Real-time measurement of resin shrinkage during cure

Schoch, K.F.; Panackal, Philip A.; Frank, Paul

doi:10.1016/j.tca.2003.12.027

Cited by 47 publications

(36 citation statements)

References 4 publications

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“…Cure shrinkage is notorious for its potentially serious consequences, depending on the application of the material [8]. Thermosets are typically used in combination with stiffer reinforcements.…”

Section: Page 3 Of 20mentioning

confidence: 99%

“…Hence, the shrinkage is constrained and residual stresses are formed in the structure. These stresses can result in early product failure due to warpage, void formation, stress cracking, delamination and poor fiber-matrix adhesion [3,[8][9][10]. Experimental work based on statistically robust test methods have further indicated that the surface roughness of the end product is a function of textile architecture and matrix shrinkage [10,11].…”

Section: Page 3 Of 20mentioning

confidence: 99%

“…A new method using rheometry is also detailed in this study and is compared to the current industry standard methods. Volume dilatometry is based on the measurement of volume change and, for many years, mercury-based dilatometers were the only means to measure shrinkage [6][7][8][12][13][14]. In this instrument, the body of the capillary dilatometer is first filled with the uncured resin and then surrounded with an immiscible fluid (often water [15] or mercury) which extends into a graduated capillary.…”

Section: Page 3 Of 20mentioning

confidence: 99%

“…Gas based pycnometers use Boyle's law to measure volume [8,17,18]. This method of measuring shrinkage offered similar accuracy and was less labor M A N U S C R I P T…”

Section: Approaches To Measure Chemical Shrinkagementioning

confidence: 99%

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Evaluation of cure shrinkage measurement techniques for thermosetting resins

2010

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Resin chemical shrinkage dictates the surface integrity and the roughness of a composite structure. Thus, to minimize surface failures and to produce a good surface quality it is a requisite to be able to measure and track resin shrinkage during the cure process. This manuscript investigates and evaluates the measuring and monitoring of real-time resin shrinkage using a rheometer, a helium-based pycnometer and a thermo-mechanical analyzer (TMA) for ambient curing UP and epoxy resins. Shrinkage readings obtained from the newly developed robust technique with the rheometer concur well with readings from the traditional pycnometric method. They also coincide within the accepted literature values of 7-10% and 3.5-4.5% for the UP and epoxy systems, respectively. Shrinkage measurements during post-cure were effectively carried out at an elevated temperature, suggesting that the methodology provided can be applied to non-ambient curing systems.The TMA was found to be unsuccessful in measuring shrinkage reliably.

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Section: Page 3 Of 20mentioning

confidence: 99%

Section: Page 3 Of 20mentioning

confidence: 99%

Section: Page 3 Of 20mentioning

confidence: 99%

“…Gas based pycnometers use Boyle's law to measure volume [8,17,18]. This method of measuring shrinkage offered similar accuracy and was less labor M A N U S C R I P T…”

Section: Approaches To Measure Chemical Shrinkagementioning

confidence: 99%

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Evaluation of cure shrinkage measurement techniques for thermosetting resins

2010

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“…This calculation is based on the assumption that the change in the gap distance with temperature represents the change in length of an unconstrained specimen. Using a parallel-plate test geometry in which the gap was automatically adjusted to maintain a fixed compressive load on the specimen, investigators previously demonstrated that the change in gap distance was in good agreement with the dimensional change of an unconstrained specimen measured by pycnometry [1].…”

Section: Methodsmentioning

confidence: 89%

Crystallization Behavior of Virgin TR-55 Silicone Rubber Measured Using Dynamic Mechanical Thermal Analysis with Liquid Nitrogen Cooling

