Chemical syntheses of biodegradable polymers

The aim of this review is to show the relationships between the structure, the process, and the properties of biodegradable multiphase systems based on plasticized starch (PLS), the so‐called “thermoplastic starch.” These mutiphase materials are obtained when associating association between plasticized starches and other biodegradable materials, such as biodegradable polyesters [polycaprolactone (PCL), polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polyesteramide (PEA), aliphatic, and aromatic copolyesters], or agro‐materials (ligno‐cellulosic fiber, lignin etc.). Depending on materials (soft, rigid) and the plastic processing system used, various structures (blends, composites, multilayers) can be obtained. The compatibility problematic between these hetero‐materials is analyzed. These starchy products show some interesting properties and have some applications in different fields: packaging, sports, catering, agriculture and gardening, or hygiene.

Biodegradable Multiphase Systems Based on Plasticized Starch: A Review

A ‘grafting from’ approach was used to graft poly(e-caprolactone) (PCL) polymers to cellulose nanocrystals by Sn(Oct)2-catalyzed ring-opening polymerization (ROP). The grafting efficiency was evidenced by the long-term stability of suspension of PCL-grafted cellulose nanocrystals in toluene. These observations were confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). Extracted nanohybrids were characterized by Differential Scanning Calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The morphology and crystalline structure of the PCL-grafted cellulose nanocrystals was examined by transmission electron microscopy (TEM) and X-Ray diffraction, respectively. Results showed that cellulose nanocrystals kept their initial morphological integrity and their native crystallinity. Nanocomposites with high content of cellulose nanocrystals were prepared using either neat cellulose nanocrystals or PCL-grafted cellulose nanocrystals and high molecular weight PCL as matrix using a casting/evaporation technique. Thermo-mechanical properties of processed nanocomposites were studied by DSC, dynamical mechanical analyses (DMA) and tensile tests. A significant improvement in terms of Young's modulus and storage modulus was obtained.

Bionanocomposites based on poly(ε-caprolactone)-grafted cellulose nanocrystals by ring-opening polymerization

Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications Cyrille Boyer,*,†,‡ Nathaniel Alan Corrigan,‡ Kenward Jung,‡ Diep Nguyen,‡ Thuy-Khanh Nguyen,‡ Nik Nik M. Adnan,†,‡ Susan Oliver,†,‡ Sivaprakash Shanmugam,‡ and Jonathan Yeow†,‡ †Australian Centre for Nanomedicine, and ‡Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales, Sydney 2052, Australia

Copper-Mediated Living Radical Polymerization (Atom Transfer Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications

Mechanistic transformations involving living and controlled/living polymerization methods

The combination of bioresorbable and biodegradable hydrophilic polysaccharides with biodegradable hydrophobic polyester chains to form totally biodegradable, nonionic brushlike amphiphilic graft copolymers useful as surfactants has been investigated. In fact, a totally controlled and original three-step procedure is described which gives access to a wide range of poly(e-caprolactone)-grafted dextran copolymer compositions. It consists of the reversible protection of the hydroxyl groups of the polysaccharide backbone by silylation, followed by the ring-opening polymerization of e-caprolactone initiated by the free remaining hydroxyl groups of the partially silylated dextran in the presence of aluminum and tin-based catalysts. The last step relies upon the removal of silylating groups under mild acidic conditions yielding the desired amphiphilic graft copolymers.

Controlled synthesis of poly(ε-caprolactone)-grafted dextran copolymers as potential environmentally friendly surfactants

Coupling atom transfer radical polymerization (ATRP) and coordination-insertion ring-opening polymerization (ROP) provided a controlled two-step access to polymethacrylate-graft-polyaliphatic ester graft copolymers. In the first step, copolymerization of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) was carried out at 80°C at high MMA concentration by using ethyl 2-bromoisobutyrate and [NiBr 2 (PPh 3 ) 2 ] as initiator and catalyst, respectively. Kinetic and molar masses measurements, as well as 1 H NMR spectra analysis of the resulting poly(MMA-co-HEMA)s highlighted the controlled character of the radical copolymerization, while the determination of the reactivity ratios attested preferential incorporation of HEMA. The second step consisted of the ROP of e-caprolactone or L,L-dilactide, in THF at 80°C, promoted by tin octoate (Sn(Oct) 2 ) and coinitiated by poly(MMA-co-HEMA)s obtained in the first step. Once again, kinetic, molar mass, and 1 H NMR data demonstrated that the copolymerization was under control and started on the hydroxyl functions available on the poly(MMA-co-HEMA) multifunctional macroinitiator. Comparison of the SEC traces for the poly(MMA-co-HEMA) macroinitiator P2 (line only), the polymethacrylate-g-PLA copolymer C2 (line marked by O), and the polymethacrylate-g-PLA C3 (line marked by Δ).

Isabelle Ydens

Papers

Controlled synthesis of poly(ε-caprolactone)-grafted dextran copolymers as potential environmentally friendly surfactants

Combining ATRP of Methacrylates and ROP of L,L-Dilactide and ε-Caprolactone

Partial or total silylation of dextran with hexamethyldisilazane

Influence of DNA condensation state on transfection efficiency in DNA/polymer complexes : An AFM and DLS comparative study

Aliphatic polyester-based biodegradable materials: new amphiphilic graft copolymers