Reprocessable Epoxy-Anhydride Resin Enabled by a Thermally Stable Liquid Transesterification Catalyst.

Introducing dynamic ester bonds into epoxy-anhydride resins enhances the reprocessability of the crosslinked network, facilitated by various types of transesterification catalysts. However, existing catalysts, such as metal salts and organic molecules, often struggle with dispersion, volatility, or structural instability issues. Here, we propose to solve such problems by incorporating a liquid-state, thermally stable transesterification catalyst into epoxy resins.

Robust liquid crystal semi-interpenetrating polymer network with superior energy-dissipation performance.

Liquid crystal networks (LCN) have attracted surging interest as extraordinary energy-dissipation materials owning to their unique dissipation mechanism based on the re-orientation of mesogens. However, how to integrate high Young's modulus, good dissipation efficiency and wide effective damping temperature range in energy-dissipation LCN remains a challenge. Here, we report a strategy to resolve this challenge by fabricating robust energy-dissipation liquid crystal semi-interpenetrating polymer network (LC-semi-IPN) consisting crystalline LC polymers (c-LCP).

Rejuvenating liquid crystal elastomers for self-growth.

To date, only one polymer can self-grow to an extended length beyond its original size at room temperature without external stimuli or energy input. This breakthrough paves the way for significant advancements in untethered autonomous soft robotics, eliminating the need for the energy input or external stimuli required by all existing soft robotics systems. However, only freshly prepared samples in an initial state can self-grow, while non-fresh ones cannot.

Effect of Rotary Swaging on Mechanical Behaviors of Axle Steel Rod.

The short-chain forming process using rotary swaging (RS) is an important method of achieving the manufacturing of lightweight axles. Axle steel, like 42CrMo, is widely used in many types of axles and shafts; however, there is no existing research on rotary-swaged axle steel's mechanical properties. It makes sense to carry out a comprehensive study on the effect of RS on the mechanical behaviors of axle steel rods.

"Cloth-to-Clothes-Like" Fabrication of Soft Actuators.

Inspired by adaptive natural organisms and living matter, soft actuators appeal to a variety of innovative applications such as soft grippers, artificial muscles, wearable electronics, and biomedical devices. However, their fabrication is typically limited in laboratories or a few enterprises since specific instruments, strong stimuli, or specialized operation skills are inevitably involved. Here a straightforward "cloth-to-clothes-like" method to prepare soft actuators with a low threshold by combining the hysteretic behavior of liquid crystal elastomers (LCEs) with the exchange reaction of dynamic covalent bonds, is proposed.

Enabling liquid crystal elastomers with tunable actuation temperature.

Liquid crystalline elastomers are regarded as a kind of desirable soft actuator material for soft robotics and other high-tech areas. The isotropization temperature (T) plays an important role as it determines the actuation temperature and other properties, which in turn has a great effect on their applications. In the past, the common physical methods (e.

Fabricating liquid crystal vitrimer actuators far below the normal processing temperature.

Liquid crystal vitrimers can be reprocessed, reshaped, welded, and healed due to exchange-reaction-enabled topology changes despite having fully covalently cross-linked network structures. Fabricating liquid crystal (LC) vitrimer actuators is invariably carried out above a characteristic temperature known as the topology freezing transition temperature (). The reason that all exchange-reaction-based operations must be performed above is because the exchange reaction is insignificant below .

Merging the Interfaces of Different Shape-Shifting Polymers Using Hybrid Exchange Reactions.

Sophisticated shape-shifting structures and integration of advanced functions often call for different-chemistry-based polymers (such as epoxy and polyurethane) in a unified system. However, permanent cross-links pose crucial obstacles to be seamless. Here, merging interfaces via hybrid exchange reactions among different dynamic covalent bonds (including ester, urethane, thiourethane, boronic-ester, and oxime-ester linkages) is proposed, breaking the long-lasting restriction that these widely used bonds only undergo self-exchange reactions.

Hot Deformation Behavior of the 25CrMo4 Steel Using a Modified Arrhenius Model.

25CrMo4 steel is widely used in the manufacturing of high-speed train axles due to its excellent mechanical properties. The purpose of this study is to develop an accurate modified constitutive model to describe the hot deformation behavior of the steel. Isothermal compression experiments were performed at different strain rates (0.