UV curing of surface coating system consisting of cycloaliphatic diepoxide-ENR-glycidyl methacrylate by cationic photoinitiators?characterization of the cured film by FTIR spectroscopy

Kumar, R. N.; Woo, C. K.; Abusamah, A.

doi:10.1002/(sici)1097-4628(19990822)73:8<1569::aid-app26>3.0.co;2-9

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…Also, the peaks at 907, 848, and 760 cm -1 , assigned to the characteristic absorption bands of the epoxide groups, ,, are present in the piCVD spectrum. The high-frequency C−H stretching at above ∼3040 cm -1 (shoulder in Figure ), assigned to the antisymmetric oxirane C−H stretching, further confirms the presence of the epoxy rings. These results show not only the retention of the pendant groups but also the intactness of the epoxy groups.…”

Section: Resultsmentioning

confidence: 62%

“…All films in Figure show alkyl C−H stretching (3000−2840 cm -1 ), ester CO stretching (1750−1725 cm -1 ), alkyl C−H bending (1470−1340 cm -1 ), and ester C−O stretching (1300−1200 cm -1 ), typical for polymethacrylates. These assignments are based on FTIR analyses of PMMA and other organic molecules in the literature. There is much evidence in the piCVD spectrum that shows the retention of the entire pendant group, −COOCH 2 CH(−O−)CH 2 .…”

Section: Resultsmentioning

confidence: 99%

“…First, the retention of the carbonyl groups is evident in the presence of the strong peak centered at ∼1730 cm -1 . Also, the peaks at 907, 848, and 760 cm -1 , assigned to the characteristic absorption bands of the epoxide groups, 15,32,33 are present in the piCVD spectrum.…”

Section: Fourier Transform Infrared Spectroscopymentioning

confidence: 94%

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Photoinitiated Chemical Vapor Deposition of Polymeric Thin Films Using a Volatile Photoinitiator

Chan

Gleason

2005

Langmuir

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Photoinitiated chemical vapor deposition (piCVD) is an evolutionary CVD technique for depositing polymeric thin films in one step without using any solvents. The technique requires no pre- or post-treatment and uses a volatile photoinitiator to initiate free-radical polymerization of gaseous monomers under UV irradiation. Glycidyl methacrylate (GMA) was used as a test monomer for its ability to undergo free-radical polymerization, and 2,2'-azobis(2-methylpropane) (ABMP) was used as the photoinitiator, as it is known to produce radicals when excited by photons. GMA and ABMP vapors were fed into a vacuum chamber in which film growth was observed on a substrate exposed to UV irradiation. The resulting poly(glycidyl methacrylate) (PGMA) thin films were comprised of linear chains and had high structural resemblance to conventionally polymerized PGMA, as shown by the high solubility in tetrahydrofuran and the infrared and X-ray photoelectron spectroscopy measurements. The introduction of ABMP into the vacuum chamber significantly increased growth rates. The maximum growth rate achieved was approximately 140 nm/min and represents a 7-fold enhancement over the case without ABMP. The molecular weight was found to increase with increasing monomer-to-initiator (M/I) feed ratio, and the polydispersity indexes (PDIs) of the samples were between 1.8 and 2.2, lower than the values obtained in conventional batch polymerization but in agreement with the theoretical expressions developed for low-conversion solution-phase polymerization, which are applicable to continuous processes such as piCVD. Molecular-weight distributions can be narrowed by filtering out wavelengths shorter than 300 nm, which induce branching and/or cross-linking. The strong dependence of the molecular weight on the M/I ratio, the rate enhancement due to the use of a radical photoinitiator, the good agreement between the experimental, and the theoretical PDIs provide evidence of a free-radical mechanism in piCVD. The clear films obtained in this work had number-average molecular weights between 12 500 and 97 000 g/mol. The similarities in growth conditions, growth rates, and molecular weights between the initiated CVD, a previously reported thermal process able to synthesize a wide range of polymers, and the piCVD of PGMA suggest that piCVD can also be used to produce those polymers and potentially others whose monomers undergo free-radical mechanisms. This paper serves as an introduction to the technique by demonstrating piCVD's ability in synthesizing high-molecular-weight PGMA thin films with narrow molecular-weight distributions from vapors of GMA and ABMP in a single, dry step under UV irradiation.

