Solution properties and dynamic bulk behavior of intramolecular cross-linked polystyrene

Intramolecular Cross-Linking Methodologies for the Synthesis of Polymer Nanoparticles

“…As mentioned above, Antonietti et al used Friedel–Crafts alkylation chemistry as a cross-linking method to study the dynamic behavior of polystyrene microgels (Scheme a). However, only small changes in the structural and dynamic properties could be observed for the intramolecularly cross-linked polystyrene microgel compared to the uncross-linked polystyrene precursor . One possible reason for the reduced impact of self-cross-linking could be the tendency to form small rings, as previously stated.…”

“…A similar trend in the reduction of size was observed by Antonietti et al in the synthesis of microgels of intramolecularly cross-linked polystyrene in a good polymer solvent (dichloroethane). 36 The microgels were prepared by Friedel−Crafts reaction-mediated intramolecular cross-linking of linear polystyrene with p-dichloroxylene in dilute dichloro-ethane solution using SnCl 4 as catalyst. 37,38 Surprisingly, the characterization of these microgels by using gel permeation chromatography (GPC), static and dynamic light scattering (DLS), and viscosity measurements revealed only a small reduction in the radius of gyration (R g ) and hydrodynamic radius (R h ) even at high degrees of cross-linking.…”

Mechanical, thermomechanical, and thermal properties of polystyrene crosslinked with a multifunctional zirconium oxo cluster

“…Generally, crosslinking with organic monomers increases the storage moduli and broadens the tan δ curves concomitant with a decrease in intensity. A shift to higher values, that is an increase in T g , was reported for systems which are crosslinked by organic molecules 39, 43, 44. A discussion of increased moduli of crosslinked hybrid polymers raises inevitably the problem of interactions, namely cluster‐polymer, cluster–cluster and polymer–polymer interactions.…”

Inter‐ and Intramolecular Crosslinking Kinetics: Partitioning According to Number of Crosslinks

“…[17][18][19][20][21][22] When o 1 ¼ 1 or 2 the intramolecular reactions are proportional to the number, or its square, of monomer units in each chain. Antonietti and Sillescu [11] show that the intramolecular crosslinking of polystyrene through Friedel-Crafts crosslinking with p-bis(chloromethyl) benzene (crosslinking agent) involves two steps: attachment of the crosslinking agent to the chain and subsequent crosslinking, with the first step being the ratedetermining step. In this case, the reaction can be approximated with o 1 ¼ 1, that is, the rate of attachment of the crosslinking agent is proportional to the number of available sites, and hence, to the molecular mass.…”

“…The properties associated with polymer size, such as intrinsic viscosity, however, are affected because the polymer size may be reduced by intramolecular crosslinking. Intrinsic viscosity is proportional to the hydrodynamic volume of the macromolecule, [11] but a quantitative correlation of crosslink density and macromolecule size has not been established. Although crosslinking reactions are clearly important, no quantitative model for simultaneous interand intramolecular crosslinking exists.…”