With the rapid development of social economy, problems such as volatile organic compound (VOC) pollution and the excessive consumption of global petroleum resources have become increasingly prominent. People are beginning to realize that these problems not only affect the ecological environment, but also hinder the development of the organic polymer material industry based on raw fossil materials. Therefore, the modification and application of bio-based materials are of theoretical and practical significance. In this study, a series of vegetable oil-based acrylate prepolymers were synthesized by one-step acrylation using palm oil, olive oil, peanut oil, rapeseed oil, corn oil, canola oil, and grapeseed oil as raw materials, and the effect of different double bond contents on the product structure and grafting rate was investigated. Furthermore, the as-prepared vegetable oil-based acrylate prepolymers, polyurethane acrylate (PUA-2665), trimethylolpropane triacrylate (TMPTA), and photoinitiator (PI-1173) were mixed thoroughly to prepare ultraviolet (UV)-curable films. The effect of different grafting numbers on the properties of these films was investigated. The results showed that as the degree of unsaturation increased, the acrylate grafting number and the cross-linking density increased, although the acrylation (grafting reaction) rate decreased. The reason was mainly because increasing the double bond content could accelerate the reaction rate, while the grafted acrylic groups had a steric hindrance effect to prevent the adjacent double bonds from participating in the reaction. Furthermore, the increase in grafting number brought about the increase in the structural functionality of prepolymers and the cross-linking density of cured films, which led to the enhancement in the thermal (glass transition temperature) and mechanical (tensile strength, Young’s modulus) properties of the cured films.
Biocompatible and biodegradable shape‐memory polymers have gained popularity as smart materials, offering a wide range of applications and environmental benefits. Herein, we investigate the possibility of fabricating regenerated water‐triggered shape‐memory keratin fibers from wool and cellulose in a more effective and environmentally friendly manner. The regenerated keratin fibers exhibit comparable shape‐memory performance to other hydration‐responsive materials, with a shape fixity ratio of 94.8 ± 2.15% and a shape recovery rate of 81.4 ± 3.84%. Owing to their well‐preserved secondary structure and crosslinking network, keratin fibers exhibit outstanding water‐stability and wet stretchability, with a maximum tensile strain of 362 ± 15.9%. In this system, we investigate the reconfiguration of the protein secondary structure between α‐helix and β‐sheet as the fundamental actuation mechanism in response to hydration. This responsiveness is studied under force loading and unloading along the fiber axis. Hydrogen bonds act as the “switches” clicked by water molecules to trigger the shape‐memory effect, while disulfide bonds and cellulose nanocrystals play the role of “net‐points” to maintain the permanent shape of the material. Water‐triggered shape‐memory keratin fibers are manipulable and exhibit potential in the fabrication of textile actuators, which may be applied in smart apparel and programmable biomedical devices.This article is protected by copyright. All rights reserved
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