The Quantitative Evaluation of the Cell Structure Uniformity of Microcellular TPU with Low Porosity via a Digital Image Processing Method.

The cell structure uniformity of microcellular polymers significantly impacts material performance, especially for low-porosity microcellular TPU used in chip polishing. The distribution of the cell structure of polishing pads directly affects the removal rate and process repeatability. Despite its importance, no quantitative method for evaluating cell structure uniformity has been reported in the literature.

In Situ Reversible and Robust Mechano-Responsive Ultralong Phosphorescence of Polyurethane Elastomer.

Though mechano-responsive luminescent materials obtained much attention, most of their responses are non-reversible, let alone in situ reversible. Here, the study presents a new strategy to push through this limitation for their applications, which relies on the reversible mechano-responsive (MR) hydrogen bonding interactions and polymer chain orientation among a doped polyurethane (PU) elastomer. The radiative and nonradiative transitions inside these phosphorescent triphenylene-based aromatic secondary amines (TpNP and TpNPO) doped in the PU matrix can be accordingly modulated by these MR variations, including the PU chains orientation and the interactions between emitters and PU, respectively.

A Camel-Fur-Inspired Micro-Extrusion Foaming Porous Elastic Fiber for All-Weather Dual-Mode Human Thermal Regulation.

Maintaining the stability of human body temperature is the basis of ensuring the normal life activities of witness, and the emergence of various functional clothing is committed to assisting the human body temperature in thermal comfort range in the changeable environment. However, achieve dual-mode thermal regulation for cooling and insulation on an integrated material without energy input and addition of functional particles has thus far been a huge challenge. Herein, a biomimetic camel-fur designed micro-extruded physically foamed porous elastic fiber (MEPF) using thermoplastic polyurethane (TPU) elastomer as raw material is reported, and its dual-layered fabric (MEPFT-d) for effective personal thermal comfortable management at extreme temperature differences.

Comparative Study of the Foaming Behavior of Ethylene-Vinyl Acetate Copolymer Foams Fabricated Using Chemical and Physical Foaming Processes.

Ethylene-vinyl acetate copolymer (EVA), a crucial elastomeric resin, finds extensive application in the footwear industry. Conventional chemical foaming agents, including azodicarbonamide and 4,4'-oxybis(benzenesulfonyl hydrazide), have been identified as environmentally problematic. Hence, this study explores the potential of physical foaming of EVA using supercritical nitrogen as a sustainable alternative, garnering considerable interest in both academia and industry.

A Review of the Preparation of Porous Fibers and Porous Parts by a Novel Micro-Extrusion Foaming Technique.

This review introduces an innovative technology termed "Micro-Extrusion Foaming (MEF)", which amalgamates the merits of physical foaming and 3D printing. It presents a groundbreaking approach to producing porous polymer fibers and parts. Conventional methods for creating porous materials often encounter obstacles such as the extensive use of organic solvents, intricate processing, and suboptimal production efficiency.

Bioinspired Self-Standing, Self-Floating 3D Solar Evaporators Breaking the Trade-Off between Salt Cycle and Heat Localization for Continuous Seawater Desalination.

Facing the global water shortage challenge, solar-driven desalination is considered a sustainable technology to obtain freshwater from seawater. However, the trade-off between the salt cycle and heat localization of existing solar evaporators (SE) hinders its further practical applications. Here, inspired by water hyacinth, a self-standing and self-floating 3D SE with adiabatic foam particles and aligned water channels is built through a continuous directional freeze-casting technique.

Supercritical Fluid Microcellular Foaming of High-Hardness TPU via a Pressure-Quenching Process: Restricted Foam Expansion Controlled by Matrix Modulus and Thermal Degradation.

High-hardness thermoplastic polyurethane (HD-TPU) presents a high matrix modulus, low-temperature durability, and remarkable abrasion resistance, and has been used in many advanced applications. However, the fabrication of microcellular HD-TPU foam is rarely reported in the literature. In this study, the foaming behavior of HD-TPU with a hardness of 75D was investigated via a pressure-quenching foaming process using CO as a blowing agent.

Biomimetic hydrophobic plastic foams with aligned channels for rapid oil absorption.

Although many oil absorption materials have been developed, it still remains a great challenge to achieve rapid absorption and efficient recovery. Over the past decade, research has focused on the development of freeze casting technology using water as a solvent. The materials prepared by this method have poor water resistance and are difficult to apply to oil absorption in aqueous environments.

Polyethylene separator supported thin-film composite forward osmosis membranes for concentrating lithium enriched brine.

To extract lithium from salt lake brine involves a process of separation and concentration. After separating lithium from brine, the lithium ion concentration is generally a few hundred mg/L which is far below the required 20-30 g/L (as Li) before precipitation as lithium carbonate. The concentration step of a lithium enriched brine is crucial but highly energy-intensive.

Robust and Multifunctional Porous Polyetheretherketone Fiber Fabricated via a Microextrusion CO Foaming.

Fabrication of multifunctional porous fibers with excellent mechanical properties has attracted abundant attention in the fields of personal thermal management textiles and smart wearable devices. However, the high cost and harsh preparation environment of the traditional solution-solvent phase separation method for making porous fibers aggravates the problems of resource consumption and environmental pollution. Herein, a microextrusion process that combines environmentally friendly CO physical foaming with fused deposition modeling technology is proposed, via the dual features of high gas uptake and restricted cell growth, to implement the continuous production of porous polyetheretherketone (PEEK) fibers with a production efficiency of 10.

