Investigation of poly(α-methyl styrene) tacticity synthesized by photo-polymerization

Jozaghkar, Mohammad Reza; Ziaee, Farshid; Azar, Amir Sepehrian

doi:10.1007/s00289-020-03381-3

Cited by 6 publications

(11 citation statements)

References 26 publications

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“…48,52,53 These alkylations are usually carried out in the presence of mineral acids such as H 2 SO 4 , HF, and H 3 PO 4 , Lewis acids such as AlCl 3 and BF 3 , or solid acids such as zeolites, clays, and sulfonic ion-exchange resins. 47,48,54 In the current study, different isomers of the 9-carbon alkylated benzenes (C 15 H 24 ) seemed to form. Lachter et al 49 explained the formation of ortho, para, and meta variants of 2-, 3-, 4-octyl-toluene isomers (C 15 H 24 ) in the reaction of toluene with OCT using a carbocation mechanism.…”

Section: Energy and Fuelsmentioning

confidence: 52%

“…The tendency for AMS to predominantly homopolymerize via cationic pathways is also supported by the literature, in which it is well established that AMS shows weak polymerization phenomena by free radical mechanisms. 37,47 The slow rate and poor yields in the free radical polymerization of AMS in the previous studies were attributed to the low ceiling temperature (61 °C) of AMS, above which depropagation (the release of the monomer) would become more pronounced. 37,44,47 Hence, homopolymerization of AMS is usually carried out through ionic polymerization.…”

Section: Energy and Fuelsmentioning

confidence: 99%

“…37,47 The slow rate and poor yields in the free radical polymerization of AMS in the previous studies were attributed to the low ceiling temperature (61 °C) of AMS, above which depropagation (the release of the monomer) would become more pronounced. 37,44,47 Hence, homopolymerization of AMS is usually carried out through ionic polymerization. 47 Further, in Table 8, the comparison of the peak areas of D 1 and D 2 in the reactions containing the same type of mineral (kaolinite or illite) indicates that the addition of pyridine influenced the dimer selectivity.…”

Section: Energy and Fuelsmentioning

confidence: 99%

“…37,44,47 Hence, homopolymerization of AMS is usually carried out through ionic polymerization. 47 Further, in Table 8, the comparison of the peak areas of D 1 and D 2 in the reactions containing the same type of mineral (kaolinite or illite) indicates that the addition of pyridine influenced the dimer selectivity. Suppression of D 1 relative to D 2 upon addition of pyridine could suggest that the acidcatalyzed double bond isomerization of D 2 to D 1 , originally promoted by the acid sites in solids in the reactions AMS + T + K and AMS + T + I was suppressed by the addition of pyridine.…”

Section: Energy and Fuelsmentioning

confidence: 99%

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Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Turuga

Klerk

2022

Energy Fuels

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Following previous evidence that hydrothermal treatment of bitumen froth does not lead to bitumen upgrading at 250 °C and promotes viscosity increase, the current study explores the free radical and cationic reactivity of clay minerals found in bitumen froth in promoting heavier material formation through addition reactions. The current investigation employed α-methylstyrene (AMS) and 1-octene as probe molecules instead of bitumen froth, and their conversion at 250 °C in the presence of clay minerals kaolinite and illite was studied in batch reactors. Thermal conversion of AMS and 1-octene at 250 °C in the absence of minerals was observed to be low. In the presence of clay minerals, not only the conversion of AMS and 1-octene was increased but also reactions such as dimerization of AMS and alkylation of 1-octene and toluene (used as solvents) were mainly promoted, leading to heavier product formation. Double-bond isomerization of 1-octene and cumene formation from AMS was side reactions that were also promoted by the clay minerals. Suppression of mineral-related conversion by pyridine and selectivity to different reaction products that enabled differentiation between free radical and cationic reaction pathways indicated that the mineral-related conversion was predominantly cationic in nature. Using the reactions in the presence of minerals and pyridine as surrogates for alkaline bitumen froth, it was concluded that even under alkaline conditions, minerals could promote heavier material formation through cationic addition.

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Section: Energy and Fuelsmentioning

confidence: 52%

Section: Energy and Fuelsmentioning

confidence: 99%

Section: Energy and Fuelsmentioning

confidence: 99%

Section: Energy and Fuelsmentioning

confidence: 99%

See 2 more Smart Citations

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Turuga

Klerk

2022

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…These photopolymerization reactions are majorly classified based on their reaction mechanism into three categories-free-radical photopolymerization [12,13,42], cationic photopolymerization [39,[43][44][45] and anionic photopolymerization [6,31]. The most extensively used method from an industrial point of view is free-radical photopolymerization.…”

Section: Photopolymerizationmentioning

confidence: 99%

A review on self-initiated and photoinitiator-free system for photopolymerization

Jagtap

2021

Polym. Bull.

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Photopolymerization is a polymerization reaction where a light source provides energy for the formation of active species and further follows the conventional polymerization process. This polymerization technique has recently gained interest because of its high curing rate, lower energy consumption, low volatile organic component and relatively low cost. In such a system, the photoinitiator is a vital component as it governs the curing rate. It is a chemical substance that absorbs the radiation and forms reactive species that further attacks the monomer and leads to the photopolymerization reaction. The photoinitiators employed are expensive, oxygensensitive, possess pungent odour and migrate to the film surface, resulting in yellowing and degradation of the polymeric system. Thus, it is a requisite to decrease the concentration of a photoinitiator in a particular system. The paper briefly discusses alternate methods for conventionally photoinitiator-based photopolymerization, such as short-wavelength sources, unique monomers such as electron acceptor/donor system, thiol-ene system and specific particles.

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Characterization and kinetics study of poly(α-methyl styrene) synthesized by living anionic polymerization

Jozaghkar,

Ziaee

2024

J Polym Res

Self Cite

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In this work, poly(α-methyl styrene) (PAMS) was synthesized through living anionic polymerization and characterized by 13 C NMR, 1 H NMR, GPC, TGA, DSC. The kinetics study was performed using multi-stage dosing of initiator. The results obtained via GPC analysis revealed that polydispersity index of the synthesized PAMS was close to the true value. Moreover, multi-stage dosing of initiator offers valuable and accurate method to determine propagation rate constant and initial impurities value of the system. 13 C NMR analysis demonstrated that Bernoullian statics model exhibits a superior t compared to 1storder Markov statics model for the assigned sequence. Furthermore, the synthesized PAMS presents higher degree of racemic addition with P m =0.439. 1 H NMR spectroscopy was utilized to ascertain number-average molecular weight of the synthesized samples, corroborating the values estimated through GPC analysis. From the thermal analysis, it was shown that PAMS containing very low molecular weight demonstrates negative glass transition temperature and broad thermal decomposition range.

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Investigation of poly(α-methyl styrene) tacticity synthesized by photo-polymerization

Cited by 6 publications

References 26 publications

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

Free Radical and Cationic Addition due to Clay Minerals Found in Bitumen Froth at 250 °C Probed with Use of α-Methylstyrene and 1-Octene

A review on self-initiated and photoinitiator-free system for photopolymerization

Characterization and kinetics study of poly(α-methyl styrene) synthesized by living anionic polymerization

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