Recyclability of Photoinduced Cross-Linked EPM Rubber with Anthracene-Grafted Groups:Problems and Their Solutions

In this paper, we present the formation of reversible covalently cross-linked networks in ethylene propylene rubber with grafted anthracene groups (EPM-g-AN) based on the principles of photoinduced anthracene dimerization. First, an industrial-grade EPM rubber grafted with maleic anhydride functional groups (EPM-g-MA) was modified with 9-anthracenemethanol. By irradiating EPM-g-AN with UV light (365 nm), the anthracene moieties dimerize via [4 + 4]cycloaddition, forming a covalent network. The network cleavage proceeds at high temperatures (>170 °C), even if with considerable (chemical) degradation. Furthermore, one of the degradation routes has been identified by 1H NMR to occur via the ester bond cleavage releasing 9-anthracenemethanol. Nevertheless, the reversibility of cross-linking has been achieved by performing the reverse reaction in decalin. The UV-vis spectroscopy clearly shows that the de-cross-linking process in these conditions is due to the anthracene dimer cleavage. Although the recovery in mechanical properties upon recycling is yet to be optimized, the disclosed results pave the way toward the use of anthracene chemistry in thermally reversible networks with possible industrial perspective applications

Automate the trading activities of a bookstore as a business process improvement factor

This article presents a project of a bookstore information system, the main purpose of which is to automate the trading activities of a bookstore, work with reports on sales and purchases. The purpose of creating the system is: to increase the number of clients served per unit of time due to the automatic generation of checks and invoices; reducing the time for processing and processing orders, searching for the necessary information about the product and generating invoices by storing and systematizing data in electronic form; reduction of costs and time for registration of deliveries of goods due to partial auto-completion of documents

Maleimide Self-Reaction in Furan/Maleimide-Based Reversibly Crosslinked Polyketones:Processing Limitation or Potential Advantage?

Polymers crosslinked via furan/maleimide thermo-reversible chemistry have been extensively explored as reprocessable and self-healing thermosets and elastomers. For such applications, it is important that the thermo-reversible features are reproducible after many reprocessing and healing cycles. Therefore, side reactions are undesirable. However, we have noticed irreversible changes in the mechanical properties of such materials when exposing them to temperatures around 150 °C. In this work, we study whether these changes are due to the self-reaction of maleimide moieties that may take place at this rather low temperature. In order to do so, we prepared a furan-grafted polyketone crosslinked with the commonly used aromatic bismaleimide (1,1′-(methylenedi-4,1-phenylene)bismaleimide), and exposed it to isothermal treatments at 150 °C. The changes in the chemistry and thermo-mechanical properties were mainly studied by infrared spectroscopy, 1H-NMR, and rheology. Our results indicate that maleimide self-reaction does take place in the studied polymer system. This finding comes along with limitations over the reprocessing and self-healing procedures for furan/maleimide-based reversibly crosslinked polymers that present their softening (decrosslinking) point at relatively high temperatures. On the other hand, the side reaction can also be used to tune the properties of such polymer products via in situ thermal treatments

Polymerization of the new double-charged monomer bis-1,3(N,N,N trimethylammonium dicyanamide)-2-propylmethacrylate and ionic conductivity of the novel polyelectrolytes

The achievement of high ionic conductivity in single-ion conducting polymer electrolytes is one of the important aims for various electrochemical devices including modern lithium batteries. One way to enhance the ionic conductivity in polyelectrolyte systems is to increase the quantity of charge carriers in each monomer unit. Highly charged poly(bis-1,3(N,N,N-trimethylammonium)-2-propylmethacrylate) with one of the most conducting anions, namely dicyanamide, was prepared via free radical bulk polymerization or using ionic liquids as reaction medium. The cationic polymers of the double-charged monomer have molar masses up to equation image = 1,830,000 g/mol and the ionic conductivity equal to 5.51 × 10−5 S/cm at 25°C. The film forming ability, crystallinity, thermal stability, and glass transition temperatures of the new polymeric ionic liquids obtained from detailed studies are presente

Recycling behavior of thermoreversibly Diels-Alder crosslinked EPM

The recyclability of thermoreversibly Diels-Alder (DA) crosslinked EPM has been studied. The retro DA reaction dominates over the dehydration-aromatization process of theDAadduct. Moreover, a negative influence of air occurred as a result of a crosslinking in air flow. Nevertheless, rubber compounds prepared from EPM-g-furan and carbon black can be recycled several times without losing mechanical strength, a feature attributed to a strong antioxidant effect of the carbon black

Automate the trading activities of a bookstore as a business process improvement factor

This article presents a project of a bookstore information system, the main purpose of which is to automate the trading activities of a bookstore, work with reports on sales and purchases. The purpose of creating the system is: to increase the number of clients served per unit of time due to the automatic generation of checks and invoices; reducing the time for processing and processing orders, searching for the necessary information about the product and generating invoices by storing and systematizing data in electronic form; reduction of costs and time for registration of deliveries of goods due to partial auto-completion of documents