1,721,012 research outputs found
Recovery of Rose Flower Waste to Formulate Eco-Friendly Biopolymer Packaging Films
Full text linkConsidering the circular principles of materials and investigating the possibility to use waste materials before their final disposal, in this work, dry rose flower (DRF) and rose flower waste (RFW), after oil extraction, have been considered as suitable materials for the formulation of biopolymer packaging films. Both DRF and RFW particles have been characterized by spectroscopy analysis, and their radical scavenger ability has been investigated. Moreover, DRF and RFW particles have been added by melt mixing to PolyLactic Acid (PLA), and formulated PLA-based films have been studied through rheology analysis, mechanical test, differential scanning calorimetry, and microscopy observations. Finally, the influence of both DRF and RFW particles on the photo-oxidation behavior of PLA has been evaluated by subjecting thin films to UVB exposure, and the progress of degradation has been monitored following the accumulations of oxygen-containing groups in time. Obtained results suggest that both DRF and RFW have a beneficial effect on the photo-oxidation behavior of PLA, and they can slow down PLA degradation upon UVB exposure. Therefore, PLA-based composite materials could be considered a good candidate for applications as packaging films
Encapsulant Materials and Their Adoption in Photovoltaic Modules: A Brief Review
Full text linkIn the last two decades, the continuous, ever-growing demand for energy has driven significant development in the production of photovoltaic (PV) modules. A critical issue in the module design process is the adoption of suitable encapsulant materials and technologies for cell embedding. Adopted encapsulants have a significant impact on module efficiency, stability, and reliability. In addition, to ensure the unchanged performance of PV modules in time, the encapsulant materials must be selected properly. The selection of encapsulant materials must maintain a good balance between the encapsulant performance in time and costs, related to materials production and technologies for cells embedding. However, the encapsulants must ensure excellent isolation of active photovoltaic elements from the environment, preserving the PV cells against humidity, oxygen, and accidental damage that may compromise the PV module's function. This review provides an overview of different encapsulant materials, their main advantages and disadvantages in adoption for PV production, and, in relation to encapsulant technologies used for cell embedding, additives and the interaction of these materials with other PV components
Biopolyester-based systems containing naturally occurring compounds with enhanced thermo-oxidative stability
No full textThis work presents a sustainable approach for the stabilization of polylactic acid (PLA) against thermo-oxidative aging
On the role of multi-functional polyhedral oligomeric silsesquioxane in polystyrene-zinc oxide nanocomposites
No full textMulti-functional trisilanol phenyl (TSPH) and trisilanol isobutyl (TSIB) polyhedral oligomeric silsesquioxane (POSS) have been used in the formulation of advanced polystyrene (PS)-zinc oxide (ZnO) nanocomposites. The neat matrix and PS/ZnO-based nanocomposites have been characterized through rheological, morphological, mechanical, and dynamic thermo-mechanical analysis. Both TSPH and TSIB are able to improve the dispersion of ZnO into the polystyrene matrix; furthermore, adding TSIB leads to better results because it facilitates better solubility into the PS matrix and interaction/reaction with the ZnO nanopowder. Finally, the optical properties and photo-oxidative resistance of the nanocomposite films have been evaluated. The POSS molecules synergistically interact with ZnO nanopowder in the protection of PS matrix against photo-oxidative process. The nanocomposite films containing both ZnO and POSS molecules, particularly TSIB, exhibit better UV-shielding properties than the PS/ZnO one, without loss of optical transparency
Improvement of the photo-stability of polystyrene-block-polybutadiene-block-polystyrene through carbon nanotubes
No full textThe photo-stability of Polystyrene-Polybutadiene-Polystyrene (SBS) based nanocomposites containing bare multi-walled carbon nanotubes (CNTs) and carbon nanotubes bearing carboxylic functional groups (CNTs-COOH) in comparison to that of pristine SBS has been studied. The photo-oxidation of pristine SBS occurs through crosslinking reactions and oxidized species formation and both these processes begin at early stage of exposure. The formation of crosslinking, formerly in polybutadiene phase, assessed by spectroscopical (FTIR), mechanical, dynamic mechanical and rheological analysis, leads to occurrence of internal mechanical stresses in the solid state and the SBS samples become prematurely unable to stretch. SBS-based nanocomposites showed a significant improved photo-stability to the respect to pristine matrix, due to the presence of CNTs and even more, of CNTs-COOH, that are able to protect efficiently SBS against UVB exposure. All obtained results suggest that the used nanotubes are able to delay the degradation process because of their acceptor-like electron properties and their ability to shield UV-light. Besides, the CNTs act as radical traps, hindering the crosslinking and slowing down the oxidation process. The presence of carboxylic functional groups onto CNTs outer surface enhances the protection ability of CNTs due to the presence of a larger amount of surface defects, that improves their radical scavenging activity
