Use of short isobornyl methacrylate building blocks to improve the heat and oil resistance of thermoplastic elastomers via RAFT emulsion polymerization

Abstract

Triblock copolymer (TCP)-based thermoplastic elastomers (TPEs) were designed via reversible addition-fragmentation chain-transfer emulsion polymerization. Short isobornyl methacrylate (IM) building blocks in the two ends of molecular chain were incorporated to guarantee the mechanical properties of the TPEs at high temperature (i.e., heat resistance) because of the high glasstransition temperature (T g ) of poly(isobornyl methacrylate) (PIM; 180 8C). The microphase separation, tensile properties at different temperatures, dynamic mechanical properties, oil resistance, and thermal stability of the TPEs were extensively characterized. The TPEs had distinct microphase separation with a wide inter-T g interval (150-185 8C). The tensile strength and elongation at break of the TPEs decreased with increasing temperature from 25 to 100 8C because of the reduced interactions in the phase domain. Even so, the TPEs had a high elongation at break beyond 200% and little change in the tensile strength even at 100 8C together with a wide quasi-platform stage between the T g values in dynamic mechanical analysis; this indicated good heat resistance. Meanwhile, the TPEs had an enhanced oil resistance and a thermal stability higher than 300 8C. These TCP-based TPEs with heat and oil resistance broaden the application potential in practical fields.

Beyond Simple AB Diblock Copolymers: Application of Bifunctional and Trifunctional RAFT Agents to PISA in Water

“…Hitherto, PISA‐derived assemblies are mainly based on simple diblock copolymers and only very few examples based on more complex architectures have been reported . In pure water, in particular, there are only a handful of reports beyond diblock copolymers, most of them based on linear block copolymers (triblock or multiblock) and to the best of our knowledge, there is only one example based on a more complex Y‐shape architecture (AB 2 ). This latter structure was formed via RAFT dispersion polymerization of diacetone acrylamide (DAAm) in water using a ω‐bifunctional poly(ethylene glycol) (PEG) macro‐CTA .…”

“…[40,41] In this communication, we study the influence of the macro-CTA architecture on the morphology of the self-assemblies obtained by aqueous RAFT dispersion polymerization in PISA, and compare amphiphilic diblock (AB) and triblock (AB) 2 with triarm, star-shaped copolymers (AB) 3 . While amphiphilic AB and (AB) 2 copolymers have already been prepared by PISA in water, [23][24][25][26][27][28][29][30][31] analogous triarm star copolymer (AB) 3 has not been reported, to the best of our knowledge. Poly(N,N-dimethylacrylamide) (PDMAc) and PDAAm were selected as the hydrophilic (A) and hydrophobic (B) blocks, respectively.…”

RAFT polymerisation of renewable terpene (meth)acrylates and the convergent synthesis of methacrylate–acrylate–methacrylate triblock copolymers

“…To assess the level of RAFT chain end fidelity in the PαPMA produced in this way, a chain extension reaction was carried out using PBuA, a very commonly used soft block for acrylic TPEs [48][49][50] with T g of ca. −50°C.…”