Design of heat‐triggered shape memory polymers based on ethylene‐acrylic acid copolymer/ nitrile‐butadiene rubber thermoplastic vulcanizates

2020 ◽  
Author(s):  
Yingtao Sun ◽  
Jing Hua ◽  
Zhaobo Wang
Keyword(s):  
Acrylic Acid ◽  
Shape Memory ◽  
Shape Memory Polymers ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
Acid Copolymer ◽  
Thermoplastic Vulcanizates ◽  
Acrylic Acid Copolymer

HEAT-TRIGGERED SHAPE MEMORY EFFECT OF PEROXIDE CROSS-LINKED ETHYLENE–METHACRYLIC ACID COPOLYMER/NITRILE–BUTADIENE RUBBER THERMOPLASTIC VULCANIZATES WITH SEA-ISLAND STRUCTURE

2021 ◽  
Author(s):  
Yingtao Sun ◽  
Jiahao Li ◽  
Kerui Liao ◽  
Jing Hua ◽  
Zhaobo Wang
Keyword(s):  
Shape Memory ◽  
Methacrylic Acid ◽  
Shape Recovery ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
Nitrile Butadiene Rubber ◽  
Acid Copolymer ◽  
Thermoplastic Vulcanizates ◽  
Switching Temperature ◽  
Shape Fixity

ABSTRACT Designing shape memory polymers (SMPs) based on thermoplastic vulcanizates (TPVs) is an essential research topic. An efficient SMP is designed with typical sea-island structured ethylene–methacrylic acid copolymer/nitrile–butadiene rubber (EMA/NBR) TPVs in which the heat-control switched phase performed by the EMA phase is related to the shape fixity ability. The results show that the heat-triggered SMPs exhibit surprising shape memory properties (shape fixity >95%, shape recovery >95%, and fast recovery speed <30 s at the switching temperature of 95 °C). Through X-ray diffraction characterization, it is seen that the shape fixity of TPVs is achieved mainly through ethylene crystallization. The switching temperature is largely determined by the melting temperature (98 °C) obtained by differential scanning calorimetery.

A novel heat-triggered shape-memory polymer based on ethylene–vinyl acetate copolymer/nitrile–butadiene rubber thermoplastic vulcanizates

2019 ◽  
Vol 33 (9) ◽  
pp. 1217-1233 ◽  
Author(s):  
Libin Wang ◽  
Kesi Xiong ◽  
Zhaobo Wang
Keyword(s):  
Shape Memory ◽  
Vinyl Acetate ◽  
Shape Memory Polymer ◽  
Weight Ratio ◽  
Ethylene Vinyl Acetate ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
Thermoplastic Vulcanizates ◽  
Acetate Copolymer ◽  
Ethylene Vinyl Acetate Copolymer

Achieving considerable shape-memory effects is a challenge for typical sea-island structured polymer blends. In this article, we successfully fabricated a novel heat-triggered shape-memory polymer (HSMP) based on ethylene–vinyl acetate copolymer/nitrile–butadiene rubber (EVA/NBR) thermoplastic vulcanizates (TPVs) via dynamic vulcanization. The influence of deformation temperature ( Td), recovery temperature ( Tr), and recovery time on the shape-memory behavior of the EVA/NBR (weight ratio = 80/20) TPV was investigated systematically. The shape-memory result of the EVA/NBR (weight ratio = 80/20) TPV demonstrated that when the Td was close to the melting temperature ( Tm) of the EVA phase (76°C), the TPV could obtain a good shape fixity ratio (>95%) and an excellent shape recovery ratio (>95%) at 100% stretch ratio. A shape-memory mechanism was proposed for this HSMP. The dynamic mechanical analysis results under temperature sweep mode showed that with increasing EVA content in TPVs, the tan δ decreased, while the storage modulus increased. The morphology observation showed that the cross-linked NBR particles were dispersed evenly in the etched surface of EVA/NBR TPV with an average diameter of approximately 2–6 μm. The longitudinal stretching surface of the EVA/NBR TPV exhibited the banding-like texture microstructure during the stretching process.

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