Recycled (Bio)Plastics and (Bio)Plastic Composites: A Trade Opportunity in a Green Future
Full text linkToday’s world is at the point where almost everyone realizes the usefulness of going green. Due to so‐called global warming, there is an urgent need to find solutions to help the Earth and move towards a green future. Many worldwide events are focusing on the global technologies in plastics, bioplastic production, the recycling industry, and waste management where the goal is to turn plastic waste into a trade opportunity among the industrialists and manufacturers. The present work aims to review the recycling process via analyzing the recycling of thermoplastic, thermoset polymers, biopolymers, and their complex composite systems, such as fiber‐reinforced polymers and nanocomposites. Moreover, it will be highlighted how the frame of the waste management, increasing the materials specificity, cleanliness, and a low level of collected material contamination will increase the potential recycling of plastics and bioplastics‐based materials. At the same time, to have a real and approachable trade opportunity in recycling, it needs to implement an integrated single market for secondary raw materials
High-performance thermoplastic elastomers/carbon nanotubes nanocomposites: Mechanical behavior, rheology, and durability
No full textAdvanced polystyrene-b-polybutadiene-b-polystyrene (SBS) based nanocomposites containing bare carbon nanotubes (CNTs) and CNTs bearing hydroxyl functional groups (CNTs-OH) have been formulated and fully characterized. In particular, the reinforcement effect of CNTs and CNTs-OH on SBS was deeply investigated through mechanical and dynamical thermo-mechanical analysis and the rheological response of SBS-based nanocomposites was investigated and discussed. The mechanical properties of SBS/CNTs and even more of SBS/CNTs-OH nanocomposites are substantially superior to those of neat SBS, due to the uniformly dispersed nanofillers throughout the polymeric matrix. The presence of -OH groups onto CNTs promotes the stress transfer from polymer to CNTs, strengthening the overall performance of the nanocomposite. Moreover, the durability of SBS-based nanocomposites was monitored through mechanical, dynamic mechanical, and rheological analysis. SBS-based nanocomposites showed a significant improved photo-stability with respect to the neat matrix, due to the presence of CNTs that are able to stabilize efficiently SBS because of their acceptor-like electron properties. The presence of -OH groups onto CNTs enhance the protection ability of CNTs due to the larger amount of surface defects, that improves their radical scavenging activity. Furthermore, CNTs-OH can act as chain-breaking electron donor, becoming responsible for radical termination during SBS degradation. POLYM. COMPOS., 38:E381âE391, 2017. © 2015 Society of Plastics Engineers
Double bond-functionalized POSS: dispersion and crosslinking in polyethylene-based hybrid obtained by reactive processing
No full textPolyethylene-based organic inorganic hybrids were prepared by one-step reactive melt mixing using a mono-functionalized nanofiller, i.e., allyl-heptaisobutyl-substituted polyhedral oligomeric silsesquioxane (1POSS) and a multi-functionalized octavinyl polyhedral oligomeric silsesquioxane (8POSS). The hybrids were also prepared in dicumyl peroxide (DCP) presence and morphological, spectroscopical and calorimetric analysis were carried out. Moreover, rheological measurement and Sohxlet extraction were performed on investigated samples. It was inferred that double bonds of POSS functional groups were triggered by radicals coming from the peroxide decomposition or from the degradation reactions occurring during preparation. The type of the functional groups (mono- or multi-reactive) of the POSS is a leading factor, along with radicals content in the systems, in the formation of a polymeric network. In particular, the presence of multi-reactive groups in 8POSS molecules results in a successful POSS grafting/crosslinking in the polymeric backbone: the covalent bonds formation between nanofillers and matrix during processing improves POSS dispersion within the polyolefin matrix and leads to a network structure formation
Rheological Percolation Threshold in High-Viscosity Polymer/CNTs Nanocomposites
No full textPolystyrene (PS)/multi-walled carbon nanotubes (CNT) nanocomposites have been prepared through melt mixing processing
aiming at obtaining a uniform and homogeneous dispersion of the used nanoparticles within the polymeric matrix. Optical and scanning
electron microscopy has been employed to determine the dispersion and distribution of CNTs at different length scales. Furthermore, the
linear viscoelastic behavior of formulated nanocomposites has been deeply investigated. As a result of CNTs added, the nanocomposites
experience a transition from liquid-like to solid-like rheological behavior, and a disappearance of relaxation processes at low frequency can be
noticed. By plotting G’ versus CNTs loading and fitting with a power-law function, the rheological threshold of PS-based nanocomposites has
been calculated. Moreover, the mechanical behavior of nanocomposites has been investigated and related to the formed CNTs network within
polymer matrix
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