“…Moreover, they attributed the reduction in stiffness to the changes in crystallization behavior due to maleic anhydride. Elnahas et al [ 94 ] reported the linear decrease in LDPE material’s stiffness with the increasing paraffin content. For 2 wt % addition, Young’s modulus was reduced by 5%, which was attributed to the presence of relatively short hydrocarbon chains compared to the structure of polyethylene.…”
The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.
“…Moreover, they attributed the reduction in stiffness to the changes in crystallization behavior due to maleic anhydride. Elnahas et al [ 94 ] reported the linear decrease in LDPE material’s stiffness with the increasing paraffin content. For 2 wt % addition, Young’s modulus was reduced by 5%, which was attributed to the presence of relatively short hydrocarbon chains compared to the structure of polyethylene.…”
The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.
“…This behavior was also presented in other past works where they have studied composites with a polymeric matrix and wax addition. In a low-density polyethylene (LDPE) matrix, the hardness of the pure material was 55 Shore A, and decreased to 51 Shore A when 2% of paraffin was added [56].…”
Polydimethylsiloxane (PDMS) is a polymer that has attracted the attention of researchers due to its unique properties such as transparency, biocompatibility, high flexibility, and physical and chemical stability. In addition, PDMS modification and combination with other materials can expand its range of applications. For instance, the ability to perform superhydrophobic coating allows for the manufacture of lenses. However, many of these processes are complex and expensive. One of the most promising modifications, which consists of the development of an interchangeable coating, capable of changing its optical characteristics according to some stimuli, has been underexplored. Thus, we report an experimental study of the mechanical and optical properties and wettability of pure PDMS and of two PDMS composites with the addition of 1% paraffin or beeswax using a gravity casting process. The composites’ tensile strength and hardness were lower when compared with pure PDMS. However, the contact angle was increased, reaching the highest values when using the paraffin additive. Additionally, these composites have shown interesting results for the spectrophotometry tests, i.e., the material changed its optical characteristics when heated, going from opaque at room temperature to transparent, with transmittance around 75%, at 70 °C. As a result, these materials have great potential for use in smart devices, such as sensors, due to its ability to change its transparency at high temperatures.
“…It can be hypothesized that at this level, phase separation occurs such as it has been seen in literature. 39 G’ and G’’ curves shifted to higher frequency, as expected for lower Mw grade.Figure 11.Storage (a, c, and e) and loss (b, d, and f) moduli versus frequency for the blended LDPE, LLDPE, and EVA-15 (master curves for bold-italicT0 = 150°C).…”
For amorphous polymers, restoring forces are generated by the progressive orientation of the macromolecular chains in the stretching direction leading to a decrease in the system entropy. Orienting the chains in the future stretching direction thus reduces the entropy variation induced by the stretching and limits the entropic restoring force magnitude. Entropic restoring forces created during stretching have been correlated to the number of junction points by previous studies. Reducing the entanglement density (i.e., the number of junction points) is supposed to limit the entropic restoring force magnitude. In this study, the influence of blend ratio of low molecular weight wax and orientation level on the mechanical properties of the thin films, especially the elastic recovery, were evaluated. Elastic energy strain recovery was calculated from hysteresis curve obtained during 60% loading (stretch) and unloading (recovery) cycle and compared to rheological and orientation measurement. It has been shown that a decrease in entanglement density can minimize elastic recovery, Nevertheless, a compromise must be found, in order to limit the permanent deformation caused by chain flow. Macromolecular orientation is also a way to adjust the film mechanical properties. A LDPE 3 × 3 biaxial orientation leads to a 25% reduction in transversal direction elastic recovery (compared to MDO cast film) without altering machine direction mechanical behavior. However, for ethylene vinyl acetate, the uniaxial macromolecular orientation seems to impact the film behavior in the transverse direction by causing a smaller inter-atom distance, favoring a higher bond strength. The latter acts as transient physical nodes, increasing entropic restoring forces.
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