Residual stress build-up in thermoset films cured above their ultimate glass transition temperature

Lange, Jakob; Toll, Staffan; Månson, Jan‐Anders E.; Hult, Anders

doi:10.1016/0032-3861(95)97876-h

Cited by 127 publications

(94 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Polymerisation shrinkage and cool-down from the process temperature are major sources of residual stress. [11,12] Combined with low stiffness, high coefficient of thermal expansion (CTE) [13] and surface tension driven viscous flow [14] these stresses lead to distortion and eventual decay of the nano-pattern.…”

Section: Introductionmentioning

confidence: 99%

Nanoimprint Lithography with UV‐Curable Hyperbranched Polymer Nanocomposites

Geiser

Jin

Leterrier

2010

Macromolecular Symposia

Self Cite

View full text Add to dashboard Cite

Summary: Nano-scale patterns were produced with UV-curable acrylated hyperbranched polymer nanocomposites using nanoimprint lithography with a glass master in a rapid, low-pressure process. The pattern of the glass master was replicated with composites containing up to 25 vol% SiO 2 with a shape fidelity better than 98%. Photo-rheology, interferometry and atomic force microscopy were used to analyze the material behavior. Attention was paid to the relationship between composition, nanoparticle dispersion, kinetics of photo-polymerisation, shrinkage, pressure and shape fidelity of nano-gratings. It was shown that the gel-point of the nanocomposite was an important factor that determined the stability as well as the dimensions of the imprinted structure. Dimensional accuracy also strongly depended on the level of internal stress, which in fact increased with the amount of silica. A resin rich layer on the surface of the composite accounted for the good surface quality of the nano-pattern.

show abstract

Section: Introductionmentioning

confidence: 99%

Nanoimprint Lithography with UV‐Curable Hyperbranched Polymer Nanocomposites

Geiser

Jin

Leterrier

2010

Macromolecular Symposia

Self Cite

View full text Add to dashboard Cite

show abstract

“…Such measurements are obtained from one dimensional or possibly two dimensional strains in the material by means of a contacting or non-contacting transducer. Examples of instruments are rheometer [2,3], pycnometer [3][4][5], fibre bragg grating [6], thermo mechanical analyzer [7][8][9], dynamic mechanical analyzer [10], ultrasonic waves [11]etc.…”

Section: Introductionmentioning

confidence: 99%

A Device to Measure the Shrinkage and Heat Transfers during the Curing Cycle of Thermoset Composites

Nawab

Boyard

Sobotka

et al. 2011

AMR

View full text Add to dashboard Cite

Abstract. Residual stresses development during manufacturing of composites depends mostly on the shrinkage behaviour of the polymer matrix from the point where stresses cannot be relaxed anymore. The matrix shrinkage may have a thermal and/or chemical origin and can leads to dimensional instability, ply cracking, delamination and fibre buckling. The approaches for measuring cure shrinkage can be classified as volume and non-volume dilatometry. Each technique has corresponding advantages and drawbacks but volume dilatometry is the one that is mostly used.In the present article, we report a home-built apparatus, named PVT-α mould, on which temperature, volume change and reaction conversion degree are measured simultaneously for an applied pressure. It can also be used to study the composite during curing and for the bulk samples having several millimetre thicknesses. The instrument is preferred over other techniques as it works in conditions close to the industrial ones. This device was used to measure cure shrinkage of resin and thermoset composite material with different fibre fractions as a function of temperature and reaction conversion degree. The heat of cure of the resin measured by PVT-α mould was compared to the results obtained by DSC.

show abstract

“…11,[23][24][25] However, no correlations with chemical conversion were made. In view of the large differences in the rates of polymerization, such a correlation is essential.…”

Section: Dgebamentioning

confidence: 84%

Influence of the reaction mechanism on the shape accuracy of optical components obtained by photoreplication

Verstegen

Faasen

Stapert

et al. 2003

J of Applied Polymer Sci

View full text Add to dashboard Cite

Light-induced crosslinking polymerization of both bis-methacrylates and bis-epoxides yields highly transparent glassy products, suitable for optical applications. Rheological changes of vitrifying liquids during photopolymerization strongly influence the shape accuracy of the final product. Comparison of a free-radical-initiated methacrylate polymerization and a cationically initiated ring-opening polymerization of an epoxide showed that different reaction mechanisms led to very different chemorheological responses and, hence, to pronounced differences in the shape accuracy of the products obtained with either of these materials. An ethoxylated bisphenol-A dimethacrylate (HEBDM) gels below 1-2% conversion and vitrifies at 15%. At higher conversion, large stresses develop through polymerization shrinkage. Relaxation occurs upon release of a product from its mold, leading to large shape deviations. Ring-opening polymerization of the diglycidyl ether of bisphenol-A (DGEBA) has an intrinsically lower polymerization shrinkage. Moreover, gelation of DGEBA polymer networks occurs at 25-30% conversion, leading to much lower stresses since most of the volume change occurs in the liquid state in which replenishment of a monomer can still occur. Upon release from a mold, there is hardly any driving force for relaxation, so a much better copy of the mold is obtained.

show abstract

Residual stress build-up in thermoset films cured above their ultimate glass transition temperature

Cited by 127 publications

References 8 publications

Nanoimprint Lithography with UV‐Curable Hyperbranched Polymer Nanocomposites

Nanoimprint Lithography with UV‐Curable Hyperbranched Polymer Nanocomposites

A Device to Measure the Shrinkage and Heat Transfers during the Curing Cycle of Thermoset Composites

Influence of the reaction mechanism on the shape accuracy of optical components obtained by photoreplication

Contact Info

Product

Resources

About