Advances in microcellular injection moulding

Injection moulding is a well-established replication process for the cost-effective manufacture of polymer-based components. The process has different applications in fields such as medical, automotive and aerospace. To expand the use of polymers to meet growing consumer demands for increased functionality, advanced injection moulding processes have been developed that modifies the polymer to create microcellular structures. Through the creation of microcellular materials, additional functionality can be gained through polymer component weight and processing energy reduction. Microcellular injection moulding shows high potential in creating innovation green manufacturing platforms. This review article aims to present the significant developments that have been achieved in different aspects of microcellular injection moulding. Aspects covered include core-back, gas counter pressure, variable thermal tool moulding and other advanced technologies. The resulting characteristics of creating microcellular injection moulding components through both plasticising agents and nucleating agents are presented. In addition, the article highlights potential areas for research exploitation. In particular, acoustic and thermal applications, nano-cellular injection moulding parts and developments of more accurate simulations.

Mixed matrix membranes based on silica nanoparticles and microcellular polymers for CO2/CH4 separation

Mixed matrix membranes made from silica nanoparticles and microcellular polymers were prepared from Matrimid® 5218 combined with tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane via the sol–gel method. The nanoparticles were prepared in situ during membrane casting yielding a homogeneous distribution inside a foamed polyimide structure. Mixed matrix membranes with SiO2 contents up to 16% wt. were treated at 60℃, 100℃, 150℃, and 200℃. Thermal gravimetric analysis and Fourier transform infrared spectroscopy analyses were performed providing information on chemical composition and thermal stability, while the porous structure (average cell diameter and cell density) was studied by scanning electron micrograph. Also, dynamic mechanical analysis was used to determine the glass transition temperature (Tg) and elastic modulus. Finally, the gas transport properties were studied in terms of treatment temperature, feed pressure, SiO2 loading, and testing temperature. CO2 permeability was found to increase by a factor of 3–4 at 3% SiO2 content using tetraethoxysilane in Matrimid, while ideal selectivity for CO2/CH4 separation was constant. Finally, the plasticization effect was practically eliminated by the introduction of SiO2 nanoparticles.

The correlation of the binding mechanism of the polypyrrole–carbon capacitive interphase with electrochemical stability of the composite electrode

Carbon–polymer composites for organic batteries, capacitors, capacitive water desalination reactors and electrochemical sensors.