1,634 research outputs found
A QM approach for the calculation of reactivity ratios in free-radical copolymerization
No full textAll previously published results in the field of predicting copolymer reactivity and composition
are collected, along with new, recently determined parameters. The copolymerizations
of a variety of monomers, including styrene, acrylates, methacrylates and vinyl acetate, are
investigated. In particular, the monomer and radical reactivity ratios for ST/HEMA, ST/GMA,
ST/BMA, ST/HEA, MMA/VAc, ST/MMA, and ST/EA are calculated. Good agreement between the
computational and experimental results is obtained for comparisons of the determined
parameters with the experimental data available in the literature. In addition, some of the
computed reactivity ratios are determined
in this work for the first time, and they can
be used as an initial guess for future experiments
Preface (Towards Circular Economy: Closing the Loop with Chemical Recycling of Solid Plastic Waste; Advances in Chemical Engineering, V. 60, 2022)
No full textPROCESSO DI DEPOLIMERIZZAZIONE DEL PET PROVENIENTE DA SCARTI DI BOTTIGLIE E DI MATERIALE TESSILE.
No full textProcesso di depolimerizzazione del PET di scarto puro proveniente da bottiglie in forma
di scaglie o da materiale tessile in forma di fibre contenente PET in quantitativi di almeno
l’80-85% mediante glicolisi con un glicole etilenico scelto tra etilen glicole,
5 dietilenglicole e/o trietilen glicole a temperature inferiori o uguali a 270°C in un unico
stadio a) in cui l’alimentazione prevede le seguenti fasi:
a1) si aggiungono i reagenti in modalità batch con eccesso di glicole etilenico rispetto al
PET per garantire la completa bagnabilità del PET,
a2) quando la frazione solida è completamente depolimerizzata, si aggiunge in modalità
10 semi batch il PET in modo da garantire un completo bagnamento nel glicole etilenico nel
BHET formato e negli oligomeri formati sino ad ottenere un rapporto molare prefissato
di glicole etilenico/ PET compreso tra 0 e 1,5, preferibilmente tra 0,1 e 1,5;
a3) al termine della fase a2) si aggiunge secondo modalità CSTR il PET ed eventualmente
il glicole etilenico nel suddetto rapporto molare compreso tra 0 e 1,5 preferibilmente tra
15 0,1 e 1,5 per ottenere prodotti oligomerici con distribuzione unimodale aventi peso
molecolare medio compreso tra 500 e 5000 Da nel caso il materiale di scarto provenga
da bottiglie oppure compreso tra 300 e 450 Da, nel caso il PET provenga da materiali
tessili di scarto
Synthesis of Polyalkylcyanoacrylates as Biodegradable Polymers for Drug Delivery Applications
No full textRelevance of backbiting and beta-scission reactions in the free radical polymerization of Acrylonitrile
No full textBioresorbable polymer nanoparticles in the medical and pharmaceutical fields: A promising field
No full textIn the last decades, a wide variety of nanoparticles (NPs) has been developed, aiming at sensible pharmaceutical and biomedical applications such as imaging and tumor treatment. Among these nanosized systems, a relevant role is played by polymer NPs. This is mainly due to the versatility of the polymer chemistry, that allows obtaining very complex structures specifically tuned for the purpose that they are projected for. However, polymer NPs have to face many hurdles before entering the clinical phase. First of all, the biocompatibility must be granted for all the employed materials. Further, the polymer matrix should be completely biodegradable, in order to grant the bioresorbability and, at the same time, to avoid the polymer accumulation inside the cells and the bloodstream. These requirements are completely fulfilled by the polyesters. In this chapter, a detailed review of the main techniques to produce bioresorbable polyester-based NPs is presented, together with a panorama about the possible applications and the hurdles this systems have to face before entering a clinical application
A quantum chemistry study of the free-radical copolymerization propagation kinetics of styrene and 2-hydroxyethyl acrylate
No full text- …
