Ultrasonic degradation of solutions of poly(vinyl acetate) in tetrahydrofuran

Taghizadeh, Mohammad Taghi; Mehrdad, Abbas

doi:10.1002/app.21686

Cited by 6 publications

(3 citation statements)

References 15 publications

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“…Models based on continuous distribution kinetics have been developed to study the ultrasonic degradation of polymers [20–22]. The ultrasonic degradation of polymers such as polystyrene [11], polyethyleneoxide [20], polyvinyl acetate [9, 21, 23], polyvinyl alcohol [24], polybutadine [25], polypropylene [25, 26], poly(vinyl‐pyrrolidone) [27, 28], poly(acrylates) [29], dextran [30], poly(methyl methacrylate) [31], low density polyethylene [32], poly(alkyl methacrylate) [33], poly(alkyl acrylate) [34] and hydrogels [35, 36]. Thus, although the degradation of a wide variety of homopolymers has been studied, there have been only studies on two sets of copolymers: styrene‐butadiene copolymers [14] and the copolymers of poly(methyl methacrylate ‐co‐ alkyl acrylate) [37].…”

Section: Introductionmentioning

confidence: 99%

Thermal and sonochemical degradation kinetics of poly(n‐butyl methacrylate‐co‐alkyl acrylates): Variation of chain strength and stability with copolymer composition

Bhagat

Madras

2012

Polymer Engineering & Sci

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The thermal degradation of poly(n‐butyl methacrylate‐co‐alkyl acrylate) was compared with ultrasonic degradation. For this purpose, different compositions of poly (n‐butyl methacrylate‐co‐methyl acrylate) (PBMAMA) and a particular composition of poly(n‐butyl methacrylate‐co‐ethyl acrylate) (PBMAEA) and poly(n‐butyl methacrylate‐co‐butyl acrylate) (PBMABA) were synthesized and characterized. The thermal degradation of polymers shows that the poly(alkyl acrylates) degrade in a single stage by random chain scission and poly(n‐butyl methacrylate) degrades in two stages. The number of stages of thermal degradation of copolymers was same as the majority component of the copolymer. The activation energy corresponding to random chain scission increased and then decreased with an increase of n‐butyl methacrylate fraction in copolymer. The effect of methyl acrylate content, alkyl acrylate substituent, and solvents on the ultrasonic degradation of these copolymers was investigated. A continuous distribution kinetics model was used to determine the degradation rate coefficients. The degradation rate coefficient of PBMAMA varied nonlinearly with n‐butyl methacrylate content. The degradation of poly (n‐butyl methacrylate‐co‐alkyl acrylate) followed the order: PBMAMA < PBMAEA < PBMABA. The variation in the degradation rate constant with composition of the copolymer was discussed in relation to the competing effects of the stretching of the polymer in solution and the electron displacement in the main chain. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Thermal and sonochemical degradation kinetics of poly(n‐butyl methacrylate‐co‐alkyl acrylates): Variation of chain strength and stability with copolymer composition

Bhagat

Madras

2012

Polymer Engineering & Sci

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“…When high‐intensity ultrasonic irradiation is subjected to polymer solution, the main‐chain scission of polymer occurs and consequently the molecular weight is decreased. The macroradicals formed through the chain scission of polymer can be terminated by radical scavengers to produce the polymers with controlled molecular weight and molecular weight distribution 9–12…”

Section: Introductionmentioning

confidence: 99%

Degradation and in situ reaction of polyolefin elastomers in the melt state induced by ultrasonic irradiation

Chen

Lai

et al. 2007

J of Applied Polymer Sci

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The degradation and in situ reaction with polystyrene (PS) of polyolefin elastomers in the melt state induced through high intensity ultrasonic wave were investigated. The effects of initial molecular weight of polyolefin elastomers, irradiation time, ultrasonic intensity, as well as reaction temperature on the ultrasonic degradation of polyolefin elastomers melt were studied using a ''static'' ultrasonic vibration system. The results show that the degradation occurs mostly at the tip of the ultrasonic probe, and little or no degradation was observed at the distance of 5 mm or greater from the tip of the probe. The intrinsic viscosity [g] of polyolefin elastomers near the tip of ultrasound probe significantly decreases with irradiation time in the first 100 s and tends toward a limiting value for all samples. The degradation rates increased with an increase in ultrasonic intensity and decrease in reaction temperature. The ultrasonic degradation kinetics of polyolefin elastomers in melt state follows the equation:The fitting results by this equation accord well with the experimental data. The feasible ultrasonic degradation mechanism is proposed based on the viscoelastic characteristic of polymer melt. FTIR analysis confirms that the copolymer forms under ultrasonic irradiation for PS/POE mixtures and in situ reaction of polymer in melt state can be induced by ultrasonic irradiation.

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“…[8,9] It has been suggested that ultrasonic irradiation of a polymer solution will proceed with induction of cavitation in the solution which will corrupt to form short-living high-temperature/pressure spots, and the polymer molecules will then be decomposed either physically by the shear forces created in corrupting walls or chemically by radical reaction with solvent or dissolving gas.…”

Section: Introductionmentioning

confidence: 99%

Determination of primary bond scissions by mass spectrometric analysis of ultrasonic degradation products of poly(ethylene oxide‐block‐propylene oxide) copolymers

et al. 2010

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Ultrasonic degradation of poly(ethylene oxide-block-propylene oxide) copolymers consisting of a hydrophilic and a hydrophobic portion was studied with the aim to determine the location of bonds involved in the initial scission of the copolymers. LC-APCI-IT-MS and LC-APCI-orbitrap-MS were used for the detailed structural analysis of degradation products. The results indicated that initial bond scissions occurred principally at the boundary regions between backbones of polyethylene oxide (PEO) and polypropylene oxide (PPO) chains. Further structural analysis revealed the presence of oxygen adducts in the degradation products. Comparison with a thermal degradation carried out in helium atmosphere, one can conclude that the oxygen adducts are formed by radical reaction with water or dissolving oxygen molecules. The study demonstrated that chemical reactions as well as physical bond stress scissions are involved in the ultrasonic degradation of the copolymers.

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Ultrasonic degradation of solutions of poly(vinyl acetate) in tetrahydrofuran

Cited by 6 publications

References 15 publications

Thermal and sonochemical degradation kinetics of poly(n‐butyl methacrylate‐co‐alkyl acrylates): Variation of chain strength and stability with copolymer composition

Thermal and sonochemical degradation kinetics of poly(n‐butyl methacrylate‐co‐alkyl acrylates): Variation of chain strength and stability with copolymer composition

Degradation and in situ reaction of polyolefin elastomers in the melt state induced by ultrasonic irradiation

Determination of primary bond scissions by mass spectrometric analysis of ultrasonic degradation products of poly(ethylene oxide‐block‐propylene oxide) copolymers

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