| 1. |
- Barbier, Christophe, 1974-, et al.
(författare)
-
On material characterization of paper coating materials by microindentation testing
- 2005
-
Ingår i: JCT. - Boston : Springer. - 0361-8773. ; 2:6, s. 463-471
-
Tidskriftsartikel (refereegranskat)abstract
- Microindentation as a method for determining important material properties of paper coating materials is studied experimentally and numerically. The bulk of the investigation is concentrated upon the short-lived elastic part of a spherical indentation test, but determination of the failure stress of the coating is also discussed. The results indicate that microindentation can be a powerful tool for material characterization of these materials, but only if careful efforts are made to account for the influence from plasticity as well as from boundary effects
|
|
| 2. |
- Huldén, M, et al.
(författare)
-
Adsorption in latex paints in relation to some of the properties of the mill base and the final coating
- 1994
-
Ingår i: JCT. - 0361-8773. ; 66:836, s. 99-105
-
Tidskriftsartikel (refereegranskat)abstract
- The rheological properties, gloss, hiding power and water absorption of some model latex paints were analysed in terms of the adsorption of surfactants, dispersing agent and thickener onto the latex and pigment particles. Special attention was paid to the order of addition of poly(acrylic acid) and ethyl(hydroxyethyl)cellulose, because this has an effect on the adsorption of the polymers onto the TiO2 pigment. The order of addition also affects the rheological properties of the mill base dispersion and the gloss of the paint. The gloss was also affected by the surfactant used to stabilise the latex. Higher gloss was obtained using a nonionic surfactant than with an anionic surfactant.
|
|
| 3. |
- Huldén, M, et al.
(författare)
-
Mixed adsorption of anionic and nonionic surfactants on latex particles
- 1994
-
Ingår i: JCT. - 0361-8773. ; 66:835, s. 67-77
-
Tidskriftsartikel (refereegranskat)abstract
- A model is presented for the asdorption of a mixture of anionic and a nonionic surfactant on latex particles. The model is based on the Langumir equation for adsorption and the regular solution theory for mixed micelle formation. Good agreement between the experimental data and the calculated adsorption was obtained with amixture of sodium dodecyl sulphate (SDS) and nonylphenol ethoxylate (NPE10). The preferential adsorption of the more surface active NPE10 is greatest at the onset of micellization and diminshes as the total surfactant concentration increases. The composition of the mixed surfactant at the surface gratly depends on the total surfactant concentration and on the surface area/solution volume ratio. This is illustrated by the calculated adsorption equilibria at differnet conditions. Addition of small amounts of organic solvents (e.g.,coalescing aids) increases the critical micelle concentration (cmc)of NPE10 and decreases the cmc of SDS. the decreade in the difference between the cmc values of the two surfactants is paralleled by a reduction in the preferential adsorption of the nonionic surfactant in the presence of a coalescing aid.
|
|
| 4. |
- Johansson, Mats K. G., et al.
(författare)
-
Novel concept for low temperature curing powder coatings based on hyperbranched polyesters
- 2000
-
Ingår i: JCT. - 0361-8773. ; 72:906, s. 49-54
-
Tidskriftsartikel (refereegranskat)abstract
- The concept of using hyperbranched polymers as scaffolds for solid thermoset resin applications is described. A series of semi-crystalline methyacrylate-functional aliphatic polyesters has been synthesized and characterized for applications as solid thermoset resins, e.g., powder coating resins. The polyester resins have been crosslinked by UV irradiation producing either amorphous or semi-crystalline crosslinked films depending on the initial structure. The resins are based on hyperbranched aliphatic polyester chains have been grafted and end-capped with methacrylate moieties. The resins exhibit a rheological behavior suitable for low temperature curing powder coatings, i.e., films that can be readily formed and UV cured at temperatures below 80 degrees C.
|
|
| 5. |
|
|
| 6. |
- Johansson, M, et al.