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Section: Resultsmentioning

confidence: 62%

Section: Resultsmentioning

confidence: 99%

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Photoinitiated Chemical Vapor Deposition of Polymeric Thin Films Using a Volatile Photoinitiator

Chan

Gleason

2005

Langmuir

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“…[48] In epoxy-PS-epoxy, peaks at 914 and 868 cm À1 are observed. The whole ring stretch of the oxirane is expected to be found near 1 250 cm À1 , [49][50][51] and a very weak peak in the telechelic PS is observed at 1 261 cm À1 .…”

Section: Quantification Of Telechelic Polymer Grafted To Nanotubesmentioning

confidence: 97%

Grafting Polymer Loops onto Functionalized Nanotubes: Monitoring Grafting and Loop Formation

Ashcraft¹,

Ji²,

Mays³

et al. 2011

Macro Chemistry & Physics

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Polystyrene functionalized at both ends (telechelic polymer) with epoxide groups (epoxy–PS–epoxy) was reacted with carboxylated multiwall carbon nanotubes (COOHMWNT) in solution in order to graft polymer chains at both ends onto the MWNT surface, forming loops. FT‐IR spectroscopy was employed to monitor the formation of aromatic esters and to quantify the amount of telechelic grafted to the nanotube surface as a function of reaction time. When the samples were further annealed in the melt, an increase in the aromatic ester peak was observed, indicating that the unreacted chain ends further grafted to MWNT surfaces to form loops. By reacting the grafted nanotube samples further with monocarboxy terminated poly(4‐methylstyrene) (COOHP4MS), the amount of epoxy–PS–epoxy that had only reacted at one end was determined. Reaction rate analysis indicates that that the grafting of epoxy–PS–epoxy to the nanotube surface is reaction controlled, as the FT‐IR spectroscopy signal grows as a function of approximately t0.3. These studies exemplify how FT‐IR spectroscopy can be used as a novel technique to quantify the amount of grafted polymer, grafting rate, and percent of difunctional polymers that form loops, and provide a method to create loop covered nanoparticles. magnified image

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“…In order to upgrade the fracture toughness of radiation cured materials, toughening agents such as rubber or elastomers, either as discrete particles or treated with epoxy resins, are incorporated into epoxy resins. [14] Conventional spectrophotometric studies [1,15] showed that the acrylic double bonds, as well as the epoxy groups of GMA, the isoprene double bond and the epoxy groups of ENR and ECC undergo reactions under the influence of the ultraviolet radiation induced by a cationic photoinitiator. The results of these preliminary studies encouraged us to carry out MAS NMR and real time FTIR spectroscopic studies of both the isolated and the combined systems.…”

Section: Introductionmentioning

confidence: 99%

Application of Real Time FTIR and MAS NMR Spectroscopy to the Characterization of UV/EB Cured Epoxidized Natural Rubber Blends

Kumar¹,

Mehnert

Scherzer

et al. 2001

Macromol. Mater. Eng.

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The UV curing of blends consisting of epoxidized natural rubber (ENR), cycloaliphatic diepoxide (ECC) and glycidyl methacrylate (GMA) induced by cationic photoinitiator was studied by real time FTIR. This technique revealed the individual reactivity of epoxy groups and double bonds under UV exposure and thermal postcuring. The epoxy groups of ECC reacted more rapidly compared to those of ENR and GMA. In addition, 13C CP MAS NMR showed that acrylic double bonds of GMA are more reactive than isoprenic ones of ENR under EB exposure. It is assumed that only few linkages exist between the diepoxide and the methacrylate interpenetrating network via GMA molecules. The stable embedding of ENR particles via chemical bonds causes toughening of the epoxy matrix while maintaining a desired hardness.

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UV curing of surface coating system consisting of cycloaliphatic diepoxide-ENR-glycidyl methacrylate by cationic photoinitiators?characterization of the cured film by FTIR spectroscopy

Cited by 14 publications

References 13 publications

Photoinitiated Chemical Vapor Deposition of Polymeric Thin Films Using a Volatile Photoinitiator

Photoinitiated Chemical Vapor Deposition of Polymeric Thin Films Using a Volatile Photoinitiator

Grafting Polymer Loops onto Functionalized Nanotubes: Monitoring Grafting and Loop Formation

Application of Real Time FTIR and MAS NMR Spectroscopy to the Characterization of UV/EB Cured Epoxidized Natural Rubber Blends

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