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In this work, a chitin-based macromolecular chain transfer agent (Chitin-CTA) was designed to graft polymers from chitin at the molecular level. Homogeneous reversible addition-fragmentation chain transfer (RAFT) polymerization was performed to prepare branched MA elastomers, chitin-graft-poly(methyl acrylate) (Chitin-g-PMA) copolymers, which were thermally stable and showed tunable glass transition temperatures. These ultra-stretchable branched MA elastomers exhibit unique strain-hardening behavior and significantly enhanced mechanical properties. Mechanical tests indicate that the chitin backbones in branched MA elastomers can act as cross-linking points to improve the tensile strength, toughness, and elasticity simultaneously. The macroscopic performance of branched MA elastomers c be further promoted by introducing hydrogen bonding as non-covalent interaction to form an additional reversible physical network. This robust and versatile grafting strategy can provide new opportunities to prepare chitin-based branched MA elastomers with extraordinary mechanical properties., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In this work, sustainable cellulose-g-poly(lauryl acrylate-co-acrylamide) [Cell-g-P(LA-co-AM)] bottlebrush copolymer elastomers derived from cellulose and plant oil were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Differential scanning calorimeter (DSC) results indicate that these thermally stable Cell-g-P(LA-co-AM) bottlebrush copolymer elastomers show adjustable melting temperatures. Monotonic and cyclic tensile tests suggest that the mechanical properties, including tensile strength, extensibility, Young's modulus, and elasticity, can be conveniently controlled by changing the LA/AM feed ratio and cellulose content. In such kind of bottlebrush copolymer elastomers, the rigid cellulose backbones act as cross-linking points to provide tensile strength. The incorporated PAM segments can form additional network structure via hydrogen bonding, resulting in enhanced tensile strength but decreased extensibility when more PAM segments are introduced. This versatile strategy can promote the development of sustainable cellulose-based bottlebrush copolymer elastomers from renewable resources., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Oligocellulose (OC) with low polydispersity indices has been produced in large quantities using an improved method of acid-assisted hydrolysis, in which long cellulose chains disintegrate in concentrated phosphoric acid at moderately elevated temperatures. The hydrolysis time has been reduced by three orders of magnitude without compromising the overall yield of the process or the quality of OC products. The efficient production of high-quality OCs in large quantities allows for developing OC-derived elastomeric materials. A series of OC- graft -poly(isobornyl methacrylate- random - n -butyl acrylate) [OC- g -P(IBOMA- r -BA)] elastomers have been synthesized via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). OC- g -P(IBOMA- r -BA) elastomers have tunable molecular architectures and phase morphologies toward desirable mechanical properties and thermal stability suitable for various applications. The methodologies of the OC production and the graft -polymers synthesis in this study would help advance technologies for broader applications of bio-based elastomers. [Display omitted] [ABSTRACT FROM AUTHOR]

With the dramatically increased environmental problems, the rational design of sustainable polymers from renewable feedstocks opens new avenues to reduce the huge pollution impact. The major challenge for sustainable polymers is the decreased mechanical performance compared to that of petroleum-based materials. In this work, fully biobased sustainable elastomers were developed by integrating renewable chitin, lignin, and plant oil into one macromolecule, in which chitin was chosen as the rigid backbone, while a lignin-derived monomer vanillin acrylate (VA) and a plant oil-based monomer lauryl acrylate (LA) were selected as the hard and soft segments for the grafted side chains. A series of Chitin- graft -poly(vanillin acrylate- co -lauryl acrylate) (Chitin- g -P(VA- co -LA)) copolymers with varied feed ratios and chitin contents were synthesized by using reversible addition-fragmentation chain transfer (RAFT) polymerization as an effective grafting strategy. In addition, a dynamic cross-linked network was incorporated via Schiff-base reaction to improve the macroscopic behavior of such kind of chitin graft elastomers. These sustainable elastomers are mechanically strong and show excellent reprocessablity, as well as outstanding UV-blocking property. This strategy is versatile and can inspire the further development of fully biobased sustainable materials from natural resources. [Display omitted] [ABSTRACT FROM AUTHOR]