Simultaneous monitoring of the imidization and cure reactions of LaRC PETI-5 sized on a braided glass fabric substrate by dynamic mechanical analysis

Cho, Donghwan; Choi, Yusong; Drzal, Lawrence T.

doi:10.1016/s0032-3861(00)00863-6

Cited by 20 publications

(12 citation statements)

References 17 publications

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“…This indicates that the interfacial adhesion is improved after 200 C treatment on carbon fiber. Since storage modulus is very sensitive to changes of molecular structure and mobility taking place in the fiber-matrix interphase, 23 dynamic mechanical mapping was adopted to determine the changes of interphase storage modulus and thickness before and after 200 C heat-treatment on carbon fiber. The results are depicted in Figure 3.…”

Section: Influence Of Heat-treatment On Interfacial Properties Of Carmentioning

confidence: 99%

Reaction of carbon fiber sizing and its influence on the interphase region of composites

et al. 2015

J of Applied Polymer Sci

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What might happen with the interphase region of composite if the sizing agent cannot afford the attack of processing temperature and firstly reacted before its combination with the resin, is rarely reported. On the basis of this, herein, effects of sizing reaction on the interphase region of composite were investigated, as well as on the carbon fiber surface properties. It showed that the interfacial shear strength of carbon fiber/epoxy composite was improved after the sizing reaction. The interphase modulus was also increased with a thinner gradient distance. Further analysis indicated that the fiber surface roughness increased, the fiber wettability with the resin lowered, and the chemical reactions between sizing agent and resin reduced after 200 C/2 h treatment on carbon fiber.These results explained the change of the interphase region, which are meaningful for sizing optimization.

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Section: Influence Of Heat-treatment On Interfacial Properties Of Carmentioning

confidence: 99%

Reaction of carbon fiber sizing and its influence on the interphase region of composites

et al. 2015

J of Applied Polymer Sci

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“…The extent of imidization gradually increases with temperature to 250 ο C. It indicates that the amic acid oligomer begins to imidize below 200 ο C and completes its imidization reaction at 250 ο C. Therefore, the major contribution in this region may be by imidization, which can be significant above 200 ο C and the minor contribution may be by solvent, which can be significant far below 200 ο C. This fluorescence result also confirms that the LaRC PETI-5 amic acid oligomer is imidized to form the corresponding LaRC PETI-5 polyimide on heating, as observed from thermal analysis studies earlier. 6,21 With the development of the imidized structure in the resin, the fluorescence emission band at wavelengths above 500 nm is enhanced with a long wavelength tail, as seen in Figure 2. The maximum of the fluorescence intensity is shifted to the longer wavelength about 30 nm due to the imidization reaction, as shown in Figure 3.…”

Section: Discussionmentioning

confidence: 98%

“…[1][2][3][4] A number of research publications have been made with the objective of understanding the reactions and properties of uncured and cured resins of phenylethynyl-terminated polyimides. [5][6][7][8][9] These studies include cure, end group reaction behavior, thermal properties, mechanical properties, interfacial characteristics, etc.…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal imidization and curing on fluorescence behavior of a phenylethynyl-terminated poly(amic acid)

2003

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The imidization and cure reaction of a thermosetting phenylethynyl-terminated amic acid (LaRC PETI-5) in film form have been monitored as a function of temperature by means of a steady-state fluorescence technique using a front-face illumination method. The variation of the fluorescence emission spectra of LaRC PETI-5 can be divided into four temperature regions; Region I: below 150 ο C, Region II: 150-250 ο C, Region III: 250-350 ο C, and Region IV: above 350 ο C. The fluorescence spectra in Region I are largely influenced by residual N-methyl-2-pyrrolidinone in the polymer and also slightly by partial imidization of the polymer. There is a combined effect of imidization and solvent removal on the fluorescence behavior in Region II. The spectra in Regions III and IV are due significantly to the cure reaction of LaRC PETI-5 and to a post-cure effect of the polyimide, respectively. This spectroscopic evidence indicating the transformation of the amic acid imide oligomer into the corresponding polyimide via imidization and cure, agrees well with thermal analysis results obtained previously. The intermediate stage of cure in the range of 250-300 ο C predominantly influences the change of the fluorescence intensity. The later stage above 300 ο C significantly influences the position of the spectrum. This fluorescence study also supports the mechanism proposed in earlier work that the crosslinking reaction takes place at the reaction sites in the conjugated polyene and the phenylethynyl end group in the polyimide chain.

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“…The frequency applied in DMA is normally much greater than that in DSC, causing the T g of DMA to shift to a higher temperature. 32 The increase in T g of the composites is attributed to the chain mobility limit for the interaction between the macromolecules and OVPOSS cages. The peak values of tand in Table III show a maximum point of POSS-4 at 0.93.…”

Section: Mechanical and Thermal Properties Of The Tfe/p-poss Compositmentioning

confidence: 98%

Structure and property of tetrafluoroethylene‐propylene elastomer‐OVPOSS composites

Cong

cancan

Meng

et al. 2013

J of Applied Polymer Sci

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Tetrafluoroethylene-propylene elastomer-octavinyl-polyhedral oligomeric silsesquioxane (TFE/P-OVPOSS) composites containing various percentages of OVPOSS are prepared via room temperature milling and heat vulcanization at 170 C. The composites are characterized by FTIR, 13 C-NMR, 29 Si-NMR, XRD, DSC, SEM, tensile test, DMA, and TGA. The crosslink bond formation between TFE/P and OVPOSS conforms to the structural characterization of the composites. The OVPOSS cages aggregate when the OVPOSS dosage is more than 6 as observed from the XRD curves and SEM images. The swelling test shows that the experimental crosslink density is lower than the calculated crosslink density, indicating that not all reacted vinyl groups are converted into crosslink bonds. Meanwhile, the incorporation of OVPOSS significantly enhances the mechanical property and elevates the glass temperature of the composites. However, the thermal property is only improved slightly.

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Simultaneous monitoring of the imidization and cure reactions of LaRC PETI-5 sized on a braided glass fabric substrate by dynamic mechanical analysis

Cited by 20 publications

References 17 publications

Reaction of carbon fiber sizing and its influence on the interphase region of composites

Reaction of carbon fiber sizing and its influence on the interphase region of composites

Effect of thermal imidization and curing on fluorescence behavior of a phenylethynyl-terminated poly(amic acid)

Structure and property of tetrafluoroethylene‐propylene elastomer‐OVPOSS composites

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