Fabrication of a highly stretchable cellulose with internally and externally dual-plasticized structure

Tunable Mechanically Interlocked Semi-Crystalline Networks

High-performance polymers based on dynamic chemistry have been widely explored for multi-field advanced applications. However, noncovalent sacrificial bond-mediated energy dissipation mechanism causes a trade-off between mechanical toughness and resilience. Herein, we achieved the synchronous boost of seemingly conflicting material properties including mechanical robustness, toughness and elasticity via the incorporation of mechanical chemistry into traditional semi-crystalline networks. Detailed rheological tests and all-atom molecular dynamics simulation reveal that the excellent mechanical robustness and toughness are attributed to the dissociation of crystalline domains threading through the sieve-shape macrocycles. Reversible nano-crystalline domains and ring-sliding-effect accelerated segment motion efficiently reduce energy dissipation to achieve instantaneous resilience. Moreover, the model polymers demonstrate that the multiple dynamic components endow the resulting polymer with excellent reprocessability under mild conditions. This mechanically interlocked semi-crystalline polymer exhibits potential applications as a thermal/photo actuator. This work reveals the synergic effects of mechanically interlocked sites and tunable crystalline domains, thus providing a reliable guide for the comprehensive improvement of material performance.

A Biodegradable, Waterproof, and Thermally Processable Cellulosic Bioplastic Enabled by Dynamic Covalent Modification

The growing environmental concern over petrochemical-based plastics continuously promotes the exploration of green and sustainable substitute materials. Compared with petrochemical products, cellulose has overwhelming superiority in terms of availability, cost, and biodegradability; however, cellulose's dense hydrogen-bonding network and highly ordered crystalline structure make it hard to be thermoformed. A strategy to realize the partial disassociation of hydrogen bonds in cellulose and the reassembly of cellulose chains via constructing a dynamic covalent network, thereby endowing cellulose with thermal processability as indicated by the observation of a moderate glass transition temperature (T_g  = 240 °C), is proposed. Moreover, the cellulosic bioplastic delivers a high tensile strength of 67 MPa, as well as excellent moisture and solvent resistance, good recyclability, and biodegradability in nature. With these advantageous features, the developed cellulosic bioplastic represents a promising alternative to traditional plastics.

Synthesis of copolyesters based on substituted and non-substituted lactones towards the control of their crystallinity and their potential effect on hydrolytic degradation in the design of soft medical devices

ROP synthesis of polyesters at different molar ratios of monomers ε-caprolactone (ε-CL) in combination with alkyl substituted lactones δ-decalactone (δ-DL), ε-decalactone (ε-DL) and δ-dodecalactone (δ-DD), as well copolymers based on ε-DL and δ-DD.