Poly(ether imide)/Epoxy Foam Composites with a Microcellular Structure and Ultralow Density: Bead Foam Fabrication, Compression Molding, Mechanical Properties, Thermal Stability, and Flame-Retardant Properties.

It is challenging to prepare ultralow-density microcellular foams based on high-performance polymers due to their low gas solubility and rigid polymer matrix. In this study, by applying microcellular foaming technology using CO/acetone as the blowing agent, ultralow-density poly(ether imide) (PEI) bead foams with an expansion ratio of 30-56 times and cell density of 10-10 cells/cm were fabricated, resulting from the enhanced plasticization effect of the mixed fluid. The slow diffusivity of acetone at room temperature ensured the saturated PEI beads to foam after desorption for more than 6 days, which potentially reduces the transportation cost of PEI bead foams significantly.

Preparation of Thermoplastic Polyurethane (TPU) Perforated Membrane via CO Foaming and Its Particle Separation Performance.

The way in which a perforated structure is formed has attracted much interest in the porous membrane research community. This novel structure gives materials an excellent antifouling property as well as a low operating pressure and other benefits. Unfortunately, the current membrane fabrication methods usually involve multi-step processes and the use of organic solvents or additives.

Carbon Composite Networks with Ultrathin Skin Layers of Graphene Film for Exceptional Electromagnetic Interference Shielding.

Natural cotton was selected as a cheap and renewable carbon source to fabricate novel carbon networks with porous three-dimensional conductive frameworks composed of numerous unique hollow carbon fibers by pyrolysis, and outstanding electromagnetic interference (EMI) shielding effectiveness (SE) of ∼26.9-46.9 dB was observed for the samples (∼0.

One-Pot Sintering Strategy for Efficient Fabrication of High-Performance and Multifunctional Graphene Foams.

Macroscopic three-dimensional (3D) graphene foams (GFs) were fabricated efficiently by immediately sintering low-temperature exfoliated graphene powder under inert atmosphere at the temperature over 500 °C. The one-pot sintering process not only integrated two-dimensional (2D) graphene sheets into 3D GF, but also accelerated the structural integrity of graphene by inducing its deoxygenation and repairing the defects. More importantly, the whole process could be finished within hours, usually less than 12 h, and the resultant GFs with interconnected graphene framework as well as meso- and macroporous structure exhibited exceptional attenuating performance for high-frequency electromagnetic interference and adsorption capacities for organic pollutants.

Compressible Graphene-Coated Polymer Foams with Ultralow Density for Adjustable Electromagnetic Interference (EMI) Shielding.

The fabrication of low-density and compressible polymer/graphene composite (PGC) foams for adjustable electromagnetic interference (EMI) shielding remains a daunting challenge. Herein, ultralightweight and compressible PGC foams have been developed by simple solution dip-coating of graphene on commercial polyurethane (PU) sponges with highly porous network structure. The resultant PU/graphene (PUG) foams had a density as low as ∼0.

Preparation and characterization of highly cross-linked polyimide aerogels based on polyimide containing trimethoxysilane side groups.

In this study, highly cross-linked and completely imidized polyimide aerogels were prepared from polyimide containing trimethoxysilane side groups, which was obtained as the condensation product of polyimide containing acid chloride side groups and 3-aminopropyltrimethoxysilane. After adding water and acid catalyst, the trimethoxysilane side groups hydrolyzed and condensed one another, and a continuous increase in the complex viscosities of the polyimide solutions with time was observed. The formed polyimide gels were dried by freeze-drying from tert-butyl alcohol to obtain polyimide aerogels, which consisted of a three-dimensional network of polyimide fibers tangled together.

Lightweight, multifunctional polyetherimide/graphene@Fe3O4 composite foams for shielding of electromagnetic pollution.

Novel high-performance polyetherimide (PEI)/graphene@Fe3O4 (G@Fe3O4) composite foams with flexible character and low density of about 0.28-0.4 g/cm(3) have been developed by using a phase separation method.

Facile preparation of lightweight microcellular polyetherimide/graphene composite foams for electromagnetic interference shielding.

We report a facile approach to produce lightweight microcellular polyetherimide (PEI)/graphene nanocomposite foams with a density of about 0.3 g/cm3 by a phase separation process. It was observed that the strong extensional flow generated during cell growth induced the enrichment and orientation of graphene on cell walls.

Melt blending in situ enhances the interaction between polystyrene and graphene through π-π stacking.

The effect of melt blending on the interaction between graphene and polystyrene (PS) matrix has been investigated in this paper. The interaction between graphene and PS was significantly enhanced by melt blending, which led to an increased amount of PS-functional graphene (PSFG) exhibiting good solubility in some solvents. The PS chains on PSFG could effectively prevent the graphene sheets from aggregating and the prepared PS/PSFG composites exhibited a homogeneous dispersion and an improved electrical property.

A study of the crystallization, melting, and foaming behaviors of polylactic acid in compressed CO₂.

The crystallization and melting behaviors of linear polylactic acid (PLA) treated by compressed CO(2) was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO(2) exposure significantly increased PLA's crystallization rate; a high crystallinity of 16.5% was achieved after CO(2) treatment for only 1 min at 100 degrees C and 6.