Synthesis and characterization of hexafluoroisopropylidene bisphenol poly(arylene ether sulfone) and polydimethylsiloxane segmented block copolymers

Preparation and Properties of Benzylsulfonyl-Containing Silicone Copolymers via Ring-opening Copolymerization of Macroheterocyclosiloxane and Cyclosiloxane

Ring-opening copolymerization (ROCP) of benzylsulfonyl macroheterocyclosiloxane (BSM) and five different cyclosiloxanes was systematically investigated. A general approach for the synthesis of benzylsulfonyl-containing silicone copolymers with various substituents, including methyl, vinyl, ethyl, and phenyl, was developed herein. A series of copolymers with variable incorporation (from 6 % to 82 %) of BSM were obtained by modifying the comonomer feed ratio and using KOH as the catalyst in a mixed solvent of dimethylformamide and toluene. The obtained copolymers exhibited various composition-dependent properties and unique viscoelasticity. Notably, the surface and fluorescent characteristics as well as the glass transition temperatures of the copolymers could be tailored by varying the amount of BSM. Unlike typical sulfone-containing polymers, such as poly(olefin sulfone)s, the prepared copolymers displayed excellent thermal and hydrolytic stability. The universal strategy developed in the present study provides a platform for the design of innovative silicone copolymers with adjustable structures and performance.

Synthesis and characterization of aromatic-PDMS segmented block copolymers and their shape-memory performance

Aromatic-PDMS (AB)_n multiblock copolymers: a one-component polymeric system that combines excellent mechanical properties with shape memory capability.

Synthesis and properties of poly(ether sulfone)–poly(tetrahydrofuran) multiblock copolymers

Multiblock copolymers consisting of poly(ether sulfone) and poly(tetrahydrofuran) (PTHF) as hard and soft segments, respectively, were synthesized by post-polymerization of poly(ether sulfone) and PTHF oligomers via the Williamson ether synthesis. Hydroxy-terminated polysulfone oligomers composed of 4,4′-dihydroxydiphenyl ether or 4,4′-dihydroxybiphenyl and 4,4′-dichlorodiphenyl sulfone were prepared as thermally stable hard segments. Bromo-terminated PTHF oligomers were prepared by ring-opening polymerization of tetrahydrofuran (THF) initiated by trifluoromethanesulfonic anhydride and terminated by lithium bromide. The high-molecular-weight multiblock copolymers ( Mw > 105 g mol−1) were obtained by post-polymerization. Both the multiblock copolymers showed good thermal stability and high transition temperatures from elastic film to viscous liquid. Flexible films of the multiblock copolymers showed much larger elongation at break than the corresponding poly(ether sulfone). Microphase separation of hard and soft domains was observed for the resulting multiblock copolymer films. The results suggest that these multiblock copolymers are promising candidates for novel, thermally stable thermoplastic elastomers.

Rheological behaviour of thermoplastic poly(ester-siloxane)s

Two series of thermoplastic elastomers (TPES) based on poly(dimethylsiloxane), (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were analyzed by dynamic mechanical spectroscopy. In the first TPES series the lengths of both hard and soft segments were varied while the mass ratio of the hard to soft segments was nearly constant (about 60 mass%). In the second series, the mass ratio of hard and soft segments was varied in the range from 60/40 to 40/60, with a constant length of soft PDMS segments. The influence of the structure and composition of TPESs on the rheological properties, such as complex dynamic viscosity, ?*, the storage, G?, and loss, G?, shear modulus as well as the microphase separation transition temperature, TMST, was examined. The obtained results showed that the storage modulus of the TPESs increased in a rubbery plateau region with increasing degree of crystallinity. The rheological measurements of TPESs also showed that a microphase reorganization occurred during the melting process. The microphase separation transition temperatures were in the range from 220 to 234 ?C. In the isotropic molten state, the complex dynamic viscosity increased with increasing both the content and lenght of hard PBT segments.