Mullins Effect and its Reversibility for Zinc Dimethacrylate-Reinforced Thermoplastic Vulcanizates Based on a Ethylene-Vinyl Acetate Copolymer/Nitrile-Butadiene Rubber Blend

2018 ◽  
Vol 58 (1) ◽  
pp. 59-72
Author(s):  
Libin Wang ◽  
Liangliang Gao ◽  
Zhaobo Wang
2019 ◽  
Vol 33 (9) ◽  
pp. 1217-1233 ◽  
Author(s):  
Libin Wang ◽  
Kesi Xiong ◽  
Zhaobo Wang

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.


2015 ◽  
Vol 30 (6) ◽  
pp. 827-839 ◽  
Author(s):  
Cancan Wang ◽  
Yufeng Zhang ◽  
Zhaobo Wang

Thermoplastic vulcanizates (TPVs) based on ethylene–vinyl acetate copolymer (EVA)/ethylene–vinyl acetate rubber (EVM) were prepared by dynamic vulcanization. Mechanical properties, morphology, and Mullins effect of the TPVs were investigated. The results showed that the EVA/EVM TPV with 40/60 weight ratio had excellent mechanical properties. There was no obvious phase separation on the fracture surface of the TPV. Mullins effect could be observed in the stress–strain curves of TPVs during the uniaxial loading–unloading cycles. Compared with TPV with 20/80 weight ratio, the TPV with 40/60 weight ratio had the relatively larger maximum stress, residual deformation, and internal friction loss at specific strain.


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