The primary objective of this research paper is to detect and quantify the necking defect and surface velocity profiles in high-speed polymer melt extrusion film casting (EFC) process using Matlab® based image processing techniques. Extrusion film casting is an industrially important manufacturing process and is used on an industrial scale to produce thousands of kilograms of polymer films/sheets and coated products. In this research, the necking defect in an EFC process has been studied experimentally and the effects of macromolecular architecture such as long chain branching (LCB) on the extent of necking have been determined using image processing methodology. The methodology is based on the analysis of a sequence of image frames taken with the help of a commercial CCD camera over a specific target area of the EFC process. The image sequence is then analyzed using Matlab® based image processing toolbox wherein a customized algorithm is written and executed to determine the edges of the extruded molten polymeric film to quantify the necking defect. Alongwith the necking defect, particle tracking velocimetry (PTV) technique is also used in conjunction with the Matlab® software to determine the centerline and transverse velocity profiles in the extruded molten film. It is concluded from this study that image processing techniques provide valuable insights into quantifying both the necking defect and the associated velocity profiles in the molten extruded film.

Laser sintering of polymers (LS) is one of the most promising additive manufacturing technologies as it allows for the fabrication of complexly structured parts with high mechanical properties without requiring additional supporting structures. Semi-crystalline thermoplastics, which are preferably used in LS, need to be processed within a certain surface temperature range enabling the simultaneous presence of the material in both, the molten and solid state. In accordance with the most common processing models, these high temperatures are held throughout the entire building phase. In the state of the art, this leads to high cooling times and delayed component availability.

In this paper, process-adapted methods, in-situ experiments and numerical simulations were carried out in order to prove that this drawback can be overcome by material-adapted processing strategies based on a deepened model understanding. These strategies base on the fact, that the crystallization and solidification of polyamide 12 is initiated a few layers below the powder bed surface at high temperature and quasi-isothermic processing conditions. Therefore, isothermal crystallization and consolidation behaviour is analyzed by process-adapted material characterization. The influence of temperature fields during laser processing was analyzed in dependence of part cross-section, layer number and fabrication parameters and correlated to the resulting part properties. Furthermore, the possibility to homogenize the parts thermal history by controlling the part cooling is highlighted by a simulational approach. The authors show that the material-dependent solidification behavior must be taken into account as a function of the geometry- and layer-dependent temperature fields and demonstrate a major influence on the material and component properties. From these findings, new processing strategies for the laser exposure process as well as for the temperature control of the build chamber in z-direction arise, which allow for the acceleration of the LS process and earlier availability of components with more uniform part properties.

Foaming of recycled poly(ethylene terephthalate) (rPET) was performed by supercritical carbon dioxide (sc-CO₂) assisted extrusion. The intrinsic viscosity (IV) of rPET was increased from 0.62 dl/g to 0.87 dl/g using an epoxy-functional chain extender, which provided adequate rheological properties for cell stabilization so that an apparent density of less than 0.15 g/cm³ became achievable. Homogeneous and talc induced heterogeneous crystal and cell nucleation, subsequent cell growth and stabilization processes were examined using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. It was found that using talc the crystallization temperature increases which results in smaller cell size distribution. A strong correlation was evinced between the apparent density and the Fourier transform near-infrared (NIR) spectrum of the foamed rPET samples enabling quick and non-destructive characterization. Accordingly, NIR spectroscopy is demonstrated as a suitable method for in-line quality monitoring during extrusion foaming of recycled PET, being especially prone to quality fluctuations.

A large amount of non-infected plastic wastes are being generated at the healthcare facilities all over the world. However, only a small fraction is recycled. Conventionally, the used plastics are either disposed in landfills or inadequately incinerated. These practices impart an adverse effect on our environment. Plastics are indispensable part of the medical sector owing to their high versatility. The outbreak of Covid-19 clearly showed the growing demand for single use plastics. Hence, completely avoiding plastics can be challenging at this point of time. Recycling of plastics is undoubtedly a solution to solve the crisis of plastic pollution. Medical plastic recycling is limited mainly due to difficulties involved in sorting or cleaning. Recycling medical plastic wastes is possible only through proper coordination between healthcare sector and recycling industries. New recycling technologies are to be adopted in a sustainable manner. Moreover, the plastics used in medical applications should be designed such that recycling is possible. This review highlights the downside of medical wastes and discusses the recycling potential of commonly used medical plastics.

With the advance of nanotechnology in the insulation materials applications the polymers underwent structural changes, seen as individual and multiple nanoparticles techniques, moreover, frequency response analysis (FRA) provides an important prospective design for multiple nanocomposites applications. In this paper, the experimental work has been done for fabrication new polyvinyl chloride nanocomposites that is using individual and multiple nanoparticles to get low dielectric loss under thermal conditions. SEM images have detected the penetration of nano additives inside polyvinyl chloride materials that are obvious the patterns of utilizing individual and multiple nanoparticles. The series of experiments have performed on multi-nanocomposites of polyvinyl chloride samples in reference to additive free multiple nanoparticles (ZnO, Clay, Al₂O₃, and Fumed Silica) for controlling on dielectric losses with variant thermal conditions. Also, this paper has been discussed the electric field distribution inside dielectric nanocomposites and multiple nanocomposites for three-core belted power cables based on charge simulation method (CSM). Finally, it has been defined the features layout of using multi-nanoparticles that are enhancing multi-disciplinary properties of polyvinyl chloride as power cables insulation.

This paper focuses on the development of polyvinylidene fluoride microfoam by implementing a chemical blowing agent through a continuous process. The objective was to investigate the effects caused by varying concentrations of chemical blowing agent, the use of a master batch as formulation variables, and variation of die temperature on the properties of polyvinylidene fluoride foam produced continuously. By using a 10% master batch formulation (contains 2% chemical blowing agent in final product), the cell density was increased while the cell size and foam density were decreased; the average cell size, cell density, and void fraction were found to be 50 μm, 7.7 × 10⁶ cells/cm³, and 33%, respectively. This is due to the increased cell density primarily due to the increased nucleation sites. At a lower chemical blowing agent, concentration of 1%, the die temperature was varied over a range of 125-145 °C, as this is approximately the melting point of the polyvinylidene fluoride. Decreasing the die temperature from 135 °C to 130 °C caused the cell density to increase and cell size to decrease, while void fraction decreased from 58% to 39%. This is due to the loss of melt strength upon increasing the temperature of the melt PVDF as it exits the die.