Chemical recycling of crosslinked poly(methyl methacrylate) and characterization of polymers produced with the recycled monomer

Braido, Rayany Stôcco; Borges, Luiz Eduardo Pizarro; Pinto, José Carlos

doi:10.1016/j.jaap.2018.03.017

Cited by 33 publications

(30 citation statements)

References 13 publications

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“…Figure 4 shows that addition of PZQ exerts low influence on the final particle size distributions, which became slightly wider with smaller shoulders placed at larger sizes. This behavior is probably due to the increase of the viscosity of the organic phase when PZQ is added, which affects the rates of breakage and coalescence of the particles. Similar behavior was reported by Paiva et al and Oliveira et al, when PZQ and doxorubicin were incorporated into microparticles through suspension polymerizations of MMA and suspension copolymerizations of vinyl acetate and MMA, respectively.…”

Section: Resultsmentioning

confidence: 99%

Development of Smart Polymer Microparticles through Suspension Polymerization for Treatment of Schistosomiasis

Paiva

Alves

Melo

et al. 2019

Macro Reaction Engineering

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Schistosomiasis is a parasitic disease that affects millions of people, especially low‐income people, and is considered a major public health problem in underdeveloped countries. The drug used most often for the treatment of the disease is praziquantel (PZQ), which has a strong and characteristic bitter taste that makes treatment of children inconvenient. For this reason, the present work investigates the development of smart pH‐sensitive polymer microparticles produced through suspension polymerizations to be used as vehicles for the controlled release of praziquantel in the body. The microparticles are produced through copolymerization of methyl methacrylate and the cationic comonomers diethylaminoethyl methacrylate or dimethylaminoethyl methacrylate. The obtained results indicate that microparticles with sizes in the range of 10–1100 µm can be formed successfully, allowing high PZQ encapsulation efficiencies (>80%). Zeta potential analyses and drug release assays confirm the pH‐sensitive responses of the cationic copolymers, leading to effective release of PZQ (around 80% in pH 1.2) in acidic media that simulate the organic fluids present in the stomach.

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Section: Resultsmentioning

confidence: 99%

Development of Smart Polymer Microparticles through Suspension Polymerization for Treatment of Schistosomiasis

Paiva

Alves

Melo

et al. 2019

Macro Reaction Engineering

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“…The PMMA waste samples contained 1 wt.% of titanium oxide (TiO2) and around 5 wt.% of the cross-linking agent ethylene glycol dimethacrylate (EGDMA), as described elsewhere [17].…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, mass conversions reported by Braido et al (2018) [17], who investigated the thermal pyrolysis of EGDMA crosslinked PMMA dental waste at isothermal conditions using a larger scale of 30 g, were further used to assess the system behaviour. Table 3.…”

Section: Simulation and Model Validationmentioning

confidence: 99%

“…The recycling of PMMA waste has been assessed by different methods, including its direct reuse in the production of new polymers [13] and asphalt mixtures [14], and its mechanical [9,15,16] and chemical [9,11,[17][18][19] recycling. Whereas the direct reuse of PMMA waste usually requires clean and uncontaminated streams, its mechanical recycling may allow for the processing of waste streams containing other types of plastics, however it usually results in polymers with inferior properties [8,15].…”

Section: Introductionmentioning

confidence: 99%

“…Whereas the direct reuse of PMMA waste usually requires clean and uncontaminated streams, its mechanical recycling may allow for the processing of waste streams containing other types of plastics, however it usually results in polymers with inferior properties [8,15]. In contrast, the chemical recycling of PMMA by thermal pyrolysis has demonstrated great potential for the recovery of the methyl methacrylate (MMA) monomer [11,[17][18][19], which can be further polymerised to result in polymer resins presenting comparable properties to those obtained by using virgin and non-recycled monomer [17,18]. Additionally, the PMMA pyrolysis can be suggested as a robust process, as impurities, such as different resins, can be separated in the MMA purification step by distillation [17] and have been reported to result in no significant impact on the MMA recovery yield [9].…”

Section: Introductionmentioning

confidence: 99%

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Modelling the chemical recycling of crosslinked poly (methyl methacrylate): Kinetics of depolymerisation

Ros

Braido

Castro

et al. 2019

Journal of Analytical and Applied Pyrolysis

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Whereas increasing plastic solid waste production constitutes one of the main challenges of modern society, mainly due to the lack of suitable recycling technologies, chemical recycling represents an attractive solution for the conversion of plastic solid waste into valuable chemical intermediates. Herein, a kinetic model for the pyrolysis of a dental industry waste, ethylene glycol dimethacrylate (EGDMA) crosslinked poly (methyl methacrylate) (PMMA), is presented for the first time. Kinetics parameters and their statistical significance have been estimated from eight non-isothermal thermogravimetric analysis (TGA) experiments with heating rates varying between 5 and 50 °C•min-1 by using nonlinear regression. Our analysis indicates that the mechanism of depolymerisation of EGDMA crosslinked PMMA is likely to involve a consecutive reaction pathway involving two steps. The developed kinetic modelcontaining five kinetic parameters only-was able to predict well all non-isothermal TGA runs, and was validated against isothermal TGA experiments at 400 °C.

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Flame retardancy of polyurethane foams prepared from green polyols with flame retardants

Lee

Jung

2021

J of Applied Polymer Sci

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Polyurethane foams (PUFs) were synthesized using bis(2-hydroxyethylene terephthalate) (BHET), 1,4-cyclohexanedimethanol (CHDM), and polycaprolactone diol (PCLD), and their flame retardancies were investigated. BHET and CHDM are eco-friendly chemicals derived from waste polyethylene terephthalate, and PCLD is a precursor monomer used for synthesizing biodegradable polymers. Expandable graphite (EG) and tris(1-chloro-2-isopropyl) phosphate (TCPP) were used as flame retardants. For conventional PUFs prepared with an aliphatic polyol, thermal stability was significantly enhanced with EG and TCPP through thermogravimetric analysis (TGA) and microcombustion calorimetry (MCC). PUFs prepared with BHET and CHDM exhibited higher thermal stability than conventional PUFs. This is attributed to the alicyclic and aromatic ring structures, which contribute to thermally stable char formation during pyrolysis. PCLD was introduced as an additional polyol, as well as a possible flame retardant, without the addition of EG and TCPP. PUFs were successfully prepared and exhibited improved resilience to burning up to 300 C due to the intrinsic thermal stability of PCLD. The limiting oxygen index (LOI) indicated that PUFs containing BHET moiety exhibited higher LOI values, whereas PUFs prepared with PCLD showed the lowest LOI value. PCLD can be used as a polyol; however, additional flame retardants are needed to obtain high flame retardancy for PUFs.

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Chemical recycling of crosslinked poly(methyl methacrylate) and characterization of polymers produced with the recycled monomer

Cited by 33 publications

References 13 publications

Development of Smart Polymer Microparticles through Suspension Polymerization for Treatment of Schistosomiasis

Development of Smart Polymer Microparticles through Suspension Polymerization for Treatment of Schistosomiasis

Modelling the chemical recycling of crosslinked poly (methyl methacrylate): Kinetics of depolymerisation

Flame retardancy of polyurethane foams prepared from green polyols with flame retardants

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