(författare)
-
On the synthesis and characterization of new low temperature curing powder coatings cured with radiation
- 1998
-
Ingår i: JCT. - 0361-8773. ; 70, s. 57-62
-
Tidskriftsartikel (refereegranskat)abstract
- The synthesis and characterization of a new type of low temperature curing powder coating is described. The type of materials used were mixtures of an amorphous methacrylate-functional prepolymer and crystalline acrylate and methacrylate monomers. The introduction of a crystalline component in an amorphous resin mixture was shown to markedly reduce the melt viscosity and thus enhance the flow properties of the powder coating. Curing experiments showed the advantage of using photoinitiation compared to thermal initiation. The reaction was much faster and the problem with oxygen inhibition could be avoided.
|
|
| 7. |
|
|
| 8. |
- JOHANSSON, M, et al.
(författare)
-
SYNTHESIS, CHARACTERIZATION, AND UV CURING OF ACRYLATE FUNCTIONAL HYPERBRANCHED POLYESTER RESINS
- 1995
-
Ingår i: JCT. - 0361-8773. ; 67, s. 35-39
-
Tidskriftsartikel (refereegranskat)abstract
- A series of different hyperbranched aliphatic polyester resins with acrylate functionality have been synthesized, characterized, and UV cured. The terminal groups have been either benzoates, propionates, or hydroxyls. The glass transition (T-g) and viscosity of the resins have been shown to depend on the polarity of the end groups. The increase in viscosity, while the propionate functional resin has the lowest T-g and viscosity. The acrylates are all free radically UV cured with little or no oxygen inhibition found. The residual unsaturation in the cured films is not detectable with Raman spectroscopy, i.e., less than five percent. The cured films are all hard with a T-g difference varying with the structure of terminal groups in the resins.
|
|
| 9. |
- Krupicka, A., et al.
(författare)
-
Mechanical surface characterization : A promising procedure to screen organic coatings
- 2003
-
Ingår i: JCT. - 0361-8773. ; 75:939, s. 19-
-
Tidskriftsartikel (refereegranskat)abstract
- Two ductile coating materials were subjected to a combined indentation and scratch test procedure designed to screen a predetermined pattern of many small sample surfaces in a limited time. The screening of 50 surface spots ordered in a matrix pattern on the surface was carried out in 4.5 hr. The test provides reproducible data in terms of indentaion modulus, elastic recovery, scratch penetration depth, and scratch residual depth, and also offers the possibility of detecting critical mechanical transitions such as rupture. The presented procedure produces sufficient data in a limited time scale to fulfill the requirements for a fast method to screen coating compositions.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Weissenborn, PK, et al.
(författare)
-
Drying of alkyd emulsion paints
- 2000
-
Ingår i: JCT. - 0361-8773. ; 72, s. 65-74
-
Tidskriftsartikel (refereegranskat)abstract
- The drying and film formation of long oil alkyud emulsions was investigated with emphasis on loss of dry upon storage. The main reason for loss of dry was adsorption of the cobalt (drier) on pigment surfaces as a precipitated hydroxide. Titanium dioxides with alumina surface treatment and organic pigments were most detrimental to drying. Acrylate- and phosphate-based dispersants also deactivated the cobalt, presumably due to complexation and precipitation of the cobalt. Emulsions prepared with an emulsifiable cobalt drier containing 2,2'-bipyridyl (complexing agent for cobalt) showed the best resistance to loss of dry. Atomic force microscopy of films formed from the emulsions showed that the emulsifier migrated to the film surface which, when washed with water, leaves holes or pits in the film. The pits were arranged in a hexagonal pattern characteristic of Bénard cells, which form due to surface tension and/or temperature gradients generated in the film during evaporation of water.
|
|
| 14. |
- Östberg, G, et al.
