High-vinyl polybutadiene rubber (HVBR) and solution-polymerized styrene-butadiene rubber (SSBR) can meet the requirements of high-performance tires due to their excellent wet skid resistance and lower rolling resistance. In this paper, the effects of the vinyl and phenyl groups and their contents on the vulcanization behavior, mechanical strength, fatigue resistance, heat resistance, and wear resistance of HVBR and SSBR were investigated, and the dynamic viscoelasticities of HVBR and SSBR vulcanizates with or without carbon black were explored by dynamic mechanical analysis (DMA). The experimental results showed that the vinyl groups contributed more to the wear resistance and fatigue resistance of vulcanizates than the phenyl groups, but the phenyl groups contributed more to the mechanical strength of the vulcanizates than the vinyl groups. The DMA results showed that the vinyl and phenyl groups could significantly improve the road-gripping capability and wet skid resistance of HVBR and SSBR vulcanizates, but carbon black could slightly weaken the effect of vinyl and phenyl groups on the wet skid resistance of vulcanizates, and the effect of carbon black on vinyl groups was more significant. Despite the presence of carbon black, the phenyl groups contributed more heat buildup to the vulcanizates than the vinyl groups.

Shape memory polymers (SMPs) are a type of smart material with potential application in aerospace engineering, biomedical devices, and sensors. In this article, we propose a new technique for the preparation of foamed Eucommia ulmoides gum (EUG) composites, which have excellent one‐way and two‐way shape memory performances. The advantages of these foamed composites are not only light weight but also good shape memory performance. For their remarkably light weight, large deformation, and efficient cost, these composites are expected to be a kind of popular smart materials in the future. We studied the properties of foamed composites via mechanical measurements, swelling experiments, thermal analysis and shape memory analysis, hoping to establish the relationship between the microstructure and macroscopic properties of composites. The results showed that the composites with 0.4 phr sulfur had superior one‐way shape memory properties and moderate mechanical properties. In the two‐way shape memory tests, the composites performed excellent two‐way shape memory properties with the applied stress ranging from 200 to 350 KPa. POLYM. COMPOS., 40:3075–3083, 2019. © 2018 Society of Plastics Engineers

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A novel series of shape memory blends of trans‐1,4‐polyisoprene (TPI) and low‐density polyethylene (LDPE) were prepared using a simple physical blending method. The mechanical, thermal and shape memory properties of the blends were studied and schemes proposed to explain their dual and triple shape memory behaviors. It was found that the microstructures played an important role in the shape memory process. In TPI/LDPE blends, both the TPI crosslinking network and LDPE crystalline regions could work as fixed domains, while crystalline regions of LDPE or TPI could act as reversible domains. The shape memory behaviors were determined by the components of the fixed and reversible domains. When the blend ratio of TPI/LDPE was 50/50, the blends showed excellent dual and triple shape memory properties with both high shape fixity ratio and shape recovery ratio. © 2017 Society of Chemical Industry

Shape-memory polymers are important smart materials with potential applications in smart textiles, medical devices, and sensors. We prepared trans-1,4-polyisoprene, low-density polyethylene (LDPE), and high-density polyethylene (HDPE) shape-memory composites using a simple mechanical blend method. The mechanical, thermal, and shape-memory properties of the composites were studied. Our results showed that the shape-memory composites could memorize 3 temporary shapes, as revealed by the presence of broad melting transition peaks in the differential scanning calorimetry curves. In the trans-1,4-polyisoprene/LDPE/HDPE composites, the cross-linked network and the crystallization of the LDPE and HDPE portions can serve as fixed domains, and all crystallizations can act as reversible domains. We proposed a schematic diagram to explain the vital role of the cross-linked network and the crystallization in the shape-memory process.

We fabricated a series of novel shape memory composites using natural Eucommia ulmoides rubber (EUR) and polybutene-1 (PB-1) as basic materials for the first time. The shape memory composites were prepared via simple physical blending and chemical crosslinking methods with co-continuous architecture and multiple shape memory behaviors. These composites and their preparation methods might be widely used in the field of heat shrinkable tubes. We studied the mechanical, thermal and shape memory properties of the composites, and proposed schemes to explain their dual and triple shape memory effects. In the EUR/PB-1 composites, both the crosslinking network of the composites and crystalline regions of PB-1 could function as the fixed domain, and the crystalline zones of EUR and PB-1 could act as the reversible domain individually or jointly. The composites exhibited excellent dual shape memory properties with blending ratios of 90/10 and 80/20, and good triple shape memory properties with blending ratios of 70/30 and 60/40.

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a novel strategy to engineer a multi-ionic network into a covalently cross-linked 1,2-polybutadiene (1,2-PB) facilitated by in-situ intercalated organic montmorillonite (OMMT) without phase separation. XRD, SEM, and TEM analysis were carried out to characterize the microstructure of the resulting polymers. Crosslinking density, dielectric performance, and cyclic tensile tests were used to demonstrate the interaction of zinc methacrylate (ZDMA) and OMMT. The dynamic nature of ionic bonds allowed it to rupture and reform to dissipate energy efficiently. Stretching orientation brought parallelism between polymer chains and OMMT layers which was beneficial for the reconstruction of the ionic network, ultimately resulting in high strength and a low stress relaxation rate. Overall, our work presented the design of a uniform and strong sacrificial network in the nano-clay/elastomer nanocomposite with outstanding mechanical performances under both static and dynamic conditions.

For rubber materials, the antioxidants are significant for maintaining the long service life when suffering from external stimuli. However, the common low-molecularweight antioxidants easily migrate to the rubber surface and lose the anti-aging effect. In this work, we develop highly anti-migration hindered phenolic antioxidants, which have been obtained by covalently grafting 3,5-di-tert-butyl-4-hydroxybenzoic acid (AO) onto carbon nanotubes (CNTs). To improve the adhesion of AO and CNTs, the polydopamine with the potential reactive functional groups was linked between antioxidants and CNTs by mussel biomimetic strategy. The binary antioxidants integrated the good reinforcement and dispersity of CNTs with the anti-aging characteristics of hindered phenol. What is more, the experimental results indicate that the total loading efficiency of AO could reach 11.7 wt%. The 1,2-Polybutadiene/CNTs-AO composites could be stored in a thermal oxidation environment for 15 days with minimal degradation of mechanical properties. This strategy proposed herein provides insights into the development of highly anti-migration and anti-aging antioxidants by a simple, cost-effective, and pollution-free method.