The γ‐initiated reversible addition–fragmentation chain‐transfer (RAFT)‐agent‐mediated free‐radical graft polymerization of styrene onto a polypropylene solid phase has been performed with cumyl phenyldithioacetate (CPDA). The initial CPDA concentrations range between 1 × 10−2 and 2 × 10−3 mol L−1 with dose rates of 0.18, 0.08, 0.07, 0.05, and 0.03 kGy h−1. The RAFT graft polymerization is compared with the conventional free‐radical graft polymerization of styrene onto polypropylene. Both processes show two distinct regimes of grafting: (1) the grafting layer regime, in which the surface is not yet totally covered with polymer chains, and (2) a regime in which a second polymer layer is formed. Here, we hypothesize that the surface is totally covered with polymer chains and that new polymer chains are started by polystyrene radicals from already grafted chains. The grafting ratio of the RAFT‐agent‐mediated process is controlled via the initial CPDA concentration. The molecular weight of the polystyrene from the solution (PSfree) shows a linear behavior with conversion and has a low polydispersity index. Furthermore, the loading of the grafted solid phase shows a linear relationship with the molecular weight of PSfree for both regimes. Regime 2 has a higher loading capacity per molecular weight than regime 1. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4180–4192, 2002

The γ‐initiated reversible addition–fragmentation chain transfer mediated free‐radical graft copolymerization of styrene and m‐isopropenyl‐α,α′‐dimethylbenzyl isocyanate (TMI) from a polypropylene (PP) solid phase was performed with cumyl phenyldithioacetate (CPDA) as the chain‐transfer agent. The initial CPDA concentration was 8 × 10−3 mol L−1. Polymerizations were performed with a dose rate of 0.18 kGy h−1 at the ambient temperature. Initial comonomer mixtures with 15, 30, and 50 mol % TMI were used. Depending on the amount of TMI in the initial comonomer mixture, the plot of the grafting ratio versus the time showed two grafting regimes (for 15 and 50 mol % TMI) or one (for 30 mol % TMI). Scavenger lanterns with 15 and 50 mol % TMI featured two isocyanate loading regimes, the second with higher loading capacities. The scavenger lanterns with 30 mol % TMI showed a linear loading capacity over the full grafting ratio. A maximum loading capacity of 110 μmol per scavenger lantern was achieved with 50 mol % TMI at a grafting ratio of approximately 60 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 857–864, 2006

Solid-phase synthesis is greatly dependent on the solid support. Here, we report the use of a new hydrophilic grafted surface on SynPhase lanterns in solid-phase organic chemistry. A convenient and facile solid-phase synthesis of disubstituted 1,4-benzodiazepine-2-ones on polyamide SynPhase lanterns is described. The key step of the synthesis involved a reduction-cyclization of a nitroaryl methyl ester with a mixture of tin(II) chloride dihydrate and ammonium acetate in water and ethanol at elevated temperature to give the desired target compounds. A library of 21 disubstituted 1,4-benzodiazepine-2-ones was prepared.

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ABSTRACT:A hydrophilic surface suitable for solid-state peptide synthesis was developed on a solid support called a lantern. The split-and-mix combinatorial technique was used to prepare about 500 surfaces in a very short time. Surfaces were analyzed according to values for gel formation, percentage weight grafted, grafted copolymer composition, and number of functional groups per lantern. These values were correlated to the purity of a peptide synthesized on these surfaces.