Design of Graft Block Polymer Thermoplastics

Abstract

Graft block polymers are defined by several architectural parameters, including backbone flexibility, graft density, backbone length, side-chain composition, and sidechain length. In this work we probe the impacts of each of these parameters on the phase behavior, rheological properties, and mechanical performance of these materials. Specifically, we examine two sets of materials prepared from backbones of different inherent flexibility. One set was prepared from poly[(n-butyl acrylate)-co-(2-hydroxyethyl acrylate)] (B x E y ) copolymers; the other was prepared from hydroxypropyl methyl cellulose (HPMC) samples. Sequential ring-opening transesterification polymerization from these hydroxyl-functionalized macroinitiatiors yielded a diblock graft architecture containing a rubbery interior block and semicrystalline exterior blocks tethered to a flexible (B x E y ) or rigid (HPMC) backbone. Good control over side-chain molar mass and composition and judicious choice of the graft block segments enabled the preparation of materials that were either ordered or disordered in the melt state. In the former case, crystallization destroys existing order in the material; in the latter case crystallization induces new microphase separation in the bulk. Many of the structure−mechanical property relationships observed for graft block copolymers with rigid backbones are maintained for graft block polymers with semiflexible backbones, including the tendency for samples to remain transparent when stretched. However, interestingly, the effects of graft density and backbone length are quite different depending on the rigidity of the backbone.

Design, Synthesis, and Self-Assembly of Polymers with Tailored Graft Distributions

“…[13][14][15][16] Recent studies have harnessed these properties in a wide variety of applications in photonics, [17][18][19] drug delivery, [20][21][22] transport, [23][24] and thermoplastics. [25][26] Continued progress in synthetic command over polymer architecture enables further studies of structure-property relationships and inspires new potential applications.…”

Photocross‐linked polymers based on plant‐derived monomers for potential application in optical 3D printing

“…It was observed that the value of Young's modulus decreased when the higher amount of MYR was present in the resin. It could be explained by the formation of MYR soft and flexible chains and by lower crosslinking density in such cases leading to the loss of polymer stiffness …”

Self‐Healable and Tough Thermoplastic Materials from Metal–Thioether Block Polymers

“…Differential scanning calorimetry (DSC) was used to reveal the phase segregation in obtained materials, as shown in Figure A. It is evident that all block polymers with varying compositions displayed two distinct glass transition temperatures ( T g, M and T g, B y T z ) . The T g values before and after metal coordination are also listed in Table .…”

“…In the current plastic industry, the few commodity homopolymers and random copolymers still occupy the majority of market share, but block polymers provide a remarkably large space for tailoring the microstructure and consequent material properties . It is benefited from the unique microphase separation and a wide window of structural parameters for the molecular architecture . In this paper, we combined the merits of block polymers and reversible metal–thioether coordination to build a new type of smart thermoplastic materials ( Scheme ).…”