Study on synthesis of macromolecule by use of plasma technique. II. Initiation of methyl methacrylate polymerization by the products of plasma reaction.

Tatsumi, Masakazu; Okashita, M.; Matsunaga, Takanobu; Ashida, Kazuhito; Yamamoto, Seika

doi:10.1246/nikkashi.1989.1909

Cited by 1 publication

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“…A number of neutral reaction products have been identified in MMA plasmas by in situ FTIR14, 15 and by other techniques in the literature 13, 18–20. The molecular dissociation products of MMA plasmas are summarized in Table I according to their molecular weight.…”

Section: Introductionmentioning

confidence: 99%

“…The structure of this 69‐amu ion was confirmed as an CH 2 C(CH 3 )C + O ion which was also observed in the mass spectrum of dimethyl ketene [DMK, (CH 3 ) 2 CCO] 21. Tatsumi et al proposed that neutral DMK is generated in MMA plasmas via this CO bond fragmentation reaction based on their ex situ NMR analysis of trapped effluent gas from MMA plasmas19: The CO bond cleavage reaction of MMA (MW = 100) into DMK (MW = 70) and COH 2 (MW = 30) involves the formation of a five‐member ring and an intramolecular rearrangement 19. The DMK/COH 2 pair was found to have very similar trends in the FTIR study of flowing MMA plasmas: Both are strongly positively correlated to MMA concentration levels (0.96 for DMK and 0.94 for COH 2 ), and both have a similar dependence on the process parameters (pressure, power, and flow rate) 15.…”

Section: Introductionmentioning

confidence: 99%

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Plasma dissociation reaction kinetics. I. Methyl methacrylate

Pan

Denton

1999

J. Appl. Polym. Sci.

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Fourier transform infrared spectroscopy (FTIR) was utilized to study the plasma gas-phase reaction kinetics and reaction mechanisms in capacitively coupled glow discharges of methyl methacrylate (MMA) under zero monomer flow rate conditions. The gas-phase study shows two major electron-impact-induced dissociation pathways in MMA plasmas: the C-O bond cleavage reaction and decarboxylations. The C-O bond cleavage reaction accounts for approximately one-half of the MMA dissociation, and neutral formaldehyde and dimethyl ketene (DMK) are produced via intramolecular rearrangement. Decarboxylations produce CO, CO 2 , and a number of radicals that subsequently stabilize to form neutrals, including propylene, allene, and methanol. These intermediate species then further dissociate in the plasma to small hydrocarbons (methane, acetylene, and ethylene), CO, CO 2 , and H 2 . Plasma power and initial monomer pressure have only minor effects on the MMA fragmentation chemistry. However, the reaction rate increases at higher-power and lower initial monomer pressure conditions. The modeling also reveals the relative reactivities of the neutrals. A time-scale transformation technique based on the MMA decomposition half-life significantly reduces the effects of the reactor condition on the kinetics. In addition, mass balance ratios are utilized to calculate the portion of plasma species that have been accounted for by the in situ technique.

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Section: Introductionmentioning

confidence: 99%