Rapid Nanowelding of Carbon Coatings onto Glass Fibers by Electrothermal Shock.

With the rapid development of nanomanufacturing, scaling up of nanomaterials requires advanced manufacturing technology to composite nanomaterials with disparate materials (ceramics, metals, and polymers) to achieve hybrid properties and coupling performances for practical applications. Attempts to assemble nanomaterials onto macroscopic materials are often accompanied by the loss of exceptional nanoscale properties during the fabrication process, which is mainly due to the poor contacts between carbon nanomaterials and macroscopic bulk materials. In this work, we proposed a novel cross-scale manufacturing concept to process disparate materials in different length scales and successfully demonstrated an electrothermal shock approach to process the nanoscale material (e.g., carbon nanotubes) and macroscale (e.g., glass fiber) with good bonding and excellent mechanical property for emerging applications. The excellent performance and potentially lower cost of the electrothermal shock technology offers a continuous, ultrafast, energy-efficient, and roll-to-roll process as a promising heating solution for cross-scale manufacturing.

Shape Memory Behavior of Carbon Black-reinforced Trans-1,4-polyisoprene and Low-density Polyethylene Composites.

Shape memory composites of trans-1,4-polyisoprene (TPI) and low-density polyethylene (LDPE) with easily achievable transition temperatures were prepared by a simple physical blending method. Carbon black (CB) was introduced to improve the mechanical properties of the TPI/LDPE composites. The mechanical, cure, thermal and shape memory properties of the TPI/LDPE/CB composites were investigated in this study. In these composites, the crosslinked network generated in both the TPI and LDPE portions acted as a fixed domain, while the crystalline regions of the TPI and LDPE portions acted as a reversible domain in shape memory behavior. We found the mechanical properties of composites were promoted significantly with an increase of CB content, accompanied with the deterioration of shape memory properties of composites. When CB dosage was 5 parts per hundred of rubber composites (phr), best shape memory property of composites was obtained with a shape fixity ratio of 95.1% and a shape recovery ratio of 95.0%.

Shape Memory Behavior of Natural Eucommia ulmoides Gum and Low-Density Polyethylene Blends with Two Response Temperatures.

A series of shape memory blends of natural Eucommia ulmoides gum (EUG) and low-density polyethylene (LDPE) with a bicontinuous cross-linked structure were prepared by a physical blending method, which could be used in the field of thermal response with two different temperatures. We report the shape memory properties of these blended materials with two response temperatures for the first time. The mechanical, curing, thermal and shape memory properties of the blends were studied in this manuscript. Schematic diagrams are proposed to illustrate the dual shape memory behaviors of the EUG/LDPE blends. Our study focused on observing the relationship between the shape memory behavior and the microscopic crystalline phase states in the blends. In the blends, both the cross-linked network and the LDPE crystalline regions could act as fixed domains, while the crystalline regions of LDPE or EUG could act as the reversible domain. The shape memory properties were mainly determined by the components of the fixed and reversible domains. We focused on the shape memory behavior of blends at 60 °C and 130 °C in this manuscript. The results showed that when the peroxide dicumyl peroxide (DCP) dosage was 1.0 phr, the blends exhibited acceptable shape behavior at 60 °C (R1f = 74.8%, R1r = 63.3%). At the same time, when DCP dosage was 0.4 phr, the shape memory behavior of the blends at 130 °C was good and much better than that at 60 °C (R2f = 91.1%, R2r = 89.4%).