic acid) were successfully obtained.…”

“…SNP under inert conditions. 159 SNP was firstly functionalised with 4-vinylbenzyl chloride (VBC), and in a separate step, the N-tert-butyl-N-[1diethylphosphono-(2,2-dimethylpropyl)nitroxide] (SG1)-capped P(MMA-co-S) was synthesised. Finally, the prepared SNP-VBC and SG1-capped P(MMA-co-S) were reacted to form graft modified SNP.…”