Small¹,

Wilson²

2010

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SUMMARYDynamic mechanical thermal analysis (DMTA) of virgin TR-55 silicone rubber specimens was conducted. Two dynamic temperature sweep tests, 25 to -100°C and 25 to -70 to 0°C (ramp rate = 1°C/min), were conducted at a frequency of 6.28 rad/s (1 Hz) using a torsion rectangular test geometry. A strain of 0.1% was used, which was near the upper limit of the linear viscoelastic region of the material based on an initial dynamic strain sweep test. Storage (G') and loss (G") moduli, the ratio G"/G' (tan δ), and the coefficient of linear thermal expansion (α) were determined as a function of temperature. Crystallization occurred between -40 and -60°C, with G' increasing from ~6×10 6 to ~4×10 8 Pa. The value of α was fairly constant before (~4×10 -4 mm/mm-°C) and after (~3×10 -4 mm/mm-°C) the transition, and peaked during the transition (~3×10 -3 mm/mm-°C). Melting occurred around -30°C upon heating. MATERIALS AND METHODSThe Dow Corning TR-55 silicone rubber material was made at Kansas City Plant. Specimens were cut by hand from a sheet using a scalpel. Specimens were approximately 45 mm long × 12 mm wide × 2 mm thick. Dynamic mechanical thermal analysis (DMTA) was conducted using the TA Instruments ARES rheometer with liquid nitrogen cooling in B132S R2729; the instrument was controlled by TA Orchestrator software. A torsion rectangle test geometry was used. The auto-tension feature was used to maintain a tensile force of approximately 10 g during the test by automatically adjusting the gap distance to compensate for thermal expansion/contraction of the specimen. Dynamic temperature ramps were recorded for the following two temperature profiles: (1) cool from 25 to -100°C at a rate of 1°C/min and (2) cool from 25 to -70°C at a rate of 1°C/min, hold at -70°C for 2 min, then heat to 0°C at a rate of 1°C/min. One specimen was tested for each of these sweep tests (specimens were not retested). During each temperature sweep the specimen was subjected to a sinusoidally oscillating strain of 0.1% at a frequency of 6.28 rad/s (1 Hz). The 0.1% strain was near the upper limit of the linear viscoelastic region of the material based on an initial isothermal dynamic strain sweep test. Shear storage and loss moduli, G' and G", respectively, and tan δ = G"/G' were recorded as a function of temperature.Taking advantage of the auto-tension feature of the ARES instrument, the change in specimen length, ΔL (i.e., gap distance), was also recorded as a function of temperature. The instantaneous coefficient of linear thermal expansion, α, at a temperature, T, was estimated from the slope of the ΔL versus T curve:where L T is the length of the specimen at the temperature, T, and the derivative of L with respect to T is equivalent to the derivative (slope) of ΔL with respect to T since L = ΔL + L 0 , where L 0 is the original length of the specimen (i.e., gap distance at the start of the test). This calculation is based on the assumption that the change in the gap distance with temperature represents the change in length of an unconstraine...

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Epoxy curing process with small shrinkage based on binary nucleophilic reagent system consisting of amine and carboxylic acid

Sudo

Isobe

Endō

2009

J of Applied Polymer Sci

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A curing process of bisphenol-A diglycidyl ether using amine-carboxylic acid salts was studied with focusing on its small-volume shrinkage. The characteristic point of the curing process was the initial high-density created by strong interactions between the ionic species such as electro-statistic one and hydrogen-bonding, which disappeared on the consumption of these species by their reactions with the epoxide to give the low-density neutral polymers. EXPERIMENTS MaterialsGlycidyl phenyl ether (GPE), bisphenol-A diglycidyl ether (Bis A-DGE), and benzoic acid (BA) were purchased from Wako Chemical, Co., and were used as received. 2-Amino-1-methoxypropane (AMP) and poly(propylene glycol) bis(2-aminopropyl ether) (PPG-diamine) were purchased from Aldrich Japan, Co., and were used as received. Instruments and measurements1 H-NMR spectra were recorded on JEOL k-300 with tetramethylsilane as an internal standard. Dynamic

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Real-time measurement of resin shrinkage during cure

Cited by 47 publications

References 4 publications

Evaluation of cure shrinkage measurement techniques for thermosetting resins

Evaluation of cure shrinkage measurement techniques for thermosetting resins

Crystallization Behavior of Virgin TR-55 Silicone Rubber Measured Using Dynamic Mechanical Thermal Analysis with Liquid Nitrogen Cooling

Epoxy curing process with small shrinkage based on binary nucleophilic reagent system consisting of amine and carboxylic acid

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