In this study, the blends of polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMWPE) were prepared by the four-and twin-screw extruders, and ethylene-propylene-diene monomer (EPDM), as the third compon...In this study, the blends of polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMWPE) were prepared by the four-and twin-screw extruders, and ethylene-propylene-diene monomer (EPDM), as the third component, was added to the binary blends. The mechanical.thermal, morphological and rheological properties of these two blends have been investigated.For the materials blended by the four-screw extruder, a 15 wt-% content of UHMWPE corresponds to a maximum lzod impact strength, and the miscibility enhancement effect of EPDM on PP/UHMWPE blends is very remarkable. Mechanical and thermal properties demonstrate that melt blending by the four-screw extruder is a better prcessing method for PP/UHMWPF blends than that by the twin-screw extruder. A co-continuous structure was observed in blends through TEM, and a novel "linear interpenetrating" toughening mechanism is proposed on the basis of this research展开更多
To change the situation of shape memory polymers(SMPs)that can only remember very few shapes and enable discretional morphing for practical application,the authors report a reversible stepless multiple SMP derived fro...To change the situation of shape memory polymers(SMPs)that can only remember very few shapes and enable discretional morphing for practical application,the authors report a reversible stepless multiple SMP derived from ultrahigh molecular weight polyethylene(UHMWPE).As the crystals of semicrystalline polymers are assembled by those with slightly different melting temperatures,and each type of crystal can remember a single shape,the crystalline region of UHMWPE is allowed to remember plenty of temporary shapes after programming.Changing the temperature of the programmed polymer within the melting/crystallization temperature ranges would lead to releasing/recovery of the memorized temporary shapes.Accordingly,multiple shape memory effects can be easily realized without an elaborate design of material structure and training process in advance as before.The temperaturedependent adjustability of the analog capacitor and soft lens with embedded programmed UHMWPE as actuators,characterized by the continuous/random/proportional responsivity,further reveals the utilization prospects of the controllable reversible stepless discretionary morphing effect.Moreover,the maximum work density of the programmed UHMWPE is found to be 210 kJ/m_(3),which is more than 10 times of piezoelectric ceramics,so that it can serve as a proof-of-concept mechanical driver for reversibly pumping of ethanediol-droplet upon heating/cooling.展开更多
文摘In this study, the blends of polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMWPE) were prepared by the four-and twin-screw extruders, and ethylene-propylene-diene monomer (EPDM), as the third component, was added to the binary blends. The mechanical.thermal, morphological and rheological properties of these two blends have been investigated.For the materials blended by the four-screw extruder, a 15 wt-% content of UHMWPE corresponds to a maximum lzod impact strength, and the miscibility enhancement effect of EPDM on PP/UHMWPE blends is very remarkable. Mechanical and thermal properties demonstrate that melt blending by the four-screw extruder is a better prcessing method for PP/UHMWPF blends than that by the twin-screw extruder. A co-continuous structure was observed in blends through TEM, and a novel "linear interpenetrating" toughening mechanism is proposed on the basis of this research
基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2019A1515110327Science Foundation for Young Teachers of Wuyi University,Grant/Award Number:2018AL017+4 种基金Innovation and Entrepreneurship Foundation of Students of Wuyi University,Grant/Award Number:2020CX16National Natural Science Foundation of China,Grant/Award Numbers:52003201,52033011Guangdong Science and Technology Major Special Fund,Grant/Award Number:2019-252Science Foundation for Young Research Group of Wuyi University,Grant/Award Number:2019td08Joint Research Fund for Wuyi University,Hong Kong and Macao Young Scholars,Grant/Award Number:2019WGALH05。
文摘To change the situation of shape memory polymers(SMPs)that can only remember very few shapes and enable discretional morphing for practical application,the authors report a reversible stepless multiple SMP derived from ultrahigh molecular weight polyethylene(UHMWPE).As the crystals of semicrystalline polymers are assembled by those with slightly different melting temperatures,and each type of crystal can remember a single shape,the crystalline region of UHMWPE is allowed to remember plenty of temporary shapes after programming.Changing the temperature of the programmed polymer within the melting/crystallization temperature ranges would lead to releasing/recovery of the memorized temporary shapes.Accordingly,multiple shape memory effects can be easily realized without an elaborate design of material structure and training process in advance as before.The temperaturedependent adjustability of the analog capacitor and soft lens with embedded programmed UHMWPE as actuators,characterized by the continuous/random/proportional responsivity,further reveals the utilization prospects of the controllable reversible stepless discretionary morphing effect.Moreover,the maximum work density of the programmed UHMWPE is found to be 210 kJ/m_(3),which is more than 10 times of piezoelectric ceramics,so that it can serve as a proof-of-concept mechanical driver for reversibly pumping of ethanediol-droplet upon heating/cooling.
