Relationships on the effect of water on glass transition temperature and young's modulus of nylon 6

Reimschuessel, H. K.

doi:10.1002/pol.1978.170160606

Cited by 128 publications

(121 citation statements)

References 6 publications

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“…14). 129,145 In PA-6, the dry T g is $42 8C and decreases monotonically toward the limiting value of À13 8C as the moisture content in the polymer increases. In fact, hydration depresses all the temperature-related transitions by about 70 8C: the a process is depressed by 40 8C by 2-3% water; 3 T B is depressed by 70 8C; the temperature at which the crystallization rate is maximum is reduced by as much as 70 8C (unpublished results); and the transformation from c to a occurs at 215 8C in dry PA-6 and at 160 8C in water (accompanied by hydrolysis).…”

Section: Chain Mobilitymentioning

confidence: 99%

“…39 Models such as the one shown in Figure 12, with three water molecules for every two neighboring amide groups, have also been used to understand the effects of hydration. 129,135 The interactions of the amide groups with water are significantly stronger than the hydrogen bond between CO and NH in the crystalline portion according to the magnitude of the frequency shift of relevant bands. 136 The activation energy and enthalpy of water desorption are expected to be high because of these strong hydrogen bonds between the host species and nylon.…”

Section: Mechanism Of Hydrationmentioning

confidence: 99%

“…12). [128][129][130] Water lowers the steric hindrance for the localized mode of dipolar orientation. 131 As a result, it weakens the interchain hydrogen bonds, enhances the mobility of the polymer chains, and dramatically affects the polymer properties; this includes lowering T g .…”

Section: Mechanism Of Hydrationmentioning

confidence: 99%

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Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

215

197

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Some salient results in nylon research are reviewed to identify the fundamental principles that are applicable to other strongly interacting or hydrogenbonded polymers, including proteins. The effects of hydrogen bonds on stress-, heat-, and solvent-induced changes in macroscopic properties are discussed. These data provide a window into the chain mobility and linkages between the crystalline and amorphous domains, both of which are important for any predictive model. The changes in the characteristics of the amorphous phase with the crystallinity and orientation require that it be modeled with at least two components: a rigid/immobile/ anisotropic component and a soft/ mobile/isotropic component. The deformation and shrinkage behavior of these polymers are discussed in terms of the relative contributions of the amorphous and crystalline domains and of the interactions between them. The premelting crystalline transition is accompanied by the merging of intersheet and intrasheet diffraction peaks in some nylons, as observed by Brill, and not in others even though the underlying mechanism that gives rise to these transitions, the onset of volume-increasing librational motion of the crystalline stems, is the same. Because the effects of the temperature, deformation, and solvent have a common origin associated with mobility, a fictive temperature can be associated with a given solvent activity or stress level. The magnitude of this fictive temperature is the amount by which the glass or Brill transition temperature is reduced in the presence of solvents ($50 8C) or stress or by which the annealing temperature can be reduced in the presence of a solvent (or active stress) to achieve the same structural state as that of a dry (or static) polymer.

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Section: Chain Mobilitymentioning

confidence: 99%

Section: Mechanism Of Hydrationmentioning

confidence: 99%

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Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

215

197

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“…Consequently, the amorphous phase is plasticized, the glass transition temperature T g [K] is lowered and the mechanical properties are altered. Reimschuessel 12 and Yokouchi and coworkers 13 describe the correlation between mechanical properties, such as the modulus of elasticity E [Pa], and the glass transition temperature T g .…”

