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1.
Macromol Rapid Commun ; 44(3): e2200650, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36350231

RESUMEN

Shape memory polymers have great potential in the fields of soft robotics, injectable medical devices, and as essential materials for advanced electronic devices. Herein, light-triggered shape-memory thermoplastic polyurethane (TPU) is reported using azido TPU grafted by the photoswitchable azo compound. The trans-cis transitions of the azobenzene on the side chain of the TPU induce the recoiling of the main chain, leading to shaping memory behavior. Under UV irradiation, cis-azo allows the oriented main chain to recoil to release residual stress and realize light-triggered shape memory behavior. The facile method proposed here for the preparation of azo-functionalized TPU can provide viable opportunities for soft robotics and smart TPU applications.


Asunto(s)
Robótica , Materiales Inteligentes , Poliuretanos/química , Rayos Ultravioleta
2.
Nat Commun ; 13(1): 7699, 2022 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-36509757

RESUMEN

The self-healing properties and ionic sensing capabilities of the human skin offer inspiring groundwork for the designs of stretchable iontronic skins. However, from electronic to ionic mechanosensitive skins, simultaneously achieving autonomously superior self-healing properties, superior elasticity, and effective control of ion dynamics in a homogeneous system is rarely feasible. Here, we report a Cl-functionalized iontronic pressure sensitive material (CLiPS), designed via the introduction of Cl-functionalized groups into a polyurethane matrix, which realizes an ultrafast, autonomous self-healing speed (4.3 µm/min), high self-healing efficiency (91% within 60 min), and mechanosensitive piezo-ionic dynamics. This strategy promotes both an excellent elastic recovery (100%) and effective control of ion dynamics because the Cl groups trap the ions in the system via ion-dipole interactions, resulting in excellent pressure sensitivity (7.36 kPa-1) for tactile sensors. The skin-like sensor responds to pressure variations, demonstrating its potential for touch modulation in future wearable electronics and human-machine interfaces.


Asunto(s)
Dispositivos Electrónicos Vestibles , Humanos , Iones , Piel , Poliuretanos , Electrónica
3.
Carbohydr Polym ; 197: 414-421, 2018 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-30007630

RESUMEN

Non-thermal effect of microwave is precisely revealed as an important factor to strengthen the hydrolysis of cellulose to sugar by a new method of synchronous cooling assisted microwave driving. Using this particular method, the thermal effect is mandatorily removed from the hydrolysis of cellulose. After systematic analysis of the hydrolysis of low crystalline regenerated cellulose (RC), the non-thermal effect of microwave is proved to strengthen hydrolysis. The enhancement of non-thermal effect effectively weaken the interaction between the hydroxyl groups of -O(2)H and -O(6)H, as well as strengthen interaction between the hydroxyl groups of -O(3)H and -O(5)H within one single molecular chain. It leads to the reduction of regularity of molecular chain and thus inhibits the recrystallization of RC. As a result, the efficiency of hydrolysis is greatly improved. This research provides an important theoretical support and technical guidance to construct new microwave driven hydrolysis with high efficiency in the future.

4.
Arch Tierernahr ; 56(5): 327-37, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12556044

RESUMEN

Two experiments were conducted to investigate the effect of dietary supplementation with alpha-galactosidase preparation and stachyose on growth performance, nutrient digestibility and intestinal bacterial populations of piglets. In Experiment I 72 crossbred piglets were allotted to three treatments, i.e. 1) control (basal) diet, 2) alpha-Gal1 and 3) alpha-Gal5, the basal diet supplemented with 0.01% and 0.05% alpha-galactosidase preparation (alpha-Gal), respectively. Average daily gain, average daily feed intake and feed conversion ratio were not influenced by alpha-Gal supplementation. In Experiment II 72 crossbred weanling piglets were randomly assigned to four treatments with a complete factorial design, i.e. 1) basal diet, 2) basal diet with 0.01% alpha-Gal supplementation, 3) basal diet with 1% stachyose supplementation and 4) basal diet with 1% stachyose and 0.01% alpha-Gal supplementation. Average daily gain and feed conversion ratio were influenced by alpha-Gal and stachyose supplementation. The ileal digestibility of stachyose, raffinose, gross energy and crude protein was improved significantly by alpha-Gal supplementation. The microbial populations in the intestine were modified by both alpha-Gal and stachyose supplementation. The data suggested that stachyose supplementation had an adverse effect on the growth performance of piglets and alpha-Gal supplementation could ameliorate it, especially in younger pigs.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Digestión , Sistema Digestivo/microbiología , Oligosacáridos/farmacología , Porcinos/crecimiento & desarrollo , alfa-Galactosidasa/farmacología , Factores de Edad , Animales , Suplementos Dietéticos , Digestión/efectos de los fármacos , Ingestión de Alimentos , Femenino , Masculino , Oligosacáridos/administración & dosificación , Oligosacáridos/efectos adversos , Distribución Aleatoria , Porcinos/metabolismo , Porcinos/microbiología , Aumento de Peso , alfa-Galactosidasa/administración & dosificación
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