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This work describes the synthesis and characterization of polyamide 6 (PA 6)‐polycaprolactone (PCL) multiblock copolymers. Low molar mass, fully amine end‐capped PA 6 was prepared by the addition of a diamine monomer during ε‐caprolactam polymerization. A low molar mass PCL was selected to be incorporated as the biodegradable block and was fully end‐capped with toluene 2,4‐diisocyanate. End group analysis and molecular weight characterizations were performed for both end‐functionalized polymers by SEC, NMR and titration analysis. Incorporation of PCL into PA 6 was mainly achieved by solution mixing of the two end‐functional blocks and, was continued after the removal of the solvent with solid state polymerization (SSP) by gradual heating until about 40 °C below the melting temperature of the PA 6. Molecular weights started to grow immediately during solution mixing and only increased marginally during the SSP treatment. FTIR and SEC studies confirmed the reaction between the two components. DSC data, in combination with the enhanced molar mass during solution mixing pointed to a blocky microstructure, for which distinct melting and crystallization temperatures were observed for the PCL and the PA 6 blocks. Hydrolytic and enzymatic degradation studies were performed at 25 °C where the degree of degradation was followed by weight loss analysis, SEM and SEC. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

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Doubly crosslinked microgels (DX microgels) are hydrogels constructed by covalently interlinked microgel particles, offering two levels of hierarchy within the network, the first one being the microgel and the second being the interlinked microgel network. Herein we describe an efficient approach for DX microgel synthesis via the ultrafast triazolinedione (TAD)-based click reaction. Cyclopentadienyl functional microgels were prepared by a conventional water in oil (W/O) suspension, free-radical copolymerization of poly (ethylene glycol) methyl ether methacrylate (M-n = 500 g mol(-1)) with glycidyl methacrylate and ethylene glycol dimethacrylate as crosslinkers. Microgel post-modification was subsequently achieved by reacting glycidyl functions with sodium cyclopentadienide (NaCp), resulting in Cp-functionalized microgels. Finally, the microgels were mixed with a bis-TAD functional crosslinker, resulting in crosslinking with adequate kinetics (minutes to seconds) to form a doubly crosslinked microgel network. Size distributions of swollen microgels before creation of the second network were followed by optical microscopy and particle size measurements. The efficient functionalization of the microgels with Cp units was demonstrated by a fluorescence labelling study. Dynamic rheology data showed the increase of mechanical properties from the microgels to the doubly crosslinked microgel network formed after addition of the TAD crosslinker. The current study thus highlights the efficiency of catalyst free modular ligation chemistry to synthesize DX microgels with a very fast gelation process from 5 minutes to 15 seconds depending on the crosslinker to Cp ratio, from 0.7 to 1 respectively