(författare)
-
Distribution of driers between the alkyd and aqueous phase in alkyd emulsions and its relation to drying properties
- 1992
-
Ingår i: JCT. - 0361-8773. ; 64:814, s. 33-43
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of pH, emulsifiers and alkyd properties on the distribution of driers between the alkyd- and water phase in alkyd emulsions has been studied. When the pH in the emulsion is decreased, cobalt and calcium driers are redistributed towards the water phase. However, zirconium was found to remain in the alkyd phase independent of pH. Hydrophilic anionic emulsifiers were found to decrease the amount of cobalt and calcium driers in the alkyd phase. The distribution is not influenced by alkyd properties such as oil length or acid values. The relation between the distribution of driers and drying properties has also been investigated. The results indicate a correlation between the early drying rate and cobalt concentration in the alkyd phase.
|
|
| 15. |
- Östberg, G, et al.
(författare)
-
Emulsification of alkyds for industrial coatings
- 1996
-
Ingår i: JCT. - 0361-8773. ; 68, s. 39-45
-
Tidskriftsartikel (refereegranskat)abstract
- Alkyd emulsions have so far mostly been used in consumer paints. These are relatively easy to emulsify due to their low viscosity. Lately alkyd emulsions for industrial paint have gained increasing attention. Alkyd for industrial paints have a much higher viscosity than alkyds for consumer paints which requires other emulsification techniques. In this work an alkyd with 40 % oil length have been emulsified by the inversion technique. Inversion emulsification by adding water to an alkyd/surfactant mixture at constant temperature give emulsions with droplet sizes below 1pm at a concentration of 3 % on the alkyd phase. Small droplets are necessary for colloidal stability of the emulsion. The solubility of surfactant in the alkyd and the water phase determines at which water concentration the emulsion inverts. High molecular weight ethoxylated anionic surfactants are effective as emulsifiers. Using these surfactants the emulsification becomes less dependent on emulsification temperature than when nonionic surfactants are used.
|
|
| 16. |
- Östberg, G, et al.
(författare)
-
Mechanical stability of alkyd emulsions. Part 1: Influence of emulsion droplet size and the emulsifier
- 1994
-
Ingår i: JCT. - 0361-8773. ; 66:832, s. 37-46
-
Tidskriftsartikel (refereegranskat)abstract
- The limited colloidal stability of alkyd emulsions compared to that of organic solvent-borne alkyd paints is a well known problem. For environmental reasons, however, they have a great advantage since they are water-borne. In this study, we have investigated the influence of emulsifier and initial droplet size on the mechanical stability of alkyd emulsions. Anionic emulsifiers have previously been shown to be more effective than nonionic emulsifiers in the formation of alkyd emulsions. Here it has been found that an anionic emulsifier also gave more stable emulsions at lower concentrations than did the nonionics. Emulsions stabilized with a nonionic emulsifier showed the same stability as the one with the anionic emulsifiers if the concentration was increased. Too high a concentration of surfactants is undesirable in paints, however, since it increases the water sensitivity of the paint film. The mechanical stability of anionically stabilized emulsions was less sensitive to the initial droplet size compared to emulsions stabilized with a nonionic emulsifier.
|
|
| 17. |
- Östberg, G, et al.
(författare)
-
Mechanical stability of alkyd emulsions. Part 2: Influence of alkyd properties
- 1994
-
Ingår i: JCT. - 0361-8773. ; 66:838, s. 37-41
-
Tidskriftsartikel (refereegranskat)abstract
- The development of water borne alkyd paints based on alkyd emulsions has been stimulated by more stringent health and environment regulations. In addition, alkyd paints may have better performance in some applications compared to other types of water -borne paints such as latex dispersions. One problem that needs to be overcome is the limited colloidal stability of alkyd emulsions. It is important that the emulsions are not destabilized when exposed to shear forces such as those produced by pumps used by the paint industry. An alkyd emulsion consist of alkyd oil droplets dispersed in water and stabilized by a surface active agent (emulsifier). Part 1 of this serie describes the influence of emulsion droplet size and type or concentration of the emulsifier on the shear stability. The present study is an additional investigation of the influence of the alkyd properties on shear stability. Increasing the acid value of the alkyd increases the stability of emulsions stabilized with nonionic emulsifiers. Emulsions made using alkyds with shorter oil lengths and higher viscosities were less stable to shear compared to alkyds with higher oil lengths and lower viscosities.
|
|
