With the rise of the fifth-generation (5G) mobile communication, electromagnetic interference (EMI) and radiation become progressively serious toward electronic devices and human health, resulting in an increasing demand for EMI shielding materials. Polymer-based EMI shielding materials have drawn considerable attention in relevant industries and academia owing to their low density, easy processing, and superior flexibility. In this review, we systematically discuss the development of polymer-based shielding materials fabricated by using polymers as matrices and precursors. The architecture design of polymer composites is emphasized including homogenous structure, porous structure, laminated structure, and segregated structure. Specific attention is also given to the polymer derivatives from synthetic and natural polymers. Finally, we summarize the recent advancements and our guidelines for the development of polymer-based EMI shielding materials in the 5G era.

PC/PBT blends have excellent comprehensive properties and are widely used in the market. It's inevitable that transesterification reaction will take place in the melting process for this kind of blends, and this reaction has decisive effects on the blend properties, in this paper, the effects of resin ratio of PC to PBT, resin viscosity and processing technology on the transesterification reaction degree were studied. Considering that the reaction occurred at the phase interface of PC and PBT, with the combination of the phase morphology and crystallization behavior of PBT phase under different resin ratios, the correlation between phase morphology and transesterification degree was established. From the perspective of PBT phase, the lower its ratio is, the smaller its phase size is, the worse its crystallinity is, and the greater the transesterification degree, besides, the lower PBT resin viscosity, the higher the transesterification degree. Moreover, through the research on processing technology, the higher the extruder speed, the higher the transesterification degree. Those studies will provide direct guidance for further research on the influence factors of the transesterification degree and the actual processing of the corresponding products.

Compared with the traditional three-platen injection molding machine, the two-platen injection molding machine has many potential advantages such as space and material saving, uniform clamping force, etc. Internal circulation clamping system is the key to realize energy-saving and high speed clamping for small and medium types of two-platen injection molding machines. This paper presented an internal circulation clamping system with supplementary volume. Compared with the other internal circulation clamping systems, the new system with supplementary volume could not only confirm the uniform tension force on tie bars for dramatic increase of service life but also improve energy-saving. In order to estimate the properties of the new system, the models of two different hydraulic clamping systems were established by using AMESim. The displacement of the moving platen, the pressure of the clamping cylinder, and the energy consumption of the hydraulic clamping system were all calculated and analyzed.

In this paper, identification system of plastic solid waste (PSW) based on near-infrared (NIR) reflectance spectroscopy in combination with Support Vector Machine (SVM) was presented. A device applied to obtain NIR spectra of plastics in the detection platform was developed. After pre-processing (normalized, 1st derivative and smooth), the repeatability of spectral absorption features was improved, which would assist the identification. A “principal component analysis (PCA)SVM” identification method was proposed to identify polypropylene (PP), polystyrene (PS), polyethylene (PE), poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate (PET) among plastics, and its identification accuracy can reach 97.5%. The type of samples could clearly be identified and the shape of samples could also be roughly discerned. It is clearly shown that this system can achieve good identification results while reducing costs considerably, which has great potential in industrial recycling.

Polyhydroxyalkanoates (PHA) have been produced by several bacteria as bioplastics in industrial scales. PHA commercialization has been challenging due to its complexity and the associated high cost together with instabilities on molecular weights (Mw) and structures, thus instability on thermo- and mechanical properties. PHA high production cost is related to complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and poor growth of microorganisms as well as complicated downstream separation. To reduce complexity of PHA production, robust microorganisms that are contamination resistant bacteria have been targeted especially extremophiles, developments of engineering approaches for extremophiles especially Halomonas spp. for better PHA production have been successfully conducted and termed as “next generation industrial biotechnology” (NGIB). Diverse PHA can also be produced by engineering Halomonas or Pseudomonas spp. This review introduces recent advances on engineering bacteria for enhanced PHA biosynthesis and diversity.

This article reviews the current state-of-the-art in the applications of shape memory alloy (SMA) wires into high performance fibre reinforced polymer composite materials (FRPs). SMAs have been investigated to date to address four main areas of properties improvement: (i) damping and vibrational response, where SMAs are integrated into composites either in the plane of the neutral axis, or as transverse stitches; (ii) impact, where SMAs are integrated in the neutral axis or as stitches; (iii) crack closure, where SMAs are integrated transverse to the crack, as stitches and (iv) shape morphing, where SMAs are integrated in plane into the composite, but in the non-neutral axis. The critical parameters for successful integration of SMAs to FRPs are highlighted, mostly from a composite processing angle. Finally, this review evaluates some hurdles remaining in the implementation of SMAs to FRPs to create smart and efficient composite structures without compromising their processing route, structural properties, weight and cost.