Electrically conductive polycarbonate/ethylene-propylene copolymer/multi-walled carbon nanotubes nanocomposites with improved mechanical properties

An impact resistant hydrogel enabled by bicontinuous phase structure and hierarchical energy dissipation

High performance hydrogels have essential applications in many fields such as tissue engineering and soft robot. Herein, we develop an impact resistant hydrogel composed of bicontinuous structures of polymer-hard phase and polymer-soft phase. This unique bicontinuous phase structure is formed by modulating various hydrogen bonding interactions. During loading, the polymer-hard phase is broken accompanied by the dissociation of hydrogen bonds to dissipate energy, while the polymer-soft phase distributes the load to avoid stress concentration, thus enabling the bicontinuous hydrogel to achieve excellent strength and toughness simultaneously. Furthermore, the fracture of hierarchical energy dissipation structures efficiently reduces impact strength and increases buffer time. Owing to the synergy of the bicontinuous phase structure and hierarchical energy dissipation, the resulting bicontinuous hydrogel remains intact even if it undergoes impact at a strain rate of ∼13 000 s^-1. Based on these findings, it is expected that the bicontinuous hydrogel has a potential application in the field of articular cartilage repair.

Melt Spinning of Flexible and Conductive Immiscible Thermoplastic/Elastomer Monofilament for Water Detection

In many textile fields, such as industrial structures or clothes, one way to detect a specific liquid leak is the electrical conductivity variation of a yarn. This yarn can be developed using melt spun of Conductive Polymer Composites (CPCs), which blend insulating polymer and electrically conductive fillers. This study examines the influence of the proportions of an immiscible thermoplastic/elastomer blend for its implementation and its water detection. The thermoplastic polymer used for the detection property is the polyamide 6.6 (PA6.6) filled with enough carbon nanotubes (CNT) to exceed the percolation threshold. However, the addition of fillers decreases the polymer fluidity, resulting in the difficulty to implement the CPC. Using an immiscible polymers blend with an elastomer, which is a propylene-based elastomer (PBE) permits to increase this fluidity and to create a flexible conductive monofilament. After characterizations (morphology, rheological and mechanical) of this blend (PA6.6_CNT/PBE) in different proportions, two principles of water detection are established and carried out with the monofilaments: the principle of absorption and the short circuit. It is found that the morphology of the immiscible polymer blend had a significant role in the water detection.

The Role of Interfacial Interactions on the Functional Properties of Ethylene-Propylene Copolymer Containing SiO2 Nanoparticles

In this paper, the mechanical properties, thermal stability, and transparency of ethylene-propylene copolymer (EPC) elastomer modified with various weight percentages (1, 3, and 5 wt.%) of SiO₂ nanofillers have been studied. The nanocomposites were prepared via a simple melt mixing method. The morphological results revealed that the nanofillers were uniformly dispersed in the elastomer, where a low concentration of SiO₂ (1 wt.%) had been added into the elastomer. The FTIR showed that there are interfacial interactions between EPC matrix and silanol groups of SiO₂ nanoparticles. Moreover, by the addition of 1 wt.% of SiO₂ in the EPC, the tensile strength and elongation at break of EPC increased by about 38% and 27%, respectively. Finally, all samples were optically transparent, and the transparency of the nanocomposites reduced by increasing the content of SiO₂ nanoparticles.

Eugenol Polysiloxane-Polycarbonate/Graphene Nanocomposite: Enhanced in Thermostability and Barrier Property

Graphene (GR) was used to blend with eugenol polysiloxane-polycarbonate (Si-PC) copolymer to prepare a Si-PC/GR nanocomposite via a solution blending method and the impact of graphene on the properties of Si-PC/GR nanocomposite was investigated. The morphology and structure of the Si-PC/GR nanocomposite were characterized. Combining morphology and property analysis, the result showed that when the graphene dispersed uniformly in the Si-PC matrix, the mechanical properties, thermostability and barrier property of Si-PC/GR nanocomposite were enhanced. Compared with Si-PC copolymer, the pyrolytic temperature of Si-PC/2.5%GR nanocomposite at 5% weight loss was 434.3 °C, which was 20.6 °C higher than Si-PC copolymer; and the oxygen barrier value of Si-PC/1.5%GR nanocomposite decreased to 160.2 cm³/m² 24 h 0.1 MPa, which was 53.2 less than pure Si-PC. The mechanical properties of Si-PC/GR nanocomposite were enhanced with an appropriate additive amount of graphene. The hydrophobicity also had been enhanced at the meantime.

Improving Oxygen Permeability and Thermostability of Polycarbonate via Copolymerization Modification with Bio-Phenol Polysiloxane

As a new kind of functionalized polysiloxane with chemical reactivity, bio-phenol polysiloxane was synthesized through facile heterogeneous catalytic route. Bio-phenol polysiloxane/polycarbonate (Si/PC) block copolymer was synthesized via a three-step approach, and the effect of the amount of bio-phenol polysiloxane on the properties of Si/PC copolymer was then studied. The structure and morphology of Si/PC copolymer were characterized, showing that, when the amount of bio-phenol polysiloxane reached 20%, the pyrolysis temperature of Si/PC copolymer at 5% weight loss was 450.8 °C which was 76.1 °C higher than pure PC. The oxygen permeability of 20%Si/PC copolymer membrane was 502.65 cm³/m²·24h·0.1MPa, which was increased by 128.4% compared with pure PC membrane. The mechanical property and hydrophobicity of Si/PC copolymer had been improved.

K A, Mathew LP, V. G G, Kalarikkal N, Thomas S, Volova T. An effective EMI shielding material based on poly(trimethylene terephthalate) blend nanocomposites with multiwalled carbon nanotubes

The effects of blend ratio and MWCNT loading on the morphology, electrical properties and electromagnetic shielding performance of poly(trimethylene terephthalate) (PTT)/polypropylene (PP) blend nanocomposites were studied.