Section: ■ Introductionmentioning

confidence: 99%

Quantitative Water Uptake Study in Thin Nylon-6 Films with NMR Imaging

Reuvers

Huinink

Fischer³

et al. 2012

Macromolecules

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Nylon-6 is widely used as an engineering plastic. Compared to other synthetic polymers, nylon-6 absorps significant amounts of water. Although the typical sorbed amounts and diffusivity of water are well-known, less is known about the relation between the diffusivity and the water content. Attempts have been made in the past to obtain such relationship from moisture content profiles as measured with NMR imaging. However, these studies were mainly performed at high temperatures and without a proper calibration of the signal. In particular, at room temperature, far below the T g of dry nylon, plasticizing effects of water will result in a strong contribution of the polymer signal. Therefore, we have studied water uptake in 200 μm nylon-6 films in this temperature range near room temperature with NMR imaging. By calibrating the NMR signal with vapor sorption data, we were able to obtain moisture content profiles. A strongly nonlinear relation between the NMR signal and the moisture was observed at room temperature, which proves that contribution of the polymer to the NMR signal can neither be neglected nor assumed to be constant in time. Furthermore, glass transition temperature measurements combined with the water distribution provide plasticization profiles during water uptake. On the basis of the moisture content profiles, the moisture content dependency of the diffusion coefficient for water uptake is deduced through a Matano−Boltzmann analysis. This relation appeared to be highly nonlinear at room temperature. The self-diffusion coefficient was calculated through combination of the sorption-isotherm and the diffusion coefficient. Exposure of a nylon film to heavy water showed that water affects only a small fraction of the amorphous nylon phase. Water transport most likely occurs in this fraction of the amorphous phase. It is concluded that the heterogeneity of the amorphous phase is an important issue for a profound understanding of water transport in nylon-6 films. ■ INTRODUCTIONPolyamides, also known as nylons, are widely used as engineering plastic and textile fiber mainly due to their excellent properties. In particular, the mechanical properties are attractive for many applications and remain unaffected in a wide range of temperatures. Nylon is also easy to process, for example by extrusion molding, which is reflected in the large variety of geometries encountered in every day life.The chemical structure of nylons consists of amide groups separated by a number of methylene units. Therefore, a variety of polyamides exist, consisting of either one single α,ω aminoacid monomer like nylon-6 (PA6) and nylon-12 or two monomers, a dicarboxylic acid and a diamine like nylon 4.6 or 6.6. The number of successive carbon atoms in the polymer backbone between the amide groups is given by the index and influences material properties such a stiffness, melting point or water absorption.1 The latter feature is especially caused by the hydrophilic character of the amide functionality.Nylons absorb amounts of wat...

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“…[ 49 ] The values of E o and c o for water in APS networks are calculated to be 420 MPa and 2.4 mmol cm − 3 , respectively. The variation of E ( c ) with c is unique in APS due to the dualhydration mechanisms of micropore fi lling and network swelling.…”

Section: Resultsmentioning

confidence: 99%

Shape‐Memory Microfluidics

Balasubramanian¹,

Morhard²,

Bettinger

2013

Adv Funct Materials

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Materials with embedded vascular networks afford rapid and enhanced control over bulk material properties including thermoregulation and distribution of active compounds such as healing agents or stimuli. Vascularized materials have a wide range of potential applications in self‐healing systems and tissue engineering constructs. Here, the application of vascularized materials for accelerated phase transitions in stimuli‐responsive microfluidic networks is reported. Poly(ester amide) elastomers are hygroscopic and exhibit thermo‐mechanical properties (Tg ≈ 37 °C) that enable heating or hydration to be used as stimuli to induce glassy‐rubbery transitions. Hydration‐dependent elasticity serves as the basis for stimuli‐responsive shape‐memory microfluidic networks. Recovery kinetics in shape‐memory microfluidics are measured under several operating modes. Perfusion‐assisted delivery of stimulus to the bulk volume of shape‐memory microfluidics dramatically accelerates shape recovery kinetics compared to devices that are not perfused. The recovery times are 4.2 ± 0.1 h and 8.0 ± 0.3 h in the perfused and non‐perfused cases, respectively. The recovery kinetics of the shape‐memory microfluidic devices operating in various modes of stimuli delivery can be accurately predicted through finite element simulations. This work demonstrates the utility of vascularized materials as a strategy to reduce the characteristic length scale for diffusion, thereby accelerating the actuation of stimuli‐responsive bulk materials.

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Relationships on the effect of water on glass transition temperature and young's modulus of nylon 6

Cited by 128 publications

References 6 publications

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Quantitative Water Uptake Study in Thin Nylon-6 Films with NMR Imaging

Shape‐Memory Microfluidics

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