Add time:08/07/2019         Source:sciencedirect.com

Most studies of coil-to-globule transitions of macromolecules have dealt exclusively with the standard polystyrene–cyclohexane system. In this work we aim to extend such investigations to halogenated polystyrenes, namely poly(4-chlorostyrene)(PPCS), poly(2-chlorostyrene)(POCS) and poly(chlorostyrene)(PCS),a mixture of 2- and 4- isomers. Changes in Rh of these polymers with temperature in their respective theta solvents were investigated by dynamic light scattering. The hydrodynamic size of PPCS in n-propyl benzene(Mw: 2.25×106 g mol−1, Mw/Mn: 1.16) decreases to 75% of that in the unperturbed state at 22.2°C. POCS (Mw: 10.32×106 and Mw: 4.30×106, Mw/Mn: 1.10) in 2-butanone exhibited LCST behaviour and a limited chain collapse was observed with increasing temperature above theta point. The parameters αh=Rh/Rh(θ) for POCS with two different molecular weights, (10.32 M and 4.30 M) were found to be 0.67 and 0.77, respectively at 37.0°C. A smooth and continuous contraction was also observed for the mixture of 2- and 4- isomers, PCS (Mw: 2.32×106 g mol−1, Mw/Mn: 1.06).

We also recommend Trading Suppliers and Manufacturers of 4-Chlorostyrene (cas 1073-67-2). Pls Click Website Link as below: cas 1073-67-2 suppliers