Macromolecular thiolysis of oxiranes: End-group modification of RAFT prepared homopolymers
MetadataShow full item record
Chain end modification of low molecular weight, RAFT-prepared polystyrene and poly(N,N-diethylacrylamide) by reaction with a range of small molecule epoxides is described. Two different routes are examined—initial dithioester end-group cleavage yielding the thiol-terminated polymer followed by catalytic thiolysis of the oxiranes and a one-pot procedure involving hydride cleavage of the dithioester end groups in the presence of an epoxide. High degrees of functionalization (>80%) are observed via the first route in the presence of ZnCl2 with molecular weight distributions remaining unimodal and narrow. However, with DBU as catalyst significant amounts of coupled species are observed. In contrast, the one-pot route, at least with poly(N,N-diethylacrylamide), resulted in essentially quantitative degrees of functionalization as evidenced by 1H NMR spectroscopy and qualitatively by FTIR spectroscopy. The effect of the newly introduced alcohol-functional end groups on the lower critical solution temperature of poly(N,N-diethylacrylamide) is demonstrated with cloud points tunable from ca. 27 to 47 °C.
Showing items related by title, author, creator and subject.
A randomised controlled trial of twelve months protein supplementation on muscle mass and strength in elderly womenMeng, Xingqiong (Rosie) (2010)Background. Aging is associated with progressive loss of muscle (sarcopenia), which can lead to reduced muscle strength and an increased risk of falls. Sarcopenia exists in otherwise healthy elderly people and its aetiology ...
Schäfer, Axel (2009)Background summary. Leg pain is a common complaint in relation to low back pain (LBP), present in up to 65% of all patients with LBP. Radiating leg pain is an important predictor for chronicity of LBP and an indicator of ...
Beatty, Shelley Ellen (2003)The long-term regular use of tobacco and hazardous alcohol use are responsible for significant mortality and morbidity as well as social and economic harm in Australia each year. There is necessary the more cost-efficient ...