On shift and resolution of relaxation maxima in two‐phase polymeric systems

Lipatov, Yu.S.; Rosovitsky, V. F.; Babich, B. V.; Kvitka, N. A.

doi:10.1002/app.1980.070250605

Cited by 22 publications

(5 citation statements)

References 4 publications

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“…The deposition of long chain macromolecules onto a surface can result in properties of the interphasial region being quite different from the bulk phase [8]. Transcrystallinity developed on surfaces further complicates the mechanisms of stress transfer from the matrix to the fiber.…”

Section: Introductionmentioning

confidence: 99%

Transcrystalline interphases in natural fiber-PP composites: effect of coupling agent

Sanadi

Caulfield

2000

Composite Interfaces

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The interest in lignocellulosic fiber composites has been growing in recent years because of their high specific properties. In this work, a new technique was used to prepare specimen to observe the transcrystalline zones in kenaf fiber-polypropylene composites. A maleated polypropylene (MAPP) coupling agent was used to improve the stress-transfer efficiency in the composites. Transcrystallinity was observed for both the uncoupled and coupled composites, although the rate of growth was higher for the coupled composites. Dynamic mechanical spectroscopy was used to observe the relaxations of the composites. The peak temperature of the β-relaxation, associated with the glass-rubber transition of the amorphous molecules, of the coupled composites was higher than that of the uncoupled composites. Restricted molecular mobility due to covalent interactions between the MAPP and the lignocellulosic surface may account for the shift to higher temperatures. It appears that during compounding the extractives sheared from the fiber surface is an important factor in determining the β-relaxation of these composites. The intensities of the α-transition, related to molecular mobility associated with the presence of crystals, is proportional to the fiber volume fraction. Thus it is possible that the molecules responsible for the α-transition are predominantly in the transcrystalline zone. These 'rigid' amorphous molecules in the transcrystalline zone do play a role in composite behavior and need to be considered when tailoring interphases.

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Section: Introductionmentioning

confidence: 99%

Transcrystalline interphases in natural fiber-PP composites: effect of coupling agent

Sanadi

Caulfield

2000

Composite Interfaces

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“…A slight initial decrease in T g was seen for clay and zinc before an increase with higher filler loadings. The study of particle‐filled polymers has shown that an increase in filler content results in a similar shift toward higher T g temperatures 40. Polymer boundaries encapsulating each particle further decrease the molecular mobility where the T g of filled polymers is linearly dependent on the volume fraction of the polymer in the boundary layer 40.…”

Section: Resultsmentioning

confidence: 99%

“…The study of particle‐filled polymers has shown that an increase in filler content results in a similar shift toward higher T g temperatures 40. Polymer boundaries encapsulating each particle further decrease the molecular mobility where the T g of filled polymers is linearly dependent on the volume fraction of the polymer in the boundary layer 40. The height of the tan δ peak decreased with increasing filler content, which suggested the restriction of molecular motion at high filler contents, with the exception of zinc‐filled RET, where a slight increase in the tan δ peak was observed from Z3 to Z8 followed by a large decrease in height from Z8 to Z39.…”

Section: Resultsmentioning

confidence: 99%

Filled reactive ethylene terpolymer primers for cathodic disbondment mitigation

Love

Karbhari

2008

J of Applied Polymer Sci

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A reactive ethylene terpolymer (RET) with inorganic fillers of clay, talc, and zinc was examined for its cathodic disbondment (CD) performance and as a potential coating primer material for pipeline applications. The filler type and volume fraction influenced the mechanical, thermal, adhesion, and CD resistance of the coatings. The tensile modulus and strength of the RETs increased at higher loadings of selected fillers. The dry adhesive strength of the clay-filled RET maintained the same level of adhesion up to approximately 23 vol %, whereas the talc-and zinc-filled RETs showed decreases in adhesive performance. CD resistance was significantly improved with 18-23 vol % clay, whereas the overall disbondment area was reduced approximately 82% from pure RET. However, the post-cathodic-disbondment adhesive strength for the clay-filled RET decreased as a result of the degradation of the primer/ topcoat interface caused by moisture absorption.

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“…(The interphase is a volume of material between the fibre and the matrix with properties different from the two main phases.) Furthermore, the deposition of long-chain macromolecules onto a surface can result in the properties of the interphasial region being quite different from the bulk phases [11]~ Methods to directly characterize the interface in reinforced composites have recently been developed and evaluated; they include the fibre-pull-out test, the single-fibre-fragmentation test, the microdebondingtension test, and the microdebonding-push-out test. Although none of these techniques has been standardized, the pull-out test has received considerable attention [12][13][14][15], because of the possibility of obtaining important information about the interface (or interphase) and the ability to distinguish between failure modes.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of wood-thermoplastic-interphase shear strengths

1993

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A macroscopic pull-out technique has been developed to determine the interphase properties in wood/low-molecular-weight-thermoplastic systems. Experimental variables affecting the shear properties of these types of composites were first identified so that the test could be used to compare the effect of different surface treatments on the interfacial properties. The relationship between the debonded force, F, and embedded length, L, was not linear, suggesting a failure mechanism that was different from interfacial yielding. Low embedded lengths provide useful comparative data on the maximum interfacial-shear strength of the system. The test is also useful for evaluating the quality of the fibre-matrix bond after exposure to water, since dimensional stability is an important consideration for wood-fibre-based composites. The test can be used to screen the effects of modifications on the lignocellulosic and/or the thermoplastic matrix on adhesive bonding for the development of composites. The use of lignocellulosic fibres (recycled wood fibres and natural fibres such as jute) in combination with recycled plastics could find applications in the automotive, furniture and building-materials industry.

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On shift and resolution of relaxation maxima in two‐phase polymeric systems

Cited by 22 publications

References 4 publications

Transcrystalline interphases in natural fiber-PP composites: effect of coupling agent

Transcrystalline interphases in natural fiber-PP composites: effect of coupling agent

Filled reactive ethylene terpolymer primers for cathodic disbondment mitigation

Evaluation of wood-thermoplastic-interphase shear strengths

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