How can xanthates control the RAFT polymerization of methacrylates ?

International audienceA xanthate bearing S-cyanoisopropyl and O-2,2,2trifluoroethyl groups was identified as a potential RAFT agent for sequential polymerization of methyl methacrylate and vinyl acetate. The intrinsic low reactivity of the xanthate for MMA polymerization was compensated by implementing a semibatch emulsion process with a thorough adjustment of the process parameters to keep MMA concentration to a minimum during polymerization. In a second stage, the xanthate-capped PMMA seed was chain extended during batch vinyl acetate polymerization at room temperature, yielding a well-defined PMMA-PVAc diblock copolymer

Stress neuropeptide levels in adults with chest pain due to coronary artery disease: potential implications for clinical assessment

: Substance P (SP) and neuropeptide Y (NPY) are neuropeptides involved in nociception. The study of biochemical markers of pain in communicating critically ill coronary patients may provide insight for pain assessment and management in critical care. Purpose of the study was to to explore potential associations between plasma neuropeptide levels and reported pain intensity in coronary critical care adults, in order to test the reliability of SP measurements for objective pain assessment in critical care