Novel plant‐oil‐derived long‐chain (C19 and C23) α,ω‐diisocyanates, optionally in combination with the corresponding long‐chain diols, provide entirely aliphatic hard segments in segmented thermoplastic polyurethane elastomers (TPUs), with carbohydrate‐based poly(trimethylene glycol) soft segments. Compared to materials based on a mid‐chain monomer analog, phase separation is higher due to an increased flexibility of the aliphatic segments. Although melting points are slightly lower than for HDPE, the long‐chain TPU's solid‐state structure is still dominated by hydrogen‐bonding.
A plant-oil derived long-chain (C 23 ) α,ω-dicarboxylic acid and the corresponding diol provide entirely aliphatic hard segments in segmented thermoplastic polyester elastomers, with poly(tetramethylene glycol) (PTMG) or carbohydrate-based poly(trimethylene glycol) (PPDO) soft segments. Physical crosslinking is provided by their polyethylene-like crystallinity. Compared to materials derived from mid-chain (C 12 ) analogs, thermal properties are significantly enhanced, with melting points up to 96°C. These novel materials feature high ductility values in combination with a good elastomeric behavior.
Abstract:We here present the synthesis and characterization of a set of biodegradable core-multishell (CMS) nanocarriers. The CMS nanocarrier structure consists of hyperbranched polyglycerol (hPG) as core material, a hydrophobic (12,15,18,19, and 36 C-atoms) inner and a polyethylene glycol monomethyl ether (mPEG) outer shell that were conjugated by ester bonds only to reduce the toxicity of metabolites. The loading capacities (LC) of the drugs, dexamethasone and tacrolimus, and the aggregate formation, phase transitions, and degradation kinetics were determined. The intermediate inner shell length (C15) system had the best overall performance with good LCs for both drugs as well as a promising degradation and release kinetics, which are of interest for dermal delivery.
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