Thermal and Viscoelastic Behavior of Hydrogenated Polystyrene

Abstract

Fully saturated hydrocarbon polymers often exhibit superior stability toward thermal, oxidative, and radiation-induced degradation. Recent improvements in catalyst technology allow for the convenient synthesis of the saturated hydrocarbon poly(cyclohexylethylene) (PCHE) from polystyrene (PS) by heterogeneous catalytic hydrogenation. The focus of this report was to prepare nearly monodisperse samples of polystyrene by anionic polymerization and to fully saturate those materials by catalytic hydrogenation. The thermal and viscoelastic properties of these materials were then evaluated using differential scanning calorimetry and dynamic mechanical spectroscopy. On the basis of these experimental results, the glass transition temperature of PCHE has been found to approach 148 °C at high molecular weight. Relationships between the zero shear viscosity, steady-state compliance, and rubbery plateau modulus of PCHE with respect to molecular weight have been determined, and entanglement spacing and packing length have been calculated from these data. PCHE shows an entanglement spacing (M e) of 40 200 g/mol, compared to 18 700 g/mol for the starting material PS. This increase in glass transition temperature and entanglement length can be attributed to the increase in steric bulk of the cyclohexyl substituent compared to the phenyl ring present in the starting material.

Phosphazene High Polymers and Models with Cyclic Aliphatic Side Groups: New Structure–Property Relationships

“…Synthesis of Poly[bis(trifluoroethoxy)phosphazene], 16. The synthesis of 16 was followed a previously published procedure.…”

“…It has unique properties such as a high glass transition temperature, high rigidity, environmental stability, low moisture uptake, and exceptional optical properties. 16,17 Moreover, cyclohexyl side groups have also been linked to other backbone systems, including polysiloxanes, 18 polymethycrylates, 19 polyvinyltriazoles, 20 and their copolymers. 21 However, the influence of cycloalkyl pendent groups on the properties of polyphosphazenes was unknown.…”

Rheological characterization of PP/jute composite melts

“…30 The virgin matrix displays a characteristic viscoelastic response of an well entangled polymer with a crossover frequency of 3 rad/s, below which it displays liquid like relaxation 31 (Fig. 4).…”

Hydrogenated poly(styrene‐co‐α‐methylstyrene) polymers: A new class of high glass‐transition‐temperature polyolefins

“…Recent advances in catalytic hydrogenation chemistry have made feasible the saturation of polystyrene (PS) resulting in a new commercially viable plastic poly(cyclohexyl ethylene) (PCHE) 1. With the exception of toughness, this material is endowed with properties superior to those associated with PS, including a T g of 140 °C 1–3. Incorporation of PCHE into block copolymers with polyethylene (PE), poly(ethyl ethylene) (PEE), or poly(ethylene‐ co ‐propylene) through sequential anionic polymerization of styrene and butadiene (or isoprene) followed by catalytic hydrogenation leads to an attractive new class of plastics and thermoplastic elastomers with tunable properties 4–12.…”

“…1 With the exception of toughness, this material is endowed with properties superior to those associated with PS, including a T g of 140°C. [1][2][3] Incorporation of PCHE into block copolymers with polyethylene (PE), poly(ethyl ethylene) (PEE), or poly(ethylene-co-propylene) through sequential anionic polymerization of styrene and butadiene (or isoprene) followed by catalytic hydrogenation leads to an attractive new class of plastics and thermoplastic elastomers with tunable properties. 4 -12 This article describes additional improvements in the upper-use temperature of PCHE-based homopolymers and block copolymers.…”