Search

Combined with the Serial Rubber Continuous Mixing Device (SRCMD) and custom-built rotors, the real continuous regeneration of waste rubber was realized. The upstream mixer effectively solves the problem of pretreatment of waste rubber and realizes its preliminary regeneration. The downstream twin-screw extruder realizes supplementary regeneration and plasticized extrusion of waste rubber. The optimal process parameters for preparing SRCMD-reclaimed rubber were explored through orthogonal experiments. Compared to the commercially-reclaimed rubber produced by the traditional vulcanization tank high-temperature regeneration method, the SRCMD-reclaimed rubber well retains the main chain structure of waste rubber and has obvious advantages in various properties. The conveyor belt coverings made by partially replacing styrene butadiene rubber with SRCMD-reclaimed rubber fully meet the requirements of the national standard in all properties and are better than commercially-reclaimed rubber, which has good application prospects and provides a guide for promoting the industrial transformation of recycled rubber. KEYWORDS continuous regeneration, conveyor belt, reclaimed rubber, waste rubber, 1 | INTRODUCTION With the rapid development of the automobile industry, the consumption of tires is increasing year by year. According to relevant reports, as many as hundreds of millions [...]

The rapid advances in photochromic devices have spurred great enthusiasm in the design and preparation of luminescent materials. It is an efficient and facile strategy to incorporate ZnS-based phosphors into crosslinking polymer substrates, obtaining photochromic materials with excellent comprehensive properties. However, crosslinking polymeric ZnS-based phosphor luminous materials are unable to be recycled and reprocess at the end of service, limiting their long-term utilization and burdening the environment. Besides, few reported works have explored photoluminescent properties of samples during multiple reprocessing and recycling. Herein, enlightened by the intriguing dynamic covalent crosslinking technology, recyclable and photoluminescent elastomers, employed polymeric flexible matrixes with dynamic covalent joints integrated with ZnS:Cu and ZnS:Cu,[M.sub.n] phosphors, were prepared in this work. Due to the breakage and reformation of exchangeable crosslinking connections and intensive interfacial interactions between polar elastomeric matrixes and luminophores, the original and recycled composites exhibit excellent recyclable, photoluminescent, and mechanical properties. We anticipate that the strategy of this work, inserted phosphors into dynamic crosslinking polymer matrixes with a facile fabrication process, paves the way for the recycling and long-term utilization of photoluminescent materials. KEYWORDS composites, elastomers, luminescence, recycling, 1 | INTRODUCTION Luminescent materials, under proper external stimuli, exhibit photoluminescent, electroluminescent, and mechano-luminescent properties, [1-6] extensively applied in display, sensing, anticounterfeiting, bioimaging, and biological probes. [7-11] Three types of [...]

Owing to its biosynthetic and biodegradable properties, polylactic acid (PLA) is considered to be a most promising biopolymer that could play a crucial role as a potentially environmentally friendly material for a sustainable bioeconomy. However, its long-life cycle indicates that it cannot be easily degraded in nature. Therefore, understanding the biodegradation mechanism of PLA is important for reducing the impacts of waste plastic and waste disposal. With the recent development of molecular biology techniques, some studies have confirmed that specific groups of microorganisms can facilitate the biodegradation of PLA. Here, recent advances in the biodegradation of PLA (i.e., microbial and enzymatic degradation) and key factors affecting the degradation efficiency were reviewed. In addition, compared with complete degradation through mineralization, upcycling is also proposed as a more recyclable strategy for disposing of waste plastics. Key words: PLA, biodegradation, microorganisms, enzymes, upcycling. En raison de son caractere biosynthetique et biodegradable, l'acide polylactique (PLA) est considere comme le biopolymere le plus prometteur parmi toutes les matieres plastiques, qui jouera un role cle en tant que materiau potentiellement ecologique dans une bioeconomie durable. Toutefois, son long cycle de vie indique qu'il ne peut pas etre facilement degrade dans la nature. Il est donc important de comprendre le mecanisme de biodegradation du PLA pour reduire les impacts des dechets plastiques. Avec le developpement recent des techniques de biologie moleculaire, certaines etudes ont confirme que des groupes specifiques de micro-organismes peuvent favoriser le processus de biodegradation du PLA. Dans cet article de synthese, les progres recents dans la biodegradation du PLA (c'est-a-dire la degradation microbienne et enzymatique) et les facteurs cles affectant l'efficacite de la degradation ont ete examines. En outre, par rapport a la degradation complete par mineralisation, le recyclage valorisant est aussi propose comme meilleure strategie de recyclage pour eliminer les dechets plastiques. [Traduit par la Redaction] Mots-cles : PLA, biodegradation, micro-organismes, enzymes, recyclage valorisant., Introduction Owing to the increased global population and considerable resource consumption, significant increases in environmental pollution and waste accumulation have occurred. Plastics have ushered in a new era for daily [...]

The objective of the article was to enhance the recycling value of solid waste rubber by surface functionalization of desulfurized rubber powder using a one-pot method based on free-radical polymerization theory. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscopy, and elemental analysis were used to characterize the maleic anhydride-grafted desulfurized rubber powder, and the grafting mechanism was also investigated. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that maleic anhydride was grafted onto the desulfurized rubber powder. Thermogravimetric analysis indicated that the maleic anhydride-grafted desulfurized rubber powder and desulfurized rubber powder possessed different thermal properties and structure. The results of scanning electron microscopy and elemental analysis illustrated that the surface of the desulfurized rubber powder was covered with a layer of fold-like maleic anhydride polymer. The mechanism of grafting desulfurized rubber powder with maleic anhydride may be achieved by replacing the active [alpha]-H on the methylene group of the desulfurized rubber macromolecule chain. KEYWORDS desulfurized rubber powder, free-radical polymerization, maleic anhydride, mechanism, 1 | INTRODUCTION With the rapid development of the automotive industry, tires are widely put into service as high-quality products that can fulfill all safety requirements. However, the tire with [...]

Micro-damage in materials could be repaired by endowing materials with self-healing performance. Herein, an epoxy resin with excellent self-healing performance grounded on thermo-reversible Diels-Alder dynamic chemical reaction was developed. Results showed that the bending strength and adhesive behavior of epoxy resin were influenced dramatically upon treatment with various temperatures. More importantly, damages created in epoxy resin could be repaired completely after suitable heat treatments. What is more, the healed epoxy resin exhibited much higher bending strength and adhesive performance than the pristine one did. The materials could be damaged and then repaired repeatedly. Meanwhile, the as-prepared self-healing epoxy resin exhibited excellent thermal reversibility and controllable adhesion. The thermo-adjusted self-healing performance endowed epoxy resin with recyclable and reusable performance. Therefore, the research made it possible of recycling waste epoxy resins. KEYWORDS adhesive, bending strength, dynamic chemical reaction, epoxy resin, self-healing, 1 | INTRODUCTION Epoxy resin is widely used in construction, mechanics, transportation, and other fields due to its excellent mechanical property, chemical stability, adhesive performance, and low shrinkage. [1-5] However, [...]

ABSTRACT The reuse of comminuted glass-fiber-reinforced resin with various granularities gathered from printed circuit manufacturing residues was investigated. As fillers, these residues were converted into polymeric composite board by an [...]

In this study, refuse excavated from a typical refuse landfill in Shanghai after 8-10 years of placement was characterized in terms of particle size, total nitrogen, total phosphorus, and biodegradable [...]